Rather than modifying the "raw" dimensions of the page, we'll instead apply the `userUnit` as an *additional* scale-factor via CSS.
*Please note:* It's not clear to me if this solution is fully correct either, or if there's other problems with it, but it at least *appears* to work.
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With these changes, the following CSS variables are now assumed to be available/set as necessary: `--total-scale-factor`, `--scale-factor`, `--user-unit`, `--scale-round-x`, and `--scale-round-y`.
Given that most inferred links will overlap existing LinkAnnotations, creating a lot of unused `borderStyle` objects seem unnecessary.
Hence we can move that into the `AnnotationLayer.prototype.addLinkAnnotations` method instead, which also allows us to slightly reduce the API-surface.
Currently we have three separate and virtually identical message handlers for this data, which can easily be combined into a single message handler instead.
Automatically detect links in the text content of a file and automatically
generate link annotations at the appropriate locations to achieve
automatic link detection and hyperlinking.
Given that we now have a few different factory-url parameters, we introduce a helper function for parsing them.
*Please note:* These parameters have always been documented as requiring a trailing slash[1], which we can now easily enforce during the `getDocument`-call.
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[1] I recall that we've occasionally seen issues because users miss that detail, and the new Error should hopefully be more easily actionable than one thrown during rendering/parsing.
This CSS feature is now available in *most* browsers that we support, with old Chromium-based browsers being the only exception; please see https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/color-mix#browser_compatibility
From this data we see that the feature in question has been supported since Chrome 111, which was released on 2023-03-01 (i.e. almost two years ago).
Please note that we've never guaranteed that all features and functionality will be available in the oldest supported browsers.
Furthermore, even with the `color-mix` fallback removed PopupAnnotations will still function just as before but may render with the default color (defined in the CSS-file) rather than the one specified in the PDF document.
At the time of PR 12896 the `fontBoundingBox{Ascent, Descent}` properties were not yet available by default in Fírefox, however that's no longer the case since Firefox 116; please see https://bugzilla.mozilla.org/show_bug.cgi?id=1801198.
Hence this patch which replaces the "full" fallback with a warning and uses the `ascent`/`descent` values from the fonts in the PDF document (as we did previously). Obviously the TextLayer won't look as good in that case, but it's a simpler and shorter solution.
Currently we're manually computing the width/height of the /Rect-entry in a number of spots throughout the worker-thread Annotation code, which these new getters help avoid.
Currently we're initializing the image-options for every page, which seems unnecessary since it should suffice to do that once per document.
Also, changes the `BasePdfManager` constructor to improve readability/documentation a little bit.
This patch is adding some code in order to extract a drawing as curves from an image.
The algorithm is basically the following:
- reduce the dimensions
- make it gray
- apply a bilateral filter in order to add some blurryness while keeping the edges
- compute the histogram
- guess what's the background color which should contain a large majority of the pixels
- make a binary image
- extract the contours in using the Suzuki algorithm
- apply the Douglas-Peucker algorithm in order to reduce the number of points
The algorithm is improvable but it should work pretty well if there's a clear difference between
the background and the drawing.
In a v2 we could use a ML model in order to improve the extraction.
There's few changes related to the UI in order to make the tool usable, but they're very basic
for the moment.
This patch fixes a bug that caused incorrect curve shapes when an endpoint lies beyond the page boundaries. It adds a check for the endpoint's position, and if it is outside the page, the point is excluded from the shape's coordinates.
Steps to reproduce this in `master`:
1. Open https://mozilla.github.io/pdf.js/web/viewer.html
2. Use the "Open"-button (in the secondaryToolbar), or drag-and-drop, to load another PDF document.
3. Enable the highlight-editor.
4. Try to pick a new colour.
Note how it's no longer possible to change the default highlight-colour.
The reason for this is that we're only initializing the viewer-toolbar `ColorPicker` *once*, which doesn't work since every PDF document gets its own `AnnotationEditorUIManager`-instance. To address this we simply need to re-initialize the viewer-toolbar `ColorPicker`, and note that this patch won't affect the Firefox PDF Viewer.
After PR 2317, which landed in 2012, we'd immediately clean-up after rendering for pages with large image resources. This had the effect that re-rendering, e.g. after zooming, would force us to re-parse the entire page which could easily lead to bad performance.
In PR 16108, which landed in 2023, we tried to lessen the impact of that by slightly delaying clean-up however that's obviously not a perfect solution (and it increased the complexity of the relevant code).
Furthermore, the condition for this "immediate" clean-up seems a bit arbitrary to me since a page could easily contain a large number of smaller images whose total size vastly exceeds the threshold.
Hence this patch, which suggests that we remove the conditional and delayed clean-up after rendering. Compared to the situation back in 2012, a number of things have improved since:
- We have *multiple* caches for repeated image-resources on the worker-thread[1], which helps reduce overall memory usage and improves performance.
- We downsize huge images on the worker-thread, which means that the images we're using on the main-thread cannot be arbitrarily large.
- The amount of available RAM on devices should be a lot higher, since more than a decade has passed.
A future improvement here, for more resource constrained environments, could be to instead clean-up when actually needed using e.g. `WeakRef`s (see issue 18148).
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[1] More specifically:
- `LocalImageCache`, which caches image-data by /Name and /Ref on the `PartialEvaluator.prototype.getOperatorList` level.
- `RegionalImageCache`, which caches image-data by /Ref on the `PartialEvaluator`-instance (i.e. at the page) level.
- `GlobalImageCache`, which caches image-data by /Ref globally at the document level.
