Having just played around with adding FreeText-annotations and then trying to print, there were `FreeTextAnnotation: OffscreenCanvas is not supported, annotation may not render correctly.` messages printed in the console.
The reason for this is that `FreeTextAnnotation` inherits from `MarkupAnnotation`, however only `WidgetAnnotation` actually defines the `_isOffscreenCanvasSupported` property.
Given that this `assert` is only intended to catch any implementation bugs in our code, and not actually to validate the PDF data directly[1], we can avoid making this function call unconditionally.
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[1] In those cases, for example a `FormatError` should have been thrown instead.
With modern EcmaScript features, we can define these fields directly instead. Please note that for backwards compatibility purposes they are still public as before, however note that this functionality is *disabled* by default (see the `pdfBug` API option).
Also, we can (slightly) simplify the two loops used in the `toString` method.
These fields were never intended to be public, since modifying them manually would lead to inconsistent state, and with modern EcmaScript features we can now enforce this.
Also, this patch removes a couple of JSDoc comments that we generally don't use.
- For text fields
* when printing, we generate a fake font which contains some widths computed thanks to
an OffscreenCanvas and its method measureText.
In order to avoid to have to layout the glyphs ourselves, we just render all of them
in one call in the showText method in using the system sans-serif/monospace fonts.
* when saving, we continue to create the appearance streams if the fonts contain the char
but when a char is missing, we just set, in the AcroForm dict, the flag /NeedAppearances
to true and remove the appearance stream. This way, we let the different readers handle
the rendering of the strings.
- For FreeText annotations
* when printing, we use the same trick as for text fields.
* there is no need to save an appearance since Acrobat is able to infer one from the
Content entry.
These variables are left-over from the initial implementation, back when `String.prototype.padStart` didn't exist and we thus had to pad manually (using a loop).
This helps improve performance for some PDF documents with a huge number of inline images, e.g. the PDF document from issue 2618.
Given that we no longer create `Stream`-instances unconditionally, we also don't need `Dict`-instances for cached inline images (since we only access the filter).
*Please note:* This only fixes the "wrong letter" part of bug 1799927.
It appears that the simple `computeAdler32` function, used when caching inline images, generates hash collisions for some (very short) TypedArrays. In this case that leads to some of the "letters", which are actually inline images, being rendered incorrectly.
Rather than switching to another hashing algorithm, e.g. the `MurmurHash3_64` class, we simply cache using a stringified version of the inline image data as the cacheKey to prevent any future collisions. While this will (naturally) lead to slightly higher peak memory usage, it'll however be limited to the current `Parser`-instance which means that it's not persistent.
One small benefit of these changes is that we can avoid creating lots of `Stream`-instances for already cached inline images.
The purpose of this patch is twofold:
- Initialize the unicode-category data *lazily* during text-extraction, since this is completely unused during general parsing/rendering.
- Stop exposing this data in the API, since it's unused on the main-thread and it seems like it was *accidentally* included.
Obviously these changes are API-observable, but hopefully no user is depending on this. Furthermore, it's trivial for a user to re-create this unicode-category data manually with a regular expression (from the exposed `unicode` property).
Currently, during text-extraction, we're repeatedly normalizing and (when necessary) reversing the unicode-values every time. This seems a little unnecessary, since the result won't change, hence this patch moves that into the `Glyph`-instance and makes it *lazily* initialized.
Taking the `tracemonkey.pdf` document as an example: When extracting the text-content there's a total of 69236 characters but only 595 unique `Glyph`-instances, which mean a 99.1 percent cache hit-rate. Generally speaking, the longer a PDF document is the more beneficial this should be.
*Please note:* The old code is fast enough that it unfortunately seems difficult to measure a (clear) performance improvement with this patch, so I completely understand if it's deemed an unnecessary change.
In order to support opening certain corrupt PDF documents, particularly hand-edited ones, this patch adds support for letting the `Catalog.getAllPageDicts` method fallback to returning an *empty* dictionary to replace (only) the first /Page of the document.
Given that the viewer cannot initialize/load without access to the first page, this will thus allow e.g. document-level scripting to run as expected. Note that by effectively replacing a corrupt or missing first /Page in this way[1], we'll now render nothing but a *blank* page for certain cases of broken/corrupt PDF documents which may look weird.
*Please note:* This functionality is controlled via the existing `stopAtErrors` option, that can be passed to `getDocument`, since it's easy to imagine use-cases where this sort of fallback behaviour isn't desirable.
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[1] Currently we still require that a /Pages-dictionary is found though, however it *may* be possible to relax even that assumption if that becomes absolutely necessary in future corrupt documents.
Note that the "trailer"-case is already a fallback, since normally we're able to use the "xref"-operator even in corrupt documents. However, when a "trailer"-operator is found we still expect "startxref" to exist and be usable in order to advance the stream position. When that's not the case, as happens in the referenced issue, we use a simple fallback to find the first "obj" occurrence instead.
This *partially* fixes issue 15590, since without this patch we fail to find any objects at all during `XRef.indexObjects`. However, note that the PDF document is still corrupt and won't render since there's no actual /Pages-dictionary and the /Root-entry simply points to the /OpenAction-dictionary instead.
After the clean-up in PR 15616, the `PdfManager.onLoadedStream` method now only has a single call-site.
Hence why this patch suggests that we remove this method and replace it with an *optional* parameter in `PdfManager.requestLoadedStream` instead. By making the new behaviour opt-in, we'll thus not change any existing call-site.
- Some events, which require a user interaction, will allow those functions to be called.
But after few seconds, if there are no more user interaction, it won't be possible
anymore.
The idea is to give an opportunity to the user to leave the pdf.
- Disable print function when we're printing, the same with saving and disallow to save
on open events.
When a form isn't changed, we used the appearances we had in the file, but when
/NeedAppearances is true, all the appearances have to be regenerated whatever they're.
*This is very old code, and it could thus do with some simplification.*
Note how in the `src/core/worker.js` file we're combining both the `PdfManager.requestLoadedStream` and `PdfManager.onLoadedStream` methods in order to access the stream-data. This seems unnecessary, and it's simple enough to always let the `PdfManager.requestLoadedStream` method return the stream-data as well.
PR 13725 was only intended as a temporary work-around, and it seems that we can now revert that.
- Firefox 102 is the currently maintained ESR-branch, and the PDF.js project only supports the active one.
- Node.js now works, thanks to the `node-canvas` package, and I've confirmed locally that following the STR in issue 13724 generates a correct image.
In the referenced PDF document there are "numbers" which consist only of `-.`, and while that's obviously not valid Adobe Reader seems to handle it just fine.
Letting this method ignore more invalid "numbers" was suggested during the review of PR 14543, so let's simply relax our the validation here.
It appears that PR 15593 broke `issue12402`, and we thus need to partially restore the /Count check.
I completely missed this when looking at the test-results for PR 15593, both locally and on the bots, since the `Driver._getLastPageNumber` method would "swallow" an unavailable page number.
- When we're editing some annotations, keeping the role="text-box" make them visible
as editable and VoiceOver (Mac) is able to read the contents when they're focused;
- Add an attribute "aria-activedescendant" in order to make the content discoverable
by NVDA on Windows.
After PR 14311, and follow-up patches, we no longer require that the /Count entry (in the /Pages dictionary) is either present or even valid in order to parse/render a PDF document.
Hence it seems strange to keep this requirement for *corrupt* PDF documents, when trying to find a usable `trailer` in the `XRef.indexObjects` method.
With the changes in the previous patch we can move the glyph-cache lookup to the top of the method and thus avoid a bunch of, in *almost* every case, completely unnecessary re-parsing for every `charCode`.
This method, and its class, was originally added in PR 4453 to reduce memory usage when parsing text. Then PR 13494 extended the `Glyph`-representation slightly to also include the `charCode`, which made the `matchesForCache` method *effectively* redundant since most properties on a `Glyph`-instance indirectly depends on that one. The only exception is potentially `isSpace` in multi-byte strings.
Also, something that I noticed when testing this code: The `matchesForCache` method never worked correctly for `Glyph`s containing `accent`-data, since Objects are passed by reference in JavaScript. For affected fonts, of which there's only a handful of examples in our test-suite, we'd fail to find an already existing `Glyph` because of this.
When we fail to find a usable PDF document `trailer` *and* there were errors during parsing, try and fallback to a *previous* generation as a last resort during fetching of uncompressed references.
*Please note:* This will not affect "normal" PDF documents, with valid /XRef data, and even most *corrupt* documents should be completely unaffected by these changes.
Part of this is very old code, and back when support for parsing the catalog-version was added things became less clear (in my opinion).
Hence this patch tries to improve things, by e.g. validating the header- and catalog-version separately.
Note how we're currently skipping all main-thread cleanup when document destruction has started, but for some reason we're still dispatching the "Cleanup" message.
This seems like a simple oversight, since destruction will already invoke the `BasePdfManager.cleanup` method (on the worker-thread) to fully clear-out all caches.
Given the sheer number of heuristics added to this method over the years, moving the *valid* unicode found case to the top should improve readability of the code.
- Fix Field::getArray in order to collect only the fields which have a value;
- Fix AFSimple_Calculate:
* allow to have a string with a list of field names as argument;
* since a field can be non-terminal, use Field::getArray to collect
the field under it and then apply the calculation on all the descendants.
This code was added all the way back in PR 6698, almost seven years ago, for backwards compatibility reasons. At this point in time, it seems that we can remove that since:
- We have more fine-grained "UnsupportedFeature" reporting elsewhere in the worker-thread code nowadays.
- The GetOperatorList-handling is now using `ReadableStream`s, which means that errors are being forwarded to the main-thread anyway.
- We're also no longer displaying a notification-bar, in the *built-in* Firefox PDF Viewer, for any of these "UnsupportedFeature" messages.
*Please note:* I don't really know what I'm doing here, however the patch appears to fix the referenced issue when comparing the rendering with Adobe Reader (with the caveat that I don't speak the language in question).
When a new PDF document is opened in the GENERIC viewer we (obviously) create a new `AnnotationEditorUIManager`-instance, since those are document-specific, and thus we need to ensure that we actually register the `editorTypes` for each one.
Note how after having found the "%PDF-" prefix we then read both the prefix and the version in the loop, only to then remove the prefix at the end.
It seems better to instead advance the stream position past the "%PDF-" prefix, and then read only the version data.
Finally the loop-condition can also be simplified slightly, to further clean-up some very old code.
*Fixes a regression from PR 15246, sorry about that!*
The return value of all `Annotation.getOperatorList` methods was changed in PR 15246, however I missed updating the error code-path in `Page.getOperatorList` which thus breaks all operatorList-parsing for pages with corrupt Annotations.
Looking at the code on the worker-thread, there doesn't appear to be any particular reason for placing *some* of the properties in a `source`-object when sending them with "GetDocRequest".
As is often the case the explanation for this structure is rather "for historical reasons", since originally we simply sent the `source`-object as-is. Doing that was obviously a bad idea, for a couple of reasons:
- It makes it less clear what is/isn't actually needed on the worker-thread.
- Sending unused properties will unnecessarily increase memory usage.
- The `source`-object may contain unclonable data, which would break the library.
Rather than sending all of these parameters individually and then grouping them together on the worker-thread, we can simply handle that in the API instead.
All of the these constants have been deprecated for a while, and with the upcoming *major* version this seems like a good time to remove them.
For the string-constants we can simply remove them, but the number-constants are left commented out since we don't want to re-number the list to prevent third-party breakage.
I noticed the 256 % 3 (which is equal to 1) so I slighty simplify the code.
The sum of the 16 Uint8 doesn't exceed 2^12, hence we can just take the
sum modulo 3.
This method was originally added in PR 1157 (back in 2012), however its only call-site was then removed in PR 2423 (also in 2012).
Hence this method has been completely unused for nearly a decade, and it should thus be safe to remove it.
This patch first of all makes `isOffscreenCanvasSupported` configurable, defaulting to `true` in browsers and `false` in Node.js environments, with a new `getDocument` parameter. While you normally want to use this, in order to improve performance, it should still be possible for users to control it (similar to e.g. `isEvalSupported`).
The specific problem, as reported in issue 14952, is that the SVG back-end doesn't support the new ImageMask data-format that's introduced in PR 14754. In particular:
- When the SVG back-end is used in Node.js environments, this patch will "just work" without the user needing to make any code changes.
- If the SVG back-end is used in browsers, this patch will require that `isOffscreenCanvasSupported: false` is added to the `getDocument`-call.
*Please note:* The referenced issue is the only mention that I can find, in either GitHub or Bugzilla, of "GoToE" actions.
Hence why I've purposely settled for a very simple, and partial, "GoToE" implementation to avoid complicating things initially.[1] In particular, this patch only supports "GoToE" actions that references the /EmbeddedFiles-dict in the PDF document.
See https://web.archive.org/web/20220309040754if_/https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2048909
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[1] Usually I always prefer having *real-world* test-cases to work with, whenever I'm implementing new features.
This is yet another small piece of clean-up of the `FontLoader`-code, since we've not used this `id`-property for anything ever since PR 6571 (which landed almost seven years ago). Furthermore, by default we're also not even using that code-path now since the Font Loading API will always be used when available.
*Please note:* This is tagged `[api-minor]` since it's technically observable from the outside, however no user ought to be directly interacting with these CSS font rules.
Currently the compatibility-file is loaded using a standard `import`-statement and while its code is enclosed in a pre-processor block, and thus is excluded in e.g. the MOZCENTRAL build-target, it still results in the *built* `pdf.js`/`pdf.worker.js` files having an effectively empty closure as a result.
By moving the checks from `src/shared/compatibility.js` and into `src/shared/util.js` instead, we can load the file using a build-time `require`-statement and thus avoid that closure.
Note that with these changes the compatibility-file will no longer be loaded in development mode, i.e. when `gulp server` is used. However, this shouldn't be a big issue given that none of its included polyfills could be loaded then anyway (since `require`-statements are being used) and that it's really only intended for the `legacy`-builds of the library.
Note that this PR only adds the "underscore"-variant of *actually existing* ligatures, however the referenced PDF document also uses a couple of non-standard ones (e.g. `ft`, `Th`, and `fh`) that we cannot easily support without larger changes (since they don't have official Unicode-entries).
Given that it's clearly the PDF document, and its fonts, that's the culprit here it's not entirely clear to me that we actually want to attempt a larger refactoring/rewriting of the `glyphlist.js` code, assuming it's even generally possible. Especially when this patch alone already improves our copy-paste behaviour when compared to both Adobe Reader and PDFium, and that this is only the *second* time this sort of bug has been reported.
Fewer dependencies shouldn't be a bad idea in general, and given that the `node-canvas` package already include a `DOMMatrix` polyfill we can simply use that one instead.
Given that Firefox supports *synchronous* font loading, when the Font Loading API isn't being used, there's really no point including code which if called would just throw in the MOZCENTRAL build. (This is safe, since the `FontLoader.isSyncFontLoadingSupported`-getter always return `true` there.)
After the changes in PR 10539 (which landed over three years ago) the `FontLoader.bind` method can only be called with *a single* font at a time, hence the `_prepareFontLoadEvent` method obviously don't need to support multiple fonts any more.
By having just *one* class, and using pre-processor blocks directly in the relevant methods, we reduce the size of this code in the *built* `pdf.js` file.
Originally, when the `BaseFontLoader` abstraction was added in PR 9982, the idea was probably that additional build-targets would get their own implementations. Given that this hasn't happened in the four years since that landed, it doesn't seem meaningful to keep it around.
The existing `loadingContext` class-property can be simplified slightly, since we've not been using the `id`-property on the requests ever since PR 3477 (which landed nine years ago).
Furthermore, by default we're also not even using that code-path now since the Font Loading API will always be used when available.
This was done all the way back in PR 8361, for a mozilla-central test that's since been removed. As can be seen in the following search results, there's no `LoopbackPort` invocation outside of the PDF.js code itself: https://searchfox.org/mozilla-central/search?q=LoopbackPort&path=
Given that the `LoopbackPort` is only used in connection with "fake workers", which is something that we don't officially recommend/support, this doesn't seem like functionality that we want to keep exposing in the public API.
