PDF.js + Webpack has drawImage check failure

[Cybourgeoisie]

The following error occurs only in Electron builds (update: it's occurring in the webpack code, not just electron) with pdfjs-dist (current version, v4.10.38) and @napi-rs/canvas (current version, v0.1.67). This issue does not happen when running the code in development, but does happen after consolidating the code into webpack, and running via electron development or a build.

Error message: Error: Value is non of these types CanvasElement, SVGCanvas, Image,

In my specific case, I've traced the exact call error down to a pdfjs function that calls drawImage on a canvas.

Error: Value is non of these types `CanvasElement`, `SVGCanvas`, `Image`, 
    at CanvasGraphics.endGroup (.../build/626.server.js:13928:16)
    at CanvasGraphics.executeOperatorList (.../build/626.server.js:12800:20)
    at InternalRenderTask._next (.../build/626.server.js:18340:37)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  code: 'InvalidArg'

The inputs, contexts, and canvases are all existent both in development and in the running Electron build, so there isn't a missing parameter, and as far as I can see, it isn't malformed.

The error seems to be triggered early in the ctx.rs::draw_image function, possibly when trying to match the type of image on line 1539 - as I was able to find that the Either3 error code is what produces the text for the above error, per https://prisma.github.io/prisma-engines/doc/src/napi/bindgen_runtime/js_values/either.rs.html#91

I will keep investigating, but it feels like moving forward is to identify why a valid CanvasElement input from Node.JS would not be identified as a valid type when the rust code is called.

[Cybourgeoisie]

I'm able to reproduce the issue with a very simple repo, which only has the objective of loading a PDF and printing the first page: https://github.com/Cybourgeoisie/webpack-pdfjs-napirscanvas-test

[nora-heydecker-axa]

We have observed the same issue. It looks like this is a regression from 0.1.65 -> 0.1.68. We saw the problem with a dependency upgrade that upgraded pdfjs-dist's dependency on @napi-rs/canvas from 0.1.65 to 0.1.68, and reverting this upgrade fixed it (note that there were some other upgrades as well, I'm not 100% sure that it really was that upgrade).

The error occurs on this line of pdfjs (pdfjs-dist@4.9.155/legacy/build/pdf.mjs:13381:

ctx.drawImage(maskCanvas, mask.offsetX, mask.offsetY);

(https://github.com/mozilla/pdf.js/blob/d5c185b90a104ca3e2eb4eec240c9414996a3a34/src/display/canvas.js#L2834)

This makes me suspect that it's related to #984.

[nora-heydecker-axa]

The error is coming from decoding this parameter:

canvas/src/ctx.rs

Line 1521 in 5944ea3

image: Either3<&mut CanvasElement, &mut SVGCanvas, &mut Image>,

The canvas passed in by pdfjs is coming from _createMaskCanvas:
https://github.com/mozilla/pdf.js/blob/d5c185b90a104ca3e2eb4eec240c9414996a3a34/src/display/canvas.js#L1276

which comes from the cached canvases:
https://github.com/mozilla/pdf.js/blob/d5c185b90a104ca3e2eb4eec240c9414996a3a34/src/display/canvas.js#L1206

and the canvas is being created from a canvas factory (without a flag, so a CanvasElement should be created):
https://github.com/mozilla/pdf.js/blob/d5c185b90a104ca3e2eb4eec240c9414996a3a34/src/display/node_utils.js#L90