By getting the width/height of the first page initially, we can slightly reduce the amount of code needed both in the `hasEqualPageSizes`-check and when building the print-styles.
For the moment there is no real consensus on how we should download a pdf on Android.
Hence we keep this solution for the moment but behind a pref (which will be true on
nightly only).
Currently we repeat the same code in lots of places, to update the "toggled" class and "aria-checked" attribute, when various toolbar buttons are clicked.
For the MOZCENTRAL build-target this patch reduces the size of the *built* `web/viewer.js` file by just over `1.2` kilo-bytes.
Apparently the `structuredClone` polyfill doesn't handle transfers correctly, and `DOMException`s may thus be thrown. This is particularly problematical in Node.js environments, where that exception (obviously) isn't available.
To work-around these issues we'll simply ignore any transfers in `legacy`-builds, since those *may* use the `structuredClone` polyfill. This will obviously lead to slightly higher memory usage in those builds, however this really only affects Node.js environments. (Browsers are only affected if workers are disabled, however that's never been an officially recommended/supported configuration.)
Currently `float: inline-start/inline-end` is only supported in Firefox, see https://developer.mozilla.org/en-US/docs/Web/CSS/float#browser_compatibility, and in order to support other browsers we're thus forced to jump through some hoops.
This leads to slightly less nice code in the *built-in* Firefox PDF Viewer, and this patch attempts to improve the current situation:
- Use Stylelint to forbid direct use of `float: inline-start/inline-end` in the CSS files, to prevent future bugs in the general PDF.js viewer.
- Do a build-time replacement, only in MOZCENTRAL builds, to replace the CSS-variables with raw `float: inline-start/inline-end` instances.
Currently we have two separate image-caches on the worker-thread:
- A local one, which is unique to each `PartialEvaluator.getOperatorList` invocation. This one caches both names *and* references, since image-resources may be accessed in either way.
- A global one, which applies to the entire PDF documents and all its pages. This one only caches references, since nothing else would work.
This patch introduces a third image-cache, which essentially sits "between" the two existing ones. The new `RegionalImageCache`[1] will be usable throughout a `PartialEvaluator` instance, and consequently it *only* caches references, which thus allows us to keep track of repeated image-resources found in e.g. different /Form and /SMask objects.
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[1] For lack of a better word, since naming things is hard...
This effectively implements some of the changes from https://phabricator.services.mozilla.com/D170496, but using our existing "direction aware" CSS-variable to limit the amount of code changes needed.
The patch changes the minimum supported version of Google Chrome as follows:
- Chrome 88, which was released on 2021-01-19; see https://en.wikipedia.org/wiki/Google_Chrome_version_history
This is done to allow use of modern CSS features, such as e.g. `:is()` and `:where()` in the code-base.
When installing the PDF.js project itself it's currently necessary to use `--force` in order for all packages to install correctly, see issue 15429, hence the same is also necessary when using the `gulp dist-install` command for local development/testing.
*Please note:* This parameter has never been used within the PDF.js library/viewer itself, and it was only ever added for backwards compatibility reasons.
This parameter was added in PR 7475, over six years ago, to try and optionally maintain the previous *default* text-extraction behaviour.
However as part of the general text-extraction improvements in PR 13257, almost two years ago, the `disableCombineTextItems` functionality was accidentally "broken" in various ways. Note how the only (very basic) unit-test was updated in a way that doesn't really make sense, since generally speaking you'd expect that using the option should result in *more* (or at least the same number of) text-items. Furthermore there's also the recent issue 16209, where the option causes almost all textContent to be concatenated together.
Hence this patch proposes that we simply remove the `disableCombineTextItems` option since it's essentially unused/untested functionality, as evident from the fact that it took almost two years for someone to notice that it's broken.
With the changes in PR 16153 we're no longer setting a `<base href>` in the Firefox PDF Viewer, hence it shouldn't be necessary to keep setting a `baseUrl` in the `PDFLinkService`-class.
Given that the original document URL is now kept, the browser itself will handle relative URLs and we can thus slightly reduce the amount of string parsing required when handling various links in the viewer.
