Comparing the currently supported browsers/environments, see [the FAQ](https://github.com/mozilla/pdf.js/wiki/Frequently-Asked-Questions#faq-support) and the [MDN compatibility data](https://developer.mozilla.org/en-US/docs/Web/API/structuredClone#browser_compatibility), the `structuredClone` polyfill is *only* needed in Google Chrome versions < 98. Because of some limitations in the core-js polyfill we're currently forced to special-case the `transfer` handling to prevent bugs, and it'd be nice to avoid that.
Note that `structuredClone`, with transfers, is only used in two spots:
- The `LoopbackPort` class, which is only used with fake workers. Given that fake workers should *never* be used in browsers, breaking that edge-case in older Google Chrome versions seem fine.
- The `AnnotationStorage` class, when Stamp-annotations have been added to the document. Given that Google Chrome isn't the main focus of development, breaking *part* of the editing-functionality in older Google Chrome versions should hopefully be acceptable.
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 user should *always* provide a correct `GlobalWorkerOptions.workerSrc` value when using the PDF.js library in browser environments. Note that the fallback:
- Has been deprecated ever since PR 11418, first released in version `2.4.456` over three years ago.
- Was always a best-effort solution, with no guarantees that it'd actually work correctly.
- With upcoming changes, w.r.t. outputting JavaScript modules, it'd now be more diffiult to determine the correct value.
When an editing button is disabled, focused and the user press Enter (or space), an
editor is automatically added at the center of the current page.
Next creations can be done in using the same keys within the focused page.
To reduced the risk of regressing something else, given that the issue only applies to a (for the default viewer) non-default configuration, this patch is purposely limited to only TextWidget-annotations in the display layer.
This has been deprecated since version `2.15.349`, which is a year ago.
Removing this will also simplify some upcoming changes, specifically outputting of JavaScript modules in the builds.
When the editor is invisible (because on a non-rendered page) its parent is null.
But when we undo its deletion, we need to have a parent to attach it.
but keep it for the text area.
Disable pointerdown on the alt-text button to disable dragging the editor
when the button is clicked (especially when slightly moving the mouse
between the down and the up).
When the user edit an existing alt-text and remove it, we want to be able
to save this state and consequently remove the done state from the
alt-text button.
Remove the button from its parent when the editor is removed: it should
help to save few Kb of memory.
Focus callback must be called only when the element has been blurred.
For example, blur callback (which implies some potential validation) is not called
because the newly focused element is an other tab, an alert dialog, ... so consequently
the focus callback mustn't be called when the element gets its focus back.
While reviewing PR 16898 it occurred to me that it's currently impossible to trigger downloading of FileAttachment annotations using the keyboard.
Hence this patch adds `Ctrl + Enter` as the keyboard shortcut to download those, thus supplementing the existing double-clicking when using a mouse.
The goal is to always have something which is focusable to let the user select
it with the keyboard.
It fixes the mentioned bug because, the annotation layer will now have a container
to attach the canvas for annotations having their own canvas.
