This is something that I noticed while attempting to debug https://bugzilla.mozilla.org/show_bug.cgi?id=1374945.
Just looking at the code, the `YRsiz` parameter seemed immediately wrong and the fact that every component used the *same* data also looked strange.
Comparing with the specification, see https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.800-200208-S!!PDF-E&type=items#page=37, confirmed that this is indeed incorrect.
Note that I haven't got any example of a PDF file that is fixed by this patch, but that might be more luck than anything else. Manually checking a couple of files with included JPEG 2000 images, the `Csiz`/`XRsiz`/`YRsiz` parameters were `1` which could explain why this hasn't been an issue before.
Obviously we shouldn't generally make changes to `core` code without adding tests, but in this case I'm simply not sure how to obtain/create one. However, since the existing code doesn't make sense this patch could hopefully be deemed acceptable anyway.
Since multiple empty lines is virtually unused in the code-base, and the few cases that do exist look like "typos", let's enforce greater consistency here; please see https://eslint.org/docs/rules/no-multiple-empty-lines.
It is only used in a few places to handle prefixing style properties if
necessary. However, we used it only for `transform`, `transformOrigin`
and `borderRadius`, which according to Can I Use are supported natively
(unprefixed) in the browsers that PDF.js 2.0 supports. Therefore, we can
remove this class, which should help performance too since this avoids
extra function calls in parts of the code that are called often.
The `gulp-util` module is now deprecated and authors are asked to stop
using it (refer to https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5 for
more information).
PDF.js does not rely on it that much, fortunately, so it's relatively
easy for us to remove the dependency. This patch does that by making the
following changes:
- Require `gulp-zip` version 4.1.0 or higher since they already removed
their `gulp-util` dependency in that version.
- Replace `gulp-util.log` with the `fancylog` module as recommended in
the article above.
- Replace `gulp-util.File` with the `Vinyl` module as recommended in the
article above.
The only change I had to make for Vinyl is removing the `base` and `cwd`
lines since they may not be empty strings anymore. This way we fall back
to the defaults Vinyl provides, which for us doesn't matter since we
move the file afterwards anyway. Moreover, I used `vfs` for `vinyl-fs`
in the `Gulpfile` to avoid confusion with `vinyl` (which is also how the
documentation names the variable).
This is all we can do on our side; the other modules that still use
`gulp-util` must be updated upstream.
I've been looking into the remaining point in 8637 about blurry images, to see if we could perhaps improve the rendering quality slightly there. After quite a bit of debugging, it seems that the issue is limited to certain progressive JPEG images.
As mentioned previously, I've got no detailed knowledge of the JPEG format, but this patch does seem to improve things quite a bit for the images in question.
Squinting at https://searchfox.org/mozilla-central/rev/6c33dde6ca02b389c52e8db3d22494df8b916f33/media/libjpeg/jdphuff.c#492-639, it seems reasonable that we should take the sign of the data into account. Furthermore, looking at the specification in https://www.w3.org/Graphics/JPEG/itu-t81.pdf#page=118, the "F.2.4.3 Decoding the binary decision sequence for non-zero DC differences and AC coefficients" section even contains a description of this (even though I cannot claim to really understand the details).
The bug that this patch fixes is limited to the built-in JPEG decoder, and was unearthed by PR 9260. The underlying issue has existed since PR 6984, where the contents of this patch ought to have been included (if it weren't for the fact that we had no *easy* way to test `src/core/jpg.js` back then).
*Please note:* The slight movement in the reference test is a result of using the `src/core/jpg.js` decoder, rather than the native browser one.
This was an oversight in PR 9095, which unfortunately breaks rendering in some PDF files (e.g. the one from issue 6737).
It thus appears that we don't have any test-coverage for this code-path, and given the relative complexity of the PDF files affected by this bug I wasn't able to easily create a reduced test-case.
*Please note:* The linked test-case included in this patch is currently *not* rendered correctly (that'd be the PR 6606), but it at least gives us some test-coverage here.
Initially I just implemented the unit tests, but quickly found that they
were failing my expectation of having a size of 256 items. Some of them
did contain 256 items and some did not. I looked up various resources
and figured that they indeed all need to have 256 items. One of the good
resources is https://github.com/davidben/poppler/blob/master/poppler/FontEncodingTables.cc
Aside from some missing `notdef` (empty string) entries at the end of
the arrays, which I assume causes issues since it may cause
out-of-bounds array access which in JavaScript gives `undefined`, there
was a `notdef` entry missing in the `MacExpertEncoding`, causing the
entries after that to be shifted. This fix for this is similar to the
one in #8589.
The unit tests verify that, for known encoding names, the return value
is not only an array, but that it is also of the right length and
contains only strings.
The PDF file in the issue uses a number of *embedded* versions of Lucida fonts, but for some reason does *not* embed the LucidaSans-Demi font. According to https://en.wikipedia.org/wiki/Lucida#Usages that one should be bold, so we can at least improve rendering here (even though it won't look perfect).
Fixes 9291.
I recall being confused as to the purpose of the `encrypted` property all the way back when working on PR 4750.
Looking at the history, this property was added in PR 1698 when password support was added to the API/viewer. However, its only purpose seem to have been to facilitate the addition of a `isEncrypted` function in the API. That function never, as far as I can tell, saw any use and was unceremoniously removed in PR 4144.
Since we want to avoid sending all non-essential data early during initial document loading (e.g. PR 4750), it seems correct to get rid of the `encrypted` property. Especially since it hasn't even been exposed in the API for over three years, with no complaints that I'm aware of.
Finally note that the `encrypt` property on the `XRef` instance isn't tied to the code that's being removed here. Given that we're calling `PDFDocument.parse` during `createDocumentHandler` in the worker which, via `PDFDocument.setup`, calls `XRef.parse` where the `Encrypt` data (if it exists) is always parsed.
This patch refactors the searching for 'endobj', to try and find the next occurance of "obj" and then check if it was in fact an 'endobj' and continue searching otherwise.
This approach is used to avoid having to first find 'endobj', and then re-check the entire contents of the object and having to run (potentially expensive) regular expressions on arbitrary long strings.
Fixes 9105.
Please note that while this could be considered a regression in user-facing behaviour, I'm not convinced that it's really a regression as such since prior to PR 8912 the Metadata would fail to parse (with an XML error) and thus be ignored when setting the viewer title.
With the refactored Metadata parsing we're now able to parse this, which uncovered issues with a subset of broken Ghostscript Metadata that uses HTML character names.
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1424938
