This way it helps to reduce the overall canvas dimensions and make the rendering faster.
The drawback is that when scrolling, the page can be blurry in waiting for the rendering.
The default value is 200% on desktop and will be 100% for GeckoView.
Instead, we update the visible canvas every 500ms.
With large canvas, updating at 60fps lead to a lot gfx transactions and it can take a lot of time.
For example, with wuppertal_2012.pdf on Windows, displaying it at 150% takes around 14 min !!! without
this patch when it takes only around 14 sec with. Even at 30% it helps to improve the performance
by around 20%.
It's already enabled by default in Firefox, and since there's no open issues regarding auto-linking I suppose that we can attempt to enable it unconditionally.
This is an admittedly very basic polyfill, to allow us to remove a bunch of inline feature testing, that I've thrown together based on reading https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/any_static and related MDN articles.
Compared to PR 19218 it's obviously much more "primitive", however the implementation is simple and it doesn't suffer from any licensing issues (since I wrote the code myself).
When zooming, we should skip rendering the detail canvas until the
zoom is done, similarly to how normal page rendering is delayed.
To do so is enough to skip details view while zooming, since the
main view rendering that already happens after the delay will also
trigger rendering of the detail views.
Browsers not only limit the maximum total canvas area, but additionally also limit their maximum width/height which affects PDF documents with e.g. very tall and narrow pages.
To address this we add a new `maxCanvasDim` viewer-option, which in Firefox will use a browser preference, such that both the total canvas area and the width/height will affect when CSS-zooming is used.
When scrolling quickly, the constant re-rendering of the detail view
significantly affects rendering performance, causing Firefox to
not render even the _background canvas_, which is just a static canvas
not being re-drawn by JavaScript.
This commit changes the viewer to only render the detail view while
scrolling if its rendering hasn't just been cancelled. This means that:
- when the user is scrolling slowly, we have enough time to render the
detail view before that we need to change its area, so the user always
sees the full screen as high resolution.
- when the user is scrolling quickly, as soon as we have to cancel a
rendering we just give up, and the user will see the lower resolution
canvas. When then the user stops scrolling, we render the detail view
for the new visible area.
When rendering big PDF pages at high zoom levels, we currently fall back
to CSS zoom to avoid rendering canvases with too many pixels. This
causes zoomed in PDF to look blurry, and the text to be potentially
unreadable.
This commit adds support for rendering _part_ of a page (called
`PDFPageDetailView` in the code), so that we can render portion of a
page in a smaller canvas without hiting the maximun canvas size limit.
Specifically, we render an area of that page that is slightly larger
than the area that is visible on the screen (100% larger in each
direction, unless we have to limit it due to the maximum canvas size).
As the user scrolls around the page, we re-render a new area centered
around what is currently visible.
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.
With the changes in PR 18843 the `AnnotationEditorUIManager.prototype.updateMode` method is now asynchronous, which we need to take into account when dispatching the "annotationeditormodechanged" event.
When a user deletes any number of annotations, they are notified of the action
by a popup message with an undo button. Besides that, this change reuses the
existing messageBar CSS class from the new alt-text dialog as much as possible.
This is similar to a lot of other code, where we've been replacing explicit `removeEventListener`-calls.
Given the somewhat limited availability of `AbortSignal.any()`, see [MDN](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/any_static#browser_compatibility), this event listener will no longer be immediately removed in older browsers (however that should be fine).
The problem seems to be caused by the browser trying to "restore" editing input-elements, in the various toolbars, to their previous values when the tab is re-opened.
Hence the simplest solution appears to be to move the event handling into the editor-code, which is also less code overall, since the listener thus won't be registered early enough for the problem to appear.
There's a fair number of event listeners in the editor-code that we're currently removing "manually", by keeping references to their event handler functions.
This was necessary since we have a "global" `AbortController` that applies to all event listeners used in the editor-code, however it's now possible to combine multiple `AbortSignal`s; please see https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/any_static
Since this functionality is [fairly new](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/any_static#browser_compatibility) the viewer will check that `AbortSignal.any()` is available before enabling the editing-functionality.
(It should hopefully be fairly straightforward, famous last words, for users to implement a polyfill to allow editing in older browsers.)
Finally, this patch also adds checks and test-only asserts to ensure that we don't add duplicate event listeners in various editor-code.
This patch adds a new entry in the secondary menu in order to open a dialog to let the user:
- disables the alt-text generation thanks to a ML model;
- deletes the alt-text model downloaded in Firefox;
- disabled the new alt-text flow.
Switching to an editing mode can be asynchronous (e.g. if an editable annotation exists on a
visible page), so we must add a new editor only when the page rendering is done.
Right now, editable annotations are using their own canvas when they're drawn, but
it induces several issues:
- if the annotation has to be composed with the page then the canvas must be correctly
composed with its parent. That means we should move the canvas under canvasWrapper
and we should extract composing info from the drawing instructions...
Currently it's the case with highlight annotations.
- we use some extra memory for those canvas even if the user will never edit them, which
the case for example when opening a pdf in Fenix.
So with this patch, all the editable annotations are drawn on the canvas. When the
user switches to editing mode, then the pages with some editable annotations are redrawn but
without them: they'll be replaced by their counterpart in the annotation editor layer.
- Use a CSS rule to display the wait-cursor during copying. Since copying may take a little while in long documents, there's a theoretical risk that something else could change the cursor in the meantime and just resetting to the saved-cursor could thus be incorrect.
- Remove the `interruptCopyCondition` listener with an AbortController, since that's slightly shorter code.
This parameter allows defining which point should remain
fixed while scaling the document. It can be used, for example,
to implement "zoom around the cursor" or "zoom around
pinch center".
The logic was previously implemented in `web/app.js`, but
moving it to the viewer scaling utilities themselves makes it
easier to implement similar zooming functionalities in
other embedders.
`updateScale` receives a `drawingDelay`, a `scaleFactor` and/or a number of `steps`.
If `scaleFactor` is a positive number different from `1` the current scale is multiplied by
that number. Otherwise, if `steps` if a positive integer the current scale is multiplied by
`DEFAULT_SCALE_DELTA` `steps` times. Finally, if `steps` is a negative integer, the
current scale is divided by `DEFAULT_SCALE_DELTA` `abs(steps)` times.
Rather than having to handle this *manually* throughout the viewer, this functionality can instead be moved into the API which simplifies the code slightly.
This replaces our custom `PromiseCapability`-class with the new native `Promise.withResolvers()` functionality, which does *almost* the same thing[1]; please see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers
The only difference is that `PromiseCapability` also had a `settled`-getter, which was however not widely used and the call-sites can either be removed or re-factored to avoid it. In particular:
- In `src/display/api.js` we can tweak the `PDFObjects`-class to use a "special" initial data-value and just compare against that, in order to replace the `settled`-state.
- In `web/app.js` we change the only case to manually track the `settled`-state, which should hopefully be OK given how this is being used.
- In `web/pdf_outline_viewer.js` we can remove the `settled`-checks, since the code should work just fine without it. The only thing that could potentially happen is that we try to `resolve` a Promise multiple times, which is however *not* a problem since the value of a Promise cannot be changed once fulfilled or rejected.
- In `web/pdf_viewer.js` we can remove the `settled`-checks, since the code should work fine without them:
- For the `_onePageRenderedCapability` case the `settled`-check is used in a `EventBus`-listener which is *removed* on its first (valid) invocation.
- For the `_pagesCapability` case the `settled`-check is used in a print-related helper that works just fine with "only" the other checks.
- In `test/unit/api_spec.js` we can change the few relevant cases to manually track the `settled`-state, since this is both simple and *test-only* code.
---
[1] In browsers/environments that lack native support, note [the compatibility data](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers#browser_compatibility), it'll be polyfilled via the `core-js` library (but only in `legacy` builds).
The following are some highlights of this patch:
- In the Worker we only extract a *subset* of the potential contents of the `Usage` dictionary, to avoid having to implement/test a bunch of code that'd be completely unused in the viewer.
- In order to still allow the user to *manually* override the default visible layers in the viewer, the viewable/printable state is purposely *not* enforced during initialization in the `OptionalContentConfig` constructor.
- Printing will now always use the *default* visible layers, rather than using the same state as the viewer (as was the case previously).
This ensures that the printing-output will correctly take the `Usage` dictionary into account, and in practice toggling of visible layers rarely seem to be necessary except in the viewer itself (if at all).[1]
---
[1] In the unlikely case that it'd ever be deemed necessary to support fine-grained control of optional content visibility during printing, some new (additional) UI would likely be needed to support that case.
- Ensure that localization works in the GENERIC viewer, even if the necessary locale files cannot be loaded.
This was the behaviour prior to the introduction of Fluent, and it seems worthwhile to keep that (especially since we already bundle the en-US strings anyway).
- Let the `GenericL10n`-implementation use the *bundled* en-US strings directly when no language is provided.
- Remove the `NullL10n`-implementation, and simply fallback to `GenericL10n`, to reduce the maintenance burden of viewer-components localization.
- Indirectly, given the previous point, stop exporting `NullL10n` in the viewer-components since it's now removed.
Note that it was never really intended to be used directly and only existed as a fallback.
*Please note:* This doesn't affect the Firefox PDF Viewer, thanks to the use of import maps.
