We want to iterate through the data in the `computeMD5` function, and `Map`s have "nicer" support for that than generic objects.
(Somewhat recently `Map` performance was improved in Firefox, however this also isn't really performance sensitive code.)
Note that we load all wasm-files manually, however the Emscripten Compiler (emcc) unfortunately generates `URL`s for fallback wasm-file loading.
In the PDF.js build-scripts we work-around that by using suitable Webpack-options, however that apparently doesn't work when third-party users re-bundle our code and we thus try to work-around this by adding "ignore comments" to these `URL`s (similar to how we handle `import`-statements).
It seems that the `@napi-rs/canvas` dependency has *basic* canvas-filter support, whereas the "old" `canvas` dependency didn't, hence we no longer need the Node.js-specific checks in the `src/display/canvas.js` file.
Note that I've successfully tested the [`pdf2png` example](https://github.com/mozilla/pdf.js/tree/master/examples/node/pdf2png) with this patch applied and things appear to work as before.
After PR 19731 the format of compiled Type3-glyphs is now simple enough that the compilation can be moved to the worker-thread, without introducing any significant additional complexity.
This allows us to, ever so slightly, simplify the implementation in `src/display/canvas.js` since the Type3 operatorLists will now directly include standard path-rendering operators (using the format introduced in PR 19689).
As part of these changes we also stop caching Type3 image masks since: we've not come across any cases where that actually helps, they're usually fairly small, and it simplifies the code.
Note that one "negative" change introduced in this patch is that we'll now compile Type3-glyphs *eagerly*, whereas previously we'd only do that lazily upon their first use.
However, this doesn't seem to impact performance in any noticeable way since the compilation is fast enough (way below 1 ms/glyph in my testing) and Type3-fonts are also limited to just 256 glyphs. Also, many (or most?) Type3-fonts don't even use image masks and are thus not affected by these changes.
In using the Firefox profiler (with JS allocations tracking) and wuppertal.pdf, I noticed
we were using a bit too much memory for a function which is supposed to just compute 2 numbers.
The memory used by itself isn't so important but having a too much objects lead to waste some time
to gc them.
So this patch aims to simplify it a bit.
This commit reduces the number of freetext editor integration test suite
failures, in full isolation, from 5 to 0 by fixing the following issues
in the "basic operations" block:
- Most tests relied on the first test to enable freetext editing mode.
For isolation we now do it explicitly in all tests.
- Most tests relied on the other tests having created editors. For
isolation we now create the editors explicitly in the tests themselves.
- Most tests relied on previous tests for the editor numbering. For
isolation we change the editor numbering to the one after initial
document load. Since we can't have state (editors) from a previous
test anymore we can remove various `clearAll` calls as well.
Currently we explicitly specify the fn-`OPS` both when adding entries to the operatorList and to the image-caches, and by using a temporary variable we can reduce a bit of duplication (similar to the existing args-handling).
The color-parameter is already available through `IR` (i.e. the internal representation), and after the changes in PR 4824 (which landed in 2014) we no longer need any special handling for it.
