The `viewerCssTheme`-implementation has always been somewhat hacky, and now it's also *partially* broken ever since we've started using CSS nesting.
Trying to support nested media queries would thus require a lot more parsing of the CSS rules, which seems inefficient and thus generally undesirable.[1]
As discussed on Matrix, let's try to remove the `viewerCssTheme`-option and see if there's any (significant) fallout from this.
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[1] If this option is brought back, it seems to me that it (in Firefox) should probably be set through the platform-code that handles theming.
Depending on the structure of the outline we could potentially need to expand a few levels, especially in long PDF documents, hence it cannot hurt to pause translation in that case as well.
With the changes in PR 17208, where browser-preferences are now handled as "regular" viewer-options, we can tweak the definition of `canvasMaxAreaInBytes` to slightly simplify things in the `PDFViewerApplication.open` method.
Given that this branch is only necessary in development mode and *during* building, but is never actually used in the final viewer-bundles, we can utilize the pre-processor to ignore this code.
Currently we *synchronously* fetch a number of browser preferences/options, from the platform code, during the viewer respectively PDF document initialization paths.
This seems unnecessary, and we can re-factor the code to instead include the relevant data when fetching the regular viewer preferences.
Note that we must append the textLayer to the DOM *before* enabling the `highlighter` and `accessibilityManager`, to avoid breaking e.g. a pending searching operation.
The least invasive solution, that I was able to come up with, is to introduce a new `TextLayerBuilder` callback-function for this purpose.
After PR 17177 the interface of `XfaLayerBuilder` is now inconsistent, since whether or not we directly append the xfaLayer to the DOM now depends on the rendering intent.
I forgot to include `web/l10n_utils.js` in PR 17161, which currently breaks `ConstL10n` since there's no longer a method called `setL10n`; sorry about that!
Most of the strings shouldn't contain special chars (<= 0x1F) so we can
have a fast path which just checks if the string contains at least one such
a char.
To prevent the *standalone* viewer-components from breaking, we need to ensure that the `NullL10n`-interface won't accidentally diverge from the actual `L10n`-implementations.
Looking at the `PDFThumbnailView.setPageLabel` method you'll see that we update e.g. the "aria-label" of the thumbnail-image for documents that contain (valid) pageLabels.
This isn't done in `PDFPageView`, which seems inconsistent, hence this patch.
This patch changes almost all viewer-components[1] to use "data-l10n-id"/"data-l10n-args" for localization, which means that in many cases we no longer need to pass around the `L10n`-instance any more.
One part of the code-base where the `L10n`-instance is still being used "directly" is the AnnotationEditors, however while it might be possible to convert (most of) that code as well that's not attempted in this patch.
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[1] The one exception is the `PDFDocumentProperties` dialog, since the way it's currently implemented makes that less straightforward to fix without a lot of code changes.
*Please note:* In the Firefox PDF Viewer this findbar is only used for PDF documents placed in e.g. `<iframe>` elements.
By registering a `ResizeObserver` when the `PDFFindBar` is open we slightly unify and simplify how the findbar layout (row vs column) is handled.
This will be especially helpful with upcoming changes, where we'll make use of "data-l10n-id"/"data-l10n-args" to trigger translation in the viewer.
- The old translation engine handled language code casing slightly differently, hence we need to tweak the non-metric locale check in `PDFDocumentProperties` to account for that.
- Use only lowercase names for the pre-defined page names, to improve overall consistency.
*Please note:* These changes only affect the GENERIC build, since `NullL10n` is only a stub elsewhere (see PR 17135).
After the changes in PR 17115, which modernized and improved l10n-handling, the `NullL10n`-implementation is no longer a good fallback for the "proper" `L10n`-classes.
To improve this situation, especially for the *standalone* viewer-components, this patch makes the following changes:
- Let the `NullL10n`-implementation extend an actual `L10n`-class, which is constant and lazily initialized, to ensure that it works *exactly* like the "proper" ones.
- Automatically bundle the "en-US" l10n-strings in the build, via the pre-processor, such that we don't need to remember to manually update them.
- Ensure that the *standalone* viewer-components register their DOM-elements for translation, similar to the default viewer, since this will allow future code improvements by using "data-l10n-id"/"data-l10n-args" in most (if not all) parts of the viewer.
- Remove the `NullL10n` from the `AnnotationLayer`, to avoid affecting bundle size too much.
For third-party users that access the `AnnotationLayer`, as exposed in the main PDF.js library, they'll now need to *manually* register it for translation. (However, the *standalone* viewer-components still works given the point above.)
Given that there's now a bit more asynchronicity in the l10n-initialization in the Firefox PDF Viewer, after PR 17115, try to limit the impact of that by moving it to occur a tiny bit earlier in the default viewer initialization.
In Firefox debug builds, there is an assertion to check that we don't connect
a subelement of an already connected root. Thanks to this assertion, we can see
that the root has already been added to Fluent, hence we don't need to do it
a second time.
We don't need to await anymore on the translation in order to update the
toolbar: it'll be done by Fluent, so we can safely remove the "localized"
event and avoid to wait for it.
*Please note:* This patch contains a couple of micro-optimizations, hence I understand if it's deemed unnecessary.
Move the `AppOptions` initialization into the `Preferences` constructor, since that allows us to remove a couple of function calls, a bit of asynchronicity and one loop that's currently happening in the early stages of the default viewer initialization.
Finally, move the `Preferences` initialization to occur a *tiny* bit earlier since that cannot hurt given that the entire viewer initialization depends on it being available.
Note that CSS-features such as e.g. `flex` didn't exist, or had poor cross-browser support, back when the JavaScript-based solution was initially implemented.
- For the generic viewer we use @fluent/dom and @fluent/bundle
- For the builtin pdf viewer in Firefox, we set a localization url
and then we rely on document.l10n which is a DOMLocalization object.
Given that we only use standard `import`/`export` statements now, after recent PRs, the "exports" global is unused.
Instead we add "__non_webpack_import__" to the `globals` to avoid having to sprinkle disable statements throughout the code.
Finally, the way that `globals` are defined has changed in ESLint and we should thus explicitly specify them as "readonly"; please find additional details at https://eslint.org/docs/latest/use/configure/language-options#specifying-globals
When pdfBug is true, the substitution font is used in the text layer in order
to be able to know what is the font really used thanks to the devtools.
And to be sure that fonts are loaded, the font cache isn't cleaned up when
the debugger is active.
It's been loaded as a JavaScript module for a long time, and given that the file is bundled as-is (without building) it seems reasonable to just change the file extension now.
At this point in time all browsers, and also Node.js, support standard `import`/`export` statements and we can now finally consider outputting modern JavaScript modules in the builds.[1]
In order for this to work we can *only* use proper `import`/`export` statements throughout the main code-base, and (as expected) our Node.js support made this much more complicated since both the official builds and the GitHub Actions-based tests must keep working.[2]
One remaining issue is that the `pdf.scripting.js` file cannot be built as a JavaScript module, since doing so breaks PDF scripting.
Note that my initial goal was to try and split these changes into a couple of commits, however that unfortunately didn't really work since it turned out to be difficult for smaller patches to work correctly and pass (all) tests that way.[3]
This is a classic case of every change requiring a couple of other changes, with each of those changes requiring further changes in turn and the size/scope quickly increasing as a result.
One possible "issue" with these changes is that we'll now only output JavaScript modules in the builds, which could perhaps be a problem with older tools. However it unfortunately seems far too complicated/time-consuming for us to attempt to support both the old and modern module formats, hence the alternative would be to do "nothing" here and just keep our "old" builds.[4]
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[1] The final blocker was module support in workers in Firefox, which was implemented in Firefox 114; please see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#browser_compatibility
[2] It's probably possible to further improve/simplify especially the Node.js-specific code, but it does appear to work as-is.
[3] Having partially "broken" patches, that fail tests, as part of the commit history is *really not* a good idea in general.
[4] Outputting JavaScript modules was first requested almost five years ago, see issue 10317, and nowadays there *should* be much better support for JavaScript modules in various tools.
The minified default viewer has never been distributed in either official releases or through pdfjs-dist, which means that it's most likely unused, and it's has never been tested nor actively maintained.
