In PR 11912 we started caching images that occur on multiple pages globally, which improved performance a lot in many PDF documents.
However, one slightly annoying limitation of the implementation is the need to re-parse the image once the global-caching threshold has been reached. Previously this was difficult to avoid, since large image-resources will cause cleanup to run on the main-thread after rendering has finished. In PR 16108 we started delaying this cleanup a little bit, to improve performance if a user e.g. zooms and/or rotates the document immediately after rendering completes.
Taking those two PRs together, we now have a situation where it's much more likely that the main-thread has "globally used" images cached at the page-level. Hence we can instead attempt to *copy* a locally cached image into the global object-cache on the main-thread and thus reduce unnecessary re-parsing of large/complex global images, which significantly reduces the rendering time in many cases.
For the PDF document in issue 11878, the rendering time of *the second page* changes as follows (on my computer):
- With the `master`-branch it takes >600 ms to render.
- With this patch that goes down to ~50 ms, which is one order of magnitude faster.
(Note that all other pages are, as expected, completely unaffected by these changes.)
This new main-thread copying is limited to "large" global images, since:
- Re-parsing of small images, on the worker-thread, is usually fast enough to not be an issue.
- With the delayed cleanup after rendering, it's still not guaranteed that an image is available in a page-level cache on the main-thread.
- This forces the worker-thread to wait for the main-thread, which is a pattern that you always want to avoid unless absolutely necessary.
There's obviously a few things wrong with the Annotations in the referenced PDF document, however parsing of an Annotation shouldn't just break if the /BS-entry isn't a dictionary.
The doorhanger for highlighting has a basic color picker composed of 5 predefined colors
to set the default color to use.
These colors can be changed thanks to a preference for now but it's something which could
be changed in the Firefox settings in the future.
Each highlight has in its own toolbar a color picker to just change its color.
The different color pickers are so similar (modulo few differences in their styles) that
this patch introduces a new class ColorPicker which provides a color picker component
which could be reused in future editors.
All in all, a large part of this patch is dedicated to color picker itself and its style
and the rest is almost a matter of wiring the component.
When a pdf as a FreeText without appearance, we use a fake font in order to render it
and that leads to create few new refs for the font.
But then when we're saving, we create some new refs which start at the same number
as the previous created ones.
Consequently, when saving we're using some wrong objects (like a font) to check if
we're able to render the newly added FreeText.
In order to fix this bug, we just remove the persistent refs (which are only used
when rendering/printing) during the saving.
Having just tested PR 17337 locally I noticed that especially the `JpxImage`-test causes a "ridiculous" amount of warning messages to be printed, which doesn't seem helpful.
Given that only actual `Error`s should be relevant here, we can easily disable this logging during the tests.
- Extend the `fetchData` helper function to also support fetching of "blob" data.
- Use the `fetchData` helper function more in the code-base, when fetching non-PDF data. Given that the Fetch API isn't supported for all protocols, this should improve compatibility for the PDF.js library.
The goal is to be able to get these outlines to fill the shape corresponding
to a text selection in order to highlight some text contents.
The outlines will be used either to show selected/hovered highlights.
- Re-factor the existing `fetchData` helper function such that it can fetch more types of data, and it now supports "arraybuffer", "json", and "text".
This only needed minor adjustments in the `DOMCMapReaderFactory` and `DOMStandardFontDataFactory` classes.[1]
- Expose the `fetchData` helper function in the API, such that the viewer is able to access it.
- Use the `fetchData` helper function in the `GenericL10n` class, since this should allow fetching of localization-data even if the default viewer is run in an environment without support for the Fetch API.
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[1] While testing this I also noticed a minor inconsistency when handling standard font-data on the worker-thread.
Some fields, somewhere under the Fields entry in Acroform, could have no name (in T)
but with a parent which has a name but which isn't somewhere under Fields.
As a side-effect, this patch prevents infinite loops because of potential cycles
under Fields.
Hopefully this is enough to address the problem of initializing the Worker in Chromium-based browsers.
Locally I've tried to *force* use of `createCDNWrapper` in development mode, by commenting out the `isSameOrigin` checks, and worker-loading fails against `master` and works with this patch.
The `fieldObjects`-getter is implemented in the `PDFDocument` class, which means that the `this._localIdFactory`-property that we pass to `AnnotationFactory.create` doesn't actually exist.
The reason that this hasn't caused any bugs, that I'm aware of, is that all /Fields-entries need to be References to actually make sense.
The `fieldObjects`-getter itself is called, from `src/core/worker.js`, in a way that'll ensure that any `MissingDataException`s are handled. However the problem is that the actual data-lookups in `fieldObjects` and `#collectFieldObjects` are done inside of a Promise, which means that `MissingDataException`s won't be handled and parsing could thus break.
To address this we change all data-lookups to be asynchronous instead.
There are environments that include *incomplete* polyfills for the `navigator`-object, which may thus cause the PDF.js library to break.
Despite that clearly not being our fault, it may still result in bug reports filed against the PDF.js project; see e.g. 15728.
Currently this even seem to affect *the latest* version of Node.js; see e.g. [here].
*Please note:* Thanks to the pre-processor none of these changes affect the Firefox PDF Viewer, however it does add "overhead" when working with and reviewing the affected code (which is why I'm not crazy about this).
