This test-case is an especially "bad" one performance wise given its PostScript function use, when falling back to the (now removed) `PostScriptEvaluator` code.
These classes, and various related code, became unused after PR 21023 with only unit-tests actually running that code now.
Also removes the `isEvalSupported` API option, since the `PostScriptCompiler` was the only remaining code where `eval` was used.
It fixes#5046.
We just generate a mesh for the pattern rectangle where the color of each vertex is computed from the function.
Since the mesh is generated in the worker we don't really take into account the current transform when it's drawn.
That being said, there are maybe some possible improvements in using directly the gpu for the shading creation
which could then take into account the current transform, but it could only work with ps function we can convert
ino wgsl language and simple enough color spaces (gray and rgb).
The main goal is to remove the eval-based interpreter.
In order to have some good performances, the new parser performs some optimizations
on the AST (similar to the ones in the previous implementation),
and the Wasm compiler generates code for the optimized AST.
For now, in case of errors or unsupported features, the Wasm compiler returns null
and the old interpreter is used as a fallback.
Few things are still missing:
- a wasm-based interpreter using a stack (in case the ps code isn't stack-free);
- a better js implementation in case of disabled wasm.
but they will be added in follow-up patches.
This function only has a single call-site (if we ignore the unit-tests), where the colors are split into separate parameters.
Given that all the color components are modified in the exact same way, it seems easier (and shorter) to pass the colors as-is to `applyOpacity` and have it use `Array.prototype.map()` instead.
This code already has an integration-test, however also having a unit-test shouldn't hurt since those are often easier to run and debug (and it nicely complements the existing `outline` unit-tests).
The patch also makes the following smaller changes to the method itself:
- Avoid creating and parsing an empty Array, when doing the `pageRef` search.
- Use `XRef.prototype.fetch` directly, when walking the parent chain, since the check just above ensures that the value is a Reference.
- Use the `lookupRect` helper when parsing the /BBox entry.
Since this code is quite old parts of it can also be simplified a little bit by using modern string methods, which removes the need for the `pad` helper function.
Some tests were failing and has been fixed:
- "Hello" + Alef + "(" + Bet: the "(" (neutral) was not considered as a part of the group Alef(Bet and the group wasn't reverted;
- some intermediate neutrals were considered as strong.
It's somewhat common for multiple test-cases to use the same PDF, for example tests for both `eq` and `text` with one PDF.
Currently the logic in `downloadManifestFiles` doesn't handle duplicate test PDFs, which leads to wasted time/resources by downloading the same PDF more than once. Naturally the effect of this is especially bad when downloading all linked PDFs.
Total number of test PDFs downloaded:
- 507, with `master`.
- 447, with this patch.
Using the Fetch API simplifies and shortens the `downloadFile` function considerably, since among other things it handles redirects[1] by default.
Also, the regular expression in `downloadManifestFiles` can be replaced with a simple string function now.
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[1] Implementations of the Fetch API should already prevent e.g. redirect loops and limit the total number of redirects allowed.
This code already isn't used (or even bundled) in the Firefox PDF Viewer, and it also slightly reduces the number of import maps that need to be maintained.
