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.
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.
In the included PDF document the Type3-font doesn't contain any glyph definition for "space", despite that character being referenced in the /Contents stream.
While missing Type3-glyphs obviously cannot be rendered, we still need to update the current canvas position such that any char/word-spacing is correctly applied.
The test-case was found at https://github.com/pdf-association/pdf-differences/tree/main/Type3WordSpacing
Similar to Webpack there's apparently other bundlers that will not leave `import`-calls alone unless magic comments are used.
Hence we extend the builder to also append `/* @vite-ignore */` comments to `import`-calls, in order to attempt to improve support for using the PDF.js builds together with Vite.
This patch also renames `__non_webpack_import__` to `__raw_import__` since the functionality is no longer bundler-specific.
***PLEASE NOTE:*** This patch is provided as-is, and it does *not* mean that the PDF.js project can/will provide official support for Vite.
Originally this function would "manually" invoke the rendering commands for Type3-glyphs, however that was changed some time ago:
- Initial `Path2D` support was added in PR 14858, but the old code kept for Node.js compatibility.
- Since PR 15951 we've been using a `Path2D` polyfill in Node.js environments.
Hence, after the previous commit, we can further simplify this function by *directly* returning/using the `Path2D` object when rendering Type3-glyphs; see also https://github.com/mozilla/pdf.js/pull/19731#discussion_r2018712695
While this won't improve performance significantly, when compared to the introduction of `Path2D`, it definately cannot hurt.
Rather than updating the transform every time that we're painting a Type3-glyph, we can instead just compute the "final" coordinates during building of the `Path2D` objects.
NVDA behaves differently depending if the user is hovering or focusing an added signature.
An aria-description is read in both cases while an aria-label is not.
By changing the return format of the various `pointsCallback` functions we can use the `Util.rectBoundingBox` helper in the `MarkupAnnotation.prototype._setDefaultAppearance` method as well, thus shortening the code slightly.
This avoids the current situation where we're accessing it through various dictionaries, since that's a somewhat brittle solution given that in the general case a `Dict`-instance may not have the `xref`-field set (see e.g. the empty-Dict).
Currently we have a `Util`-helper for computing the bounding-box of a Bézier curve, however for simple points and rectangles we repeat virtually identical code in many spots throughout the code-base.
- Introduce new `Util.pointBoundingBox` and `Util.rectBoundingBox` helpers.
- Remove the "fallback" from `Util.bezierBoundingBox` and only support passing in a `minMax`-array, since there's only a single call-site using the other format and it could be easily updated.
The rendering bug with issue17779.pdf is due to the fact that we call save on the suspended ctx
but not on the the current ctx. So each time we've something like save/transform/restore then
the transform not "removed" when restoring.
So this patch just apply the save/restore operations to ctx which are mirrored on the suspended one.
With this patch, all the paths components are collected in the worker until a path
operation is met (i.e., stroke, fill, ...).
Then in the canvas a Path2D is created and will replace the path data transfered from the worker,
this way when rescaling, the Path2D can be reused.
In term of performances, using Path2D is very slightly improving speed when scaling the canvas.
