It has few cool features:
- all the canvas used during the rendering can be viewed;
- the different properties in the graphics state can be viewed;
- the different paths can be viewed.
In PR 20016 the actual uses of the `enableHWA` option was removed from the viewer, but for some reason it's still being provided when initializing `PDFViewer` and `PDFThumbnailViewer` despite the fact that it's now dead code.
This is consistent with a bunch of other viewer code, since an `AbortSignal` can only be aborted once any "abort" listeners can thus be removed when invoked.
This patch adds right-click support for images in the PDF, allowing
users to download them. To minimize memory consumption, we:
- Do not store the images separately, and instead crop them out of the
PDF page canvas
- Only extract the images when needed (i.e. when the user right-clicks
on them), rather than eagery having all of them available.
To do so, we layer one empty 0x0 canvas per image, stretched to cover
the whole image, and only populate its contents on right click.
These images need to be inside the text layer: they cannot be _behind_
it, otherwise they would be covered by the text layer's container and
not be clickable, and they cannot be in front of it, otherwise they
would make the text spans unselectable.
This feature is managed by a new preference, `imagesRightClickMinSize`:
- when it's set to `-1`, right-click support is disabled
- when set to `0`, all images are available for right click
- when set to a positive integer, only images whose width and height are
greater than or equal to that value (in the PDF page frame of
reference) are available for right click.
This features is disabled by default outside of MOZCENTRAL, as it
significantly degrades the text selection experience in non-Firefox
browsers.
The one from pdf.js.utils is a bit too old: a lot of bugs have been fixed
in the code that parses PDF files since then.
It's just an internal development tool, so it doesn't need to be perfect,
but it should be good enough to be useful.
With these changes `0`, `NaN`, `null`, and `undefined` in the `total`-property all result in `percent === NaN` being reported by the callback, since previously e.g. `0` would result in `percent === 100` being reported unconditionally which doesn't make a lot of sense.
Also, remove the "indeterminate" loadingBar (in the viewer) if the `PDFDocumentLoadingTask` fails since there won't be any more data arriving and displaying the animation thus seems wrong.
The original issue can only be reproduce when the thumbnails are on two lines.
The fix is just a matter of computing the number of elements on the last line once we've
finished the first line.
The user has to select some pages and then click on the "Save As" menu item in the Manage menu.
If they modify the structure of the pdf (deleted, moved, copied pages), they have to use the usual
save button.
Working on PR 20784, I couldn't help noticing that this code can be improved a little bit.
- Only initialize `PdfTextExtractor` in development mode and MOZCENTRAL builds, since it's unused elsewhere.
- Re-factor how `PdfTextExtractor` waits for the viewer to be available/ready, by using existing (internal) events.
This simplifies the `PdfTextExtractor` class and removes its `setViewer` method, which improves general consistency since normally the viewer-components don't use such a method in that way (here it was effectively used as a stand-in for a `setDocument` method).
- Finally, while slightly unrelated, rename the `#getAllTextInProgress` field in the `PDFViewer` class to `#copyAllInProgress` to clearly indicate what it's for since the `getAllText` method is used more generally now.
Given that extracting all text can take a while to complete, especially in long PDF documents[1], it's technically possible for the user to "select all", copy, and finally abort copying (with the `Esc` key) while `PdfTextExtractor.prototype.extractTextContent` is still running.
If that happens the `PDFViewer.prototype.getAllText` code would be interrupted, and text-extraction would thus fail in an intermittent and (likely) hard to debug way. To avoid this we replace the current "global" interrupt handling with an optional `AbortSignal` instead.
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[1] See e.g. `pdf.pdf` in the test-suite.
Hopefully I'm not misunderstanding why it was written like that, however using an existing method should be a tiny bit more efficient than querying the DOM.
