50a0b392e1
Le canvas PDF restait vide après rendu (blank-detected): la détection d'encre reposait sur un seuil de blanc trop sensible et un fond de canvas non maîtrisé. Le rendu passe à un fond sentinel explicite avec classification rendered-ok/blank-detected et un seuil de pixels visibles. Le lecteur est par ailleurs ramené à une base minimale stable: layout plein viewport (app-main-reader), suppression des modes de lecture et des préférences par livre, helpers de pagination/viewport extraits dans readerLayout.ts. Shell, lecteurs CBZ/EPUB et styles alignés sur cette base. Refs #31 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
53 lines
2.0 KiB
TypeScript
53 lines
2.0 KiB
TypeScript
import type { ReaderSize } from "./readerLayout";
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const PDF_SENTINEL_BACKGROUND = { red: 247, green: 240, blue: 223 };
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const PDF_BACKGROUND_TOLERANCE = 5;
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const PDF_VISIBLE_DELTA = 10;
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const PDF_MIN_VISIBLE_PIXELS = 12;
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export type PdfRenderResult = "rendered-ok" | "blank-detected";
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export function pdfRenderScale(frameSize: ReaderSize, pageSize: ReaderSize) {
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if (frameSize.width <= 0 || frameSize.height <= 0 || pageSize.width <= 0 || pageSize.height <= 0) return 1;
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return Math.min(frameSize.width / pageSize.width, frameSize.height / pageSize.height);
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}
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export function pdfCanvasVisible(pageRendered: boolean, hasPageError: boolean) {
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return pageRendered && !hasPageError;
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}
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function isNearSentinel(red: number, green: number, blue: number) {
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return (
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Math.abs(red - PDF_SENTINEL_BACKGROUND.red) <= PDF_BACKGROUND_TOLERANCE &&
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Math.abs(green - PDF_SENTINEL_BACKGROUND.green) <= PDF_BACKGROUND_TOLERANCE &&
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Math.abs(blue - PDF_SENTINEL_BACKGROUND.blue) <= PDF_BACKGROUND_TOLERANCE
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);
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}
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function isVisibleInk(red: number, green: number, blue: number, alpha: number) {
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if (alpha < 24) return false;
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if (isNearSentinel(red, green, blue)) return false;
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const distanceFromWhite = Math.max(255 - red, 255 - green, 255 - blue);
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return distanceFromWhite >= PDF_VISIBLE_DELTA;
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}
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export function pdfCanvasHasVisibleContent(imageData: Pick<ImageData, "data">) {
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let visiblePixels = 0;
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const data = imageData.data;
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for (let index = 0; index < data.length; index += 4) {
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if (isVisibleInk(data[index] ?? 255, data[index + 1] ?? 255, data[index + 2] ?? 255, data[index + 3] ?? 255)) {
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visiblePixels += 1;
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if (visiblePixels >= PDF_MIN_VISIBLE_PIXELS) return true;
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}
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}
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return false;
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}
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export function classifyPdfCanvas(imageData: Pick<ImageData, "data">): PdfRenderResult {
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return pdfCanvasHasVisibleContent(imageData) ? "rendered-ok" : "blank-detected";
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}
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export function pdfSentinelBackground() {
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return `rgb(${PDF_SENTINEL_BACKGROUND.red}, ${PDF_SENTINEL_BACKGROUND.green}, ${PDF_SENTINEL_BACKGROUND.blue})`;
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}
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