This improves and simplifies #13102 in order to make printing of test-cases
like the one in bug 1698414 (where the real page is bigger than the target
page) much better, see incoming screenshots.
The reason why we need to stop setting .style.width / .style.height is to get
the right auto-sizing behavior in both axes. This shouldn't change behavior as
long as the print resolution is >= the CSS resolution, which seems like a
reasonable assumption.
If you try to print with a lower resolution than CSS, then instead of an
stretched canvas, you'd get a centered CSS-quality canvas, which seems
sensible. This could maybe be fixed with some CSS hackery (some combination of
min / max and viewport units perhaps?), but I think it's more trouble than it's
worth.
- implement few positioning properties: position, width, height, anchor;
- implement font element;
- implement fill element (used by font) and its children (linear, radial, ...);
- font property is inherited from ancestor container (see https://www.pdfa.org/wp-content/uploads/2020/07/XFA-3_3.pdf#page=43) so let CSS handles that stuff;
- in order to reduce the number of properties to set, only set non default properties and put the default in CSS;
- set a background to some containers to be able to see them (will be removed in a future commit).
The intention, in PR 12493, was that the page we're adding to the browser history should behave as if it were a "regular" internal destination (to properly convey user intent).
Unfortunately, since I didn't consider all the edge-cases correctly, it ended up behaving like a URL-hash instead which obviously wasn't intended. Note that currently this isn't a problem, however it can become an issue (in some cases) with upcoming re-factoring around `PDFHistory` and OpenAction support[1].
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[1] I've started working on fixing the following TODO, which will require a couple of smaller tweaks here and there: 9d0ce6e79f/web/app.js (L1680-L1681)
In the `getAll`-method, we can have just one *explicit* loop rather than two indirect ones via the old `Object.assign`-call.
Also, changes the `get`-method to be slightly more compact (while keeping the logic intact).
Looking at this now, I cannot understand why we'd need to initialize `this.prefs` with all of the values from `this.defaults`.
Not only does this *indirectly* require one extra loop, via the `Object.assign`-call, but it also means that in GENERIC-builds changes to default-preference values might not be picked-up unless the the existing user-prefs are cleared (if the user had *manually* set prefs previously).
Given that the `enableXfa` parameter must to be passed to the API/Worker, and thus included in the `getDocument` call, it's not necessary to include it when initializing the `PDFViewer`-instance used in the default viewer. (Also, in `AppOptions`, the parameter is clearly marked with `OptionKind.API`.)
Furthermore, we probably don't want to display the fallback bar (in Firefox) for XFA documents when `enableXfa = true` is set.
While it's still not entirely clear if this would've prevented the issue as reported, given that the particular use-case reported apparently no longer applies, this small change really cannot hurt in general *and* it won't effect "regular" viewer builds in any way.
Given how the compatibility-values are being handled, it's not actually possible to override a *truthy* default-value with a *falsy* compatibility-value.
This is a simple oversight on my part, and with modern ECMAScript features this is very easy to support.
With the changes made in the previous patch, we can now list "disableTelemetry" in the `AppOptions` only for the `CHROME`-builds and thus remove the special-casing in the `checkChromePreferencesFile` helper function.
Originally the default preferences where simply placed in a JSON-file, checked into the repository, which over time became impractical, annoying, and error-prone to maintain; please see PR 10548.
While that improved the overall situation a fair bit, it however inherited one quite unfortunate property of the old JSON-based solution[1]: It's still not possible for *different* build targets to specify their *own* default preference values.
With some preferences, such as e.g. `enableScripting`, it's not inconceivable that you'd want to (at least) support build-specific default preference values. Currently that's not really possible, which is why this PR re-factors the default preferences generation to support this.
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[1] This fact isn't really clear from the `AppOptions` implementation, unless you're familiar with the `gulpfile.js` code, which could lead to some confusion for those new to this part of the code-base.
A number of the currently supported *scripting* events only make sense in the "normal" viewer mode, and not when PresentationMode is active. For example:
- Changing the zoom-level will outright break rendering in PresentationMode, since it relies on "page-fit" being used.
- Focusing a particular (AcroForm) element won't work, and could break keyboard navigation, since forms should not be editable in PresentationMode (see issue 12232).
While this will perhaps not be perfect for *every* PDF document with mixed page orientation, based on the large number of bugs/issues seen over the years I'm however pretty convinced that it'll be an overall improvement in a majority of cases.
In order to improve things further, we'd probably need Firefox to support e.g. `@page` such that the viewer can provide better information to the print engine.
Currently, with `enablePrintAutoRotate = true` set, we're forced to loop through all the pages *twice* when checking for any landscape pages.
This seems completely unnecessary now, and using only *one* loop should be marginally more efficient in general.
Currently landscape pages are rotated *clockwise*, which for most documents feel wrong since holding the printed pages at their *left* edge causes the landscape pages to be viewed "upside down".
In general, since most documents are LTR ones, it feels more appropriate to instead rotate landscape pages *counterclockwise* for printing.
- add an option to enable XFA rendering if any;
- for now, let the canvas layer: it could be useful to implement XFAF forms (embedded pdf in xml stream for the background and xfa form for the foreground);
- ui elements in template DOM are pretty close to their html counterpart so we generate a fake html DOM from template one:
- it makes easier to translate template properties to html ones;
- it makes faster the creation of the html element in the main thread.
Given that https://bugzilla.mozilla.org/show_bug.cgi?id=1699219 has enabled scripting for all Firefox-channels, it seems reasonable to simply set `enableScripting = true` unconditionally in the viewer preferences/options.
For now, this patch leaves the standalone viewer-components alone (such as e.g. `BaseViewer`), and if those are used scripting will thus have to be manually enabled (see e.g. the "simpleviewer"/"singlepageviewer" examples).
It seems reasonable to place this alongside the *similar* `getFilenameFromUrl` helper function. This way, with the changes in the next patch, we also avoid having to expose the `isDataScheme` function in the API itself and we instead expose `getPdfFilenameFromUrl` in the API (which feels overall more appropriate).
The issue that this patch fixes is extremely unlikely, but still theoretically possible, and I really should've caught this earlier.
Note how `BaseViewer.pagesPromise` will only be defined when a document is active, see below, and that if a printing event (triggered from scripting) arrives while the document is been closed there's a small chance that the promise isn't defined.
eb92ed12f2/web/base_viewer.js (L426-L428)
This builds on top of #13100, but this changes printing behavior intentionally
so I thought it was worth discussing separately, to improve the rendering on
test-cases like the one in https://bugzil.la/1697778.
This matches what e.g. Evince does when you print the PDF in there on an A4
printer.
We use margins to center horizontally, and flex to center vertically. The
reasoning for this is that it should have better browser support (though maybe
pdf.js no longer supports browsers without flex support?) and it's just as
simple.
@supports() is not supposed to report support for page descriptors, this is
depending on a Chromium bug, which doesn't treat as invalid:
```
<div style="size: 1pt 1pt">
```
Even though it should. That is
https://bugs.chromium.org/p/chromium/issues/detail?id=1079214
There's no need to use @supports for this. If the descriptor is not accepted it
will just be ignored.
That way, when Firefox implements @page { size }, which is in progress, it will
get the right behavior.
First, there's just no need to do something like this, this is simpler and
closer to what the screen renderer does.
Second, this causes overflow, which Firefox tries to compensate for when
fitting to page width, and fails at it. That is tracked in:
https://bugzilla.mozilla.org/show_bug.cgi?id=1698136
But this bug works around it by not causing overflow.
For modern browsers, we could avoid the duplication setting the style attribute
by using something like width: min/max-content, but this is not a big deal I
think, let me know if you'd prefer that.
Also I had to add a max-height for Chromium not to create extra pages. This
is harmless in Firefox and workarounds the Chromium bug, so so be it.
A significant portion of the code-base has now been converted to use `let`/`const`, rather than `var`, hence it should be possible to simply enable the ESLint `no-var` rule globally.
This way we can ensure that new code won't accidentally use `var`, and it also removes the need to manually enable the rule in various folders.
Obviously it makes sense to continue the efforts to replace `var`, but that should probably happen on a file and/or folder basis.
Please note that this patch excludes the following code:
- The `extensions/` folder, since that seemed easiest for now (and I don't know exactly what the support situation is for the Chromium-extension).
- The entire `external/` folder is ignored, since most of it's currently excluded from linting.
For the code that isn't imported from elsewhere (and should be ignored), we should probably (at some point) bring the code up to the same linting/formatting standard as the rest of the code-base.
- Various files in the `test/` folder are ignored, as necessary, since the way that a lot of this code is loaded will require some care (or perhaps larger re-factoring) when removing `var` usage.
*Please note:* Given the pre-existing issues raised in PR 13056, which seem to block immediate progress there, this patch extracts some *overall* improvements of the scripting/sandbox destruction in `PDFScriptingManager`.
As can be seen in `BaseViewer.setDocument`, it's currently necessary to *manually* delay the `PDFScriptingManager`-destruction in order for things to work correctly. This is, in hindsight, obviously an *extremely poor* design choice on my part; sorry about the churn here!
In order to improve things overall, the `PDFScriptingManager._destroyScripting`-method is re-factored to wait for the relevant events to be dispatched *before* sandbox-destruction occurs.
To avoid the scripting/sandbox-destruction hanging indefinitely, we utilize a timeout to force-destroy the sandbox after a short time (currently set to 1 second).
By moving this code from the `BaseViewer` and into `PDFScriptingManager`, all of the scripting initialization/handling code is now limited to just one file/class which help overall readability (in my opinion). Also, this patch is a *net reduction* in number of lines of code which can never hurt.
As part of these changes, the intermediary "pageopen"/"pageclose" events are now removed in favor of using the "regular" viewer events directly in `PDFScriptingManager`. Hence this removes some (strictly unnecessary) indirection in the current code, when handling PageOpen/PageClose events, which leads to overall fewer function calls in this part of the code.
The *main* purpose of this patch is to allow scripting to be used together with the viewer components, note the updated "simpleviewer"/"singlepageviewer" examples, in addition to the full default viewer.
Given how the scripting functionality is currently implemented in the default viewer, trying to re-use this with the standalone viewer components would be *very* hard and ideally you'd want it to work out-of-the-box.
For an initial implementation, in the default viewer, of the scripting functionality it probably made sense to simply dump all of the code in the `app.js` file, however that cannot be used with the viewer components.
To address this, the functionality is moved into a new `PDFScriptingManager` class which can thus be handled in the same way as all other viewer components (and e.g. be passed to the `BaseViewer`-implementations).
Obviously the scripting functionality needs quite a lot of data, during its initialization, and for the default viewer we want to maintain the current way of doing the lookups since that helps avoid a number of redundant API-calls.
To that end, the `PDFScriptingManager` implementation accepts (optional) factories/functions such that we can maintain the current behaviour for the default viewer. For the viewer components specifically, fallback code-paths are provided to ensure that scripting will "just work"[1].
Besides moving the viewer handling of the scripting code to its own file/class, this patch also takes the opportunity to re-factor the functionality into a number of helper methods to improve overall readability[2].
Note that it's definitely possible that the `PDFScriptingManager` class could be improved even further (e.g. for general re-use), since it's still heavily tailored to the default viewer use-case, however I believe that this patch is still a good step forward overall.
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[1] Obviously *all* the relevant document properties might not be available in the viewer components use-case (e.g. the various URLs), but most things should work just fine.
[2] The old `PDFViewerApplication._initializeJavaScript` method, where everything was simply inlined, have over time (in my opinion) become quite large and somewhat difficult to *easily* reason about.
These changes will be necessary for the next patch, since we don't want to accidentally pull in the entire default viewer in the standalone viewer components.
Given that scripting is now enabled in Firefox Nightly (but only there), it seems weird to not have scripting enabled by default in `gulp server` mode.
Rather than having to spell out the English fallback strings at *every* single `IL10n.get` call-site throughout the viewer, we can simplify things by collecting them in *one* central spot.
This provides a much better overview of the fallback l10n strings used, which makes future changes easier and ensures that fallback strings occuring in multiple places cannot accidentally get out of sync.
Furthermore, by making the `fallback` parameter of the `IL10n.get` method *optional*[1] many of the call-sites (and their surrounding code) become a lot less verbose.
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[1] It's obviously still possible to pass in a fallback string, it's just not required.
