Note, this only really fixes Radial/Axial shading patterns with masks.
I'm guessing tiling patterns and mesh patterns would also be broken
if applied like the test pdf. Hopefully I'll have some time to make
test cases for the other shadings.
Fixes#13372
- and fix few bugs:
- avoid infinite loop when layout the document;
- avoid confusion between break and layout failure;
- don't add margin width in tb layout when getting available space.
- it aims to avoid to loop forever when opening pdf in #13213;
- the idea is to consider subformSet as inexistent when running in the tree. So if we've subformA > subformSet > subformB then subformB will be visited as a direct child of subformA.
- Some js files contain scale factors for each glyph in order to rescale Liberation to have a final font with the correct width.
- A lot of XFA have some containers where their dimensions are based on their text content, so using default font from browser can lead to an almost unreadable pdf.
For Type3 fonts where the /CharProcs-streams of the individual glyph starts with a `d1` operator, we can use that to build a fallback bounding box for the font and thus improve text-selection in some cases.
For HighlightAnnotations with a built-in appearance stream, we still rely on it to specify the opacity correctly via a suitable blend mode. However, if the Annotation-drawing operators are placed *within* a /XObject of the /Form-type, the /ExtGState won't apply to the final rendering and the result is that the highlighting obscures the underlying text.
The more *correct* and general solution would likely be to somehow modify the implementation in `src/display/canvas.js`, to special-case handling of /Form-type /XObjects when rendering Annotations. Since we can very easily work-around this problem for now by using the "no appearance stream" code-path, doing *something* here ought to be preferable.
This patch is (obviously) merely a work-around, but given that the referenced issue is (as far as I know) the first case we've seen of this problem a simple solution will hopefully suffice for now.
This fixes the colours, by respecting the strokeAlpha/fillAlpha-values, for a couple of Annotations in the PDF document from issue 13447.[1]
---
[1] Some of the annotations still won't render at all, when compared with Adobe Reader, but that could/should probably be handled separately.
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.
- 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.
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
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.
- app.alert and few other function can use an object as parameter ({cMsg: ...});
- support app.alert with a question and a yes/no answer;
- update field siblings when one is changed in an action;
- stop calculation if calculate is set to false in the middle of calculations;
- get a boolean for checkboxes when they've been set through annotationStorage instead of a string.
- but don't validate them for now;
- Firefox will display a bar to warn that the signature validation is not supported (see https://bugzilla.mozilla.org/show_bug.cgi?id=854315)
- almost all (all ?) pdf readers display signatures;
- validation is done in edge but for now it's behind a pref.
When a PDF is "marked" we now generate a separate DOM that represents
the structure tree from the PDF. This DOM is inserted into the <canvas>
element and allows screen readers to walk the tree and have more
information about headings, images, links, etc. To link the structure
tree DOM (which is empty) to the text layer aria-owns is used. This
required modifying the text layer creation so that marked items are
now tracked.
The fontName, as defined in the PDF document, cannot be found in *any* of the "name"-tables in the TrueType Collection font. To work-around that, this patch adds a *fallback* code-path to allow using an approximately matching fontName rather than outright failing.
Fixes#13107
In the issue, some TrueType glyph names have the format `uniXXXX`.
Font's `Encoding` dictionary has the entry `Differences` but no
`BaseEncoding`. `uniXXXX` names are converted to glyph indices
using font's `post` table but currently that is done only when
`BaseEncoding` exists. We must enable the conversion also when only
`Differences` exists.
* JS - Handle correctly hierarchy of fields
- it aims to fix#13132;
- annotations can inherit their actions from the parent field;
- there are some fields which act as a container for other fields:
- they can be access through js so need to add them with an empty type (nothing in the spec about that but checked in Acrobat);
- calculation order list (CO) can reference them so need make them through this.getField;
- getArray method must return kids.
- field values are number, string, ... depending of their type but nothing in the spec on how to know what's the type:
- according to the comment for Canonical Format: https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#page=461
- it seems that this "type" can be guessed from js action Format (when setting a type in Acrobat DC, the only affected thing is this action).
- util.scand with an empty string returns the current date.
This extends PR 13033 slightly, with a heuristic to support corrupt PDF documents where the `LineAnnotation`s have an empty /Rect-entry. Please note that while I have no idea if this is "correct", this patch at least makes us output the same /BBox as re-saving in Adobe Reader does.
- strokeColor corresponds to borderColor;
- support fillColor and textColor;
- support colors on the different annotations;
- fix typo in aforms (+test).
*As far as I can tell, this has been broken ever since PR 3289 (back in 2013) without anyone noticing.*
For any non-`MissingDataException` errors encountered in `ObjectLoader._walk`, we're simply throwing immediately which thus has the potential to *completely* break rendering of an entire page.
In practice this is obviously only an issue for PDF documents which are in one way or another corrupt, since that's the only way that `XRef.fetch` will throw non-`MissingDataException` errors. To make matters worse these errors are *intermittent*, since they can only occur if the document is still loading when the `ObjectLoader`-code runs (note the early return in `ObjectLoader.load`).
Please note that we cannot simply catch the error and let "normal" parsing continue in `ObjectLoader._walk`, since that could lead to errors elsewhere given that resources "below" the current one (in the graph) might not be checked as intended then.
All-in-all, the only way to make absolutely sure that we won't cause *unexpected* `MissingDataException`s somewhere else in the code-base is to fallback to fetching the *entire* document in this edge-case.
- Remove a *duplicated* reference test, see "issue12810", from the manifest.
- Improve the spelling in a couple of comments in `src/core/canvas.js`, most notable of the word "parallelogram".
- Update a comment, also in `src/core/canvas.js`, to actually agree with the value used to reduce confusion when reading the code.
While PR 12725 fixed bug 1671312 as reported, i.e. the "In the upper right corner "Purposes' has bad kerning."-part, it however broke other parts of the text rendering.
Note in particular the tables, e.g. on page 2 and beyond, where the glyphs are now rendered too close together. The reason for this is that the fonts in question are non-embedded ArialNarrow, which we just replace with Helvetica which obviously is not narrow. Given that the font replacement isn't a perfect fit for non-embedded ArialNarrow, we still need to re-measure the glyph widths in this case.
This patch is a rebased *and* refactored version of PR 9448, such that it applies cleanly given that `PDFFindController` has changed since that PR was opened; obviously keeping the original author information intact.
This patch will thus ensure that e.g. fractions, and other things that we normalize before searching, will still be highlighted correctly in the textLayer.
Furthermore, this patch also adds basic unit-tests for this functionality.
*Note:* The `[api-minor]` tag is added, since third-party implementations of the `PDFFindController` must now always use the `pageMatchesLength` property to get accurate length information (see the `web/text_layer_builder.js` changes).
Co-authored-by: Ross Johnson <ross@mazira.com>
Co-authored-by: Jonas Jenwald <jonas.jenwald@gmail.com>
* add a comment to explain how minimal linewidth is computed.
* when context.linewidth < 1 after transform, firefox and chrome
don't render in the same way (issue #12810).
* set lineWidth to 1 after transform and before stroking
- aims fix issue #12295
- a pixel can be transformed into a rectangle with both heights < 1.
A single rescale leads to a rectangle with dim equals to 1 and
the other to something greater than 1.
* change the way to render rectangle with null dimensions:
- right now we rely on the lineWidth set before "re" but
it can be set after "re" and before "S" and in this case the rendering
will be wrong.
- render such rectangles as a single line.
Given that the PDF document in the issue contains the same very large JPEG image *three* times, this patch includes a test-case where only the first page has been extracted from it.
Currently any errors thrown in `preEvaluateFont`, which is a *synchronous* method, will not be handled at all in the `loadFont` method and we were thus failing to return an `ErrorFont`-instance as intended here.
Also, add an *explicit* check in `PartialEvaluator.preEvaluateFont` to ensure that Type0-fonts always have a *valid* dictionary.
Similar to other markers that we currently skip, by ignoring unsupported Coding style default (COD) options we'll at least render *something* here (although some JPEG 2000 images may look slightly wrong).
Note that if the unsupported COD options lead to additional errors, during parsing, we'll still abort parsing of the JPEG 2000 image.
* the goal is to execute actions like Open or OpenAction
* can be tested with issue6106.pdf (auto-print)
* once #12701 is merged, we can add page actions
Similar to other markers that we currently skip, by ignoring the Coding style component (COC) marker we'll at least prevent outright errors (although some JPEG 2000 images may look slightly wrong).
It appears that the PDF document in [bug 1292316](https://bugzilla.mozilla.org/show_bug.cgi?id=1292316) now renders "correctly"[1] when compared to e.g. Adobe Reader and PDFium. Most likely this bug was fixed by a *somewhat* recent patch, or patches, to the `XRef.indexObjects` method.
Before just closing [bug 1292316](https://bugzilla.mozilla.org/show_bug.cgi?id=1292316) as WFM, I figured that it probably can't hurt to add it as a new test-case to avoid accidentally regressing this document in the future.
---
[1] Given that the XRef table is corrupt, and that we're forced to recover, there's generally speaking probably some question as to what actually constitutes "correct" in this case.
There doesn't seem to be anything definitive about this in
the spec, but from experimenting, it seems acrobat lets
PDFs override the widths of the standard fonts.
This seems like a very minor issue, since in general we can't really help if domains are blocked from certain networks, however in this particular case I suppose that using the Internet Archive should work.
In addition to the existing /Root and /Pages validation, also check that the /Pages-entry actually is a dictionary and that it has a valid /Count-entry.
This way we can avoid picking a trailer candidate which e.g. the `Catalog.numPages` getter will just end up rejecting, thus breaking PDF document loading completely.
* remove 1st param of _createPopup (almost useless for a method)
* prepend popup div to avoid to have them on top of some highlights (and so "disable" partially mouse events)
* add a ref test for issue #12504
* in some pdf, there are actions with "event.source.hidden = ..."
* in order to handle visibility when printing, annotationStorage is extended to store multiple properties (value, hidden, editable, ...)
Different fonts incorrectly end up with *identical* hashes, despite having different /ToUnicode data.
The issue, and it's very interesting that we've apparently not seen it before, appears to be caused by the fact that different /ToUnicode entries share the *same* underlying `ArrayBuffer`, which thus becomes problematic at the `const dataUint32 = new Uint32Array(data.buffer, 0, blockCounts);` line. The simplest solution thus seem to be to just *copy* the input, when it's an `ArrayBuffer`, rather than using it as-is. (Note that if we'd stringified the input, when calling `MurmurHash3_64.update`, the issue would also have been fixed. In this case, we're already creating an unique TypedArray.)
This changes the `transformOrigin` calculations in `AnnotationElement._createContainer` and `PopupAnnotationElement.render`, to ensure that e.g. the clickable area of annotations and/or popups are both positioned correctly.
The problem occurs for *negative* values, since they're not negated correctly because of how the `transformOrigin` strings were build; see issue 12406 for a more in-depth explanation. Previously, for negative values, the `transformOrigin` strings would thus be ignored since they're not valid.
This patch contains a possible approach for fixing issue 12294, which compared to other PRs is purposely limited to the affected `WidgetAnnotation` code.
As mentioned elsewhere, considering that we're (at least for now) trying to fix *one specific* case, I think that we should avoid modifying the `Dict` primitive[1] and/or avoid a solution that (indirectly) modifies an existing `Dict`-instance[2].
This patch simply fixes the issue at hand, since that seems easiest for now, and I'd suggest that we worry about a more general approach if/when that actually becomes necessary.
Hence the solution implemented here, for `WidgetAnnotation`, is to simply use a combination of the local *and* AcroForm /DR resources during OperatorList-parsing to ensure that things work correctly regardless of where a particular /Font resource is found.
For saving of form-data, on the other hand, we want to avoid increasing the file-size unnecessarily and need to be smarter than just merging all of the available resources. To achive this, a new `WidgetAnnotation._getSaveFieldResources` method will when necessary produce a combined resources `Dict` with only the minimum amount of data from the AcroForm /DR resources included.
---
[1] You want to avoid anything that could cause the general `Dict` implementation to become slower, or more complex, just for handling an edge-case in my opinion.
[2] If an existing `Dict`-instance is modified unexpectedly, that could very easily lead to problems elsewhere since e.g. `Dict`-instances created during parsing are not expected to be changed.
In issue 12120, the font has a 1,0 cmap and is marked symbolic which
according to the spec means we should directly use the cmap instead of
the extra steps that are defined in 9.6.6.4.
However, just fixing that caused bug 1057544 to break. The font in bug
1057544 has a 0,1 cmap (Unicode 1.1) which we were not using, but is
easy to support. We're also easily able to support some of the other
unicode cmaps, so I added those as well.
There was also a second issue with bug 1057544, the cmap doesn't have
a mapping for the "quoteright" glyph, but it is defined in the post
table. To handle this, I've moved post table as a fallback for any
font that has an encoding.
In addition to the unit tests these reference tests make sure that this
document, that triggered some edge cases in our code, can be rendered
and printed successfully now.
This is *similar* to the existing transfer function support for SMasks, but extended to simple image data.
Please note that the extra amount of data now being sent to the worker-thread, for affected /ExtGState entries, is limited to *at most* 4 `Uint8Array`s each with a length of 256 elements.
Refer to https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf#G9.1658137 for additional details.
Some fonts have loca tables that aren't sorted or use 0 as an offset to
signal a missing glyph. This fixes the bad loca tables by sorting them
and then rewriting the loca table and potentially re-ordering the glyf
table to match.
Fixes#11131 and bug 1650302.
Issue 4398 was fixed by PR 4437, however a test-case wasn't included as far as I can tell. Given that PR 12186 is now in the process of re-factoring that code, adding a test-case cannot hurt as far as I'm concerned.
Add a new method to the API to get the optional content configuration. Add
a new render task param that accepts the above configuration.
For now, the optional content is not controllable by the user in
the viewer, but renders with the default configuration in the PDF.
All of the test files added exhibit different uses of optional content.
Fixes#269.
Fix test to work with optional content.
- Change the stopAtErrors test to ensure the operator list has something,
instead of asserting the exact number of operators.
This should reduce the possibility of accidentally truncating some inline images, while *not* causing the "EI" detection to become significantly slower.[1]
There's obviously a possibility that these added checks are not sufficient to catch *every* single case of "EI" sequences within the actual inline image data, but without specific test-cases I decided against over-engineering the solution here.
*Please note:* The interpolation issues are somewhat orthogonal to the main issue here, which is the truncated image, and it's already tracked elsewhere.
---
[1] I've looked at the issue a few times, and this is the first approach that I was able to come up with that didn't cause *unacceptable* performance regressions in e.g. issue 2618.
*First of all, I should mention that my understanding of the finer details of the `QueueOptimizer` (and its related `CanvasGraphics` methods) is somewhat limited.*
Hence I'm not sure if there's actually a very good reason for *only* considering ImageMasks where the "skew" transformation matrix elements are zero as *repeated*, however simply looking at the code I just don't see why these elements cannot be non-zero as long as they are *all identical* for the ImageMasks.
Furthermore, looking at the *group* case (which is what we're currently falling back to), there's no particular limitation placed upon the transformation matrix elements.
While this patch obviously isn't enough to *completely* fix the issue, since there should be a visible Pattern rendered as well[1], it seem (at least to me) like enough of an improvement that submitting this is justified.
With these changes the referenced PDF document will no longer hang the *entire* browser, and rendering also finishes in a *reasonable* time (< 10 seconds for me) which seem fine given the *huge* number of identical inline images present.[2]
---
[1] Temporarily changing the Pattern to a solid color *does* render the correct/expected area, which suggests that the remaining problem is a pre-existing issue related to the Pattern-handling itself rather than the `QueueOptimizer` functionality.
[2] The document isn't exactly rendered immediately in e.g. Adobe Reader either.
Because of a really stupid `Promise`-related mistake on my part, when re-factoring `PDFImage.buildImage` during the `NativeImageDecoder` removal, we're no longer re-throwing errors occuring during image parsing/decoding as intended.
The result is that some (fairly) corrupt documents will never finish loading, and unfortunately there were apparently no sufficiently corrupt images in the test-suite to catch this.
On ISO/IEC 10918-6:2013 (E), section 6.1: (http://www.itu.int/rec/T-REC-T.872-201206-I/en)
"Images encoded with three components are assumed to be RGB data encoded as YCbCr unless the image contains an APP14 marker segment as specified in 6.5.3, in which case the colour encoding is considered either RGB or YCbCr according to the application data of the APP14 marker segment"
But common jpeg libraries consider RGB too if components index are ASCII R (0x52), G (0x47) and B (0x42): https://stackoverflow.com/questions/50798014/determining-color-space-for-jpeg/50861048
Issue #11931
Currently image resources, as opposed to e.g. font resources, are handled exclusively on a page-specific basis. Generally speaking this makes sense, since pages are separate from each other, however there's PDF documents where many (or even all) pages actually references exactly the same image resources (through the XRef table). Hence, in some cases, we're decoding the *same* images over and over for every page which is obviously slow and wasting both CPU and memory resources better used elsewhere.[1]
Obviously we cannot simply treat all image resources as-if they're used throughout the entire PDF document, since that would end up increasing memory usage too much.[2]
However, by introducing a `GlobalImageCache` in the worker we can track image resources that appear on more than one page. Hence we can switch image resources from being page-specific to being document-specific, once the image resource has been seen on more than a certain number of pages.
In many cases, such as e.g. the referenced issue, this patch will thus lead to reduced memory usage for image resources. Scrolling through all pages of the document, there's now only a few main-thread copies of the same image data, as opposed to one for each rendered page (i.e. there could theoretically be *twenty* copies of the image data).
While this obviously benefit both CPU and memory usage in this case, for *very* large image data this patch *may* possibly increase persistent main-thread memory usage a tiny bit. Thus to avoid negatively affecting memory usage too much in general, particularly on the main-thread, the `GlobalImageCache` will *only* cache a certain number of image resources at the document level and simply fallback to the default behaviour.
Unfortunately the asynchronous nature of the code, with ranged/streamed loading of data, actually makes all of this much more complicated than if all data could be assumed to be immediately available.[3]
*Please note:* The patch will lead to *small* movement in some existing test-cases, since we're now using the built-in PDF.js JPEG decoder more. This was done in order to simplify the overall implementation, especially on the main-thread, by limiting it to only the `OPS.paintImageXObject` operator.
---
[1] There's e.g. PDF documents that use the same image as background on all pages.
[2] Given that data stored in the `commonObjs`, on the main-thread, are only cleared manually through `PDFDocumentProxy.cleanup`. This as opposed to data stored in the `objs` of each page, which is automatically removed when the page is cleaned-up e.g. by being evicted from the cache in the default viewer.
[3] If the latter case were true, we could simply check for repeat images *before* parsing started and thus avoid handling *any* duplicate image resources.
This should ensure that a page will always render successfully, even if there's errors during the Annotation fetching/parsing.
Additionally the `OperatorList.addOpList` method is also adjusted to ignore invalid data, to make it slightly more robust.
- Add a reduced test-case for issue 11768, to prevent future regressions.
(Given that PR 11769 is only a work-around, rather than a proper solution, it may not be entirely accurate for the issue to be closed as fixed.)
- Add more validation of the charCode, as found by the heuristics, in `PartialEvaluator._buildSimpleFontToUnicode` to prevent future issues.
At this point in time, compared to when the "ignore single-char" code was added, we *should* generally be doing a much better job of combining text into as few chunks as possible.
However, there's still bad cases where we're not able to combine text as much as one would like, which is why I'm *not* proposing to simply measure/scale all text. Instead this patch will to only measure/scale single-char text in cases where the horizontal/vertical scale is off significantly, since that's were you'd expect bad text-selection behaviour otherwise.
Note that most of the movement caused by this patch is with Type3 fonts, which is a somewhat special font type and one where our current text-selection behaviour is probably the least good.
Fixes#11718 in which the `ff` ligature glyph is at index zero in a CFF font. Beacuse this is a CIDFont, glyph names are CIDs, which are integers. Thus the string `".notdef"` is not correct. The rest of the charset data is already parsed correctly as integers when the boolean argument `cid` is true.
The /Differences array of the problematic font contains a `/c.1` entry, which is consequently detected as a *possible* Cdd{d}/cdd{d} glyphName by the existing heuristics.
Because of how the base 10 conversion is implemented, which is necessary for the base 16 special case, the parsed charCode becomes `0.1` thus causing `String.fromCodePoint` to throw since that obviously isn't a valid code point.
To fix the referenced issue, and to hopefully prevent similar ones in the future, the patch adds *additional* validation of the charCode found by the heuristics.
The PDF document in question is *corrupt*, since it contains an XObject with a truncated dictionary and where the stream contents start without a "stream" operator.
Fixes#11477
The PDF draws many space characters but the embedded fonts don't have a glyph named `space`, so `.notdef` should be drawn instead. PDF.js assumed that Type1 fonts define `.notdef` as the first glyph (index 0). However, now the fonts have the glyph `A` at index 0 and `.notdef` is the last one, so `A` appears where spaces are expected.
Because the rest of the font machinery in `core/fonts.js` assumes `.notdef` is at index zero, it's easiest to modify `core/type1_parser.js` so that it "repairs" fonts and makes sure `.notdef` is at index 0.
The PDF document in question is *corrupt*, since it contains multiple instances of incorrect operators.
We obviously don't want to slow down parsing of *all* documents (since most are valid), just to accommodate a particular bad PDF generator, hence the reason for the inline check before calling the `ensureStateFont` method.
*This whole patch feels somewhat arbitrary, and I'd be slightly worried about possibly breaking something else.*
To limit the impact of these changes, we only re-parse JPEG images using a reduced `scanLines` value if and only if: An unexpected EOI (End of Image) marker was encountered during decoding of Scan data *and* the "actual" `scanLines` value is at least one order of magnitude smaller than expected.
While it would be nice to change the `PDFFormatVersion` property, as returned through `PDFDocumentProxy.getMetadata`, to a number (rather than a string) that would unfortunately be a breaking API change.
However, it does seem like a good idea to at least *validate* the PDF header version on the worker-thread, rather than potentially returning an arbitrary string.
In the current `AnnotationLayer` implementation, Popup annotations require that the parent annotation have already been rendered (otherwise they're simply ignored).
Usually the annotations are ordered, in the `/Annots` array, in such a way that this isn't a problem, however there's obviously no guarantee that all PDF generators actually do so. Hence we simply ensure, when rendering the `AnnotationLayer`, that the Popup annotations are handled last.
- Re-factor the "incorrect encoding" check, since this can be easily achieved using the general `findNextFileMarker` helper function (with a suitable `startPos` argument).
- Tweak a condition, to make it easier to see that the end of the data has been reached.
- Add a reference test for issue 1877, since it's what prompted the "incorrect encoding" check.
Fixes#11403
The PDF uses the non-embedded Type1 font Helvetica. Character codes 194 and 160 (`Â` and `NBSP`) are encoded as `.notdef`. We shouldn't show those glyphs because it seems that Acrobat Reader doesn't draw glyphs that are named `.notdef` in fonts like this.
In addition to testing `glyphName === ".notdef"`, we must test also `glyphName === ""` because the name `""` is used in `core/encodings.js` for undefined glyphs in encodings like `WinAnsiEncoding`.
The solution above hides the `Â` characters but now the replacement character (space) appears to be too wide. I found out that PDF.js ignores font's `Widths` array if the font has no `FontDescriptor` entry. That happens in #11403, so the default widths of Helvetica were used as specified in `core/metrics.js` and `.nodef` got a width of 333. The correct width is 0 as specified by the `Widths` array in the PDF. Thus we must never ignore `Widths`.
The original issue did not contain a (reduced) test case that we could
include and linked test cases are not ideal for unit tests, so the
original PR could only be verified manually.
I found this a bit unfortunate considering that the print data is
exposed through the API, so I thought about how we could have an
automated test and managed to create a reduced test case with the
OpenAction dictionary from the file in the original issue.
Therefore, this commit includes a unit test for parsing OpenAction
dictionaries without `Type` entries. I verified that this PDF file
behaves the same as the original one, i.e., no print dialog is shown for
older viewers and the print dialog is shown for the most recent viewer.
In the PDF document in question, there's an ASCII85Decode inline image where the '>' part of EOD (end-of-data) marker is missing; hence the PDF document is corrupt.
For documents with a Linearization dictionary the computed `startXRef` position will be relative to the raw file, rather than the actual PDF document itself (which begins with `%PDF-`).
Hence it's necessary to subtract `stream.start` in this case, since otherwise the `XRef.readXRef` method will increment the position too far resulting in parsing errors.
This will allow us to attempt to recover as much as possible of a page, rather than immediately failing, when a broken/unsupported ColorSpace is encountered. This patch thus extends the framework added in PRs such as e.g. 8240 and 8922, to also cover parsing of ColorSpaces.
Obviously this won't look exactly right, but considering that the PDF file doesn't bother embedding non-standard fonts this is the best that we can do here.
