Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1200096.
The problematic font has a `format 2` cmap, which we've never supported properly. Prior to PR 2606, we were able to fallback to a working state, despite not having proper support for that cmap format.
Obviously the best/correct solution would be to implement actual support for more cmap formats[1]. However, I'm hoping that a simple patch will be OK for now, given that:
- `format 2` cmaps seem to be quite rare in practice, since this has been broken for 2.5 years before anyone noticed.
- Having a simple patch will make potential uplifts a lot easier.
[1] See the specification at https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6cmap.html
Re: PR 4731.
Since the URL points to the Internet Archive, I think that adding a linked test-case should be OK. (Also, it's difficult to create reduced, or even `unit`, tests that accurately captures the brokenness of real-world PDF files.)
*Please note:* Since this is a `load` test, `makeref`ing won't be needed.
Our current test coverage for vertical text is somewhat lacking, as evident from e.g. issue 6387. That regression could easily have been avoided if the `taro` test-case would have been an `eq` test, as well as an `text` test.
Currently we only attempt to test the *first* page, since `lastPage == 1`, but given that it's subsequently skipped we end up not testing anything.
*Note:* I've verified that the *second* page actually contains the kind of Colour space that the test was intended to check for.
This patch improves the detection of `xref` in files where it is followed by an arbitrary whitespace character (not just a line-breaking char).
It also adds a check for missing whitespace, e.g. `1 0 obj<<`, to speed up `readToken` for the PDF file in the referenced issue.
Finally, the patch also replaces a bunch of magic numbers with suitably named constants.
Fixes 5752.
Also improves 6243, but there are still issues.
The problem with the PDF files in the issue, besides the obviously broken XRef tables which we're able to recover from, is that many/most of the streams have Dictionaries where the `Length` entry is set to `0`. This causes us to return `NullStream`, instead of the appropriate one in `Parser_makeFilter`.
Fixes 6360.
Short story: somebody got lost in two different indices. pi is an index in the stream and is explained on page 198 of the 32000-spec (however 1-based there), and ps is an index to something in PDF.js. I used the code from flag 0 (which works) to understand which is which. It is also important to understand that for flags 1,2 and 3, the stream is always assigned to the same coordinates and colors. What changes is which "old" coordinates and colors are assigned to what is "missing" in the stream. This is why for these flags, the code is identical except for the assignments in the first "row".
When the parser finds a stream, it retrieves the Length from the stream
dictionary and advances the lexer to the offset as specified in Length.
If this Length is incorrect, the lexer could end up anywhere.
When the lexer gets in an invalid state, it could throw errors. For
example, in issue 6108, the lexer ends up inside the stream data. This
stream has the ASCIIHexDecode filter, so all characters are made up from
ASCII characters, and the lexer interprets it as a command token. Tokens
cannot be longer than 127 bytes, so eventually 128 bytes are consumed
and the lexer throws "Command token too long" error.
Another possible error is "Illegal character: 41" when the lexer happens
to end up at a ')' due to the length mismatch.
These problems are solved by catching lexer errors and recovering the
parser via the existing stream length detection branch.
Xref offsets are relative to the start of the PDF data, not to the start
of the PDF file. This is clear if you look at the other code:
- In the XRef's readXRefTable and processXRefTable methods of XRef, the
offset of a xref entry is set to the bytes as given by a PDF file.
These values are always relative to the start of the PDF file (%PDF-).
- The XRef's readXRef method adds the start offset of the stream to
Xref entry's offset: "stream.pos = startXRef + stream.start".
Clearly, this line assumes that the entry offset excludes the start
offset.
However, when the PDF is parsed in recovery mode, the xref table is
filled with entries whose offset is relative to the start of the stream
rather than the PDF file. This is incorrect, and the fix is to subtract
the start offset of the stream from the entry's byte offset.
The manually created PDF file serves as a regression test. It is a valid
PDF, except:
- The integer to point to the start of the xref table and the %%EOF
trailer are missing. This will activate recovery mode in PDF.js
- Some junk was added before the start of the PDF file. This exposes the
bad offset bug.
This patch adds:
- Unit tests for the annotation border style class
- Regression test (self-made) for the annotation border style class
- Documentation generation using JSDoc
Fixes 6068.
The most notable issue with the font in question is that the `differences` array contains lots of strange entries (of the type `uniXXXX`, instead of proper glyph names).
For passwords where the encoding already is correct, the conversion is a no-op.
Also, since `encodeURIComponent` might throw, we need to make sure that we handle that case too.
Fixes 6010.
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1050040.
With this patch the file is completely readable, but given that the font is broken enough to be rejected by OTS the rendering differs slightly from Adobe Reader.
*Note:* the PDF file is sufficiently broken that even Adobe Reader complains about the font, *and* also about another more general issue.
Prior to PR 4259, we *incorrectly* ignored `toUnicode` for Type3 fonts. Since we now handle that correctly, this patch adds a `text` test-case to prevent regressions.
According to practical experiments, falling back to "Helvetica" when we encounter a non-embedded "[Century Gothic](http://en.wikipedia.org/wiki/Century_Gothic)" `CIDFontType2` font seems to work well.
(Also, the section on Wikipedia about "Printer ink usage" *might* provide some anecdotal evidence that Century Gothic is a fairly standard sans-serif font.)
Obviously this patch doesn't make "Century Gothic" fonts render perfectly, as is often the case with non-embedded fonts, but all the text is now legible in the referenced issues.
Fixes 4722.
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=879561.
When submitting PR 5276 there wasn't a good PDF file to include in the test suite. However, with https://bugzilla.mozilla.org/show_bug.cgi?id=1108753, we now have a better source for a test file, hence this patch.
