Rather than having two different (but connected) options for the textLayer, I think that it makes sense to try and unify this. For example: currently if `disableTextLayer === true`, then the value of `enhanceTextSelection` is simply ignored.
Since PDF.js version `2.0` already won't be backwards compatible in lots of ways, I don't think that we need to worry about migrating existing preferences here.
This removes the `PDFJS.externalLinkTarget`/`PDFJS.externalLinkRel` dependency from the viewer components, but please note that as a *temporary* solution the default viewer still uses it.
This removes the `PDFJS.imageResourcesPath` dependency from the viewer components and the test-suite, but please note that as a *temporary* solution the default viewer still uses it.
This removes the `PDFJS.maxCanvasPixels` dependency from the viewer components, but please note that as a *temporary* solution the default viewer still uses it.
This removes the `PDFJS.useOnlyCssZoom` dependency from the viewer components, but please note that as a *temporary* solution the default viewer still uses it.
Unfortunately, as far as I can tell, we still need the ability to adjust certain viewer options depending on the browser environment in PDF.js version `2.0`. However, we should be able to separate this from the general compatibility code in the `src/shared/compatibility.js` file.
This rule is available from https://www.npmjs.com/package/eslint-plugin-mozilla, and is enforced in mozilla-central. Note that we have the necessary `Array`/`String` polyfills and that most cases have already been fixed, see PRs 9032 and 9434.
This rule is available from https://www.npmjs.com/package/eslint-plugin-mozilla, and is enforced in mozilla-central. Note that we have a polyfill for `ChildNode.remove()` and that most cases have already been fixed, see PRs 8056 and 8138.
Fallback to the built-in JPEG decoder when browser decoding fails, and attempt to handle JPEG images with DNL (Define Number of Lines) markers (issue 8614)
The code responsible for highlighting/scrolling thumbnails is quite old, and parts of it hasn't really changed much over time.
In particular, the `scrollThumbnailIntoView` method is currently using `document.querySelector` in order to find both the new/current thumbnail element. This seems totally unnessary, since we can easily keep track of the current thumbnail (similar to the "regular" viewer) and thus avoid unnecessary DOM look-ups.
Furthermore, note how the `PDFThumbnailView` constructor is currently highlighting the *first* thumbnail. This is yet another leftover from older viewer code, which we can now remove and instead take care of in `PDFThumbnailViewer.setDocument`.
Given that `PDFThumbnailView` does not, nor should it, have any concept of which thumbnail is currently selected, this change also improves the general structure of this code a tiny bit.
First of all, note how in both `fetch_stream.js` and `node_stream.js` we always overwrite the `this._contentLength` property even when the response headers doesn't actually contain any (valid) length information. This could thus result in the `length` parameter, as passed to the network stream, being completely ignored despite having no better information available.
Secondly, in `node_stream.js` the `this._isRangeSupported` property wasn't always updated correctly based on the response headers.
Please refer to the specification, found at https://www.w3.org/Graphics/JPEG/itu-t81.pdf#page=49
Given how the JPEG decoder is currently implemented, we need to know the value of the scanLines parameter (among others) *before* parsing of the SOS (Start of Scan) data begins.
Hence the best solution I could come up with here, is to re-parse the image in the *hopefully* rare case of JPEG images that include a DNL (Define Number of Lines) marker.
Fixes 8614.
This works by making `PartialEvaluator.buildPaintImageXObject` wait for the success/failure of `loadJpegStream` on the API side *before* parsing continues.
Please note that in practice, it should be quite rare for the browser to fail loading/decoding of a JPEG image. In the general case, it should thus not be completely surprising if even `src/core/jpg.js` will fail to decode the image.
Since `loadJpegStream` is only used at a *single* spot in the code-base, and given that it's very heavily tailored to the calling code (since it relies on the data structure of `PDFObjects`), this patch simply inlines the code in `src/display/api.js` instead.
This method currently requires a fair number of parameters, which creates quite unwieldy call-sites. When invoking `buildPaintImageXObject`, you have to remember not only which arguments to supply, but also the correct order, to prevent run-time errors.
After the latest update of the minimum supported Firefox version, the development addon is no longer being signed. Hence this patch attempts to address that, by pinning the `minVersion` to a specific version number instead.
*Please note:* The version numbers were taken from https://addons.mozilla.org/en-US/firefox/pages/appversions/, so it ought to have worked.
At this point in time, trying to keep the development addon compatible with prior Firefox versions is already quite difficult and will become even harder very soon.
Please keep in mind that since Firefox 57, only WebExtensions are allowed/possible to install. The only exceptions are Firefox Nightly, with the `xpinstall.signatures.required` preference[1] set to `false`, and the (as of this writing) current ESR release.[2]
With the current compatibility situation, we thus need to effectively support both Nightly *and* ESR in the addon, while trying to keep up with current/upcoming changes in `mozilla-central`. With old addons no longer being officially supported, the amount of old code being removed/refactored is now increasing quite quickly.
*Please note:* The changes proposed here was to a large extent prompted by bugs such as:
- https://bugzilla.mozilla.org/show_bug.cgi?id=1431533 (already landed)
- https://bugzilla.mozilla.org/show_bug.cgi?id=767640 (already landed)
- https://bugzilla.mozilla.org/show_bug.cgi?id=1432992 (still open)
Upstreaming all of those changes for the `MOZCENTRAL` version of PDF.js, while also keeping the Firefox addon running in older versions of the browser, would quickly become non-trivial.
Since we're using the ruleset from `eslint-plugin-mozilla` for the addon files, which is enforced in `mozilla-central`, we must ensure that the neccessary changes are upstreamed to the PDF.js repo such that the `mozilla-central` version of PDF.js can still be updated without failures.
Trying to feature detect, for the `FIREFOX` build target, some of the changes in the referenced bugs would probably become both quite messy and (not to mention) difficult. E.g. with the upcoming and automatically defined `Cc, Ci, Cu, Cr` variables, any sort of feature detection might be tricky since those need to be defined in the global scope of the files in question.
Finally, given the amount of effort that we'd now need to spend to even attempt to keep the Firefox addon compatible, I just don't think it's worth the effort any more. Especially since the number of people that have, thus far, been doing this work is *very* low and those resources would be better spend elsewhere.
Unfortunately, this probably means that the development addon will no longer be compatible with release versions of Seamonkey. However the README has already mentioned, for quite some time, that support isn't guaranteed.
*In closing:* For all of the reasons mentioned above, I thus propose that we reduce the maintenance burden of the Firefox addon by only supporting the current Firefox Nightly.
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[1] While the preference exists, and can be toggled, its value is ignored in non-Nightly versions of Firefox.
[2] There's unbranded builds of e.g. the release/beta versions of Firefox, where old and non-WebExtensions addons can be installed. However those builds can probably be assumed to be officially unsupported, and thus not recommended for users.
