For simplicity we will abort /Form XObject parsing *immediately* when encountering a circular reference, rather than letting it continue up until some limit (as e.g. PDFium appears to do), which should be fine since there are never any guarantees if/how *corrupt* PDF documents will render.
Previously we'd only do this for Type1/CFF fonts, see e.g. PR 6736, since the font-program may update the /FontMatrix.
However, it seems that we should do this unconditionally to account for fonts with non-default /FontMatrix-entries in the font-dictionary (which seem to be pretty rare).
In PDF version 2.0 the handling of Indexed color spaces was clarified as follows:
> The index value should be an integer in the range 0 to hival. If the value is a real number, it shall be rounded to the nearest integer (0.5 values shall be rounded up); if it is outside the range 0 to hival, it shall be adjusted to the nearest value within that range.
Please refer to https://github.com/pdf-association/pdf-differences/tree/main/IndexedColor
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
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.
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.
This patch extends the approach of PR 14543, by also treating e.g. minus signs followed by '(' or '<' as zero.
Inside of a /Contents stream those characters will generally mean the start of one or more glyphs.
For Type3 glyphs with `d1` operators it's easy to compute a fallback bounding box, however for `d0` the situation is more difficult.
Given that we nowadays compute the min/max of basic path-rendering operators on the worker-thread, we can utilize that by parsing these Type3 operatorLists to guess a more suitable fallback bounding box.
One of the images have a corrupt SMask, where the /Height-entry is bogus; see the excerpt below (via https://brendandahl.github.io/pdf.js.utils/browser/).
```
SMask (stream) [id: 17, gen: 0]
ColorSpace = /DeviceGray
Height = /Length
Subtype = /Image
Filter = /FlateDecode
Type = /XObject
Width = 157
Matte (array)
BitsPerComponent = 8
Length = 3893
<view contents> download
```
Hence we enable SMask/Mask images to fallback to the parent image dimensions, and also add more validation of the width/height to get a better error message when that data is wrong.
With the recently added OpenJPEG no-wasm fallback we need to send the `wasmUrl` option to the worker-thread *regardless* of the value of the `useWorkerFetch` option, since the fallback won't work if we don't have a URL to `import` it from.
For consistency the code is re-factored to always send the factory-urls to the worker-thread, and simply check the `useWorkerFetch` option there instead.
Also, as a follow-up to PR 19525, introduce a new `useWasm` option that can be used in e.g. browser-tests to forcibly disable WebAssembly usage.
During the XRef stream parsing we're attempting to lookup an entry that hasn't yet been found, since parsing is currently running, and given that we'd also cache free/missing XRef entries we'd then return an incorrect value during normal PDF parsing.
The simplest solution here is to just not cache free/missing XRef entries, since a properly generated PDF document shouldn't be trying to access objects it doesn't contain.
Furthermore, the amount of "extra" parsing now needed for such XRef entries shouldn't be significant enough to be an issue.
Rather than modifying the "raw" dimensions of the page, we'll instead apply the `userUnit` as an *additional* scale-factor via CSS.
*Please note:* It's not clear to me if this solution is fully correct either, or if there's other problems with it, but it at least *appears* to work.
---
With these changes, the following CSS variables are now assumed to be available/set as necessary: `--total-scale-factor`, `--scale-factor`, `--user-unit`, `--scale-round-x`, and `--scale-round-y`.
It fixes#19360.
Each glyph in the test case has a fill and a stroke pattern, so the current transform used
to scale the glyph outline must be the same.
In setting the stroke color to green, I noticed that the last outline contains some non-closed
subpaths, so when generating the glyph outline, every time we 'moveTo', we close the previous
subpath.
In order to fix bug 1935076, we'll have to add a pure js fallback in case wasm is disabled
or simd isn't supported. Unfortunately, this fallback will take some space.
So, the main goal of this patch is to reduce the overall size (by ~93k).
As a side effect, it should make easier to use an other wasm file (which must export
_jp2_decode, _malloc and _free).
In the affected font the total number of mapping-entries is `1142348`, and no less than `997473` of them are duplicates.
Given that every duplicate causes a lot of Array elements to be moved this becomes extremely inefficient, which we can avoid by keeping track of seen `charCode`s and directly build the final mappings-Array instead.
This appears to have regressed in PR 13808, since it removed the `matrix`-entry from array returned by the `MeshShading.prototype.getIR` method *without* also updating the indexes in the `MeshShadingPattern` constructor.
The `/Root/AcroForm/Fields` array contains a "ridiculous" number of LinkAnnotations, which obviously makes no sense since those are not form fields.
To improve performance we'll thus ignore those when collecting the field objects.
From section [11.6.4.3 Mask Shape and Opacity](https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf#G10.4848628) in the PDF specification:
- An image XObject may contain its own *soft-mask image* in the form of a subsidiary image XObject in the `SMask` entry of the image dictionary (see "Image Dictionaries"). This mask, if present, shall override any explicit or colour key mask specified by the image dictionary's `Mask` entry. Either form of mask in the image dictionary shall override the current soft mask in the graphics state.
This patch makes a clear separation between the way to draw and the editing stuff.
It adds a class DrawEditor which should be extended in order to create new drawing tools.
As an example, the ink tool has been rewritten in order to use it.
Given that `browsertest` repeatedly timeout in Google Chrome, and considering that Firefox is the primary development target, we stop running them on the bots to avoid having to repeatedly deal with this.
Note that we already disabled these tests *on Windows* almost three years ago, because of stability issues; see PR 14392.
