Note that no other image stream implements a special `getBytes` method, which makes `JpegStream` look somewhat odd.
I'm actually not sure what purpose this methods serves, since I successfully ran all tests locally with it commented out. Furhermore, I also ran tests with an added `if (length && length !== this.bufferLength) { throw new Error('length mismatch'); }` check, and didn't get a single test failure in that case either.
Looking at the history, it seems that this code originated back in PR 4528, but as far as I can tell there's no mention in either commit messages nor PR comments of why it was necessary to add a "special" `getBytes` function for the `JpegStream`.
My assumption is that there's a good reason why this method was added, e.g. to address a *specific* regression in one of the reference tests. However, I did check out commit 58f697f977 locally and ran tests with this method commented out, and there didn't seem to be any image-related failures in that case either!?
Hence I'm suggesting that we attempt to simplify this code slightly be removing this special `getBytes` method. However, please note that there's perhaps a *small* risk of regressions in an edge-case where we currently have insufficient test-coverage.
There's a number of issues with the fonts in the referenced PDF file. First of all, they contain broken `ToUnicode` data (`NUL` bytes all over the place). However even if you skip those, the `ToUnicode` data appears to contain nothing but a `IdentityH` CMap which won't help provide a proper glyph mapping.
The real issue actually turns out to be that the PDF file uses the "Calibri" font[1], but doesn't include any font files. Since that one isn't a standard font, and uses a fairly different CID to GID map compared to the standard fonts, we're not able to render the file even remotely correct.
To work around this, I'm thus proposing that we include a (incomplete) glyph map for Calibri, and fallback to the standard Helvetica font. Obviously this isn't going to look perfect, but it's really the best that we can hope to achieve given that the PDF file is missing the necessary font data.
Finally, please note that none of the PDF readers I've tried (Adobe Reader, PDFium in Chrome) were able to extract the text (which isn't very surprising, given the broken `ToUnicode` data).
Fixes 9195.
---
[1] According to Wikipedia, see https://en.wikipedia.org/wiki/Calibri, Calibri is (primarily) a Windows font.
In some fonts, the included `ToUnicode` data is incomplete causing text-selection to not work properly. For simple fonts that contain encoding data, we can manually build a `ToUnicode` map to attempt to improve things.
Please note that since we're currently using the `ToUnicode` data during glyph mapping, in an attempt to avoid rendering regressions, I purposely didn't want to amend to original `ToUnicode` data for this text-selection edge-case.
Instead, I opted for the current solution, which will (hopefully) give slightly better text-extraction results in PDF file with incomplete `ToUnicode` data.
According to the PDF specification, see [section 9.10.2](http://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf#G8.1873172):
> A conforming reader can use these methods, in the priority given, to map a character code to a Unicode value.
> ...
Reading that paragraph literally, it doesn't seem too unreasonable to use *different* methods for different charcodes.
Fixes 8229.
The interface of all of the "image" streams look kind of weird, and I'm actually a bit surprised that there hasn't been any errors because of it.
For example: None of them actually implement `readBlock` methods, and it seems more luck that anything else that we're not calling `getBytes()` (without providing a length) for those streams, since that would trigger a code-path in `getBytes` that assumes `readBlock` to exist.
To address this long-standing issue, the `ensureBuffer` methods are thus renamed to `readBlock`. Furthermore, the new `ensureBuffer` methods are now no-ops.
Finally, this patch also replaces `var` with `let` in a number of places.
In the PDF file, the `ToUnicode` data first maps the hyphen correctly, and then *overwrites* it to point to the softhyphen instead. That one cannot be rendered in browsers, and an empty space thus appear instead.
Fixes 9084.
This patch makes use of the existing `ignoreErrors` property in `src/core/evaluator.js`, see PRs 8240 and 8441, thus allowing us to attempt to recovery as much as possible of a page even when it contains broken XObjects.
Fixes 8702.
Fixes 8704.
*Follow-up to PR 8909.*
This requires us to pass around `pdfFunctionFactory` to quite a lot of existing code, however I don't see another way of handling this while still guaranteeing that we can access `PDFFunction` as freely as in the old code.
Please note that the patch passes all tests locally (unit, font, reference), and I *very* much hope that we have sufficient test-coverage for the code in question to catch any typos/mistakes in the re-factoring.
The `inline` parameter is passed to a number of methods/functions in `PDFImage`, despite not actually being used. Its value is never checked, nor is it ever assigned to the current `PDFImage` instance (i.e. no `this.inline = inline` exists).
Looking briefly at the history of this code, I was also unable to find a point in time where `inline` was being used.
As far as I'm concerned, `inline` does nothing more than add clutter to already very unwieldy method/function signatures, hence why I'm proposing that we just remove it.
To further simplify call-sites using `PDFImage`/`NativeImageDecoder`, a number of methods/functions are changed to take Objects rather than a bunch of (somewhat) randomly ordered parameters.
I don't have a good example at hand right know, but I recall seeing custom deployments of PDF.js that bundle a *specific* version of the `build/pdf.js` file and then set `PDFJS.workerSrc` to point to https://mozilla.github.io/pdf.js/build/pdf.worker.js.
That practice seems really bad since, besides (obviously) causing unnecessary server load, it will very quickly result in a version mismatch between the `pdf.js` and `pdf.worker.js` files in those PDF.js deployments.
Such a version mismatch could easily lead to either breaking errors, or even worse slightly inconsistent behaviour for an API call (if the API -> Worker interface changes, which does happen from time to time).
To avoid the problems described above, I'm thus proposing that we enforce that the versions of the `pdf.js` and `pdf.worker.js` files must always match.
Looking at `ColorSpace.parseToIR`, it will do one of the following things when called:
1. Return a String.
2. Return an Array.
3. Throw a `FormatError`.
4. In one case, return the result of *another* `ColorSpace.parseToIR` call.
However, under no circumstances will it ever return an `AlternateCS` instance.
Since it's often useful to understand why code, which has become unused, existed in the first place, let's grab a hard hat and a shovel and start digging through the history of this code :-)
The current condition was introduced in commit c198ec4323, in PR 794, but it was actually already obsolete by that time.
The preceeding `instanceof SeparationCS` condition predates commit a7278b7fbc, in PR 700.
That condition was originally introduced all the way back in commit 4e3f87b60c, in PR 692. However, it was made obsolete by commit 9dcefe1efc, which is included in the very same PR!
Hence we're left with the conclusion that not only has this code be unused for *almost* six years, it was basically never used at all save for a few refactoring commits that're part of PR 692.
Bug 1392647 has a PDF where the default width of the font
is 0. It draws some charcodes that don't have glyphs, but
we were wrongly using the 1000 default width for these
charcodes causing some text to be overlapping.
(for issue #6289)
This does the same for 16 bit as the existing 8 bit tiff predictor code, an addition of the last word to this word.
The last two "& 0xFF" may or may not be needed, I see this isn't done in the 8 bit code, but I'm not a JS developer.
Currently `PDFFunction` is implemented (basically) like a class with only `static` methods. Since it's used directly in a number of different `src/core/` files, attempting to pass in `isEvalSupported` would result in code that's *very* messy, not to mention difficult to maintain (since *every* single `PDFFunction` method call would need to include a `isEvalSupported` argument).
Rather than having to wait for a possible re-factoring of `PDFFunction` that would avoid the above problems by design, it probably makes sense to at least set `isEvalSupported` globally for `PDFFunction`.
Please note that there's one caveat with this solution: If `PDFJS.getDocument` is used to open multiple files simultaneously, with *different* `PDFJS.isEvalSupported` values set before each call, then the last one will always win.
However, that seems like enough of an edge-case that we shouldn't have to worry about it. Besides, since we'll also test that `eval` is actually supported, it should be fine.
Fixes 5573.
When looking briefly at using `Number.isInteger`/`Number.isNan` rather than `isInt`/`isNaN`, I noticed that there's a couple of not entirely straightforward cases to consider.
At first I really couldn't understand why `parseInt` is being used like it is in `XRef.fetchUncompressed`, since the `num` and `gen` properties of an object reference should *always* be integers.
However, doing a bit of code archaeology pointed to PR 4348, and it thus seem that this was a very deliberate change. Since I didn't want to inadvertently introduce any regressions, I've kept the `parseInt` calls intact but moved them to occur *only* when actually necessary.[1]
Secondly, I noticed that there's a redundant `isCmd` check for an edge-case of broken operators. Since we're throwing a `FormatError` if `obj3` isn't a command, we don't need to repeat that check.
In practice, this patch could perhaps be considered as a micro-optimization, but considering that `XRef.fetchUncompressed` can be called *many* thousand times when loading larger PDF documents these changes at least cannot hurt.
---
[1] I even ran all tests locally, with an added `assert(Number.isInteger(obj1) && Number.isInteger(obj2));` check, and everything passed with flying colours.
However, since it appears that this was in fact necessary at one point, one possible explanation is that the failing test-case(s) have now been replaced by reduced ones.
Since this patch will now treat (some) `NUL` bytes as "ASCII", the number of `followingBytes` checked are thus increased to (hopefully) reduce the risk of introducing new false positives.
Fixes 8823.
According to the specification, see http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/PDF32000_2008.pdf#page=377, a `Dest` entry in an outline item should *not* contain a dictionary.
Unsurprisingly there's PDF generators that completely ignore this, treating is an `A` entry instead.
The patch also adds a little bit more validation code in `Catalog.parseDestDictionary`.
Since we're now using `Uint8ClampedArray`, rather than `Uint8Array`, doing manual clamping shouldn't be necessary given that that is now handled natively.
This shouldn't have any measurable performance impact, but just to sanity check that I've done some quick benchmarking with the following manifest file:
```json
[
{ "id": "S2-eq",
"file": "pdfs/S2.pdf",
"md5": "d0b6137846df6e0fe058f234a87fb588",
"rounds": 100,
"type": "eq"
}
]
```
which gave the following results against the current `master` (repeated benchmark runs didn't result in any meaningful differences):
```
-- Grouped By browser, stat --
browser | stat | Count | Baseline(ms) | Current(ms) | +/- | % | Result(P<.05)
------- | ------------ | ----- | ------------ | ----------- | --- | ----- | -------------
firefox | Overall | 100 | 592 | 592 | 1 | 0.12 |
firefox | Page Request | 100 | 3 | 3 | 0 | -9.88 |
firefox | Rendering | 100 | 588 | 589 | 1 | 0.18 |
```
This patch removes the `clamp0to255` helper function, as well as manual clamping code in `src/core/jpg.js`.
The adjusted constants in `_convertCmykToRgb` were taken from CMYK to RGB conversion code found in `src/core/colorspace.js`.
*Please note:* There will be some very slight movement in a number of existing test-cases, since `Uint8ClampedArray` appears to use `Math.round` (or equivalent) and the old code used (basically) `Math.floor`.
This appears to simply have been forgotten in the re-factoring in PR 4815, where the `coded` property was renamed to the *much* more descriptive `isType3Font` property.
From looking at blame, it seems that these checks became obsolete with PR 692 (which landed close to six years ago). Note how, after that PR, there's no longer anything being assigned to the `code` property of an Object.
In issue #8707, there's a char code mapped to a non-
existing glyph which shouldn't be drawn. However, we
saw it was missing and tried to then use the post table and
end up mapping it incorrectly.
This illuminated a problem with issue #5704 and bug
893730 where glyphs disappeared after above fix. This was
from the cmap returning the wrong glyph id. Which in turn was
caused because the font had multiple of the same type of cmap
table and we were choosing the last one. Now, we instead
default to the first one. I'm unsure if we should instead be
merging the multiple cmaps, but using only the first one works.
Added unit-tests for DeviceGray, DeviceRGB and DeviceCMYK
Added unit-tests for CalGray
Added unit-tests for CalRGB
Removed redundant code
Added unit-tests for LabCS
Added unit-tests for IndexedCS
Update comment
Change lookup to Uint8Array as mentioned in pdf specs(these tests will pass after PR #8666 is merged).
Added unit-tests for AlternateCS
Resolved code-style issues
Fixed code-style issues
Addressed issues pointed out in https://github.com/mozilla/pdf.js/pull/8611#pullrequestreview-52865469
The initial issue with #8255 was I added a missing glyphs
check to adjustMapping, but this caused us to skip re-mapping
a glyph if the fontCharCode was a missingGlyph which in turn
caused us to overwrite a valid glyph id with an invalid one. While
fixing this, I also added a warning if the private use area is full since
this also accidentally happened when I made a different mistake.
This brought to light a number of issues where we map
missing glyphs to notdef, but often the notdef is actually defined
and then ends up being drawn. Now the glyphs don't get
mapped in toFontChar and so they are not drawn by the canvas.
Fixing the above brought up another issue though in bug1050040.pdf.
In this PDF, the font fails to load by the browser and before we were still
drawing the glyphs because it looked like the font had them, but with the fixes
above the glyphs showed up as missing so we didn't attempt draw them. To
fix this, I now throw an error when the loca table is in really bad shape and
we fall back to trying to use a system font. We now also use this fall back if
there are any format errors during converting fonts.
The PDF file uses a non-embedded SegoeUISymbol font, which is *not* a standard font (and is mainly used by Microsoft, see https://en.wikipedia.org/wiki/Segoe).
Fixes 8697.
This replaces `assert` calls with `throw new FormatError()`/`throw new Error()`.
In a few places, throwing an `Error` (which is what `assert` meant) isn't correct since the enclosing function is supposed to return a `Promise`, hence some cases were changed to `Promise.reject(...)` and similarily for `createPromiseCapability` instances.
