fix(image-pipeline): make preview histogram opt-in

lib/image-pipeline/image-pipeline.worker.ts

@@ -8,6 +8,7 @@ type PreviewWorkerPayload = {
   sourceUrl: string;
   steps: readonly PipelineStep[];
   previewWidth: number;
+  includeHistogram?: boolean;
 };
 
 type WorkerRequestMessage =
@@ -93,6 +94,7 @@ async function handlePreviewRequest(requestId: number, payload: PreviewWorkerPay
       sourceUrl: payload.sourceUrl,
       steps: payload.steps,
       previewWidth: payload.previewWidth,
+      includeHistogram: payload.includeHistogram,
       signal: controller.signal,
     });
 

lib/image-pipeline/preview-renderer.ts

@@ -1,5 +1,5 @@
 import type { PipelineStep } from "@/lib/image-pipeline/contracts";
-import { computeHistogram, type HistogramData } from "@/lib/image-pipeline/histogram";
+import { computeHistogram, emptyHistogram, type HistogramData } from "@/lib/image-pipeline/histogram";
 import { applyPipelineStep } from "@/lib/image-pipeline/render-core";
 import { loadSourceBitmap } from "@/lib/image-pipeline/source-loader";
 
@@ -54,6 +54,7 @@ export async function renderPreview(options: {
   sourceUrl: string;
   steps: readonly PipelineStep[];
   previewWidth: number;
+  includeHistogram?: boolean;
   signal?: AbortSignal;
 }): Promise<PreviewRenderResult> {
   const bitmap = await loadSourceBitmap(options.sourceUrl, {
@@ -82,7 +83,9 @@ export async function renderPreview(options: {
     }
   }
 
-  const histogram = computeHistogram(imageData.data);
+  const histogram = options.includeHistogram === false
+    ? emptyHistogram()
+    : computeHistogram(imageData.data);
 
   return {
     width,

lib/image-pipeline/worker-client.ts

@@ -13,6 +13,7 @@ type PreviewWorkerPayload = {
   sourceUrl: string;
   steps: readonly PipelineStep[];
   previewWidth: number;
+  includeHistogram?: boolean;
 };
 
 type WorkerRequestMessage =
@@ -261,6 +262,7 @@ export async function renderPreviewWithWorkerFallback(options: {
   sourceUrl: string;
   steps: readonly PipelineStep[];
   previewWidth: number;
+  includeHistogram?: boolean;
   signal?: AbortSignal;
 }): Promise<PreviewRenderResult> {
   try {
@@ -270,6 +272,7 @@ export async function renderPreviewWithWorkerFallback(options: {
         sourceUrl: options.sourceUrl,
         steps: options.steps,
         previewWidth: options.previewWidth,
+        includeHistogram: options.includeHistogram,
       },
       signal: options.signal,
     });