According to the specification, see https://web.archive.org/web/20210404042322if_/https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf#G6.2384179, the keys of a NameTree/NumberTree should be ordered.
For corrupt PDF files, which violate this assumption, it's thus possible that trying to lookup a single entry fails.
Previously, in PR 10274, we implemented a fallback that only applies to the "bottom" node of a NameTree/NumberTree, which in general might not actually help for sufficiently corrupt NameTree/NumberTree data.
Instead we remove the current *limited* fallback from `NameOrNumberTree.get`, and defer to the call-site to handle this case explicitly e.g. by using `NameOrNumberTree.getAll` for data where that makes sense. For well-formed documents, these changes should *not* lead to any additional data fetching/parsing.
Finally, as part of these changes, the validation of named destination data is improved in the `Catalog` and a new unit-test is also added.
To get the maximum benefit from something like Prettier, you obviously don't want to disable the automatic formatting unless absolutely necessary. When we added Prettier there were a number of cases, mostly involving larger Arrays, which required disabling of the automatic formatting for overall readability and/or to not break inline comments.
With changes in Prettier version `2.3.0`, see [the release notes](https://prettier.io/blog/2021/05/09/2.3.0.html#concise-formatting-of-number-only-arrays-10106httpsgithubcomprettierprettierpull10106-10160httpsgithubcomprettierprettierpull10160-by-thorn0httpsgithubcomthorn0), there's now better formatting support for Arrays containing only numbers. Hence we can now remove a number of `// prettier-ignore` comments, and thus get the benefit of automatic formatting in (slightly) more of the code-base.
- in charstring specs at page 21 (section 4.2): "Also, it may appear in the charstring as the difference from nominalWidthX" so the number we've on the stack doesn't have to be positive.
- currently this bug has probably no visible effect
- but when the font is loaded to be used with XFA, then the rendering is incorrect.
As can be seen in PR 13371, some of the `no-var` changes in the `PartialEvaluator.{getOperatorList, getTextContent}` methods caused errors in `gulp server`-mode.
However, there's a handful of instances of `var` in other methods which should be completely *safe* to convert since there's no strange scope-issues present in that code.
With modern JavaScript modules, where only *explicitly* exported properties are visible to the outside, the `QueueOptimizerClosure` should no longer be necessary.
Furthermore, to reduce the possibility of `NullOptimizer` and `QueueOptimizer` getting out of sync (note e.g. the inconsistency fixed in PR 10784), we now let the latter extend the former one.
This patch replaces the old structure with a abstract base-class, which the new RadialAxial/Mesh-shading classes then inherit from.[1]
The old `MeshClosure` can now be removed, since it's not necessary any more, and most of the functions inside of it are now instead methods on the new `MeshShading` class. This is particularly nice, in my opinion, since we previously were *manually* passing around a reference to the current `Mesh`-instance.
---
[1] If we want/need to, in the future, split e.g. the Mesh-handling into multiple classes that should now be easy to do.
Neither the `type` or the `cs` properties are used outside of the "constructors", and we can thus remove them.[1]
Note that a lot of this code is very old, and that it actually predates the main/worker-thread split before which the *same* file was used on both the main- *and* worker-threads.
---
[1] On the main-thread, a similar `type` property was removed in PR 12591.
- Right now, a glyph with an erroneous outline is replaced by an empty glyph
if the error is far enough from the start there's likely something to render
so the idea is to replace a command with args by an endchar when no args are
on the stack: this way OTS is likely happy (no remaining args on stack) and we
can draw something which is likely better than nothing.
First of all, by using `Dict.getArray` in the `Page.content` getter we remove the need to manually iterate through and fetch the sub-streams (when they exist) in the `Page.getContentStream` method.
Secondly, we can simplify the code in `Page.{getOperatorList, extractTextContent}` by letting `Page.getContentStream` ensure that `content` is available and returning a Promise instead.
Similar to the `get`/`getAsync` methods, this should be a *tiny* bit more efficient which cannot hurt considering that `getArray` is now used a lot more than when initially added.
This reverts commit 0ef9b5aafc88094f19fec793c174c622e7e15542, since it cases a lot of warnings (see below) *locally* with e.g. the document from issue 9627.
Strangely enough, this only occurs with `gulp server`-mode and the actual builds are apparently fine. It seems that this *may* be some unfortunate interaction with the old Babel-plugin that's used together with SystemJS.
```
Warning: getTextContent - ignoring ExtGState: "FormatError: ExtGState should be a dictionary.".
```
Rather than taking the risk that this could actually cover a more serious bug, and since I cannot immediately figure out what's wrong, it thus seem safest to revert this for now and we can (carefully) revisit this once SystemJS has been removed (see PR 12563).
This patch was tested using the PDF file from issue 2618, i.e. https://bug570667.bugzilla-attachments.gnome.org/attachment.cgi?id=226471, with the following manifest file:
```
[
{ "id": "issue2618",
"file": "../web/pdfs/issue2618.pdf",
"md5": "",
"rounds": 50,
"type": "eq"
}
]
```
which gave the following results when comparing this patch against the `master` branch:
```
-- Grouped By browser, stat --
browser | stat | Count | Baseline(ms) | Current(ms) | +/- | % | Result(P<.05)
------- | ------------ | ----- | ------------ | ----------- | --- | ---- | -------------
firefox | Overall | 50 | 3417 | 3426 | 9 | 0.27 |
firefox | Page Request | 50 | 1 | 1 | 0 | 5.41 |
firefox | Rendering | 50 | 3416 | 3426 | 9 | 0.27 |
```
Based on these results, there's no significant performance regression from using standard classes and this patch should thus be OK.
Previously, we set the base transformation and pattern matrix
directly to the main rendering ctx of the page, however doing this
caused the current transform to be lost. This would cause issues
with things like shear missing so the pattern was misaligned or when
stroke was used the scale of the line width or dash would be wrong.
Instead we should leave the current transform and use setTransfrom
on the pattern so it is applied correctly. For axial and radial shadings I had
to create a temporary canvas to draw the shading so I could in turn
use setTransform.
Fixes: #13325, #6769, #7847, #11018, #11597, #11473
The following already in the corpus are improved:
issue8078-page1
issue1877-page1
Compared to other data-structures, such as e.g. `Dict`s, we're purposely *not* caching Streams on the `XRef`-instance.[1]
The, somewhat unfortunate, effect of Streams not being cached is that repeatedly getting the *same* Stream-data requires re-parsing/re-initializing of a bunch of data; see `XRef.fetch` and related methods.
For the font-parsing in particular we're currently fetching the `toUnicode`-data, which is very often a Stream, in `PartialEvaluator.preEvaluateFont` and then *again* in `PartialEvaluator.extractDataStructures` soon afterwards.
By instead letting `PartialEvaluator.preEvaluateFont` export the "raw" `toUnicode`-data, we can avoid *some* unnecessary re-parsing/re-initializing when handling fonts.
*Please note:* In this particular case, given that `PartialEvaluator.preEvaluateFont` only accesses the "raw" `toUnicode` data, exporting a Stream should be safe.
---
[1] The reasons for this include:
- Streams, especially `DecodeStream`-instances, can become *very* large once read. Hence caching them really isn't a good idea simply because of the (potential) memory impact of doing so.
- Attempting to read from the *same* Stream-instance more than once won't work, unless it's `reset` in between, since using any method such as e.g. `getBytes` always starts at the current data position.
- Given that parsing, even in the worker-thread, is now fairly asynchronous it's generally impossible to assert that any one Stream-instance isn't being accessed "concurrently" by e.g. different `getOperatorList` calls. Hence `reset`-ing a cached Stream-instance isn't going to work in the general case.
Rather than re-fetching/re-parsing these properties immediately in `PartialEvaluator.translateFont`, we can simply export them instead. (Obviously the effect will be really tiny, but there is less parsing overall this way.)
*Please note:* While I don't have a document that this patches fixes, the current code is however not entirely correct as far as I can tell.
Looking at how the `Widths` array is parsed in `PartialEvaluator.extractWidths`, it's clear that the implementation in `PartialEvaluator.preEvaluateFont` is a bit too simplistic. In particular, by only wrapping the data into a TypedArray, there's no attempt to handle *indirect* objects which could potentially lead to colliding `hash`es being computed.
To hopefully help prevent any future bugs, make sure that composite/non-composite fonts cannot accidentally get matching `hash`es. Given the differences between those font types, that's very unlikely to be useful or even correct in general.
Without this some *composite* fonts may incorrectly end up with matching `hash`es, thus breaking rendering since we'll not actually try to load/parse some of the fonts.
*Please note:* Given that the document, in the referenced issue, doesn't embed *any* of its fonts there's no guarantee that it renders correctly in all configurations even with this patch.
With modern JavaScript modules, where you explicitly list the properties that should be exported, it's no longer necessary to wrap *all* of the code within one file into a top-level closure.[1]
This patch reduces the size, of even the *built* `pdf.worker.js` file, since there's now a lot less unnecessary whitespace.
---
[1] For files which contain *different* functionality, some closures may however still make sense in order to separate the code.
It might be possible to remove some of those cases later, e.g. once private class fields becomes generally available/usable in browsers.
*My apologies for breaking this; thankfully PR 13303 hasn't reach mozilla-central yet.*
It's (obviously) necessary to initialize a `PredictorStream`-instance fully, since otherwise breakage may occur if there's errors during the actual stream parsing.
To reproduce this issue, try opening the PDF document from issue 13051 locally and observe the following message in the console:
```
Warning: Invalid stream: "ReferenceError: this hasn't been initialised - super() hasn't been called"
```
It shouldn't be possible for the `getBytes`-call to throw a `MissingDataException`, since all resources are loaded *before* e.g. font-parsing ever starts; see f0817015bd/src/core/object_loader.js (L111-L126)
Furthermore, even if we'd *somehow* re-throw a `MissingDataException` here that still won't help considering where the `Type1Font`-instance is created. Note how in the `Font`-constructor we simply catch any errors and fallback to a standard font, which means that a `MissingDataException` would just lead to rendering errors anyway; see f0817015bd/src/core/fonts.js (L648-L691)
All-in-all, it's not possible for a `MissingDataException` to be thrown in `getHeaderBlock` and this code-path can thus be removed.
