The issue described in the mentioned bug is reall because
Acrobat is rendering the XFA instead of the Acroform.
The original patch just tried to workaround the issue but it
induces some regressions.
This was added in PR 14899, over a year ago, however it's still completely unused in the PDF.js library/viewer. In hindsight I think that it was a mistake to add unused functionality, and the issue should probably have been WONTFIXed instead, however we probably can't just remove it now.
Thanks to the pre-processor, we can at least exclude this code in the *built-in* Firefox PDF Viewer.
After the changes in PR 16828 the `StampEditor` can now be initialized with a File, in addition to a URL, hence it seems that the `isEmpty` method ought to take that property into account as well.
Looking at this I also noticed that the assignment in the constructor may cause the `this.#bitmapUrl`/`this.#bitmapFile` fields be `undefined` which "breaks" the comparisons in the `isEmpty` method.
We could obviously fix those specific cases, but it seemed overall safer (with future changes) to just update the `isEmpty` method to be less sensitive to exactly how these fields are initialized and reset.
Currently we're repeating virtually the same code *four times* when fetching the bitmap-data, which seems unnecessary.
Also, ensure that the `#bitmapPromise` is always `null`ed by moving that into the `StampEditor.#getBitmapDone` method.
Currently this unit-test will pass just fine if compression is disabled, e.g. by commenting out the relevant code in the `src/core/writer.js` file.
While we don't have a simple way of *directly* checking that the Annotation text-content is compressed, we can however use the resulting file-size as a fairly good proxy. (Note that if compression is disabled the file-size is more than doubled.)
Please note that for performance reasons it's not really advised to use the same worker-thread *in parallel* for parsing multiple PDF documents, since they will then unnecessarily compete for resources.
However, given that it's still possible to do that e.g. when using the global `workerPort` it probably won't hurt to add a unit-test for this particular situation.
Given that the `PDFDocumentLoadingTask.destroy()`-method is documented as being asynchronous, you thus need to await its completion before attempting to load a new PDF document when using the global `workerPort`.
If you don't await destruction as intended then a new `getDocument`-call can remain pending indefinitely, without any kind of indication of the problem, as shown in the issue.
In order to improve the current situation, without unnecessarily complicating the API-implementation, we'll now throw during the `getDocument`-call if the global `workerPort` is in the process of being destroyed.
This part of the code-base has apparently never been covered by any tests, hence the patch adds unit-tests for both the *correct* usage (awaiting destruction) as well as the specific case outlined in the issue.
- The `src/core/unicode.js` exclude ought to have become unnecessary already with PR 16200, which significantly shortened and simplified that file.
- The `src/core/glyphlist.js` exclude no longer seems necessary in practice either, possibly because of improvements in Babel.
The main stamp button will be used to just enter in a add/edit image mode:
- the user can add a new image in using the new button.
- the user can edit an image in resizing, moving it.
In image mode, when the user clicks outside on the page but not on an editor,
then all the selected editors will be unselected.
After the `src/core/`-changes in PR 16779 the `PDFDocumentProxy.getJSActions` method should no longer be able to return *empty* entries, which means that we can simplify the "JavaScript support is not enabled"-warning in the viewer.
Furthermore, improve the auto-printing hack used when scripting is disabled.
Given that the FieldObjects are parsed in parallel, in combination with the existing caching in the `getPage`-method and `annotations`-getter, adding additional caches for this fallback code-path doesn't seem entirely necessary.
