Skip to content

fix(pdf): reliably extract PDF images across browsers #216

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
slaveofcode merged 1 commit into from
Aug 14, 2026
Merged

fix(pdf): reliably extract PDF images across browsers #216

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 16 additions & 6 deletions src/tools/pdf/extract-images.lib.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -38,10 +38,18 @@ async function objToBlob(obj: PdfImageObj): Promise<{ blob: Blob; width: number;
const ctx = canvas.getContext('2d');
if (!ctx) return null;

if (obj.bitmap) {
canvas.width = obj.bitmap.width;
canvas.height = obj.bitmap.height;
ctx.drawImage(obj.bitmap, 0, 0);
const drawable = obj.bitmap as CanvasImageSource | undefined;
const w = obj.width || (drawable as { width?: number })?.width || 0;
const h = obj.height || (drawable as { height?: number })?.height || 0;

if (drawable && w && h) {
canvas.width = w;
canvas.height = h;
try {
ctx.drawImage(drawable, 0, 0, w, h);
} catch {
return null; // e.g. a detached ImageBitmap
}
} else if (obj.data && obj.width && obj.height) {
const { width, height, data } = obj;
const pixels = width * height;
Expand Down Expand Up @@ -79,8 +87,10 @@ function resolveObj(page: { objs: { has(n: string): boolean; get(n: string, cb?:

/** Extract every embedded raster image from the PDF bytes. */
export async function extractPdfImages(data: ArrayBuffer | Uint8Array): Promise<ExtractedImage[]> {
const pdfjs = await import('pdfjs-dist');
const PdfjsWorker = (await import('pdfjs-dist/build/pdf.worker.min.mjs?worker')).default;
// Use the legacy build: it polyfills newer JS (e.g. Uint8Array.prototype.toHex,
// which pdf.js's default build assumes) so extraction works on older browsers.
const pdfjs = await import('pdfjs-dist/legacy/build/pdf.mjs');
const PdfjsWorker = (await import('pdfjs-dist/legacy/build/pdf.worker.min.mjs?worker')).default;
const worker = new PdfjsWorker();
pdfjs.GlobalWorkerOptions.workerPort = worker;

Expand Down
Loading