*Please note:* This is only a, hopefully generally helpful, work-around rather than a proper solution to issue 15292.
There's something that's "special" about the Type1 fonts in the referenced PDF document, since we don't manage to find any actual font programs and thus cannot render anything.
Given that it shouldn't make sense for a Type1 font program to ever be empty, since that means that there's no glyph-data to render, we simply fallback to a standard font to at least try and render *something* in these rare cases.
Given that the change in PR 13393 was slightly speculative, given the lack of test-cases, let's just revert part of that to fix the referenced issue.
Based on a quick look at old issues and existing test-cases, it seems that most (if not all) PDF documents that benefit from using the font-data in this way lack any /ToUnicode maps which should mean that they're unaffected by these changes.
Given that the official Bower website, since almost five years, has been advising users to utilize other tools it doesn't seem entirely necessary to keep including the `bower.json` file in the `pdfjs-dist` repository; see e.g. https://bower.io/blog/2017/how-to-migrate-away-from-bower/
This patch proposes removing the `browserify` example for the following reasons:
- The last `browserify` release was almost two years ago, according to both https://github.com/browserify/browserify/releases and https://www.npmjs.com/package/browserify?activeTab=versions
- The project no longer seems to be actively maintained, since so far this year there's only been *a single* (seemingly trivial) patch merged; see https://github.com/browserify/browserify/commits/master
- Because of the previous points `browserify` doesn't support modern and up-to-date JavaScript features, as evident from e.g. issue 14731 and multiple issues found in https://github.com/browserify/browserify/issues
- Our `browserify` example is most likely not very commonly used, judging by the very low volume of issues/PRs related to it. Looking at the `git` history of that example the only changes have been lint- or maintenance-related.[1]
- Providing an example for a framework that's no longer actively maintained doesn't seem like a good idea in general, since we probably don't want to steer users towards using (possibly) older frameworks.
- Given that we've never used `browserify` in the PDF.js project, it's also quite difficult to provide support for the example.
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[1] It's interesting to compare with the `webpack` example, since that's generated both issues *and* also PRs (for missing features) from users.
Note that this patch implements the `SetOCGState`-handling in `PDFLinkService`, rather than as a new method in `OptionalContentConfig`[1], since this action is nothing but a series of `setVisibility`-calls and that it seems quite uncommon in real-world PDF documents.
The new functionality also required some tweaks in the `PDFLayerViewer`, to ensure that the `layersView` in the sidebar is updated correctly when the optional-content visibility changes from "outside" of `PDFLayerViewer`.
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[1] We can obviously move this code into `OptionalContentConfig` instead, if deemed necessary, but for an initial implementation I figured that doing it this way might be acceptable.
It slightly helps to reduce the code size and its complexity.
But the cool thing is that it allows to copy/paste some anntations from a pdf
to an other.
Apparently this is implemented in e.g. Adobe Reader, and the specification does support it, however it cannot be commonly used in real-world PDF documents since it took over ten years for this feature to be requested.
A number of Annotation-types are currently creating their own PopupAnnotations, since they need to use a custom `trigger`-element. However, because of where that check is currently implemented[1] we end up attaching empty/unused containers for those PopupAnnotations to the DOM[2]; see e.g. the `annotation-line.pdf` file in the test-suite for one example.
By instead moving the types-check into the `PopupAnnotationElement` constructor, we can completely skip those PopupAnnotations that are being explicitly handled elsewhere.
Note that I don't *believe* that this is a new issue, although I've not tried to bisect it, but this likely goes back quite some time (possibly even as far as PR 8228).
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[1] In the `PopupAnnotationElement.render` method.
[2] Please note that the actual Popup-element *itself* isn't being attached/rendered here, just its container which by itself serves no purpose as far as I can tell.
There's three notable exceptions here:
- The `saveDocument` one is converted into a permanent `warn`, since it still works when the `annotationStorage` is empty although it's (obviously) less efficient than `getData`.
- The `fallbackWorkerSrc` functionality (for browsers), since just removing it would risk too much third-party breakage.
- The SVG back-end, since a final decision is yet to be made. (It might be completely removed, or left as-is in an essentially "frozen" state.)
