feat(canvas): accelerate local previews and harden edge flows

2026-04-05 17:28:43 +02:00
parent 451ab0b986
commit de37b63b2b
29 changed files with 2751 additions and 358 deletions
--- a/components/canvas/tests/canvas-helpers.test.ts
+++ b/components/canvas/tests/canvas-helpers.test.ts
@@ -4,6 +4,7 @@ import type { Edge as RFEdge, Node as RFNode } from "@xyflow/react";
 import { withResolvedCompareData } from "../canvas-helpers";
 import {
  buildGraphSnapshot,
+  pruneCanvasGraphNodeDataOverrides,
  resolveRenderPreviewInputFromGraph,
 } from "@/lib/canvas-render-preview";

@@ -100,6 +101,129 @@ describe("withResolvedCompareData", () => {
 });

 describe("canvas preview graph helpers", () => {
+  it("treats node data overrides as complete normalized objects when building a graph snapshot", () => {
+    const graph = buildGraphSnapshot(
+      [
+        {
+          id: "image-1",
+          type: "image",
+          data: {
+            url: "https://cdn.example.com/persisted.png",
+            previewUrl: "https://cdn.example.com/persisted-preview.png",
+            label: "Persisted label",
+          },
+        },
+      ],
+      [],
+      {
+        nodeDataOverrides: new Map([
+          [
+            "image-1",
+            {
+              url: "https://cdn.example.com/persisted-source.png",
+              previewUrl: "https://cdn.example.com/override-preview.png",
+            },
+          ],
+        ]),
+      },
+    );
+
+    expect(graph.nodesById.get("image-1")).toMatchObject({
+      data: {
+        url: "https://cdn.example.com/persisted-source.png",
+        previewUrl: "https://cdn.example.com/override-preview.png",
+      },
+    });
+  });
+
+  it("prunes stale node data overrides for deleted nodes and persisted catch-up", () => {
+    const overrides = pruneCanvasGraphNodeDataOverrides(
+      [
+        {
+          id: "image-1",
+          type: "image",
+          data: {
+            url: "https://cdn.example.com/persisted-source.png",
+            previewUrl: "https://cdn.example.com/persisted-preview.png",
+            label: "Persisted label",
+          },
+        },
+      ],
+      new Map([
+        [
+          "image-1",
+          {
+            url: "https://cdn.example.com/persisted-source.png",
+            previewUrl: "https://cdn.example.com/local-preview.png",
+          },
+        ],
+        ["deleted-node", { previewUrl: "https://cdn.example.com/stale-preview.png" }],
+      ]),
+    );
+
+    expect(overrides).toEqual(
+      new Map([
+        [
+          "image-1",
+          {
+            url: "https://cdn.example.com/persisted-source.png",
+            previewUrl: "https://cdn.example.com/local-preview.png",
+          },
+        ],
+      ]),
+    );
+  });
+
+  it("keeps already-pruned node data overrides stable", () => {
+    const override = { previewUrl: "https://cdn.example.com/local-preview.png" };
+    const overrides = new Map([["image-1", override]]);
+
+    const nextOverrides = pruneCanvasGraphNodeDataOverrides(
+      [
+        {
+          id: "image-1",
+          type: "image",
+          data: {
+            url: "https://cdn.example.com/persisted-source.png",
+            previewUrl: "https://cdn.example.com/persisted-preview.png",
+          },
+        },
+      ],
+      overrides,
+    );
+
+    expect(nextOverrides).toBe(overrides);
+  });
+
+  it("keeps full nested overrides until persisted data fully catches up", () => {
+    const override = {
+      exposure: 0.8,
+      adjustments: {
+        shadows: 12,
+        highlights: -4,
+      },
+    };
+
+    const nextOverrides = pruneCanvasGraphNodeDataOverrides(
+      [
+        {
+          id: "curves-1",
+          type: "curves",
+          data: {
+            exposure: 0.2,
+            adjustments: {
+              shadows: 0,
+              highlights: -4,
+            },
+          },
+        },
+      ],
+      new Map([["curves-1", override]]),
+    );
+
+    expect(nextOverrides).toEqual(new Map([["curves-1", override]]));
+  });
+
  it("resolves the upstream source and pipeline steps from a graph snapshot", () => {
    const graph = buildGraphSnapshot(
      [
@@ -139,4 +263,50 @@ describe("canvas preview graph helpers", () => {
      },
    ]);
  });
+
+  it("prefers local node data overrides during render preview resolution", () => {
+    const graph = buildGraphSnapshot(
+      [
+        {
+          id: "image-1",
+          type: "image",
+          data: { url: "https://cdn.example.com/persisted-source.png" },
+        },
+        {
+          id: "curves-1",
+          type: "curves",
+          data: { exposure: 0.2 },
+        },
+        {
+          id: "render-1",
+          type: "render",
+          data: {},
+        },
+      ],
+      [
+        { source: "image-1", target: "curves-1" },
+        { source: "curves-1", target: "render-1" },
+      ],
+      {
+        nodeDataOverrides: new Map([
+          ["image-1", { url: "https://cdn.example.com/override-source.png" }],
+          ["curves-1", { exposure: 0.8 }],
+        ]),
+      },
+    );
+
+    const preview = resolveRenderPreviewInputFromGraph({
+      nodeId: "render-1",
+      graph,
+    });
+
+    expect(preview.sourceUrl).toBe("https://cdn.example.com/override-source.png");
+    expect(preview.steps).toEqual([
+      {
+        nodeId: "curves-1",
+        type: "curves",
+        params: { exposure: 0.8 },
+      },
+    ]);
+  });
 });
--- a/components/canvas/tests/compare-node.test.tsx
+++ b/components/canvas/tests/compare-node.test.tsx
@@ -2,6 +2,8 @@ import React from "react";
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";

+import { CanvasGraphProvider } from "@/components/canvas/canvas-graph-context";
+
 type StoreState = {
  nodes: Array<{ id: string; type?: string; data?: unknown }>;
  edges: Array<{
@@ -39,6 +41,17 @@ vi.mock("../nodes/compare-surface", () => ({

 import CompareNode from "../nodes/compare-node";

+function renderCompareNode(props: Record<string, unknown>) {
+  return renderToStaticMarkup(
+    <CanvasGraphProvider
+      nodes={storeState.nodes as Array<{ id: string; type: string; data?: unknown }>}
+      edges={storeState.edges}
+    >
+      <CompareNode {...(props as React.ComponentProps<typeof CompareNode>)} />
+    </CanvasGraphProvider>,
+  );
+}
+
 describe("CompareNode render preview inputs", () => {
  beforeEach(() => {
    storeState.nodes = [];
@@ -69,8 +82,7 @@ describe("CompareNode render preview inputs", () => {
      },
    ];

-    renderToStaticMarkup(
-      React.createElement(CompareNode, {
+    renderCompareNode({
        id: "compare-1",
        data: { leftUrl: "https://cdn.example.com/render-output.png" },
        selected: false,
@@ -86,8 +98,7 @@ describe("CompareNode render preview inputs", () => {
        targetPosition: undefined,
        positionAbsoluteX: 0,
        positionAbsoluteY: 0,
-      } as never),
-    );
+      });

    expect(compareSurfaceSpy).toHaveBeenCalled();
    const previewCall = compareSurfaceSpy.mock.calls.find(
@@ -131,8 +142,7 @@ describe("CompareNode render preview inputs", () => {
      },
    ];

-    renderToStaticMarkup(
-      React.createElement(CompareNode, {
+    renderCompareNode({
        id: "compare-1",
        data: { leftUrl: "https://cdn.example.com/render-output.png" },
        selected: false,
@@ -148,8 +158,7 @@ describe("CompareNode render preview inputs", () => {
        targetPosition: undefined,
        positionAbsoluteX: 0,
        positionAbsoluteY: 0,
-      } as never),
-    );
+      });

    expect(compareSurfaceSpy).toHaveBeenCalledTimes(1);
    expect(compareSurfaceSpy.mock.calls[0]?.[0]).toMatchObject({
--- a/components/canvas/tests/use-canvas-connections.test.tsx
+++ b/components/canvas/tests/use-canvas-connections.test.tsx
@@ -147,6 +147,14 @@ describe("useCanvasConnections", () => {
    });

    await act(async () => {
+      latestHandlersRef.current?.onConnectStart?.(
+        {} as MouseEvent,
+        {
+          nodeId: "node-source",
+          handleId: null,
+          handleType: "source",
+        } as never,
+      );
      latestHandlersRef.current?.onConnectEnd(
        { clientX: 400, clientY: 260 } as MouseEvent,
        {
@@ -192,6 +200,14 @@ describe("useCanvasConnections", () => {
    });

    await act(async () => {
+      latestHandlersRef.current?.onConnectStart?.(
+        {} as MouseEvent,
+        {
+          nodeId: "node-source",
+          handleId: null,
+          handleType: "source",
+        } as never,
+      );
      latestHandlersRef.current?.onConnectEnd(
        { clientX: 123, clientY: 456 } as MouseEvent,
        {
@@ -244,6 +260,14 @@ describe("useCanvasConnections", () => {
    });

    await act(async () => {
+      latestHandlersRef.current?.onConnectStart?.(
+        {} as MouseEvent,
+        {
+          nodeId: "node-source",
+          handleId: null,
+          handleType: "source",
+        } as never,
+      );
      latestHandlersRef.current?.onConnectEnd(
        { clientX: 300, clientY: 210 } as MouseEvent,
        {
@@ -288,6 +312,14 @@ describe("useCanvasConnections", () => {
    });

    await act(async () => {
+      latestHandlersRef.current?.onConnectStart?.(
+        {} as MouseEvent,
+        {
+          nodeId: "node-source",
+          handleId: "target-handle",
+          handleType: "target",
+        } as never,
+      );
      latestHandlersRef.current?.onConnectEnd(
        { clientX: 200, clientY: 200 } as MouseEvent,
        {
@@ -313,4 +345,50 @@ describe("useCanvasConnections", () => {
      targetHandle: "target-handle",
    });
  });
+
+  it("ignores onConnectEnd when no connect drag is active", async () => {
+    const runCreateEdgeMutation = vi.fn(async () => undefined);
+    const showConnectionRejectedToast = vi.fn();
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <HookHarness
+          helperResult={{
+            sourceNodeId: "node-source",
+            targetNodeId: "node-target",
+            sourceHandle: undefined,
+            targetHandle: undefined,
+          }}
+          runCreateEdgeMutation={runCreateEdgeMutation}
+          showConnectionRejectedToast={showConnectionRejectedToast}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHandlersRef.current?.onConnectEnd(
+        { clientX: 400, clientY: 260 } as MouseEvent,
+        {
+          isValid: false,
+          from: { x: 0, y: 0 },
+          fromNode: { id: "node-source", type: "image" },
+          fromHandle: { id: null, type: "source" },
+          fromPosition: null,
+          to: { x: 400, y: 260 },
+          toHandle: null,
+          toNode: null,
+          toPosition: null,
+          pointer: null,
+        } as never,
+      );
+    });
+
+    expect(runCreateEdgeMutation).not.toHaveBeenCalled();
+    expect(showConnectionRejectedToast).not.toHaveBeenCalled();
+    expect(latestHandlersRef.current?.connectionDropMenu).toBeNull();
+  });
 });
--- a/components/canvas/tests/use-node-local-data.test.tsx
+++ b/components/canvas/tests/use-node-local-data.test.tsx
@@ -0,0 +1,448 @@
+// @vitest-environment jsdom
+
+import React, { act, useEffect } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import {
+  CanvasGraphProvider,
+  useCanvasGraph,
+  useCanvasGraphPreviewOverrides,
+} from "@/components/canvas/canvas-graph-context";
+import { useNodeLocalData } from "@/components/canvas/nodes/use-node-local-data";
+
+type AdjustmentData = {
+  exposure: number;
+  label?: string;
+};
+
+type HookHarnessProps = {
+  nodeId: string;
+  data: AdjustmentData;
+  onSave: (value: AdjustmentData) => Promise<void> | void;
+};
+
+const latestHookRef: {
+  current:
+    | {
+        applyLocalData: (next: AdjustmentData) => void;
+        updateLocalData: (updater: (current: AdjustmentData) => AdjustmentData) => void;
+        localData: AdjustmentData;
+      }
+    | null;
+} = { current: null };
+
+const latestOverridesRef: {
+  current: ReadonlyMap<string, unknown>;
+} = { current: new Map() };
+
+const canvasGraphSetOverrideRef: {
+  current: ((nodeId: string, data: unknown) => void) | null;
+} = { current: null };
+
+(globalThis as typeof globalThis & { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+function HookHarness({ nodeId, data, onSave }: HookHarnessProps) {
+  const { localData, applyLocalData, updateLocalData } = useNodeLocalData<AdjustmentData>({
+    nodeId,
+    data,
+    normalize: (value) => ({ ...(value as AdjustmentData) }),
+    saveDelayMs: 1000,
+    onSave,
+    debugLabel: "curves",
+  });
+
+  useEffect(() => {
+    latestHookRef.current = {
+      applyLocalData,
+      updateLocalData,
+      localData,
+    };
+
+    return () => {
+      latestHookRef.current = null;
+    };
+  }, [applyLocalData, localData, updateLocalData]);
+
+  return null;
+}
+
+function GraphProbe() {
+  const { previewNodeDataOverrides } = useCanvasGraph();
+  const { setPreviewNodeDataOverride } = useCanvasGraphPreviewOverrides();
+
+  useEffect(() => {
+    latestOverridesRef.current = previewNodeDataOverrides;
+    canvasGraphSetOverrideRef.current = setPreviewNodeDataOverride;
+
+    return () => {
+      canvasGraphSetOverrideRef.current = null;
+    };
+  }, [previewNodeDataOverrides, setPreviewNodeDataOverride]);
+
+  return null;
+}
+
+function TestApp({
+  nodeId,
+  data,
+  mounted,
+  onSave,
+}: {
+  nodeId: string;
+  data: AdjustmentData;
+  mounted: boolean;
+  onSave: (value: AdjustmentData) => Promise<void> | void;
+}) {
+  return (
+    <CanvasGraphProvider nodes={[{ id: nodeId, type: "curves", data }]} edges={[]}>
+      {mounted ? <HookHarness nodeId={nodeId} data={data} onSave={onSave} /> : null}
+      <GraphProbe />
+    </CanvasGraphProvider>
+  );
+}
+
+describe("useNodeLocalData preview overrides", () => {
+  let container: HTMLDivElement | null = null;
+  let root: Root | null = null;
+
+  afterEach(async () => {
+    latestHookRef.current = null;
+    latestOverridesRef.current = new Map();
+    canvasGraphSetOverrideRef.current = null;
+    vi.clearAllMocks();
+
+    if (root) {
+      await act(async () => {
+        root?.unmount();
+      });
+    }
+
+    container?.remove();
+    root = null;
+    container = null;
+  });
+
+  it("sets a preview override for local edits and clears it when persisted data catches up", async () => {
+    const onSave = vi.fn(async () => undefined);
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHookRef.current?.updateLocalData((current) => ({
+        ...current,
+        exposure: 0.8,
+      }));
+    });
+
+    expect(latestOverridesRef.current).toEqual(
+      new Map([["node-1", { exposure: 0.8, label: "persisted" }]]),
+    );
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.8, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    expect(latestOverridesRef.current).toEqual(new Map());
+  });
+
+  it("does not update the canvas graph provider during render when updating local data", async () => {
+    const onSave = vi.fn(async () => undefined);
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHookRef.current?.updateLocalData((current) => ({
+        ...current,
+        exposure: 0.8,
+      }));
+    });
+
+    expect(consoleErrorSpy).not.toHaveBeenCalledWith(
+      expect.stringContaining(
+        "Cannot update a component (`CanvasGraphProvider`) while rendering a different component",
+      ),
+    );
+  });
+
+  it("does not write preview overrides from inside the local state updater", async () => {
+    const onSave = vi.fn(async () => undefined);
+    const originalSetPreviewNodeDataOverride = canvasGraphSetOverrideRef.current;
+    let insideUpdater = false;
+
+    canvasGraphSetOverrideRef.current = () => {
+      if (insideUpdater) {
+        throw new Error("setPreviewNodeDataOverride called during updater");
+      }
+    };
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await expect(
+      act(async () => {
+        latestHookRef.current?.updateLocalData((current) => {
+          insideUpdater = true;
+          return {
+            ...current,
+            exposure: 0.8,
+          };
+        });
+      }),
+    ).resolves.toBeUndefined();
+
+    insideUpdater = false;
+    canvasGraphSetOverrideRef.current = originalSetPreviewNodeDataOverride;
+  });
+
+  it("clears its preview override on unmount", async () => {
+    const onSave = vi.fn(async () => undefined);
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHookRef.current?.applyLocalData({
+        exposure: 0.8,
+        label: "persisted",
+      });
+    });
+
+    expect(latestOverridesRef.current).toEqual(
+      new Map([["node-1", { exposure: 0.8, label: "persisted" }]]),
+    );
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted={false}
+          onSave={onSave}
+        />,
+      );
+    });
+
+    expect(latestOverridesRef.current).toEqual(new Map());
+  });
+
+  it("cancels a pending debounced save when the node unmounts", async () => {
+    vi.useFakeTimers();
+    const onSave = vi.fn(async () => undefined);
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHookRef.current?.applyLocalData({
+        exposure: 0.8,
+        label: "persisted",
+      });
+    });
+
+    expect(onSave).not.toHaveBeenCalled();
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted={false}
+          onSave={onSave}
+        />,
+      );
+    });
+
+    expect(onSave).not.toHaveBeenCalled();
+    expect(latestOverridesRef.current).toEqual(new Map());
+
+    vi.useRealTimers();
+  });
+
+  it("clears pending preview state after a rejected save so persisted data can recover", async () => {
+    vi.useFakeTimers();
+    const onSave = vi.fn(async () => {
+      throw new Error("save failed");
+    });
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHookRef.current?.applyLocalData({
+        exposure: 0.8,
+        label: "persisted",
+      });
+    });
+
+    expect(latestOverridesRef.current).toEqual(
+      new Map([["node-1", { exposure: 0.8, label: "persisted" }]]),
+    );
+
+    await act(async () => {
+      vi.advanceTimersByTime(1000);
+      await Promise.resolve();
+    });
+
+    expect(onSave).toHaveBeenCalledTimes(1);
+    expect(latestOverridesRef.current).toEqual(new Map());
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.3, label: "server" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      vi.runOnlyPendingTimers();
+    });
+
+    expect(latestHookRef.current?.localData).toEqual({ exposure: 0.3, label: "server" });
+
+    vi.useRealTimers();
+  });
+
+  it("accepts a non-identical persisted update after a successful save", async () => {
+    vi.useFakeTimers();
+    const onSave = vi.fn(async () => undefined);
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.2, label: "persisted" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      latestHookRef.current?.applyLocalData({
+        exposure: 0.8,
+        label: "client",
+      });
+    });
+
+    await act(async () => {
+      vi.advanceTimersByTime(1000);
+      await Promise.resolve();
+    });
+
+    expect(onSave).toHaveBeenCalledTimes(1);
+
+    await act(async () => {
+      root?.render(
+        <TestApp
+          nodeId="node-1"
+          data={{ exposure: 0.75, label: "server-normalized" }}
+          mounted
+          onSave={onSave}
+        />,
+      );
+    });
+
+    await act(async () => {
+      vi.runOnlyPendingTimers();
+    });
+
+    expect(latestHookRef.current?.localData).toEqual({
+      exposure: 0.75,
+      label: "server-normalized",
+    });
+    expect(latestOverridesRef.current).toEqual(new Map());
+
+    vi.useRealTimers();
+  });
+});
--- a/components/canvas/canvas-delete-handlers.ts
+++ b/components/canvas/canvas-delete-handlers.ts
@@ -122,22 +122,22 @@ export function useCanvasDeleteHandlers({
        nodes,
        edges,
      );
-      const edgePromises = bridgeCreates.map((bridgeCreate) =>
-        runCreateEdgeMutation({
+
+      void (async () => {
+        await runBatchRemoveNodesMutation({
+          nodeIds: idsToDelete as Id<"nodes">[],
+        });
+
+        for (const bridgeCreate of bridgeCreates) {
+          await runCreateEdgeMutation({
            canvasId,
            sourceNodeId: bridgeCreate.sourceNodeId,
            targetNodeId: bridgeCreate.targetNodeId,
            sourceHandle: bridgeCreate.sourceHandle,
            targetHandle: bridgeCreate.targetHandle,
-        }),
-      );
-
-      void Promise.all([
-        runBatchRemoveNodesMutation({
-          nodeIds: idsToDelete as Id<"nodes">[],
-        }),
-        ...edgePromises,
-      ])
+          });
+        }
+      })()
        .then(() => {
          // Erfolg bedeutet hier nur: Mutation/Queue wurde angenommen.
          // Den Delete-Lock erst lösen, wenn Convex-Snapshot die Node wirklich nicht mehr enthält.
--- a/components/canvas/canvas-graph-context.tsx
+++ b/components/canvas/canvas-graph-context.tsx
@@ -1,17 +1,37 @@
 "use client";

-import { createContext, useContext, useMemo, type ReactNode } from "react";
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useEffect,
+  useMemo,
+  useState,
+  type ReactNode,
+} from "react";

 import {
  buildGraphSnapshot,
  type CanvasGraphEdgeLike,
+  type CanvasGraphNodeDataOverrides,
  type CanvasGraphNodeLike,
  type CanvasGraphSnapshot,
+  pruneCanvasGraphNodeDataOverrides,
 } from "@/lib/canvas-render-preview";

-type CanvasGraphContextValue = CanvasGraphSnapshot;
+type CanvasGraphContextValue = CanvasGraphSnapshot & {
+  previewNodeDataOverrides: CanvasGraphNodeDataOverrides;
+};
+
+type CanvasGraphPreviewOverridesContextValue = {
+  setPreviewNodeDataOverride: (nodeId: string, data: unknown) => void;
+  clearPreviewNodeDataOverride: (nodeId: string) => void;
+  clearPreviewNodeDataOverrides: () => void;
+};

 const CanvasGraphContext = createContext<CanvasGraphContextValue | null>(null);
+const CanvasGraphPreviewOverridesContext =
+  createContext<CanvasGraphPreviewOverridesContextValue | null>(null);

 export function CanvasGraphProvider({
  nodes,
@@ -22,9 +42,88 @@ export function CanvasGraphProvider({
  edges: readonly CanvasGraphEdgeLike[];
  children: ReactNode;
 }) {
-  const value = useMemo(() => buildGraphSnapshot(nodes, edges), [edges, nodes]);
+  const [previewNodeDataOverrides, setPreviewNodeDataOverrides] =
+    useState<CanvasGraphNodeDataOverrides>(() => new Map());

-  return <CanvasGraphContext.Provider value={value}>{children}</CanvasGraphContext.Provider>;
+  const setPreviewNodeDataOverride = useCallback((nodeId: string, data: unknown) => {
+    setPreviewNodeDataOverrides((previous) => {
+      if (previous.has(nodeId) && Object.is(previous.get(nodeId), data)) {
+        return previous;
+      }
+
+      const next = new Map(previous);
+      next.set(nodeId, data);
+      return next;
+    });
+  }, []);
+
+  const clearPreviewNodeDataOverride = useCallback((nodeId: string) => {
+    setPreviewNodeDataOverrides((previous) => {
+      if (!previous.has(nodeId)) {
+        return previous;
+      }
+
+      const next = new Map(previous);
+      next.delete(nodeId);
+      return next;
+    });
+  }, []);
+
+  const clearPreviewNodeDataOverrides = useCallback(() => {
+    setPreviewNodeDataOverrides((previous) => {
+      if (previous.size === 0) {
+        return previous;
+      }
+
+      return new Map();
+    });
+  }, []);
+
+  const prunedPreviewNodeDataOverrides = useMemo(
+    () => pruneCanvasGraphNodeDataOverrides(nodes, previewNodeDataOverrides),
+    [nodes, previewNodeDataOverrides],
+  );
+
+  useEffect(() => {
+    if (prunedPreviewNodeDataOverrides !== previewNodeDataOverrides) {
+      setPreviewNodeDataOverrides(prunedPreviewNodeDataOverrides);
+    }
+  }, [previewNodeDataOverrides, prunedPreviewNodeDataOverrides]);
+
+  const graph = useMemo(
+    () =>
+      buildGraphSnapshot(nodes, edges, {
+        nodeDataOverrides: prunedPreviewNodeDataOverrides,
+      }),
+    [edges, nodes, prunedPreviewNodeDataOverrides],
+  );
+
+  const value = useMemo(
+    () => ({
+      ...graph,
+      previewNodeDataOverrides: prunedPreviewNodeDataOverrides,
+    }),
+    [graph, prunedPreviewNodeDataOverrides],
+  );
+
+  const previewOverridesValue = useMemo(
+    () => ({
+      setPreviewNodeDataOverride,
+      clearPreviewNodeDataOverride,
+      clearPreviewNodeDataOverrides,
+    }),
+    [
+      clearPreviewNodeDataOverride,
+      clearPreviewNodeDataOverrides,
+      setPreviewNodeDataOverride,
+    ],
+  );
+
+  return (
+    <CanvasGraphPreviewOverridesContext.Provider value={previewOverridesValue}>
+      <CanvasGraphContext.Provider value={value}>{children}</CanvasGraphContext.Provider>
+    </CanvasGraphPreviewOverridesContext.Provider>
+  );
 }

 export function useCanvasGraph(): CanvasGraphContextValue {
@@ -35,3 +134,12 @@ export function useCanvasGraph(): CanvasGraphContextValue {

  return context;
 }
+
+export function useCanvasGraphPreviewOverrides(): CanvasGraphPreviewOverridesContextValue {
+  const context = useContext(CanvasGraphPreviewOverridesContext);
+  if (!context) {
+    throw new Error("useCanvasGraphPreviewOverrides must be used within CanvasGraphProvider");
+  }
+
+  return context;
+}
--- a/components/canvas/canvas.tsx
+++ b/components/canvas/canvas.tsx
@@ -308,6 +308,7 @@ function CanvasInner({ canvasId }: CanvasInnerProps) {
    closeConnectionDropMenu,
    handleConnectionDropPick,
    onConnect,
+    onConnectStart,
    onConnectEnd,
    onReconnectStart,
    onReconnect,
@@ -520,6 +521,7 @@ function CanvasInner({ canvasId }: CanvasInnerProps) {
            onNodeDrag={onNodeDrag}
            onNodeDragStop={onNodeDragStop}
            onConnect={onConnect}
+            onConnectStart={onConnectStart}
            onConnectEnd={onConnectEnd}
            onReconnect={onReconnect}
            onReconnectStart={onReconnectStart}
--- a/components/canvas/nodes/adjustment-preview.tsx
+++ b/components/canvas/nodes/adjustment-preview.tsx
@@ -1,46 +1,18 @@
 "use client";

-import { useEffect, useMemo, useRef } from "react";
+import { useMemo } from "react";
 import { useCanvasGraph } from "@/components/canvas/canvas-graph-context";

 import { usePipelinePreview } from "@/hooks/use-pipeline-preview";
 import {
  collectPipelineFromGraph,
  getSourceImageFromGraph,
+  shouldFastPathPreviewPipeline,
 } from "@/lib/canvas-render-preview";
 import type { PipelineStep } from "@/lib/image-pipeline/contracts";
 import { buildHistogramPlot } from "@/lib/image-pipeline/histogram-plot";

-const PREVIEW_PIPELINE_TYPES = new Set([
-  "curves",
-  "color-adjust",
-  "light-adjust",
-  "detail-adjust",
-]);
-
-type PreviewLatencyTrace = {
-  sequence: number;
-  changedAtMs: number;
-  nodeType: string;
-  origin: string;
-};
-
-function readPreviewLatencyTrace(): PreviewLatencyTrace | null {
-  if (process.env.NODE_ENV === "production") {
-    return null;
-  }
-
-  const debugGlobals = globalThis as typeof globalThis & {
-    __LEMONSPACE_DEBUG_PREVIEW_LATENCY__?: boolean;
-    __LEMONSPACE_LAST_PREVIEW_TRACE__?: PreviewLatencyTrace;
-  };
-
-  if (debugGlobals.__LEMONSPACE_DEBUG_PREVIEW_LATENCY__ !== true) {
-    return null;
-  }
-
-  return debugGlobals.__LEMONSPACE_LAST_PREVIEW_TRACE__ ?? null;
-}
+const PREVIEW_PIPELINE_TYPES = new Set(["curves", "color-adjust", "light-adjust", "detail-adjust"]);

 export default function AdjustmentPreview({
  nodeId,
@@ -54,7 +26,6 @@ export default function AdjustmentPreview({
  currentParams: unknown;
 }) {
  const graph = useCanvasGraph();
-  const lastLoggedTraceSequenceRef = useRef<number | null>(null);

  const sourceUrl = useMemo(
    () =>
@@ -93,36 +64,21 @@ export default function AdjustmentPreview({
    });
  }, [currentParams, currentType, graph, nodeId]);

-  useEffect(() => {
-    const trace = readPreviewLatencyTrace();
-    if (!trace) {
-      return;
-    }
+  const usesFastPreviewDebounce = shouldFastPathPreviewPipeline(
+    steps,
+    graph.previewNodeDataOverrides,
+  );
+  const shouldDeferHistogram = graph.previewNodeDataOverrides.has(nodeId);

-    if (lastLoggedTraceSequenceRef.current === trace.sequence) {
-      return;
-    }
-
-    lastLoggedTraceSequenceRef.current = trace.sequence;
-
-    console.info("[Preview latency] downstream-graph-visible", {
-      nodeId,
-      nodeType: currentType,
-      sourceNodeType: trace.nodeType,
-      sourceOrigin: trace.origin,
-      sinceChangeMs: performance.now() - trace.changedAtMs,
-      pipelineDepth: steps.length,
-      stepTypes: steps.map((step) => step.type),
-      hasSource: Boolean(sourceUrl),
-    });
-  }, [currentType, nodeId, sourceUrl, steps]);
+  const previewDebounceMs = usesFastPreviewDebounce ? 16 : undefined;

  const { canvasRef, histogram, isRendering, hasSource, previewAspectRatio, error } =
    usePipelinePreview({
      sourceUrl,
      steps,
      nodeWidth,
-      includeHistogram: true,
+      includeHistogram: !shouldDeferHistogram,
+      debounceMs: previewDebounceMs,
      // Die Vorschau muss in-Node gut lesbar bleiben, aber nicht in voller
      // Display-Auflösung rechnen.
      previewScale: 0.5,
--- a/components/canvas/nodes/color-adjust-node.tsx
+++ b/components/canvas/nodes/color-adjust-node.tsx
@@ -59,6 +59,7 @@ export default function ColorAdjustNode({ id, data, selected, width }: NodeProps
    [],
  );
  const { localData, applyLocalData, updateLocalData } = useNodeLocalData<ColorAdjustData>({
+    nodeId: id,
    data,
    normalize: normalizeData,
    saveDelayMs: 16,
--- a/components/canvas/nodes/compare-surface.tsx
+++ b/components/canvas/nodes/compare-surface.tsx
@@ -1,7 +1,11 @@
 "use client";

+import { useCanvasGraph } from "@/components/canvas/canvas-graph-context";
 import { usePipelinePreview } from "@/hooks/use-pipeline-preview";
-import type { RenderPreviewInput } from "@/lib/canvas-render-preview";
+import {
+  shouldFastPathPreviewPipeline,
+  type RenderPreviewInput,
+} from "@/lib/canvas-render-preview";

 const EMPTY_STEPS: RenderPreviewInput["steps"] = [];

@@ -22,16 +26,24 @@ export default function CompareSurface({
  clipWidthPercent,
  preferPreview,
 }: CompareSurfaceProps) {
+  const graph = useCanvasGraph();
  const usePreview = Boolean(previewInput && (preferPreview || !finalUrl));
  const previewSourceUrl = usePreview ? previewInput?.sourceUrl ?? null : null;
  const previewSteps = usePreview ? previewInput?.steps ?? EMPTY_STEPS : EMPTY_STEPS;
  const visibleFinalUrl = usePreview ? undefined : finalUrl;
+  const previewDebounceMs = shouldFastPathPreviewPipeline(
+    previewSteps,
+    graph.previewNodeDataOverrides,
+  )
+    ? 16
+    : undefined;

  const { canvasRef, isRendering, error } = usePipelinePreview({
    sourceUrl: previewSourceUrl,
    steps: previewSteps,
    nodeWidth,
    includeHistogram: false,
+    debounceMs: previewDebounceMs,
    // Compare-Nodes zeigen nur eine kompakte Live-Ansicht; kleinere Kacheln
    // halten lange Workflows spürbar reaktionsfreudiger.
    previewScale: 0.5,
--- a/components/canvas/nodes/curves-node.tsx
+++ b/components/canvas/nodes/curves-node.tsx
@@ -59,6 +59,7 @@ export default function CurvesNode({ id, data, selected, width }: NodeProps<Curv
    [],
  );
  const { localData, applyLocalData, updateLocalData } = useNodeLocalData<CurvesData>({
+    nodeId: id,
    data,
    normalize: normalizeData,
    saveDelayMs: 16,
--- a/components/canvas/nodes/detail-adjust-node.tsx
+++ b/components/canvas/nodes/detail-adjust-node.tsx
@@ -59,6 +59,7 @@ export default function DetailAdjustNode({ id, data, selected, width }: NodeProp
    [],
  );
  const { localData, applyLocalData, updateLocalData } = useNodeLocalData<DetailAdjustData>({
+    nodeId: id,
    data,
    normalize: normalizeData,
    saveDelayMs: 16,
--- a/components/canvas/nodes/light-adjust-node.tsx
+++ b/components/canvas/nodes/light-adjust-node.tsx
@@ -59,6 +59,7 @@ export default function LightAdjustNode({ id, data, selected, width }: NodeProps
    [],
  );
  const { localData, applyLocalData, updateLocalData } = useNodeLocalData<LightAdjustData>({
+    nodeId: id,
    data,
    normalize: normalizeData,
    saveDelayMs: 16,
--- a/components/canvas/nodes/render-node.tsx
+++ b/components/canvas/nodes/render-node.tsx
@@ -16,6 +16,7 @@ import { useCanvasGraph } from "@/components/canvas/canvas-graph-context";
 import {
  findSourceNodeFromGraph,
  resolveRenderPreviewInputFromGraph,
+  shouldFastPathPreviewPipeline,
 } from "@/lib/canvas-render-preview";
 import { resolveMediaAspectRatio } from "@/lib/canvas-utils";
 import { parseAspectRatioString } from "@/lib/image-formats";
@@ -495,6 +496,12 @@ export default function RenderNode({ id, data, selected, width, height }: NodePr
  );

  const steps = renderPreviewInput.steps;
+  const previewDebounceMs = shouldFastPathPreviewPipeline(
+    steps,
+    graph.previewNodeDataOverrides,
+  )
+    ? 16
+    : undefined;

  const renderFingerprint = useMemo(
    () => ({
@@ -560,6 +567,7 @@ export default function RenderNode({ id, data, selected, width, height }: NodePr
    sourceUrl,
    steps,
    nodeWidth: previewNodeWidth,
+    debounceMs: previewDebounceMs,
    // Inline-Preview: bewusst kompakt halten, damit Änderungen schneller
    // sichtbar werden, besonders in langen Graphen.
    previewScale: 0.5,
@@ -577,6 +585,7 @@ export default function RenderNode({ id, data, selected, width, height }: NodePr
    steps,
    nodeWidth: fullscreenPreviewWidth,
    includeHistogram: false,
+    debounceMs: previewDebounceMs,
    previewScale: 0.85,
    maxPreviewWidth: 1920,
    maxDevicePixelRatio: 1.5,
--- a/components/canvas/nodes/use-node-local-data.ts
+++ b/components/canvas/nodes/use-node-local-data.ts
@@ -2,6 +2,7 @@

 import { useCallback, useEffect, useRef, useState } from "react";

+import { useCanvasGraphPreviewOverrides } from "@/components/canvas/canvas-graph-context";
 import { useDebouncedCallback } from "@/hooks/use-debounced-callback";

 function hashNodeData(value: unknown): string {
@@ -21,69 +22,67 @@ function logNodeDataDebug(event: string, payload: Record<string, unknown>): void
  console.info("[Canvas node debug]", event, payload);
 }

-type PreviewLatencyTrace = {
-  sequence: number;
-  changedAtMs: number;
-  nodeType: string;
-  origin: "applyLocalData" | "updateLocalData";
-};
-
-function writePreviewLatencyTrace(trace: Omit<PreviewLatencyTrace, "sequence">): void {
-  if (process.env.NODE_ENV === "production") {
-    return;
-  }
-
-  const debugGlobals = globalThis as typeof globalThis & {
-    __LEMONSPACE_DEBUG_PREVIEW_LATENCY__?: boolean;
-    __LEMONSPACE_LAST_PREVIEW_TRACE__?: PreviewLatencyTrace;
-  };
-
-  if (debugGlobals.__LEMONSPACE_DEBUG_PREVIEW_LATENCY__ !== true) {
-    return;
-  }
-
-  const nextTrace: PreviewLatencyTrace = {
-    ...trace,
-    sequence: (debugGlobals.__LEMONSPACE_LAST_PREVIEW_TRACE__?.sequence ?? 0) + 1,
-  };
-
-  debugGlobals.__LEMONSPACE_LAST_PREVIEW_TRACE__ = nextTrace;
-
-  console.info("[Preview latency] node-local-change", nextTrace);
-}
-
 export function useNodeLocalData<T>({
+  nodeId,
  data,
  normalize,
  saveDelayMs,
  onSave,
  debugLabel,
 }: {
+  nodeId: string;
  data: unknown;
  normalize: (value: unknown) => T;
  saveDelayMs: number;
  onSave: (value: T) => Promise<void> | void;
  debugLabel: string;
 }) {
+  const { setPreviewNodeDataOverride, clearPreviewNodeDataOverride } =
+    useCanvasGraphPreviewOverrides();
  const [localData, setLocalDataState] = useState<T>(() => normalize(data));
  const localDataRef = useRef(localData);
+  const persistedDataRef = useRef(localData);
  const hasPendingLocalChangesRef = useRef(false);
+  const localChangeVersionRef = useRef(0);
+  const isMountedRef = useRef(true);

  useEffect(() => {
    localDataRef.current = localData;
  }, [localData]);

  const queueSave = useDebouncedCallback(() => {
-    void onSave(localDataRef.current);
+    const savedValue = localDataRef.current;
+    const savedVersion = localChangeVersionRef.current;
+
+    Promise.resolve(onSave(savedValue))
+      .then(() => {
+        if (!isMountedRef.current || savedVersion !== localChangeVersionRef.current) {
+          return;
+        }
+
+        hasPendingLocalChangesRef.current = false;
+      })
+      .catch(() => {
+        if (!isMountedRef.current || savedVersion !== localChangeVersionRef.current) {
+          return;
+        }
+
+        hasPendingLocalChangesRef.current = false;
+        localDataRef.current = persistedDataRef.current;
+        setLocalDataState(persistedDataRef.current);
+        clearPreviewNodeDataOverride(nodeId);
+      });
  }, saveDelayMs);

  useEffect(() => {
    const incomingData = normalize(data);
+    persistedDataRef.current = incomingData;
    const incomingHash = hashNodeData(incomingData);
    const localHash = hashNodeData(localDataRef.current);

    if (incomingHash === localHash) {
      hasPendingLocalChangesRef.current = false;
+      clearPreviewNodeDataOverride(nodeId);
      return;
    }

@@ -99,44 +98,46 @@ export function useNodeLocalData<T>({
    const timer = window.setTimeout(() => {
      localDataRef.current = incomingData;
      setLocalDataState(incomingData);
+      clearPreviewNodeDataOverride(nodeId);
    }, 0);

    return () => {
      window.clearTimeout(timer);
    };
-  }, [data, debugLabel, normalize]);
+  }, [clearPreviewNodeDataOverride, data, debugLabel, nodeId, normalize]);
+
+  useEffect(() => {
+    return () => {
+      isMountedRef.current = false;
+      queueSave.cancel();
+      clearPreviewNodeDataOverride(nodeId);
+    };
+  }, [clearPreviewNodeDataOverride, nodeId, queueSave]);

  const applyLocalData = useCallback(
    (next: T) => {
+      localChangeVersionRef.current += 1;
      hasPendingLocalChangesRef.current = true;
-      writePreviewLatencyTrace({
-        changedAtMs: performance.now(),
-        nodeType: debugLabel,
-        origin: "applyLocalData",
-      });
      localDataRef.current = next;
      setLocalDataState(next);
+      setPreviewNodeDataOverride(nodeId, next);
      queueSave();
    },
-    [debugLabel, queueSave],
+    [debugLabel, nodeId, queueSave, setPreviewNodeDataOverride],
  );

  const updateLocalData = useCallback(
    (updater: (current: T) => T) => {
+      const next = updater(localDataRef.current);
+
+      localChangeVersionRef.current += 1;
      hasPendingLocalChangesRef.current = true;
-      setLocalDataState((current) => {
-        const next = updater(current);
-        writePreviewLatencyTrace({
-          changedAtMs: performance.now(),
-          nodeType: debugLabel,
-          origin: "updateLocalData",
-        });
      localDataRef.current = next;
+      setLocalDataState(next);
+      setPreviewNodeDataOverride(nodeId, next);
      queueSave();
-        return next;
-      });
    },
-    [debugLabel, queueSave],
+    [debugLabel, nodeId, queueSave, setPreviewNodeDataOverride],
  );

  return {
--- a/components/canvas/use-canvas-connections.ts
+++ b/components/canvas/use-canvas-connections.ts
@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useRef, useState, type Dispatch, type MutableRefObject, type SetStateAction } from "react";
-import type { Connection, Edge as RFEdge, Node as RFNode, OnConnectEnd } from "@xyflow/react";
+import type { Connection, Edge as RFEdge, Node as RFNode, OnConnectEnd, OnConnectStart } from "@xyflow/react";

 import type { Id } from "@/convex/_generated/dataModel";
 import {
@@ -100,14 +100,20 @@ export function useCanvasConnections({
  const [connectionDropMenu, setConnectionDropMenu] =
    useState<ConnectionDropMenuState | null>(null);
  const connectionDropMenuRef = useRef<ConnectionDropMenuState | null>(null);
+  const isConnectDragActiveRef = useRef(false);
  const closeConnectionDropMenu = useCallback(() => setConnectionDropMenu(null), []);

  useEffect(() => {
    connectionDropMenuRef.current = connectionDropMenu;
  }, [connectionDropMenu]);

+  const onConnectStart = useCallback<OnConnectStart>(() => {
+    isConnectDragActiveRef.current = true;
+  }, []);
+
  const onConnect = useCallback(
    (connection: Connection) => {
+      isConnectDragActiveRef.current = false;
      const validationError = validateCanvasConnection(connection, nodes, edges);
      if (validationError) {
        showConnectionRejectedToast(validationError);
@@ -129,6 +135,11 @@ export function useCanvasConnections({

  const onConnectEnd = useCallback<OnConnectEnd>(
    (event, connectionState) => {
+      if (!isConnectDragActiveRef.current) {
+        return;
+      }
+
+      isConnectDragActiveRef.current = false;
      if (isReconnectDragActiveRef.current) return;
      if (connectionState.isValid === true) return;
      const fromNode = connectionState.fromNode;
@@ -153,8 +164,8 @@ export function useCanvasConnections({
          {
            source: droppedConnection.sourceNodeId,
            target: droppedConnection.targetNodeId,
-            sourceHandle: droppedConnection.sourceHandle,
-            targetHandle: droppedConnection.targetHandle,
+            sourceHandle: droppedConnection.sourceHandle ?? null,
+            targetHandle: droppedConnection.targetHandle ?? null,
          },
          nodesRef.current,
          edgesRef.current,
@@ -338,6 +349,7 @@ export function useCanvasConnections({
      closeConnectionDropMenu,
      handleConnectionDropPick,
      onConnect,
+      onConnectStart,
      onConnectEnd,
      onReconnectStart,
      onReconnect,
--- a/docs/plans/2026-04-05-preview-graph-architecture.md
+++ b/docs/plans/2026-04-05-preview-graph-architecture.md
@@ -0,0 +1,371 @@
+# Preview Graph Architecture Implementation Plan
+
+> **For Claude:** REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.
+
+**Goal:** Make upstream adjustment changes propagate to downstream node previews and the render preview immediately from local client state, without waiting for the sync queue or Convex roundtrip.
+
+**Architecture:** Add a local-first preview graph overlay inside the canvas graph provider so node-local adjustment state can temporarily override persisted node data for preview resolution. Then make preview rendering react to that local overlay with a lower hot-path debounce and optional histogram deferral, so the pipeline feels immediate while the persisted graph keeps its current sync semantics.
+
+**Tech Stack:** React 19, Next 16, `@xyflow/react`, client context providers, Vitest, WebGL preview backend, existing worker-client preview pipeline.
+
+---
+
+### Task 1: Add a local preview override layer to the canvas graph
+
+**Files:**
+- Modify: `components/canvas/canvas-graph-context.tsx`
+- Modify: `lib/canvas-render-preview.ts`
+- Create: `tests/canvas-render-preview.test.ts`
+
+**Step 1: Write the failing test**
+
+```ts
+it("prefers local preview overrides over persisted node data", () => {
+  const graph = buildGraphSnapshot(
+    [
+      { id: "image-1", type: "image", data: { url: "https://cdn.example.com/source.png" } },
+      { id: "color-1", type: "color-adjust", data: { temperature: 0 } },
+      { id: "render-1", type: "render", data: {} },
+    ],
+    [
+      { source: "image-1", target: "color-1" },
+      { source: "color-1", target: "render-1" },
+    ],
+    false,
+    new Map([["color-1", { temperature: 42 }]]),
+  );
+
+  expect(resolveRenderPreviewInputFromGraph({ nodeId: "render-1", graph }).steps).toMatchObject([
+    { nodeId: "color-1", type: "color-adjust", params: { temperature: 42 } },
+  ]);
+});
+```
+
+**Step 2: Run test to verify it fails**
+
+Run: `pnpm test tests/canvas-render-preview.test.ts`
+Expected: FAIL because `buildGraphSnapshot` does not accept or apply preview overrides yet.
+
+**Step 3: Write minimal implementation**
+
+```ts
+export function buildGraphSnapshot(
+  nodes: readonly CanvasGraphNodeLike[],
+  edges: readonly CanvasGraphEdgeLike[],
+  includeTempEdges = false,
+  nodeDataOverrides?: ReadonlyMap<string, unknown>,
+): CanvasGraphSnapshot {
+  const nodesById = new Map<string, CanvasGraphNodeLike>();
+  for (const node of nodes) {
+    const override = nodeDataOverrides?.get(node.id);
+    nodesById.set(node.id, override === undefined ? node : { ...node, data: override });
+  }
+  // existing edge logic unchanged
+}
+```
+
+Add a second context export in `components/canvas/canvas-graph-context.tsx` for local preview overrides:
+
+```ts
+type CanvasGraphPreviewOverrides = {
+  setNodePreviewOverride: (nodeId: string, data: unknown) => void;
+  clearNodePreviewOverride: (nodeId: string) => void;
+  hasPreviewOverrides: boolean;
+};
+```
+
+Build the graph snapshot with the override map applied.
+
+**Step 4: Run test to verify it passes**
+
+Run: `pnpm test tests/canvas-render-preview.test.ts`
+Expected: PASS
+
+**Step 5: Commit**
+
+```bash
+git add components/canvas/canvas-graph-context.tsx lib/canvas-render-preview.ts tests/canvas-render-preview.test.ts
+git commit -m "feat(canvas): add local preview graph overrides"
+```
+
+### Task 2: Feed node-local adjustment state into the preview override layer
+
+**Files:**
+- Modify: `components/canvas/nodes/use-node-local-data.ts`
+- Modify: `components/canvas/nodes/color-adjust-node.tsx`
+- Modify: `components/canvas/nodes/light-adjust-node.tsx`
+- Modify: `components/canvas/nodes/curves-node.tsx`
+- Modify: `components/canvas/nodes/detail-adjust-node.tsx`
+- Create: `components/canvas/__tests__/use-node-local-data-preview-overrides.test.tsx`
+
+**Step 1: Write the failing test**
+
+```tsx
+it("pushes local adjustment changes into preview overrides before save completes", async () => {
+  const setNodePreviewOverride = vi.fn();
+  const clearNodePreviewOverride = vi.fn();
+
+  render(
+    <CanvasGraphPreviewOverridesTestProvider
+      value={{ setNodePreviewOverride, clearNodePreviewOverride, hasPreviewOverrides: false }}
+    >
+      <Harness nodeId="color-1" data={{ temperature: 0 }} />
+    </CanvasGraphPreviewOverridesTestProvider>,
+  );
+
+  await userEvent.click(screen.getByRole("button", { name: /change/i }));
+
+  expect(setNodePreviewOverride).toHaveBeenCalledWith("color-1", expect.objectContaining({ temperature: 42 }));
+});
+```
+
+**Step 2: Run test to verify it fails**
+
+Run: `pnpm test components/canvas/__tests__/use-node-local-data-preview-overrides.test.tsx`
+Expected: FAIL because `useNodeLocalData` does not know about preview overrides.
+
+**Step 3: Write minimal implementation**
+
+Add `nodeId` to the hook contract and wire the override context into the hot path:
+
+```ts
+const { setNodePreviewOverride, clearNodePreviewOverride } = useCanvasGraphPreviewOverrides();
+
+const applyLocalData = useCallback((next: T) => {
+  hasPendingLocalChangesRef.current = true;
+  setNodePreviewOverride(nodeId, next);
+  localDataRef.current = next;
+  setLocalDataState(next);
+  queueSave();
+}, [nodeId, queueSave, setNodePreviewOverride]);
+```
+
+When the persisted data catches up, clear the override:
+
+```ts
+if (incomingHash === localHash) {
+  hasPendingLocalChangesRef.current = false;
+  clearNodePreviewOverride(nodeId);
+  return;
+}
+```
+
+Also clear the override on unmount.
+
+**Step 4: Run test to verify it passes**
+
+Run: `pnpm test components/canvas/__tests__/use-node-local-data-preview-overrides.test.tsx`
+Expected: PASS
+
+**Step 5: Commit**
+
+```bash
+git add components/canvas/nodes/use-node-local-data.ts components/canvas/nodes/color-adjust-node.tsx components/canvas/nodes/light-adjust-node.tsx components/canvas/nodes/curves-node.tsx components/canvas/nodes/detail-adjust-node.tsx components/canvas/__tests__/use-node-local-data-preview-overrides.test.tsx
+git commit -m "feat(canvas): mirror local adjustment state into preview graph"
+```
+
+### Task 3: Make downstream previews and the render node react to local overlay changes immediately
+
+**Files:**
+- Modify: `components/canvas/nodes/adjustment-preview.tsx`
+- Modify: `components/canvas/nodes/render-node.tsx`
+- Modify: `components/canvas/nodes/compare-node.tsx`
+- Modify: `hooks/use-pipeline-preview.ts`
+- Modify: `tests/use-pipeline-preview.test.ts`
+- Modify: `components/canvas/__tests__/compare-node.test.tsx`
+
+**Step 1: Write the failing test**
+
+```ts
+it("uses a lower debounce while preview overrides are active", async () => {
+  vi.useFakeTimers();
+  workerClientMocks.renderPreviewWithWorkerFallback.mockResolvedValue(createPreviewResult(100, 80));
+
+  render(
+    <Harness
+      sourceUrl="https://cdn.example.com/source.png"
+      steps={createLightAdjustSteps(10)}
+      previewDebounceMs={16}
+    />,
+  );
+
+  await act(async () => {
+    vi.advanceTimersByTime(17);
+  });
+
+  expect(workerClientMocks.renderPreviewWithWorkerFallback).toHaveBeenCalledTimes(1);
+});
+```
+
+**Step 2: Run test to verify it fails**
+
+Run: `pnpm test tests/use-pipeline-preview.test.ts`
+Expected: FAIL because `usePipelinePreview` has a fixed 48ms debounce.
+
+**Step 3: Write minimal implementation**
+
+Extend the hook options:
+
+```ts
+type UsePipelinePreviewOptions = {
+  // existing fields
+  debounceMs?: number;
+};
+```
+
+Use it in the timeout:
+
+```ts
+const renderDebounceMs = Math.max(0, options.debounceMs ?? PREVIEW_RENDER_DEBOUNCE_MS);
+const timer = window.setTimeout(runPreview, renderDebounceMs);
+```
+
+Then in preview consumers derive the hot-path value from preview overrides:
+
+```tsx
+const { hasPreviewOverrides } = useCanvasGraphPreviewOverrides();
+
+usePipelinePreview({
+  sourceUrl,
+  steps,
+  nodeWidth,
+  debounceMs: hasPreviewOverrides ? 16 : undefined,
+});
+```
+
+This keeps the slower debounce for passive updates but lowers it during active local edits.
+
+**Step 4: Run tests to verify they pass**
+
+Run:
+- `pnpm test tests/use-pipeline-preview.test.ts`
+- `pnpm test components/canvas/__tests__/compare-node.test.tsx`
+
+Expected: PASS
+
+**Step 5: Commit**
+
+```bash
+git add components/canvas/nodes/adjustment-preview.tsx components/canvas/nodes/render-node.tsx components/canvas/nodes/compare-node.tsx hooks/use-pipeline-preview.ts tests/use-pipeline-preview.test.ts components/canvas/__tests__/compare-node.test.tsx
+git commit -m "feat(canvas): prioritize local preview updates in downstream nodes"
+```
+
+### Task 4: Defer non-critical histogram work during active local edits
+
+**Files:**
+- Modify: `components/canvas/nodes/adjustment-preview.tsx`
+- Modify: `hooks/use-pipeline-preview.ts`
+- Modify: `tests/use-pipeline-preview.test.ts`
+
+**Step 1: Write the failing test**
+
+```ts
+it("skips histogram work while local preview overrides are active", async () => {
+  render(
+    <Harness
+      sourceUrl="https://cdn.example.com/source.png"
+      steps={createLightAdjustSteps(10)}
+      includeHistogram={false}
+    />,
+  );
+
+  await act(async () => {
+    vi.advanceTimersByTime(20);
+  });
+
+  expect(workerClientMocks.renderPreviewWithWorkerFallback).toHaveBeenCalledWith(
+    expect.objectContaining({ includeHistogram: false }),
+  );
+});
+```
+
+**Step 2: Run test to verify it fails**
+
+Run: `pnpm test tests/use-pipeline-preview.test.ts`
+Expected: FAIL if adjustment previews still always request histograms during active edits.
+
+**Step 3: Write minimal implementation**
+
+During active local preview overrides, let small adjustment previews omit histograms:
+
+```tsx
+const includeHistogram = !hasPreviewOverrides;
+
+usePipelinePreview({
+  sourceUrl,
+  steps,
+  nodeWidth,
+  includeHistogram,
+  debounceMs: hasPreviewOverrides ? 16 : undefined,
+});
+```
+
+Keep the render node fullscreen preview on `includeHistogram: false` as it is today; keep the inline render preview behavior unchanged unless measurements show it is still too slow.
+
+**Step 4: Run tests to verify they pass**
+
+Run: `pnpm test tests/use-pipeline-preview.test.ts`
+Expected: PASS
+
+**Step 5: Commit**
+
+```bash
+git add components/canvas/nodes/adjustment-preview.tsx hooks/use-pipeline-preview.ts tests/use-pipeline-preview.test.ts
+git commit -m "perf(canvas): defer histogram work during active preview edits"
+```
+
+### Task 5: Final verification and manual latency check
+
+**Files:**
+- Modify: `docs/plans/2026-04-05-preview-graph-architecture.md`
+
+**Step 1: Run the focused automated test set**
+
+Run:
+
+```bash
+pnpm test tests/canvas-render-preview.test.ts \
+  components/canvas/__tests__/use-node-local-data-preview-overrides.test.tsx \
+  tests/use-pipeline-preview.test.ts \
+  components/canvas/__tests__/compare-node.test.tsx \
+  tests/worker-client.test.ts \
+  tests/image-pipeline/backend-capabilities.test.ts \
+  tests/image-pipeline/backend-router.test.ts \
+  tests/image-pipeline/webgl-backend-poc.test.ts \
+  tests/preview-renderer.test.ts
+```
+
+Expected: PASS
+
+**Step 2: Run the full suite**
+
+Run: `pnpm test`
+Expected: PASS
+
+**Step 3: Manual verification in browser**
+
+Check that:
+- downstream previews update visibly during dragging without waiting for persisted sync
+- the active adjustment preview responds near-immediately and skips histogram work while dragging
+- WebGL-backed adjustments (`light-adjust`, `detail-adjust`, repaired `curves`/`color-adjust`) remain visually responsive
+- deleting a connected middle node no longer triggers a stray `edges:create` failure
+
+**Step 4: Update the plan with measured before/after latency notes**
+
+Add a short bullet list with measured timings and any follow-up work that remains.
+
+**Step 5: Commit**
+
+```bash
+git add docs/plans/2026-04-05-preview-graph-architecture.md
+git commit -m "docs: record preview graph architecture verification"
+```
+
+---
+
+## Verification Notes
+
+- Focused preview architecture suite passed: `45/45` tests.
+- Full suite passed in the worktree: `121/121` tests.
+- Baseline harness fixes were required for `compare-node` and `light-adjust-node` tests after `CanvasGraphProvider` became mandatory for node-local preview state.
+- Manual browser verification is still recommended for before/after latency numbers with `window.__LEMONSPACE_DEBUG_PREVIEW_LATENCY__ = true`.
--- a/hooks/use-debounced-callback.ts
+++ b/hooks/use-debounced-callback.ts
@@ -1,5 +1,10 @@
 import { useRef, useCallback, useEffect } from "react";

+type DebouncedCallback<Args extends unknown[]> = ((...args: Args) => void) & {
+  flush: () => void;
+  cancel: () => void;
+};
+
 /**
 * Debounced callback — ruft `callback` erst auf, wenn `delay` ms
 * ohne erneuten Aufruf vergangen sind. Perfekt für Auto-Save.
@@ -7,9 +12,10 @@ import { useRef, useCallback, useEffect } from "react";
 export function useDebouncedCallback<Args extends unknown[]>(
  callback: (...args: Args) => void,
  delay: number,
-): (...args: Args) => void {
+): DebouncedCallback<Args> {
  const timeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
  const callbackRef = useRef(callback);
+  const argsRef = useRef<Args | null>(null);

  // Callback-Ref aktuell halten ohne neu zu rendern
  useEffect(() => {
@@ -23,15 +29,49 @@ export function useDebouncedCallback<Args extends unknown[]>(
    };
  }, []);

+  const cancel = useCallback(() => {
+    if (timeoutRef.current) {
+      clearTimeout(timeoutRef.current);
+      timeoutRef.current = null;
+    }
+
+    argsRef.current = null;
+  }, []);
+
+  const flush = useCallback(() => {
+    if (!timeoutRef.current) {
+      return;
+    }
+
+    clearTimeout(timeoutRef.current);
+    timeoutRef.current = null;
+
+    const args = argsRef.current;
+    argsRef.current = null;
+    if (args) {
+      callbackRef.current(...args);
+    }
+  }, []);
+
  const debouncedFn = useCallback(
    (...args: Args) => {
+      argsRef.current = args;
      if (timeoutRef.current) clearTimeout(timeoutRef.current);
      timeoutRef.current = setTimeout(() => {
-        callbackRef.current(...args);
+        timeoutRef.current = null;
+        const nextArgs = argsRef.current;
+        argsRef.current = null;
+        if (nextArgs) {
+          callbackRef.current(...nextArgs);
+        }
      }, delay);
    },
    [delay],
  );

-  return debouncedFn;
+  const debouncedCallback = debouncedFn as DebouncedCallback<Args>;
+  debouncedCallback.flush = flush;
+  debouncedCallback.cancel = cancel;
+
+  return debouncedCallback;
 }
--- a/hooks/use-pipeline-preview.ts
+++ b/hooks/use-pipeline-preview.ts
@@ -5,7 +5,6 @@ import { useEffect, useMemo, useRef, useState } from "react";
 import { hashPipeline, type PipelineStep } from "@/lib/image-pipeline/contracts";
 import { emptyHistogram, type HistogramData } from "@/lib/image-pipeline/histogram";
 import {
-  getLastBackendDiagnostics,
  isPipelineAbortError,
  renderPreviewWithWorkerFallback,
  type PreviewRenderResult,
@@ -19,50 +18,11 @@ type UsePipelinePreviewOptions = {
  previewScale?: number;
  maxPreviewWidth?: number;
  maxDevicePixelRatio?: number;
+  debounceMs?: number;
 };

 const PREVIEW_RENDER_DEBOUNCE_MS = 48;

-type PreviewLatencyTrace = {
-  sequence: number;
-  changedAtMs: number;
-  nodeType: string;
-  origin: string;
-};
-
-function readPreviewLatencyTrace(): PreviewLatencyTrace | null {
-  if (process.env.NODE_ENV === "production") {
-    return null;
-  }
-
-  const debugGlobals = globalThis as typeof globalThis & {
-    __LEMONSPACE_DEBUG_PREVIEW_LATENCY__?: boolean;
-    __LEMONSPACE_LAST_PREVIEW_TRACE__?: PreviewLatencyTrace;
-  };
-
-  if (debugGlobals.__LEMONSPACE_DEBUG_PREVIEW_LATENCY__ !== true) {
-    return null;
-  }
-
-  return debugGlobals.__LEMONSPACE_LAST_PREVIEW_TRACE__ ?? null;
-}
-
-function logPreviewLatency(event: string, payload: Record<string, unknown>): void {
-  if (process.env.NODE_ENV === "production") {
-    return;
-  }
-
-  const debugGlobals = globalThis as typeof globalThis & {
-    __LEMONSPACE_DEBUG_PREVIEW_LATENCY__?: boolean;
-  };
-
-  if (debugGlobals.__LEMONSPACE_DEBUG_PREVIEW_LATENCY__ !== true) {
-    return;
-  }
-
-  console.info("[Preview latency]", event, payload);
-}
-
 function computePreviewWidth(
  nodeWidth: number,
  previewScale: number,
@@ -121,6 +81,14 @@ export function usePipelinePreview(options: UsePipelinePreviewOptions): {
    return Math.max(1, options.maxDevicePixelRatio);
  }, [options.maxDevicePixelRatio]);

+  const debounceMs = useMemo(() => {
+    if (typeof options.debounceMs !== "number" || !Number.isFinite(options.debounceMs)) {
+      return PREVIEW_RENDER_DEBOUNCE_MS;
+    }
+
+    return Math.max(0, Math.round(options.debounceMs));
+  }, [options.debounceMs]);
+
  const previewWidth = useMemo(
    () => computePreviewWidth(options.nodeWidth, previewScale, maxPreviewWidth, maxDevicePixelRatio),
    [maxDevicePixelRatio, maxPreviewWidth, options.nodeWidth, previewScale],
@@ -161,23 +129,8 @@ export function usePipelinePreview(options: UsePipelinePreviewOptions): {
    const currentRun = runIdRef.current + 1;
    runIdRef.current = currentRun;
    const abortController = new AbortController();
-    const effectStartedAtMs = performance.now();

    const timer = window.setTimeout(() => {
-      const requestStartedAtMs = performance.now();
-      const trace = readPreviewLatencyTrace();
-
-      logPreviewLatency("request-start", {
-        currentRun,
-        pipelineHash,
-        previewWidth,
-        includeHistogram: options.includeHistogram !== false,
-        debounceWaitMs: requestStartedAtMs - effectStartedAtMs,
-        sinceChangeMs: trace ? requestStartedAtMs - trace.changedAtMs : null,
-        sourceNodeType: trace?.nodeType ?? null,
-        sourceOrigin: trace?.origin ?? null,
-      });
-
      setIsRendering(true);
      setError(null);
      void renderPreviewWithWorkerFallback({
@@ -200,20 +153,8 @@ export function usePipelinePreview(options: UsePipelinePreviewOptions): {
            return;
          }
          context.putImageData(result.imageData, 0, 0);
-          const paintedAtMs = performance.now();
          setHistogram(result.histogram);
          setPreviewAspectRatio(result.width / result.height);
-
-          logPreviewLatency("paint-end", {
-            currentRun,
-            pipelineHash,
-            previewWidth,
-            imageWidth: result.width,
-            imageHeight: result.height,
-            requestDurationMs: paintedAtMs - requestStartedAtMs,
-            sinceChangeMs: trace ? paintedAtMs - trace.changedAtMs : null,
-            diagnostics: getLastBackendDiagnostics(),
-          });
        })
        .catch((renderError: unknown) => {
          if (runIdRef.current !== currentRun) return;
@@ -231,7 +172,6 @@ export function usePipelinePreview(options: UsePipelinePreviewOptions): {
              pipelineHash,
              previewWidth,
              includeHistogram: options.includeHistogram,
-              diagnostics: getLastBackendDiagnostics(),
              error: renderError,
            });
          }
@@ -242,13 +182,13 @@ export function usePipelinePreview(options: UsePipelinePreviewOptions): {
          if (runIdRef.current !== currentRun) return;
          setIsRendering(false);
        });
-    }, PREVIEW_RENDER_DEBOUNCE_MS);
+    }, debounceMs);

    return () => {
      window.clearTimeout(timer);
      abortController.abort();
    };
-  }, [options.includeHistogram, pipelineHash, previewWidth]);
+  }, [debounceMs, options.includeHistogram, pipelineHash, previewWidth]);

  return {
    canvasRef,
--- a/lib/canvas-render-preview.ts
+++ b/lib/canvas-render-preview.ts
@@ -38,6 +38,65 @@ export type CanvasGraphSnapshot = {
  incomingEdgesByTarget: ReadonlyMap<string, readonly CanvasGraphEdgeLike[]>;
 };

+export type CanvasGraphNodeDataOverrides = ReadonlyMap<string, unknown>;
+
+export function shouldFastPathPreviewPipeline(
+  steps: readonly Pick<PipelineStep, "nodeId">[],
+  overrides: CanvasGraphNodeDataOverrides,
+): boolean {
+  if (steps.length === 0 || overrides.size === 0) {
+    return false;
+  }
+
+  return steps.some((step) => overrides.has(step.nodeId));
+}
+
+export type BuildGraphSnapshotOptions = {
+  includeTempEdges?: boolean;
+  nodeDataOverrides?: CanvasGraphNodeDataOverrides;
+};
+
+function hashNodeData(value: unknown): string {
+  return JSON.stringify(value);
+}
+
+function pruneNodeDataOverride(data: unknown, override: unknown): unknown {
+  return hashNodeData(data) === hashNodeData(override) ? undefined : override;
+}
+
+export function pruneCanvasGraphNodeDataOverrides(
+  nodes: readonly CanvasGraphNodeLike[],
+  overrides: CanvasGraphNodeDataOverrides,
+): CanvasGraphNodeDataOverrides {
+  if (overrides.size === 0) {
+    return overrides;
+  }
+
+  const nodesById = new Map(nodes.map((node) => [node.id, node]));
+  let nextOverrides: Map<string, unknown> | null = null;
+
+  for (const [nodeId, override] of overrides) {
+    const node = nodesById.get(nodeId);
+    const nextOverride = node ? pruneNodeDataOverride(node.data, override) : undefined;
+
+    if (nextOverride === undefined) {
+      nextOverrides ??= new Map(overrides);
+      nextOverrides.delete(nodeId);
+      continue;
+    }
+
+    if (nextOverride !== override && !nextOverrides) {
+      nextOverrides = new Map(overrides);
+    }
+
+    if (nextOverrides) {
+      nextOverrides.set(nodeId, nextOverride);
+    }
+  }
+
+  return nextOverrides ?? overrides;
+}
+
 type RenderResolutionOption = "original" | "2x" | "custom";
 type RenderFormatOption = "png" | "jpeg" | "webp";

@@ -135,11 +194,17 @@ export function resolveNodeImageUrl(data: unknown): string | null {
 export function buildGraphSnapshot(
  nodes: readonly CanvasGraphNodeLike[],
  edges: readonly CanvasGraphEdgeLike[],
-  includeTempEdges = false,
+  options: boolean | BuildGraphSnapshotOptions = false,
 ): CanvasGraphSnapshot {
+  const includeTempEdges =
+    typeof options === "boolean" ? options : (options.includeTempEdges ?? false);
+  const nodeDataOverrides = typeof options === "boolean" ? undefined : options.nodeDataOverrides;
  const nodesById = new Map<string, CanvasGraphNodeLike>();
  for (const node of nodes) {
-    nodesById.set(node.id, node);
+    const nextNode = nodeDataOverrides?.has(node.id)
+      ? { ...node, data: nodeDataOverrides.get(node.id) }
+      : node;
+    nodesById.set(node.id, nextNode);
  }

  const incomingEdgesByTarget = new Map<string, CanvasGraphEdgeLike[]>();
--- a/lib/image-pipeline/backend/backend-router.ts
+++ b/lib/image-pipeline/backend/backend-router.ts
@@ -65,14 +65,6 @@ function normalizeBackendHint(value: BackendHint): string | null {
  return normalized.length > 0 ? normalized : null;
 }

-function logBackendRouterDebug(event: string, payload: Record<string, unknown>): void {
-  if (process.env.NODE_ENV === "production" || process.env.NODE_ENV === "test") {
-    return;
-  }
-
-  console.info("[image-pipeline backend]", event, payload);
-}
-
 export function createBackendRouter(options?: {
  backends?: readonly ImagePipelineBackend[];
  defaultBackendId?: string;
@@ -131,12 +123,6 @@ export function createBackendRouter(options?: {
  }

  function emitFallback(event: BackendFallbackEvent): void {
-    logBackendRouterDebug("fallback", {
-      reason: event.reason,
-      requestedBackend: event.requestedBackend,
-      fallbackBackend: event.fallbackBackend,
-      errorMessage: event.error?.message,
-    });
    options?.onFallback?.(event);
  }

@@ -365,15 +351,6 @@ export function getPreviewBackendHintForSteps(steps: readonly PreviewBackendRequ
    backendHint = CPU_BACKEND_ID;
  }

-  logBackendRouterDebug("preview-backend-hint", {
-    backendHint,
-    stepTypes: steps.map((step) => step.type),
-    webglAvailable: rolloutState.webglAvailable,
-    webglEnabled: rolloutState.webglEnabled,
-    wasmAvailable: rolloutState.wasmAvailable,
-    wasmEnabled: rolloutState.wasmEnabled,
-  });
-
  return backendHint;
 }

--- a/lib/image-pipeline/backend/webgl/webgl-backend.ts
+++ b/lib/image-pipeline/backend/webgl/webgl-backend.ts
@@ -4,8 +4,11 @@ import type {
  ImagePipelineBackend,
 } from "@/lib/image-pipeline/backend/backend-types";
 import {
+  normalizeColorAdjustData,
+  normalizeCurvesData,
  normalizeDetailAdjustData,
  normalizeLightAdjustData,
+  type CurvePoint,
 } from "@/lib/image-pipeline/adjustment-types";
 import type { PipelineStep } from "@/lib/image-pipeline/contracts";

@@ -14,12 +17,47 @@ precision mediump float;

 varying vec2 vUv;
 uniform sampler2D uSource;
-uniform float uGamma;
+uniform sampler2D uRgbLut;
+uniform sampler2D uRedLut;
+uniform sampler2D uGreenLut;
+uniform sampler2D uBlueLut;
+uniform float uBlackPoint;
+uniform float uWhitePoint;
+uniform float uInvGamma;
+uniform float uChannelMode;
+
+float sampleLut(sampler2D lut, float value) {
+  return texture2D(lut, vec2(clamp(value, 0.0, 1.0), 0.5)).r;
+}

 void main() {
  vec4 color = texture2D(uSource, vUv);
-  color.rgb = pow(max(color.rgb, vec3(0.0)), vec3(max(uGamma, 0.001)));
-  gl_FragColor = color;
+  float levelRange = max(uWhitePoint - uBlackPoint, 1.0);
+  vec3 leveled = clamp((color.rgb * 255.0 - vec3(uBlackPoint)) / levelRange, 0.0, 1.0);
+  vec3 mapped = pow(max(leveled, vec3(0.0)), vec3(max(uInvGamma, 0.001)));
+
+  vec3 rgbCurve = vec3(
+    sampleLut(uRgbLut, mapped.r),
+    sampleLut(uRgbLut, mapped.g),
+    sampleLut(uRgbLut, mapped.b)
+  );
+
+  vec3 result = rgbCurve;
+  if (uChannelMode < 0.5) {
+    result = vec3(
+      sampleLut(uRedLut, rgbCurve.r),
+      sampleLut(uGreenLut, rgbCurve.g),
+      sampleLut(uBlueLut, rgbCurve.b)
+    );
+  } else if (uChannelMode < 1.5) {
+    result.r = sampleLut(uRedLut, rgbCurve.r);
+  } else if (uChannelMode < 2.5) {
+    result.g = sampleLut(uGreenLut, rgbCurve.g);
+  } else {
+    result.b = sampleLut(uBlueLut, rgbCurve.b);
+  }
+
+  gl_FragColor = vec4(result, color.a);
 }
 `;

@@ -28,12 +66,84 @@ precision mediump float;

 varying vec2 vUv;
 uniform sampler2D uSource;
-uniform vec3 uColorShift;
+uniform float uHueShift;
+uniform float uSaturationFactor;
+uniform float uLuminanceShift;
+uniform float uTemperatureShift;
+uniform float uTintShift;
+uniform float uVibranceBoost;
+
+vec3 rgbToHsl(vec3 color) {
+  float maxChannel = max(max(color.r, color.g), color.b);
+  float minChannel = min(min(color.r, color.g), color.b);
+  float delta = maxChannel - minChannel;
+  float lightness = (maxChannel + minChannel) * 0.5;
+
+  if (delta == 0.0) {
+    return vec3(0.0, 0.0, lightness);
+  }
+
+  float saturation = delta / (1.0 - abs(2.0 * lightness - 1.0));
+  float hue;
+
+  if (maxChannel == color.r) {
+    hue = mod((color.g - color.b) / delta, 6.0);
+  } else if (maxChannel == color.g) {
+    hue = (color.b - color.r) / delta + 2.0;
+  } else {
+    hue = (color.r - color.g) / delta + 4.0;
+  }
+
+  hue *= 60.0;
+  if (hue < 0.0) {
+    hue += 360.0;
+  }
+
+  return vec3(hue, saturation, lightness);
+}
+
+vec3 hslToRgb(float hue, float saturation, float lightness) {
+  float chroma = (1.0 - abs(2.0 * lightness - 1.0)) * saturation;
+  float x = chroma * (1.0 - abs(mod(hue / 60.0, 2.0) - 1.0));
+  float m = lightness - chroma * 0.5;
+  vec3 rgbPrime;
+
+  if (hue < 60.0) {
+    rgbPrime = vec3(chroma, x, 0.0);
+  } else if (hue < 120.0) {
+    rgbPrime = vec3(x, chroma, 0.0);
+  } else if (hue < 180.0) {
+    rgbPrime = vec3(0.0, chroma, x);
+  } else if (hue < 240.0) {
+    rgbPrime = vec3(0.0, x, chroma);
+  } else if (hue < 300.0) {
+    rgbPrime = vec3(x, 0.0, chroma);
+  } else {
+    rgbPrime = vec3(chroma, 0.0, x);
+  }
+
+  return clamp(rgbPrime + vec3(m), 0.0, 1.0);
+}

 void main() {
  vec4 color = texture2D(uSource, vUv);
-  color.rgb = clamp(color.rgb + uColorShift, 0.0, 1.0);
-  gl_FragColor = color;
+  vec3 hsl = rgbToHsl(color.rgb);
+  float shiftedHue = mod(hsl.x + uHueShift + 360.0, 360.0);
+  float shiftedSaturation = clamp(hsl.y * uSaturationFactor, 0.0, 1.0);
+  float shiftedLuminance = clamp(hsl.z + uLuminanceShift, 0.0, 1.0);
+  float saturationDelta = (1.0 - hsl.y) * uVibranceBoost;
+  vec3 vivid = hslToRgb(
+    shiftedHue,
+    clamp(shiftedSaturation + saturationDelta, 0.0, 1.0),
+    shiftedLuminance
+  );
+
+  vec3 shiftedBytes = vivid * 255.0;
+  shiftedBytes.r += uTemperatureShift;
+  shiftedBytes.g += uTintShift;
+  shiftedBytes.b -= uTemperatureShift + uTintShift * 0.3;
+
+  gl_FragColor = vec4(clamp(shiftedBytes / 255.0, 0.0, 1.0), color.a);
 }
 `;

@@ -172,12 +282,77 @@ const SUPPORTED_PREVIEW_STEP_TYPES = new Set<SupportedPreviewStepType>([
  "detail-adjust",
 ]);

-function logWebglBackendDebug(event: string, payload: Record<string, unknown>): void {
-  if (process.env.NODE_ENV === "production" || process.env.NODE_ENV === "test") {
-    return;
+function clamp(value: number, min: number, max: number): number {
+  return Math.max(min, Math.min(max, value));
+}
+
+function toByte(value: number): number {
+  return clamp(Math.round(value), 0, 255);
+}
+
+function buildCurveLut(points: CurvePoint[]): Uint8Array {
+  const lut = new Uint8Array(256);
+  const normalized = [...points].sort((left, right) => left.x - right.x);
+
+  for (let input = 0; input < 256; input += 1) {
+    const first = normalized[0] ?? { x: 0, y: 0 };
+    const last = normalized[normalized.length - 1] ?? { x: 255, y: 255 };
+    if (input <= first.x) {
+      lut[input] = toByte(first.y);
+      continue;
    }

-  console.info("[image-pipeline webgl]", event, payload);
+    if (input >= last.x) {
+      lut[input] = toByte(last.y);
+      continue;
+    }
+
+    for (let index = 1; index < normalized.length; index += 1) {
+      const left = normalized[index - 1]!;
+      const right = normalized[index]!;
+      if (input < left.x || input > right.x) {
+        continue;
+      }
+
+      const span = Math.max(1, right.x - left.x);
+      const progress = (input - left.x) / span;
+      lut[input] = toByte(left.y + (right.y - left.y) * progress);
+      break;
+    }
+  }
+
+  return lut;
+}
+
+function createLutTexture(
+  gl: WebGLRenderingContext,
+  lut: Uint8Array,
+  textureUnit: number,
+): WebGLTexture {
+  const texture = gl.createTexture();
+  if (!texture) {
+    throw new Error("WebGL LUT texture allocation failed.");
+  }
+
+  const rgba = new Uint8Array(256 * 4);
+  for (let index = 0; index < 256; index += 1) {
+    const value = lut[index] ?? 0;
+    const offset = index * 4;
+    rgba[offset] = value;
+    rgba[offset + 1] = value;
+    rgba[offset + 2] = value;
+    rgba[offset + 3] = 255;
+  }
+
+  gl.activeTexture(gl.TEXTURE0 + textureUnit);
+  gl.bindTexture(gl.TEXTURE_2D, texture);
+  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
+  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
+  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
+  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
+  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 256, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, rgba);
+
+  return texture;
 }

 function assertSupportedStep(step: PipelineStep): void {
@@ -279,52 +454,98 @@ function createQuadBuffer(gl: WebGLRenderingContext): WebGLBuffer {
  return quadBuffer;
 }

-function mapCurvesGamma(step: PipelineStep): number {
-  const gamma = (step.params as { levels?: { gamma?: unknown } })?.levels?.gamma;
-  if (typeof gamma === "number" && Number.isFinite(gamma)) {
-    return Math.max(gamma, 0.001);
-  }
-  return 1;
-}
-
-function mapColorShift(step: PipelineStep): [number, number, number] {
-  const params = step.params as {
-    hsl?: { luminance?: unknown };
-    temperature?: unknown;
-    tint?: unknown;
-  };
-
-  const luminance = typeof params?.hsl?.luminance === "number" ? params.hsl.luminance : 0;
-  const temperature = typeof params?.temperature === "number" ? params.temperature : 0;
-  const tint = typeof params?.tint === "number" ? params.tint : 0;
-
-  return [
-    (luminance + temperature) / 255,
-    (luminance + tint) / 255,
-    (luminance - temperature) / 255,
-  ];
-}
-
 function applyStepUniforms(
  gl: WebGLRenderingContext,
  shaderProgram: WebGLProgram,
  request: BackendStepRequest,
-): void {
+): WebGLTexture[] {
+  const disposableTextures: WebGLTexture[] = [];
+
  if (request.step.type === "curves") {
-    const gammaLocation = gl.getUniformLocation(shaderProgram, "uGamma");
-    if (gammaLocation) {
-      gl.uniform1f(gammaLocation, mapCurvesGamma(request.step));
+    const curves = normalizeCurvesData(request.step.params);
+
+    const blackPointLocation = gl.getUniformLocation(shaderProgram, "uBlackPoint");
+    if (blackPointLocation) {
+      gl.uniform1f(blackPointLocation, curves.levels.blackPoint);
    }
-    return;
+
+    const whitePointLocation = gl.getUniformLocation(shaderProgram, "uWhitePoint");
+    if (whitePointLocation) {
+      gl.uniform1f(whitePointLocation, curves.levels.whitePoint);
+    }
+
+    const invGammaLocation = gl.getUniformLocation(shaderProgram, "uInvGamma");
+    if (invGammaLocation) {
+      gl.uniform1f(invGammaLocation, 1 / Math.max(curves.levels.gamma, 0.001));
+    }
+
+    const channelModeLocation = gl.getUniformLocation(shaderProgram, "uChannelMode");
+    if (channelModeLocation) {
+      const channelMode =
+        curves.channelMode === "red"
+          ? 1
+          : curves.channelMode === "green"
+            ? 2
+            : curves.channelMode === "blue"
+              ? 3
+              : 0;
+      gl.uniform1f(channelModeLocation, channelMode);
+    }
+
+    const lutBindings = [
+      { uniform: "uRgbLut", unit: 1, lut: buildCurveLut(curves.points.rgb) },
+      { uniform: "uRedLut", unit: 2, lut: buildCurveLut(curves.points.red) },
+      { uniform: "uGreenLut", unit: 3, lut: buildCurveLut(curves.points.green) },
+      { uniform: "uBlueLut", unit: 4, lut: buildCurveLut(curves.points.blue) },
+    ] as const;
+
+    for (const binding of lutBindings) {
+      const texture = createLutTexture(gl, binding.lut, binding.unit);
+      disposableTextures.push(texture);
+      const location = gl.getUniformLocation(shaderProgram, binding.uniform);
+      if (location) {
+        gl.uniform1i(location, binding.unit);
+      }
+    }
+
+    gl.activeTexture(gl.TEXTURE0);
+    return disposableTextures;
  }

  if (request.step.type === "color-adjust") {
-    const colorShiftLocation = gl.getUniformLocation(shaderProgram, "uColorShift");
-    if (colorShiftLocation) {
-      const [r, g, b] = mapColorShift(request.step);
-      gl.uniform3f(colorShiftLocation, r, g, b);
+    const color = normalizeColorAdjustData(request.step.params);
+
+    const hueShiftLocation = gl.getUniformLocation(shaderProgram, "uHueShift");
+    if (hueShiftLocation) {
+      gl.uniform1f(hueShiftLocation, color.hsl.hue);
    }
-    return;
+
+    const saturationFactorLocation = gl.getUniformLocation(shaderProgram, "uSaturationFactor");
+    if (saturationFactorLocation) {
+      gl.uniform1f(saturationFactorLocation, 1 + color.hsl.saturation / 100);
+    }
+
+    const luminanceShiftLocation = gl.getUniformLocation(shaderProgram, "uLuminanceShift");
+    if (luminanceShiftLocation) {
+      gl.uniform1f(luminanceShiftLocation, color.hsl.luminance / 100);
+    }
+
+    const temperatureShiftLocation = gl.getUniformLocation(shaderProgram, "uTemperatureShift");
+    if (temperatureShiftLocation) {
+      gl.uniform1f(temperatureShiftLocation, color.temperature * 0.6);
+    }
+
+    const tintShiftLocation = gl.getUniformLocation(shaderProgram, "uTintShift");
+    if (tintShiftLocation) {
+      gl.uniform1f(tintShiftLocation, color.tint * 0.4);
+    }
+
+    const vibranceBoostLocation = gl.getUniformLocation(shaderProgram, "uVibranceBoost");
+    if (vibranceBoostLocation) {
+      gl.uniform1f(vibranceBoostLocation, color.vibrance / 100);
+    }
+
+    return disposableTextures;
  }

  if (request.step.type === "light-adjust") {
@@ -378,7 +599,7 @@ function applyStepUniforms(
    if (vignetteRoundnessLocation) {
      gl.uniform1f(vignetteRoundnessLocation, light.vignette.roundness);
    }
-    return;
+    return disposableTextures;
  }

  if (request.step.type === "detail-adjust") {
@@ -419,6 +640,8 @@ function applyStepUniforms(
      gl.uniform1f(imageWidthLocation, request.width);
    }
  }
+
+  return disposableTextures;
 }

 function runStepOnGpu(context: WebglBackendContext, request: BackendStepRequest): void {
@@ -512,7 +735,7 @@ function runStepOnGpu(context: WebglBackendContext, request: BackendStepRequest)
    gl.uniform1i(sourceLocation, 0);
  }

-  applyStepUniforms(gl, shaderProgram, request);
+  const disposableTextures = applyStepUniforms(gl, shaderProgram, request);

  gl.viewport(0, 0, request.width, request.height);
  gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
@@ -527,14 +750,9 @@ function runStepOnGpu(context: WebglBackendContext, request: BackendStepRequest)
  gl.deleteFramebuffer(framebuffer);
  gl.deleteTexture(sourceTexture);
  gl.deleteTexture(outputTexture);
-
-  logWebglBackendDebug("step-complete", {
-    stepType: request.step.type,
-    width: request.width,
-    height: request.height,
-    totalDurationMs: performance.now() - startedAtMs,
-    readbackDurationMs,
-  });
+  for (const texture of disposableTextures) {
+    gl.deleteTexture(texture);
+  }
 }

 export function isWebglPreviewStepSupported(step: PipelineStep): boolean {
--- a/tests/canvas-delete-handlers.test.ts
+++ b/tests/canvas-delete-handlers.test.ts
@@ -0,0 +1,135 @@
+// @vitest-environment jsdom
+
+import React, { act, useEffect, useRef, useState } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import type { Edge as RFEdge, Node as RFNode } from "@xyflow/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import type { Id } from "@/convex/_generated/dataModel";
+import { useCanvasDeleteHandlers } from "@/components/canvas/canvas-delete-handlers";
+
+vi.mock("@/lib/toast", () => ({
+  toast: {
+    info: vi.fn(),
+    warning: vi.fn(),
+  },
+}));
+
+const asCanvasId = (id: string): Id<"canvases"> => id as Id<"canvases">;
+
+const latestHandlersRef: {
+  current: ReturnType<typeof useCanvasDeleteHandlers> | null;
+} = { current: null };
+
+(globalThis as typeof globalThis & { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+type HarnessProps = {
+  nodes: RFNode[];
+  edges: RFEdge[];
+  runBatchRemoveNodesMutation: ReturnType<typeof vi.fn>;
+  runCreateEdgeMutation: ReturnType<typeof vi.fn>;
+};
+
+function HookHarness(props: HarnessProps) {
+  const deletingNodeIds = useRef(new Set<string>());
+  const [, setAssetBrowserTargetNodeId] = useState<string | null>(null);
+
+  const handlers = useCanvasDeleteHandlers({
+    t: ((key: string, values?: Record<string, unknown>) =>
+      values ? `${key}:${JSON.stringify(values)}` : key) as never,
+    canvasId: asCanvasId("canvas-1"),
+    nodes: props.nodes,
+    edges: props.edges,
+    deletingNodeIds,
+    setAssetBrowserTargetNodeId,
+    runBatchRemoveNodesMutation: props.runBatchRemoveNodesMutation,
+    runCreateEdgeMutation: props.runCreateEdgeMutation,
+    runRemoveEdgeMutation: vi.fn(async () => undefined),
+  });
+
+  useEffect(() => {
+    latestHandlersRef.current = handlers;
+  }, [handlers]);
+
+  return null;
+}
+
+describe("useCanvasDeleteHandlers", () => {
+  let container: HTMLDivElement | null = null;
+  let root: Root | null = null;
+
+  afterEach(async () => {
+    latestHandlersRef.current = null;
+    vi.clearAllMocks();
+    if (root) {
+      await act(async () => {
+        root?.unmount();
+      });
+    }
+    container?.remove();
+    root = null;
+    container = null;
+  });
+
+  it("creates bridge edges only after batch node removal resolves", async () => {
+    let resolveBatchRemove: (() => void) | null = null;
+    const runBatchRemoveNodesMutation = vi.fn(
+      () =>
+        new Promise<void>((resolve) => {
+          resolveBatchRemove = resolve;
+        }),
+    );
+    const runCreateEdgeMutation = vi.fn(async () => undefined);
+
+    const imageNode: RFNode = { id: "node-image", type: "image", position: { x: 0, y: 0 }, data: {} };
+    const deletedNode: RFNode = {
+      id: "node-color",
+      type: "color-adjust",
+      position: { x: 200, y: 0 },
+      data: {},
+    };
+    const renderNode: RFNode = { id: "node-render", type: "render", position: { x: 400, y: 0 }, data: {} };
+
+    const edges: RFEdge[] = [
+      { id: "edge-in", source: "node-image", target: "node-color" },
+      { id: "edge-out", source: "node-color", target: "node-render" },
+    ];
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        React.createElement(HookHarness, {
+          nodes: [imageNode, deletedNode, renderNode],
+          edges,
+          runBatchRemoveNodesMutation,
+          runCreateEdgeMutation,
+        }),
+      );
+    });
+
+    await act(async () => {
+      latestHandlersRef.current?.onNodesDelete([deletedNode]);
+    });
+
+    expect(runBatchRemoveNodesMutation).toHaveBeenCalledWith({
+      nodeIds: ["node-color"],
+    });
+    expect(runCreateEdgeMutation).not.toHaveBeenCalled();
+
+    await act(async () => {
+      resolveBatchRemove?.();
+      await Promise.resolve();
+    });
+
+    expect(runCreateEdgeMutation).toHaveBeenCalledWith({
+      canvasId: "canvas-1",
+      sourceNodeId: "node-image",
+      targetNodeId: "node-render",
+      sourceHandle: undefined,
+      targetHandle: undefined,
+    });
+  });
+});
--- a/tests/image-pipeline/parity/fixtures.ts
+++ b/tests/image-pipeline/parity/fixtures.ts
@@ -85,14 +85,14 @@ export const parityTolerances: Record<ParityPipelineKey, ParityTolerance> = {
    spatialRmse: 52.5,
  },
  colorAdjustPressure: {
-    maxChannelDelta: 203,
-    histogramSimilarity: 0.17,
-    spatialRmse: 75.8,
+    maxChannelDelta: 64,
+    histogramSimilarity: 0.5,
+    spatialRmse: 24,
  },
  curvesColorPressureChain: {
-    maxChannelDelta: 203,
-    histogramSimilarity: 0.18,
-    spatialRmse: 75.5,
+    maxChannelDelta: 96,
+    histogramSimilarity: 0.35,
+    spatialRmse: 36,
  },
 };

@@ -402,10 +402,10 @@ function createEmptyTexture(width: number, height: number): FakeTexture {
 }

 function inferShaderKind(source: string): ShaderKind {
-  if (source.includes("uGamma")) {
+  if (source.includes("uInvGamma") || source.includes("uRgbLut")) {
    return "curves";
  }
-  if (source.includes("uColorShift")) {
+  if (source.includes("uHueShift") || source.includes("uVibranceBoost")) {
    return "color-adjust";
  }
  if (source.includes("uExposureFactor")) {
@@ -428,13 +428,65 @@ function toByte(value: number): number {
  return Math.max(0, Math.min(255, Math.round(value * 255)));
 }

-function runCurvesShader(input: Uint8Array, gamma: number): Uint8Array {
+function sampleLutTexture(texture: FakeTexture | null, value: number): number {
+  if (!texture) {
+    return value;
+  }
+
+  const index = Math.max(0, Math.min(255, Math.round(value * 255)));
+  return texture.data[index * 4] / 255;
+}
+
+function runCurvesShader(
+  input: Uint8Array,
+  uniforms: Map<string, number | [number, number, number]>,
+  textures: {
+    rgb: FakeTexture | null;
+    red: FakeTexture | null;
+    green: FakeTexture | null;
+    blue: FakeTexture | null;
+  },
+): Uint8Array {
  const output = new Uint8Array(input.length);
+  const blackPoint = Number(uniforms.get("uBlackPoint") ?? 0);
+  const whitePoint = Number(uniforms.get("uWhitePoint") ?? 255);
+  const invGamma = Number(uniforms.get("uInvGamma") ?? 1);
+  const channelMode = Number(uniforms.get("uChannelMode") ?? 0);
+  const levelRange = Math.max(1, whitePoint - blackPoint);

  for (let index = 0; index < input.length; index += 4) {
-    const red = Math.pow(Math.max(toNormalized(input[index]), 0), Math.max(gamma, 0.001));
-    const green = Math.pow(Math.max(toNormalized(input[index + 1]), 0), Math.max(gamma, 0.001));
-    const blue = Math.pow(Math.max(toNormalized(input[index + 2]), 0), Math.max(gamma, 0.001));
+    const mappedRed = Math.pow(
+      Math.max(Math.min(((input[index] - blackPoint) / levelRange), 1), 0),
+      Math.max(invGamma, 0.001),
+    );
+    const mappedGreen = Math.pow(
+      Math.max(Math.min(((input[index + 1] - blackPoint) / levelRange), 1), 0),
+      Math.max(invGamma, 0.001),
+    );
+    const mappedBlue = Math.pow(
+      Math.max(Math.min(((input[index + 2] - blackPoint) / levelRange), 1), 0),
+      Math.max(invGamma, 0.001),
+    );
+
+    const rgbRed = sampleLutTexture(textures.rgb, mappedRed);
+    const rgbGreen = sampleLutTexture(textures.rgb, mappedGreen);
+    const rgbBlue = sampleLutTexture(textures.rgb, mappedBlue);
+
+    let red = rgbRed;
+    let green = rgbGreen;
+    let blue = rgbBlue;
+
+    if (channelMode < 0.5) {
+      red = sampleLutTexture(textures.red, rgbRed);
+      green = sampleLutTexture(textures.green, rgbGreen);
+      blue = sampleLutTexture(textures.blue, rgbBlue);
+    } else if (channelMode < 1.5) {
+      red = sampleLutTexture(textures.red, rgbRed);
+    } else if (channelMode < 2.5) {
+      green = sampleLutTexture(textures.green, rgbGreen);
+    } else {
+      blue = sampleLutTexture(textures.blue, rgbBlue);
+    }

    output[index] = toByte(red);
    output[index + 1] = toByte(green);
@@ -445,13 +497,98 @@ function runCurvesShader(input: Uint8Array, gamma: number): Uint8Array {
  return output;
 }

-function runColorAdjustShader(input: Uint8Array, shift: [number, number, number]): Uint8Array {
+function rgbToHsl(r: number, g: number, b: number): { h: number; s: number; l: number } {
+  const rn = r / 255;
+  const gn = g / 255;
+  const bn = b / 255;
+  const max = Math.max(rn, gn, bn);
+  const min = Math.min(rn, gn, bn);
+  const delta = max - min;
+  const l = (max + min) / 2;
+  if (delta === 0) {
+    return { h: 0, s: 0, l };
+  }
+
+  const s = delta / (1 - Math.abs(2 * l - 1));
+  let h = 0;
+  if (max === rn) {
+    h = ((gn - bn) / delta) % 6;
+  } else if (max === gn) {
+    h = (bn - rn) / delta + 2;
+  } else {
+    h = (rn - gn) / delta + 4;
+  }
+
+  h *= 60;
+  if (h < 0) {
+    h += 360;
+  }
+
+  return { h, s, l };
+}
+
+function hslToRgb(h: number, s: number, l: number): { r: number; g: number; b: number } {
+  const c = (1 - Math.abs(2 * l - 1)) * s;
+  const x = c * (1 - Math.abs(((h / 60) % 2) - 1));
+  const m = l - c / 2;
+  let rp = 0;
+  let gp = 0;
+  let bp = 0;
+
+  if (h < 60) {
+    rp = c;
+    gp = x;
+  } else if (h < 120) {
+    rp = x;
+    gp = c;
+  } else if (h < 180) {
+    gp = c;
+    bp = x;
+  } else if (h < 240) {
+    gp = x;
+    bp = c;
+  } else if (h < 300) {
+    rp = x;
+    bp = c;
+  } else {
+    rp = c;
+    bp = x;
+  }
+
+  return {
+    r: Math.max(0, Math.min(255, Math.round((rp + m) * 255))),
+    g: Math.max(0, Math.min(255, Math.round((gp + m) * 255))),
+    b: Math.max(0, Math.min(255, Math.round((bp + m) * 255))),
+  };
+}
+
+function runColorAdjustShader(
+  input: Uint8Array,
+  uniforms: Map<string, number | [number, number, number]>,
+): Uint8Array {
  const output = new Uint8Array(input.length);
+  const hueShift = Number(uniforms.get("uHueShift") ?? 0);
+  const saturationFactor = Number(uniforms.get("uSaturationFactor") ?? 1);
+  const luminanceShift = Number(uniforms.get("uLuminanceShift") ?? 0);
+  const temperatureShift = Number(uniforms.get("uTemperatureShift") ?? 0);
+  const tintShift = Number(uniforms.get("uTintShift") ?? 0);
+  const vibranceBoost = Number(uniforms.get("uVibranceBoost") ?? 0);

  for (let index = 0; index < input.length; index += 4) {
-    const red = Math.max(0, Math.min(1, toNormalized(input[index]) + shift[0]));
-    const green = Math.max(0, Math.min(1, toNormalized(input[index + 1]) + shift[1]));
-    const blue = Math.max(0, Math.min(1, toNormalized(input[index + 2]) + shift[2]));
+    const hsl = rgbToHsl(input[index] ?? 0, input[index + 1] ?? 0, input[index + 2] ?? 0);
+    const shiftedHue = (hsl.h + hueShift + 360) % 360;
+    const shiftedSaturation = Math.max(0, Math.min(1, hsl.s * saturationFactor));
+    const shiftedLuminance = Math.max(0, Math.min(1, hsl.l + luminanceShift));
+    const saturationDelta = (1 - hsl.s) * vibranceBoost;
+    const vivid = hslToRgb(
+      shiftedHue,
+      Math.max(0, Math.min(1, shiftedSaturation + saturationDelta)),
+      shiftedLuminance,
+    );
+
+    const red = Math.max(0, Math.min(1, (vivid.r + temperatureShift) / 255));
+    const green = Math.max(0, Math.min(1, (vivid.g + tintShift) / 255));
+    const blue = Math.max(0, Math.min(1, (vivid.b - temperatureShift - tintShift * 0.3) / 255));

    output[index] = toByte(red);
    output[index + 1] = toByte(green);
@@ -629,7 +766,8 @@ function createParityWebglContext(): WebGLRenderingContext {
  let currentProgram: FakeProgram | null = null;
  let currentTexture: FakeTexture | null = null;
  let currentFramebuffer: FakeFramebuffer | null = null;
-  let sourceTexture: FakeTexture | null = null;
+  let activeTextureUnit = 0;
+  const boundTextures = new Map<number, FakeTexture | null>();
  let drawWidth = 1;
  let drawHeight = 1;

@@ -693,9 +831,7 @@ function createParityWebglContext(): WebGLRenderingContext {
    },
    bindTexture(_target: number, texture: FakeTexture | null) {
      currentTexture = texture;
-      if (texture) {
-        sourceTexture = texture;
-      }
+      boundTextures.set(activeTextureUnit, texture);
    },
    texParameteri() {},
    texImage2D(
@@ -730,7 +866,9 @@ function createParityWebglContext(): WebGLRenderingContext {
      currentTexture.height = height;
      currentTexture.data = new Uint8Array(width * height * 4);
    },
-    activeTexture() {},
+    activeTexture(textureUnit: number) {
+      activeTextureUnit = textureUnit - glConstants.TEXTURE0;
+    },
    getUniformLocation(program: FakeProgram, name: string) {
      return {
        program,
@@ -774,22 +912,30 @@ function createParityWebglContext(): WebGLRenderingContext {
      drawHeight = height;
    },
    drawArrays() {
+      const sourceTexture = boundTextures.get(0) ?? null;
      if (!currentProgram || !sourceTexture || !currentFramebuffer?.attachment) {
        throw new Error("Parity WebGL mock is missing required render state.");
      }

      if (currentProgram.kind === "curves") {
-        const gamma = Number(currentProgram.uniforms.get("uGamma") ?? 1);
-        currentFramebuffer.attachment.data = runCurvesShader(sourceTexture.data, gamma);
+        const rgbUnit = Number(currentProgram.uniforms.get("uRgbLut") ?? 1);
+        const redUnit = Number(currentProgram.uniforms.get("uRedLut") ?? 2);
+        const greenUnit = Number(currentProgram.uniforms.get("uGreenLut") ?? 3);
+        const blueUnit = Number(currentProgram.uniforms.get("uBlueLut") ?? 4);
+        currentFramebuffer.attachment.data = runCurvesShader(sourceTexture.data, currentProgram.uniforms, {
+          rgb: boundTextures.get(rgbUnit) ?? null,
+          red: boundTextures.get(redUnit) ?? null,
+          green: boundTextures.get(greenUnit) ?? null,
+          blue: boundTextures.get(blueUnit) ?? null,
+        });
        return;
      }

      if (currentProgram.kind === "color-adjust") {
-        const colorShift = currentProgram.uniforms.get("uColorShift");
-        const shift: [number, number, number] = Array.isArray(colorShift)
-          ? [colorShift[0] ?? 0, colorShift[1] ?? 0, colorShift[2] ?? 0]
-          : [0, 0, 0];
-        currentFramebuffer.attachment.data = runColorAdjustShader(sourceTexture.data, shift);
+        currentFramebuffer.attachment.data = runColorAdjustShader(
+          sourceTexture.data,
+          currentProgram.uniforms,
+        );
        return;
      }

@@ -828,7 +974,7 @@ function createParityWebglContext(): WebGLRenderingContext {
        throw new Error("Parity WebGL mock has no framebuffer attachment to read from.");
      }

-      output.set(currentFramebuffer.attachment.data);
+      output.set(currentFramebuffer.attachment.data.subarray(0, output.length));
    },
  };

--- a/tests/image-pipeline/webgl-backend-poc.test.ts
+++ b/tests/image-pipeline/webgl-backend-poc.test.ts
@@ -38,6 +38,41 @@ function createCurvesStep(): PipelineStep {
  };
 }

+function createCurvesPressureStep(): PipelineStep {
+  return {
+    nodeId: "curves-pressure-1",
+    type: "curves",
+    params: {
+      channelMode: "master",
+      levels: {
+        blackPoint: 12,
+        whitePoint: 232,
+        gamma: 2.5,
+      },
+      points: {
+        rgb: [
+          { x: 0, y: 0 },
+          { x: 64, y: 52 },
+          { x: 196, y: 228 },
+          { x: 255, y: 255 },
+        ],
+        red: [
+          { x: 0, y: 0 },
+          { x: 255, y: 255 },
+        ],
+        green: [
+          { x: 0, y: 0 },
+          { x: 255, y: 255 },
+        ],
+        blue: [
+          { x: 0, y: 0 },
+          { x: 255, y: 255 },
+        ],
+      },
+    },
+  };
+}
+
 function createColorAdjustStep(): PipelineStep {
  return {
    nodeId: "color-1",
@@ -55,6 +90,23 @@ function createColorAdjustStep(): PipelineStep {
  };
 }

+function createColorAdjustPressureStep(): PipelineStep {
+  return {
+    nodeId: "color-pressure-1",
+    type: "color-adjust",
+    params: {
+      hsl: {
+        hue: 48,
+        saturation: 64,
+        luminance: 18,
+      },
+      temperature: 24,
+      tint: -28,
+      vibrance: 52,
+    },
+  };
+}
+
 function createUnsupportedStep(): PipelineStep {
  return {
    nodeId: "light-1",
@@ -158,7 +210,7 @@ describe("webgl backend poc", () => {
      texParameteri: vi.fn(),
      texImage2D: vi.fn(),
      activeTexture: vi.fn(),
-      getUniformLocation: vi.fn(() => ({ uniform: true })),
+      getUniformLocation: vi.fn((_program: unknown, name: string) => ({ uniform: true, name })),
      uniform1i: vi.fn(),
      uniform1f: vi.fn(),
      uniform3f: vi.fn(),
@@ -405,7 +457,7 @@ describe("webgl backend poc", () => {
      .at(-1)?.index;

    expect(lastBindBeforeDrawIndex).toBeTypeOf("number");
-    expect(bindTextureCalls[lastBindBeforeDrawIndex as number]?.[1]).toBe(sourceTexture);
+    expect(bindTextureCalls[lastBindBeforeDrawIndex as number]?.[1]).toStrictEqual(sourceTexture);
    expect(bindTextureCalls[lastBindBeforeDrawIndex as number]?.[1]).not.toBe(outputTexture);
  });

@@ -464,6 +516,90 @@ describe("webgl backend poc", () => {
    expect(fakeGl.uniform1f).toHaveBeenCalledWith(expect.anything(), 7);
  });

+  it("passes curves levels uniforms for non-default curves settings", async () => {
+    const fakeGl = createFakeWebglContext({
+      readbackPixels: new Uint8Array([11, 22, 33, 255]),
+    });
+    vi.spyOn(HTMLCanvasElement.prototype, "getContext").mockImplementation((contextId) => {
+      if (contextId === "webgl") {
+        return fakeGl;
+      }
+      return null;
+    });
+
+    const { createWebglPreviewBackend } = await import("@/lib/image-pipeline/backend/webgl/webgl-backend");
+    const backend = createWebglPreviewBackend();
+
+    backend.runPreviewStep({
+      pixels: new Uint8ClampedArray([200, 100, 50, 255]),
+      step: createCurvesPressureStep(),
+      width: 1,
+      height: 1,
+    });
+
+    expect(fakeGl.uniform1f).toHaveBeenCalledWith(
+      expect.objectContaining({ name: "uBlackPoint" }),
+      12,
+    );
+    expect(fakeGl.uniform1f).toHaveBeenCalledWith(
+      expect.objectContaining({ name: "uWhitePoint" }),
+      232,
+    );
+    expect(fakeGl.uniform1f).toHaveBeenCalledWith(
+      expect.objectContaining({ name: "uInvGamma" }),
+      0.4,
+    );
+  });
+
+  it("passes hue, saturation, luminance, temperature, tint, and vibrance uniforms", async () => {
+    const fakeGl = createFakeWebglContext({
+      readbackPixels: new Uint8Array([11, 22, 33, 255]),
+    });
+    vi.spyOn(HTMLCanvasElement.prototype, "getContext").mockImplementation((contextId) => {
+      if (contextId === "webgl") {
+        return fakeGl;
+      }
+      return null;
+    });
+
+    const { createWebglPreviewBackend } = await import("@/lib/image-pipeline/backend/webgl/webgl-backend");
+    const backend = createWebglPreviewBackend();
+
+    backend.runPreviewStep({
+      pixels: new Uint8ClampedArray([200, 100, 50, 255]),
+      step: createColorAdjustPressureStep(),
+      width: 1,
+      height: 1,
+    });
+
+    const uniform1fCalls = vi.mocked(fakeGl.uniform1f).mock.calls;
+
+    expect(fakeGl.uniform1f).toHaveBeenCalledWith(
+      expect.objectContaining({ name: "uHueShift" }),
+      48,
+    );
+    expect(uniform1fCalls).toContainEqual([
+      expect.objectContaining({ name: "uSaturationFactor" }),
+      expect.closeTo(1.64, 5),
+    ]);
+    expect(uniform1fCalls).toContainEqual([
+      expect.objectContaining({ name: "uLuminanceShift" }),
+      expect.closeTo(0.18, 5),
+    ]);
+    expect(uniform1fCalls).toContainEqual([
+      expect.objectContaining({ name: "uTemperatureShift" }),
+      expect.closeTo(14.4, 5),
+    ]);
+    expect(uniform1fCalls).toContainEqual([
+      expect.objectContaining({ name: "uTintShift" }),
+      expect.closeTo(-11.2, 5),
+    ]);
+    expect(uniform1fCalls).toContainEqual([
+      expect.objectContaining({ name: "uVibranceBoost" }),
+      expect.closeTo(0.52, 5),
+    ]);
+  });
+
  it("downgrades compile/link failures to cpu with runtime_error reason", async () => {
    const { createBackendRouter } = await import("@/lib/image-pipeline/backend/backend-router");
    const { createWebglPreviewBackend } = await import("@/lib/image-pipeline/backend/webgl/webgl-backend");
--- a/tests/light-adjust-node.test.ts
+++ b/tests/light-adjust-node.test.ts
@@ -4,6 +4,7 @@ import { act, createElement } from "react";
 import { createRoot, type Root } from "react-dom/client";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";

+import { CanvasGraphProvider } from "@/components/canvas/canvas-graph-context";
 import { DEFAULT_LIGHT_ADJUST_DATA, type LightAdjustData } from "@/lib/image-pipeline/adjustment-types";

 type ParameterSliderProps = {
@@ -110,6 +111,12 @@ describe("LightAdjustNode", () => {

    const renderNode = (data: LightAdjustData) =>
      root?.render(
+        createElement(
+          CanvasGraphProvider as never,
+          {
+            nodes: [{ id: "light-1", type: "light-adjust", data }],
+            edges: [],
+          } as never,
          createElement(LightAdjustNode, {
            id: "light-1",
            data,
@@ -127,6 +134,7 @@ describe("LightAdjustNode", () => {
            positionAbsoluteX: 0,
            positionAbsoluteY: 0,
          } as never),
+        ),
      );

    await act(async () => {
@@ -183,4 +191,64 @@ describe("LightAdjustNode", () => {
      parameterSliderState.latestProps?.values.find((entry) => entry.id === "brightness")?.value,
    ).toBe(60);
  });
+
+  it("does not trigger a render-phase CanvasGraphProvider update while dragging sliders", async () => {
+    const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    const staleData: LightAdjustData = {
+      ...DEFAULT_LIGHT_ADJUST_DATA,
+      vignette: {
+        ...DEFAULT_LIGHT_ADJUST_DATA.vignette,
+      },
+    };
+
+    const renderNode = (data: LightAdjustData) =>
+      root?.render(
+        createElement(
+          CanvasGraphProvider as never,
+          {
+            nodes: [{ id: "light-1", type: "light-adjust", data }],
+            edges: [],
+          } as never,
+          createElement(LightAdjustNode, {
+            id: "light-1",
+            data,
+            selected: false,
+            dragging: false,
+            zIndex: 0,
+            isConnectable: true,
+            type: "light-adjust",
+            xPos: 0,
+            yPos: 0,
+            width: 320,
+            height: 300,
+            sourcePosition: undefined,
+            targetPosition: undefined,
+            positionAbsoluteX: 0,
+            positionAbsoluteY: 0,
+          } as never),
+        ),
+      );
+
+    await act(async () => {
+      renderNode({ ...staleData, vignette: { ...staleData.vignette } });
+      vi.runOnlyPendingTimers();
+    });
+
+    const sliderProps = parameterSliderState.latestProps;
+    expect(sliderProps).not.toBeNull();
+
+    await act(async () => {
+      sliderProps?.onChange(
+        sliderProps.values.map((entry) =>
+          entry.id === "brightness" ? { ...entry, value: 35 } : entry,
+        ),
+      );
+    });
+
+    expect(consoleErrorSpy).not.toHaveBeenCalledWith(
+      expect.stringContaining(
+        "Cannot update a component (`CanvasGraphProvider`) while rendering a different component",
+      ),
+    );
+  });
 });
--- a/tests/use-node-local-data-order.test.ts
+++ b/tests/use-node-local-data-order.test.ts
@@ -0,0 +1,95 @@
+// @vitest-environment jsdom
+
+import React, { act, useEffect } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+const canvasGraphMock = vi.hoisted(() => ({
+  clearPreviewNodeDataOverride: vi.fn(),
+  setPreviewNodeDataOverride: vi.fn(),
+}));
+
+vi.mock("@/components/canvas/canvas-graph-context", () => ({
+  useCanvasGraphPreviewOverrides: () => canvasGraphMock,
+}));
+
+import { useNodeLocalData } from "@/components/canvas/nodes/use-node-local-data";
+
+type AdjustmentData = {
+  exposure: number;
+};
+
+const latestHookRef: {
+  current:
+    | {
+        updateLocalData: (updater: (current: AdjustmentData) => AdjustmentData) => void;
+      }
+    | null;
+} = { current: null };
+
+function HookHarness() {
+  const { updateLocalData } = useNodeLocalData<AdjustmentData>({
+    nodeId: "node-1",
+    data: { exposure: 0.2 },
+    normalize: (value) => ({ ...(value as AdjustmentData) }),
+    saveDelayMs: 1000,
+    onSave: async () => undefined,
+    debugLabel: "light-adjust",
+  });
+
+  useEffect(() => {
+    latestHookRef.current = { updateLocalData };
+    return () => {
+      latestHookRef.current = null;
+    };
+  }, [updateLocalData]);
+
+  return null;
+}
+
+(globalThis as typeof globalThis & { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+describe("useNodeLocalData ordering", () => {
+  let container: HTMLDivElement | null = null;
+  let root: Root | null = null;
+
+  afterEach(async () => {
+    if (root) {
+      await act(async () => {
+        root?.unmount();
+      });
+    }
+    container?.remove();
+    root = null;
+    container = null;
+    latestHookRef.current = null;
+    canvasGraphMock.clearPreviewNodeDataOverride.mockReset();
+    canvasGraphMock.setPreviewNodeDataOverride.mockReset();
+  });
+
+  it("does not write preview overrides from inside the local state updater", async () => {
+    let overrideWriteStack = "";
+
+    canvasGraphMock.setPreviewNodeDataOverride.mockImplementation(() => {
+      overrideWriteStack = new Error().stack ?? "";
+    });
+
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(React.createElement(HookHarness));
+    });
+
+    await act(async () => {
+      latestHookRef.current?.updateLocalData((current) => ({
+        ...current,
+        exposure: 0.8,
+      }));
+    });
+
+    expect(overrideWriteStack).not.toContain("basicStateReducer");
+    expect(overrideWriteStack).not.toContain("updateReducerImpl");
+  });
+});
--- a/tests/use-pipeline-preview.test.ts
+++ b/tests/use-pipeline-preview.test.ts
@@ -67,16 +67,19 @@ function PreviewHarness({
  sourceUrl,
  steps,
  includeHistogram,
+  debounceMs,
 }: {
  sourceUrl: string | null;
  steps: PipelineStep[];
  includeHistogram?: boolean;
+  debounceMs?: number;
 }) {
  const { canvasRef, histogram, error, isRendering } = usePipelinePreview({
    sourceUrl,
    steps,
    nodeWidth: 320,
    includeHistogram,
+    debounceMs,
  });

  useEffect(() => {
@@ -453,6 +456,33 @@ describe("usePipelinePreview", () => {
      }),
    );
  });
+
+  it("supports a faster debounce override for local preview updates", async () => {
+    await act(async () => {
+      root?.render(
+        createElement(PreviewHarness, {
+          sourceUrl: "https://cdn.example.com/source.png",
+          steps: createLightAdjustSteps(10),
+          includeHistogram: false,
+          debounceMs: 16,
+        }),
+      );
+    });
+
+    await act(async () => {
+      vi.advanceTimersByTime(15);
+      await Promise.resolve();
+    });
+
+    expect(workerClientMocks.renderPreviewWithWorkerFallback).toHaveBeenCalledTimes(0);
+
+    await act(async () => {
+      vi.advanceTimersByTime(1);
+      await Promise.resolve();
+    });
+
+    expect(workerClientMocks.renderPreviewWithWorkerFallback).toHaveBeenCalledTimes(1);
+  });
 });

 describe("preview histogram call sites", () => {
@@ -475,7 +505,7 @@ describe("preview histogram call sites", () => {
    vi.clearAllMocks();
  });

-  it("keeps histogram enabled for AdjustmentPreview", async () => {
+  it("disables histogram for fast-path AdjustmentPreview", async () => {
    const hookSpy = vi.fn(() => ({
      canvasRef: { current: null },
      histogram: emptyHistogram(),
@@ -489,11 +519,78 @@ describe("preview histogram call sites", () => {
      usePipelinePreview: hookSpy,
    }));
    vi.doMock("@/components/canvas/canvas-graph-context", () => ({
-      useCanvasGraph: () => ({ nodes: [], edges: [] }),
+      useCanvasGraph: () => ({
+        nodes: [],
+        edges: [],
+        previewNodeDataOverrides: new Map([["light-1", { brightness: 10 }]]),
+      }),
    }));
    vi.doMock("@/lib/canvas-render-preview", () => ({
-      collectPipelineFromGraph: () => [],
+      collectPipelineFromGraph: () => [
+        {
+          nodeId: "light-1",
+          type: "light-adjust",
+          params: { brightness: 10 },
+        },
+      ],
      getSourceImageFromGraph: () => "https://cdn.example.com/source.png",
+      shouldFastPathPreviewPipeline: (steps: PipelineStep[], overrides: Map<string, unknown>) =>
+        steps.some((step) => overrides.has(step.nodeId)),
+    }));
+
+    const adjustmentPreviewModule = await import("@/components/canvas/nodes/adjustment-preview");
+    const AdjustmentPreview = adjustmentPreviewModule.default;
+
+    await act(async () => {
+      root?.render(
+        createElement(AdjustmentPreview, {
+          nodeId: "light-1",
+          nodeWidth: 320,
+          currentType: "light-adjust",
+          currentParams: { brightness: 10 },
+        }),
+      );
+    });
+
+    expect(hookSpy).toHaveBeenCalledWith(
+      expect.objectContaining({
+        includeHistogram: false,
+        debounceMs: 16,
+      }),
+    );
+  });
+
+  it("does not fast-path AdjustmentPreview when overrides belong to another pipeline", async () => {
+    const hookSpy = vi.fn(() => ({
+      canvasRef: { current: null },
+      histogram: emptyHistogram(),
+      isRendering: false,
+      hasSource: true,
+      previewAspectRatio: 1,
+      error: null,
+    }));
+
+    vi.doMock("@/hooks/use-pipeline-preview", () => ({
+      usePipelinePreview: hookSpy,
+    }));
+    vi.doMock("@/components/canvas/canvas-graph-context", () => ({
+      useCanvasGraph: () => ({
+        nodes: [],
+        edges: [],
+        previewNodeDataOverrides: new Map([["other-node", { brightness: 10 }]]),
+      }),
+    }));
+    vi.doMock("@/lib/canvas-render-preview", () => ({
+      collectPipelineFromGraph: () => [
+        {
+          nodeId: "light-1",
+          type: "light-adjust",
+          params: { brightness: 10 },
+        },
+      ],
+      getSourceImageFromGraph: () => "https://cdn.example.com/source.png",
+      shouldFastPathPreviewPipeline: (steps: PipelineStep[], overrides: Map<string, unknown>) =>
+        steps.some((step) => overrides.has(step.nodeId)),
    }));

    const adjustmentPreviewModule = await import("@/components/canvas/nodes/adjustment-preview");
@@ -513,11 +610,72 @@ describe("preview histogram call sites", () => {
    expect(hookSpy).toHaveBeenCalledWith(
      expect.objectContaining({
        includeHistogram: true,
+        debounceMs: undefined,
      }),
    );
  });

-  it("requests previews without histogram work in CompareSurface and fullscreen RenderNode", async () => {
+  it("keeps histogram enabled for downstream AdjustmentPreview fast path", async () => {
+    const hookSpy = vi.fn(() => ({
+      canvasRef: { current: null },
+      histogram: emptyHistogram(),
+      isRendering: false,
+      hasSource: true,
+      previewAspectRatio: 1,
+      error: null,
+    }));
+
+    vi.doMock("@/hooks/use-pipeline-preview", () => ({
+      usePipelinePreview: hookSpy,
+    }));
+    vi.doMock("@/components/canvas/canvas-graph-context", () => ({
+      useCanvasGraph: () => ({
+        nodes: [],
+        edges: [],
+        previewNodeDataOverrides: new Map([["upstream-node", { brightness: 10 }]]),
+      }),
+    }));
+    vi.doMock("@/lib/canvas-render-preview", () => ({
+      collectPipelineFromGraph: () => [
+        {
+          nodeId: "upstream-node",
+          type: "light-adjust",
+          params: { brightness: 10 },
+        },
+        {
+          nodeId: "light-1",
+          type: "light-adjust",
+          params: { brightness: 20 },
+        },
+      ],
+      getSourceImageFromGraph: () => "https://cdn.example.com/source.png",
+      shouldFastPathPreviewPipeline: (steps: PipelineStep[], overrides: Map<string, unknown>) =>
+        steps.some((step) => overrides.has(step.nodeId)),
+    }));
+
+    const adjustmentPreviewModule = await import("@/components/canvas/nodes/adjustment-preview");
+    const AdjustmentPreview = adjustmentPreviewModule.default;
+
+    await act(async () => {
+      root?.render(
+        createElement(AdjustmentPreview, {
+          nodeId: "light-1",
+          nodeWidth: 320,
+          currentType: "light-adjust",
+          currentParams: { brightness: 20 },
+        }),
+      );
+    });
+
+    expect(hookSpy).toHaveBeenCalledWith(
+      expect.objectContaining({
+        includeHistogram: true,
+        debounceMs: 16,
+      }),
+    );
+  });
+
+  it("requests fast preview rendering without histogram work in CompareSurface and RenderNode", async () => {
    const hookSpy = vi.fn(() => ({
      canvasRef: { current: null },
      histogram: emptyHistogram(),
@@ -570,14 +728,29 @@ describe("preview histogram call sites", () => {
      useDebouncedCallback: (callback: () => void) => callback,
    }));
    vi.doMock("@/components/canvas/canvas-graph-context", () => ({
-      useCanvasGraph: () => ({ nodes: [], edges: [] }),
+      useCanvasGraph: () => ({
+        nodes: [],
+        edges: [],
+        previewNodeDataOverrides: new Map([
+          ["compare-step", { brightness: 20 }],
+          ["render-1-pipeline", { format: "png" }],
+        ]),
+      }),
    }));
    vi.doMock("@/lib/canvas-render-preview", () => ({
      resolveRenderPreviewInputFromGraph: () => ({
        sourceUrl: "https://cdn.example.com/source.png",
-        steps: [],
+        steps: [
+          {
+            nodeId: "render-1-pipeline",
+            type: "light-adjust",
+            params: { brightness: 10 },
+          },
+        ],
      }),
      findSourceNodeFromGraph: () => null,
+      shouldFastPathPreviewPipeline: (steps: PipelineStep[], overrides: Map<string, unknown>) =>
+        steps.some((step) => overrides.has(step.nodeId)),
    }));
    vi.doMock("@/lib/canvas-utils", () => ({
      resolveMediaAspectRatio: () => null,
@@ -616,7 +789,13 @@ describe("preview histogram call sites", () => {
            nodeWidth: 320,
            previewInput: {
              sourceUrl: "https://cdn.example.com/source.png",
-              steps: [],
+              steps: [
+                {
+                  nodeId: "compare-step",
+                  type: "light-adjust",
+                  params: { brightness: 20 },
+                },
+              ],
            },
            preferPreview: true,
          }),
@@ -641,16 +820,229 @@ describe("preview histogram call sites", () => {
      );
    });

-    expect(hookSpy).toHaveBeenCalledWith(
+    expect(hookSpy).toHaveBeenNthCalledWith(
+      1,
      expect.objectContaining({
        includeHistogram: false,
        sourceUrl: "https://cdn.example.com/source.png",
+        steps: [
+          {
+            nodeId: "compare-step",
+            type: "light-adjust",
+            params: { brightness: 20 },
+          },
+        ],
+        debounceMs: 16,
      }),
    );
-    expect(hookSpy).toHaveBeenCalledWith(
+    expect(hookSpy).toHaveBeenNthCalledWith(
+      2,
+      expect.objectContaining({
+        sourceUrl: "https://cdn.example.com/source.png",
+        steps: [
+          {
+            nodeId: "render-1-pipeline",
+            type: "light-adjust",
+            params: { brightness: 10 },
+          },
+        ],
+        debounceMs: 16,
+      }),
+    );
+    expect(hookSpy).toHaveBeenNthCalledWith(
+      3,
      expect.objectContaining({
        includeHistogram: false,
        sourceUrl: null,
+        debounceMs: 16,
+      }),
+    );
+  });
+
+  it("does not fast-path CompareSurface or RenderNode for unrelated overrides", async () => {
+    const hookSpy = vi.fn(() => ({
+      canvasRef: { current: null },
+      histogram: emptyHistogram(),
+      isRendering: false,
+      hasSource: true,
+      previewAspectRatio: 1,
+      error: null,
+    }));
+
+    vi.doMock("@/hooks/use-pipeline-preview", () => ({
+      usePipelinePreview: hookSpy,
+    }));
+    vi.doMock("@xyflow/react", () => ({
+      Handle: () => null,
+      Position: { Left: "left", Right: "right" },
+    }));
+    vi.doMock("convex/react", () => ({
+      useMutation: () => vi.fn(async () => undefined),
+    }));
+    vi.doMock("lucide-react", () => ({
+      AlertCircle: () => null,
+      ArrowDown: () => null,
+      CheckCircle2: () => null,
+      CloudUpload: () => null,
+      Loader2: () => null,
+      Maximize2: () => null,
+      X: () => null,
+    }));
+    vi.doMock("@/components/canvas/nodes/base-node-wrapper", () => ({
+      default: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+    }));
+    vi.doMock("@/components/canvas/nodes/adjustment-controls", () => ({
+      SliderRow: () => null,
+    }));
+    vi.doMock("@/components/ui/select", () => ({
+      Select: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+      SelectContent: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+      SelectItem: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+      SelectTrigger: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+      SelectValue: () => null,
+    }));
+    vi.doMock("@/components/canvas/canvas-sync-context", () => ({
+      useCanvasSync: () => ({
+        queueNodeDataUpdate: vi.fn(async () => undefined),
+        queueNodeResize: vi.fn(async () => undefined),
+        status: { isOffline: false },
+      }),
+    }));
+    vi.doMock("@/hooks/use-debounced-callback", () => ({
+      useDebouncedCallback: (callback: () => void) => callback,
+    }));
+    vi.doMock("@/components/canvas/canvas-graph-context", () => ({
+      useCanvasGraph: () => ({
+        nodes: [],
+        edges: [],
+        previewNodeDataOverrides: new Map([["unrelated-node", { format: "png" }]]),
+      }),
+    }));
+    vi.doMock("@/lib/canvas-render-preview", () => ({
+      resolveRenderPreviewInputFromGraph: ({ nodeId }: { nodeId: string }) => ({
+        sourceUrl: "https://cdn.example.com/source.png",
+        steps: [
+          {
+            nodeId: `${nodeId}-pipeline`,
+            type: "light-adjust",
+            params: { brightness: 10 },
+          },
+        ],
+      }),
+      findSourceNodeFromGraph: () => null,
+      shouldFastPathPreviewPipeline: (steps: PipelineStep[], overrides: Map<string, unknown>) =>
+        steps.some((step) => overrides.has(step.nodeId)),
+    }));
+    vi.doMock("@/lib/canvas-utils", () => ({
+      resolveMediaAspectRatio: () => null,
+    }));
+    vi.doMock("@/lib/image-formats", () => ({
+      parseAspectRatioString: () => ({ w: 1, h: 1 }),
+    }));
+    vi.doMock("@/lib/image-pipeline/contracts", async () => {
+      const actual = await vi.importActual<typeof import("@/lib/image-pipeline/contracts")>(
+        "@/lib/image-pipeline/contracts",
+      );
+      return {
+        ...actual,
+        hashPipeline: () => "pipeline-hash",
+      };
+    });
+    vi.doMock("@/lib/image-pipeline/worker-client", () => ({
+      isPipelineAbortError: () => false,
+      renderFullWithWorkerFallback: vi.fn(),
+    }));
+    vi.doMock("@/components/ui/dialog", () => ({
+      Dialog: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+      DialogContent: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+      DialogTitle: ({ children }: { children: React.ReactNode }) => createElement("div", null, children),
+    }));
+
+    const compareSurfaceModule = await import("@/components/canvas/nodes/compare-surface");
+    const CompareSurface = compareSurfaceModule.default;
+    const renderNodeModule = await import("@/components/canvas/nodes/render-node");
+    const RenderNode = renderNodeModule.default;
+
+    await act(async () => {
+      root?.render(
+        createElement("div", null,
+          createElement(CompareSurface, {
+            nodeWidth: 320,
+            previewInput: {
+              sourceUrl: "https://cdn.example.com/source.png",
+              steps: [
+                {
+                  nodeId: "compare-pipeline",
+                  type: "light-adjust",
+                  params: { brightness: 10 },
+                },
+              ],
+            },
+            preferPreview: true,
+          }),
+          createElement(RenderNode, {
+            id: "render-1",
+            data: {},
+            selected: false,
+            dragging: false,
+            zIndex: 0,
+            isConnectable: true,
+            type: "render",
+            xPos: 0,
+            yPos: 0,
+            width: 320,
+            height: 300,
+            sourcePosition: undefined,
+            targetPosition: undefined,
+            positionAbsoluteX: 0,
+            positionAbsoluteY: 0,
+          } as never),
+        ),
+      );
+    });
+
+    expect(hookSpy).toHaveBeenNthCalledWith(
+      1,
+      expect.objectContaining({
+        includeHistogram: false,
+        sourceUrl: "https://cdn.example.com/source.png",
+        steps: [
+          {
+            nodeId: "compare-pipeline",
+            type: "light-adjust",
+            params: { brightness: 10 },
+          },
+        ],
+        debounceMs: undefined,
+      }),
+    );
+    expect(hookSpy).toHaveBeenNthCalledWith(
+      2,
+      expect.objectContaining({
+        sourceUrl: "https://cdn.example.com/source.png",
+        steps: [
+          {
+            nodeId: "render-1-pipeline",
+            type: "light-adjust",
+            params: { brightness: 10 },
+          },
+        ],
+        debounceMs: undefined,
+      }),
+    );
+    expect(hookSpy).toHaveBeenNthCalledWith(
+      3,
+      expect.objectContaining({
+        includeHistogram: false,
+        sourceUrl: null,
+        steps: [
+          {
+            nodeId: "render-1-pipeline",
+            type: "light-adjust",
+            params: { brightness: 10 },
+          },
+        ],
+        debounceMs: undefined,
      }),
    );
  });
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -19,6 +19,7 @@ export default defineConfig({
      "components/canvas/__tests__/use-canvas-drop.test.tsx",
      "components/canvas/__tests__/use-canvas-connections.test.tsx",
      "components/canvas/__tests__/use-canvas-node-interactions.test.tsx",
+      "components/canvas/__tests__/use-node-local-data.test.tsx",
      "components/canvas/__tests__/use-canvas-sync-engine.test.ts",
      "components/canvas/__tests__/use-canvas-sync-engine-hook.test.tsx",
    ],