- For wrapped scrolling, we unfortunately need to do a fair bit of parsing of the *current* page layout. Compared to e.g. the spread-modes, where we can easily tell how the pages are laid out, with wrapped scrolling we cannot tell without actually checking. In particular documents with varying page sizes require some care, since we need to check all pages on the "row" of the current page are visible and that there aren't any "holes" present. Otherwise, in the general case, there's a risk that we'd skip over pages if we'd simply always advance to the previous/next "row" in wrapped scrolling.
- For horizontal scrolling, this patch simply maintains the current behaviour of advancing *one* page at a time. The reason for this is to prevent inconsistent behaviour for the next and previous cases, since those cannot be handled identically. For the next-case, it'd obviously be simple to advance to the first not completely visible page. However for the previous-case, we'd only be able to go back *one* page since it's not possible to (easily) determine the page layout of non-visible pages (documents with varying page sizes being a particular issue).
- For vertical scrolling, this patch maintains the current behaviour by default. When spread-modes are being used, we'll now attempt to advance to the next *spread*, rather than just the next page, whenever possible. To prevent skipping over a page, this two-page advance will only apply when both pages of the current spread are visible (to avoid breaking documents with varying page sizes) and when the second page in the current spread is fully visible *horizontally* (to handle larger zoom values).
In order to reduce the performance impact of these changes, note that the previous/next-functionality will only call `getVisibleElements` for the scroll/spread-modes where that's necessary and that "normal" vertical scrolling is thus unaffected by these changes.
To support these changes, the `getVisibleElements` helper function will now also include the `widthPercent` in addition to the existing `percent` property.
The `PDFViewer._updateHelper` method is changed slightly w.r.t. updating the `currentPageNumber` for the non-vertical/spread modes, i.e. won't affect "normal" vertical scrolling, since that helped simplify the overall calculation of the page advance.
Finally, these new `BaseViewer` methods also allow (some) simplification of previous/next-page functionality in various viewer components.
*Please note:* There's one thing that this patch does not attempt to change, namely disabling of the previous/next toolbarButtons respectively the firstPage/lastPage secondaryToolbarButtons. The reason for this is that doing so would add quite a bit of complexity in general, and if for some reason `BaseViewer._getPageAdvance` would get things wrong we could end up incorrectly disabling the buttons. Hence it seemed overall safer to *not* touch this, and accept that the buttons won't be `disabled` despite in some edge-cases no further scrolling being possible.
This patch will help reduce memory usage, especially for longer documents, when the user scrolls around in the thumbnailView (in the sidebar).
Note how the `PDFPageProxy.cleanup` method will, assuming it's safe to do so, release main-thread resources associated with the page. These include things such as e.g. image data (which can be arbitrarily large), and also the operatorList (which can also be quite large).
Hence when pages are evicted from the `PDFPageViewBuffer`, on the `BaseViewer`-instance, the `PDFPageView.destroy` method is invoked which will (among other things) call `PDFPageProxy.cleanup` in the API.
However, looking at the `PDFThumbnailViewer`/`PDFThumbnailView` classes you'll notice that there's no attempt to ever call `PDFPageProxy.cleanup`, which implies that in certain circumstances we'll essentially keep all resources allocated permanently on the `PDFPageProxy`-instances in the API.
In particular, this happens when the users opens the sidebar and starts scrolling around in the thumbnails. Generally speaking you obviously need to keep all thumbnail *images* around, since otherwise the thumbnailView is useless, but there's still room for improvement here.
Please note that the case where a *rendered page* is used to create the thumbnail is (obviously) completely unaffected by the issues described above, and this rather only applies to thumbnails being explicitly rendered by the `PDFThumbnailView.draw` method.
For the latter case, we can fix these issues simply by calling `PDFPageProxy.cleanup` once rendering has finished. To prevent *accidentally* pulling the rug out from under `PDFPageViewBuffer` in the viewer, which expects data to be available, this required adding a couple of new methods[1] to enable checking that it's indeed safe to call `PDFPageProxy.cleanup` from the `PDFThumbnailView.draw` method.
It's really quite fascinating that no one has noticed this issue before, since it's been around since basically "forever".
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[1] While it should be *very* rare for `PDFThumbnailView.draw` to be called for a pageView that's also in the `PDFPageViewBuffer`, given that pages are rendered before thumbnails and that the *rendered page* is used to create the thumbnail, it can still happen since rendering is asynchronous.
Furthermore, it's also possible for `PDFThumbnailView.setImage` to be disabled, in which case checking the `PDFPageViewBuffer` for active pageViews *really* matters.
This patch addresses a review comment, which pointed out that we should *also* handle the pageNumber-input, from PR 12493.
Given that a user *manually* changing pages using the pageNumber-input, on the toolbar, could be regarded as a pretty strong indication of user-intent w.r.t. navigation in the document, hence I suppose that updating the browser history in this case as well probably won't hurt.
All of these methods will, in one way or another, cause e.g. scrolling or zooming to occur and consequently they don't really make sense unless there's an active PDF document. Especially since all of these methods end up calling into a `BaseViewer`-instance, which already contains similar early returns in essentially all of it's methods and setters.
Ensure that these tooltip-only Annotations are handled as "internalLink"s, to ensure that they behave as expected in PresentationMode (e.g. they should still use a `pointer`-cursor).
Ensure that `PDFLinkService.getDestinationHash` won't create links with empty hashes, since those don't really make a lot of sense in general (this improves things for tooltip-only Annotations).
This PDF file can be used for testing: http://mirrors.ctan.org/macros/latex/contrib/pdfcomment/doc/pdfcomment.pdf#page=14
While the referenced issue could very well be seen as an edge-case, this patch adds support for updating of the browser history when interacting with the thumbnails in the sidebar (assuming we want to do this).
The main reason for adding the history implementation in the first place, was to simplify navigating back to a previous position in the document when named/explicit destinations are used (e.g. when clicking on "links" or when using the outline in the sidebar).
As such, it never really crossed by mind to update the browser history when the thumbnails are used. However, a user clicking on thumbnails could be regarded as a pretty strong indication of user-intent w.r.t. navigation in the document, hence I suppose that updating the browser history in this particular case probably won't hurt.
This modernizes and improves the code, by using `async`/`await` and by extracting the helper function to its own method.
To hopefully avoid confusion, given the next patch, the method is also re-named to `goToDestination` to make is slightly clearer what it actually does.
Given that the `PDFLinkService.setHash` method itself if completely synchronous, moving the handling of "nameddest" to occur last *shouldn't* cause any problems (famous last words).
This way the destination will still override any previous parameter, such as e.g. the "page", as expected. Furthermore, given that the `PDFLinkService.navigateTo` method is asynchronous that should provide additional guarantees that the "nameddest" parameter is always respected.
As sort-of expected, this fairly innocent looking change also required some tweaks in the `PDFHistory` to prevent dummy history entires upon document load (only an issue when both "page" *and* "nameddest" parameters are provided in the hash).
*Please note:* These changes were done automatically, using the `gulp lint --fix` command.
This rule is already enabled in mozilla-central, see https://searchfox.org/mozilla-central/rev/567b68b8ff4b6d607ba34a6f1926873d21a7b4d7/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js#103-104
The main advantage, besides improved consistency, of this rule is that it reduces the size of the code (by 3 bytes for each case). In the PDF.js code-base there's close to 8000 instances being fixed by the `dot-notation` ESLint rule, which end up reducing the size of even the *built* files significantly; the total size of the `gulp mozcentral` build target changes from `3 247 456` to `3 224 278` bytes, which is a *reduction* of `23 178` bytes (or ~0.7%) for a completely mechanical change.
A large number of these changes affect the (large) lookup tables used on the worker-thread, but given that they are still initialized lazily I don't *think* that the new formatting this patch introduces should undo any of the improvements from PR 6915.
Please find additional details about the ESLint rule at https://eslint.org/docs/rules/dot-notation
The correct/intended way of working with the "viewer components" is by providing an `EventBus` instance upon initialization, and the `getGlobalEventBus` was only added for backwards compatibility.
Note, for example, that using `getGlobalEventBus` doesn't really work at all well with a use-case where there's *multiple* `PDFViewer` instances on a one page, since it may then be difficult/impossible to tell which viewer a particular event originated from.
All of the "viewer components" examples have been previously updated, such that there's no longer any code/examples which relies on the now removed `getGlobalEventBus` functionality.
In order to eventually get rid of SystemJS and start using native `import`s instead, we'll need to provide "complete" file identifiers since otherwise there'll be MIME type errors when attempting to use `import`.
This covers the handful of cases that the `--fix` command couldn't deal with, and the changes aren't just fixing the linting errors but attempt to slightly improve the relevant code.
Please find additional details about the ESLint rule at https://eslint.org/docs/rules/prefer-const
Note that this patch is generated automatically, by using the ESLint `--fix` argument, and will thus require some additional clean-up (which is done separately).
Note that Prettier, purposely, has only limited [configuration options](https://prettier.io/docs/en/options.html). The configuration file is based on [the one in `mozilla central`](https://searchfox.org/mozilla-central/source/.prettierrc) with just a few additions (to avoid future breakage if the defaults ever changes).
Prettier is being used for a couple of reasons:
- To be consistent with `mozilla-central`, where Prettier is already in use across the tree.
- To ensure a *consistent* coding style everywhere, which is automatically enforced during linting (since Prettier is used as an ESLint plugin). This thus ends "all" formatting disussions once and for all, removing the need for review comments on most stylistic matters.
Many ESLint options are now redundant, and I've tried my best to remove all the now unnecessary options (but I may have missed some).
Note also that since Prettier considers the `printWidth` option as a guide, rather than a hard rule, this patch resorts to a small hack in the ESLint config to ensure that *comments* won't become too long.
*Please note:* This patch is generated automatically, by appending the `--fix` argument to the ESLint call used in the `gulp lint` task. It will thus require some additional clean-up, which will be done in a *separate* commit.
(On a more personal note, I'll readily admit that some of the changes Prettier makes are *extremely* ugly. However, in the name of consistency we'll probably have to live with that.)
Sometimes we also used `@return` or `@returns`, but `@type` is what
the JSDoc documentation recommends. This also improves the documentation
because before this commit the types were not shown and now they are.
By using the same internal formatting here as in the `Ref.toString` method, in `src/core/primitives.js`, all cache-keys will become at least two bytes shorter (and most three bytes shorter).
Obviously this won't have a huge effect on memory since there's only one cache entry per page, but it nonetheless seems wasteful to use longer keys than strictly required.
Currently we'll only attempt to start from the current page when a new search is done, however for 'findagain' operations we'll always continue from the last match position.
This could easily lead to confusing behaviour if the user has scrolled to a completely different part of the document. In an attempt to improve this somewhat, for repeated 'findagain' operations, we'll instead reset the position to the current page when it's *absolutely* certain that the user has scrolled.
Note that this required adding a new `BaseViewer` method, and exposing that through `PDFLinkService`, in order to check if a given page is visible.
In an attempt to avoid issues, in custom implementations of `PDFFindController`, the code checks for the existence of the `PDFLinkService.isPageVisible` method *before* using it.
This attempts to reduced the level of indirection, and the amount of code, when dispatching `fileattachmentannotation` events, by removing the `PDFLinkService.onFileAttachmentAnnotation` method and just accessing `PDFLinkService.eventBus` directly in the `FileAttachmentAnnotationElement` constructor.
Given that other properties, such as `externalLinkTarget`/`externalLinkRel`, are already being accessed directly this pattern seems fine here as well.
This way the resetting of `PDFLinkService`/`PDFDocumentProperties` instances, as is done in `PDFViewerApplication.close`, only requires passing in *one* `null` argument instead of two.
This removes the `PDFJS.externalLinkTarget`/`PDFJS.externalLinkRel` dependency from the viewer components, but please note that as a *temporary* solution the default viewer still uses it.
This rule is available from https://www.npmjs.com/package/eslint-plugin-mozilla, and is enforced in mozilla-central. Note that we have the necessary `Array`/`String` polyfills and that most cases have already been fixed, see PRs 9032 and 9434.
This patch completely re-implements `PDFHistory` to get rid of various bugs currently present, and to hopefully make maintenance slightly easier. Most of the interface is similar to the existing one, but it should be somewhat simplified.
The new implementation should be more robust against failure, compared to the old one. Previously, it was too easy to end up in a state which basically caused the browser history to lock-up, preventing the user from navigating back/forward. (In the new implementation, the browser history should not be updated rather than breaking if things go wrong.)
Given that the code has to deal with various edge-cases, it's still not as simple as I would have liked, but it should now be somewhat easier to deal with.
The main source of complication in the code is actually that we allow the user to change the hash of a already loaded document (we'll no longer try to navigate back-and-forth in this case, since the next commit contains a workaround).
In the new code, there's also *a lot* more comments (perhaps too many?) to attempt to explain the logic. This is something that the old implementation was serverly lacking, which is a one of the reasons why it was so difficult to maintain.
One particular thing to note is that the new code uses the `pagehide` event rather than `beforeunload`, since the latter seems to be a bad idea based on https://bugzilla.mozilla.org/show_bug.cgi?id=1336763.
The current implementation of `PDFHistory` contains a number of smaller bugs, which are *very* difficult to address without breaking other parts of its code.
Possibly the main issue with the current implementation, is that I wrote it quite some time ago, and at the time my understanding of the various edge-cases the code has to deal with was quite limited.
Currently `PDFHistory` may, despite most of those cases being fixed, in certain edge-cases lock-up the browser history, essentially preventing the user from navigating back/forward.
Hence rather than trying to iterate on `PDFHistory` to make it better, the only viable approach is unfortunately rip it out in its entirety and re-write it from scratch.
PR 7341 added special handling for `nameddest`s that look like pageNumbers, to prevent issues since we previously *incorrectly* supported specifying a pageNumber directly in the hash; i.e. `#10` versus the correct `#page=10` format.
Since this behaviour wasn't correct, PR 7757 fixed and deprecated the old format, which means that we no longer need to maintain the `nameddest` hack in multiple files.
This patch replaces a `var self = this;` statement with arrow functions, and `var` with `let` in `PDFLinkService.navigateTo`.
Furthermore, when I started looking at this method, it quickly became clear that its code is somewhat of a mess. Since I'm one of the persons that have touched this code over the years, I figured that it'd be a good idea to try and clean it up a bit.
Please see http://eslint.org/docs/rules/object-shorthand.
For the most part, these changes are of the search-and-replace kind, and the previously enabled `no-undef` rule should complement the tests in helping ensure that no stupid errors crept into to the patch.
Note that as discussed on IRC, this makes the viewer slightly slower to load *only* in `gulp server` mode, however the difference seem slight enough that I think it will be fine.
Other PDF viewers, e.g. Adobe Reader, seem to append `FileAttachment`s to their attachments views.
One obvious difference in PDF.js is that we cannot append all the annotations on document load, since that would require parsing *every* page. Despite that, it still seems like a good idea to add `FileAttachment`s, since it's thus possible to access all the various types of attachments from a single place.
*Note:* With the previous patch we display a notification when a `FileAttachment` is added to the sidebar, which thus makes appending the contents of these annotations to the sidebar slightly more visible/useful.
There's no mention of our `#{pagenum}` form in http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_open_parameters.pdf, and Adobe Reader doesn't seem to support it either.
Hence this patch removes support for it in the extensions, but keeps it in the `GENERIC` build with a deprecation warning and a fallback to handle it as a destination.
Fixes 7746.
