Having some interactive elements forces the screen readers to switch to form mode
and consequently they delegate the keyboard stuff to the browser.
This patch sets an aria label on each editor in order to have a better description than just
'application'.
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.
This addresses an inconsistency in the viewer, since the thumbnails don't respect the `maxCanvasPixels` option.
Note that, as far as I know, this has not lead to any bugs since the thumbnails render with a fixed (and small) width, however it really cannot hurt to address this (especially after the introduction of the `maxCanvasDim` option).
To support this a new `OutputScale`-method was added, to avoid having to duplicate code in multiple files.
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.
These methods were introduced in *the first* commit of PR 4938, however they became unused in *the second* commit of that PR.
Hence it seems that we've been accidentally shipping, a small amount of, unused code for over a decade.
While initializing the `padded` Uint8Arrays we're manually assigning zeros to some entries, which is completely unnecessary since that's the default value for a TypedArray, and instead we can just increment the index.
When creating the `StyleMapping` for the "xfa-font-horizontal-scale" and "xfa-font-vertical-scale" properties there's currently pointless `Math.min` usage, since we're not actually comparing with anything.
This combines the `PDFFunctionFactory.create` and `PDFFunctionFactory.createFromArray` methods, which helps simplify and shorten the code.
Additionally, to simplify the parameter handling we pass the `PDFFunctionFactory`-instance directly to the various `PDFFunction`-methods.
This may not be possible to trigger in practice, however it seems that if `StampAnnotation.prototype.mustBeViewedWhenEditing` is called back-to-back with `isEditing === true` set then the second invocation could overwrite the `#savedHasOwnCanvas`-field and thus lose its initial state.
Currently we have a number of spots in the code-base where we need to clamp a value to a [min, max] range. This is either implemented using `Math.min`/`Math.max` or with a local helper function, which leads to some unnecessary duplication.
Hence this patch adds and re-uses a single helper function for this, which we'll hopefully be able to remove in the future once https://github.com/tc39/proposal-math-clamp/ becomes generally available.
With the changes in PR 19564 the actual `ColorSpace`-classes where separated from the various static "helper" methods.
Hence it seems that we can now simplify/shorten this old code to instead cache the "standard" ColorSpaces directly on the `ColorSpaceUtils`-class.
This patch reduces the number of `ColorSpaceUtils` static-methods, and in particular the `parseAsync` method is removed and it's now instead possible to have `parse` optionally return a Promise.
This thus removes the need to manually check if a `ColorSpace`-instance is cached, note the changes in the `src/core/evaluator.js` file.
Some ColorSpaces can reference other ColorSpaces, and since it's fairly common for many pages to use the same ColorSpaces (see e.g. `issue17061.pdf`) this can help reduce a lot of unnecessary re-parsing especially for e.g. `ICCBased` ColorSpaces.
This complements the existing `LocalColorSpaceCache`, which is unique to each `getOperatorList`-invocation since it also caches by `Name`, which should help reduce unnecessary re-parsing especially for e.g. `ICCBased` ColorSpaces once we properly support those.
Currently we re-implement the same helper function twice, which in hindsight seems like the wrong decision since that way it's quite easy for the implementations to accidentally diverge.
The reason for doing it this way was because the code in the worker-thread is able to check for `Ref`- and `Name`-instances directly, which obviously isn't possible in the viewer but can be solved by passing validation-functions to the helper.
Currently we're first loading the font, and then for Type3 fonts we're invoking `loadType3Data` every time that the font is encountered.
That seems completely unnecessary, and it's probably connected to the age of this code, since the `loadType3Data`-method will only run once anyway (note the caching).
