By using the (heuristic) `POSITION_UPDATED_THRESHOLD` constant, we can ensure that the current document position will be added to the browser history when a sufficiently "large" number of `updateviewarea` events have been dispatched.
This patch attempts to address an issue in the old `PDFHistory` implementation, where the current position wouldn't be correctly saved when the browser was closed.
In theory this *should* already be working, however as the discussion in https://bugzilla.mozilla.org/show_bug.cgi?id=1153393 showed, it seems that both `pagehide` and `beforeunload` arrive to late to successfully update the history during closing.
Hence a timeout is used to *temporarily* add the current position to the browser history when the viewer is idle.
Note that we need to take care not to update the browser history too often, since that would render the viewer more or unusable. Furthermore, if the timeout is *too* long it may end up effectively disable this whole functionality.
The `UPDATE_VIEWAREA_TIMEOUT` constant is thus a heuristic value, which we may need to tweak taking the above into account.
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.
*It appears that this accidentally broke with PR 8394.*
Currently, the following will be printed in the console:
```
An error occurred while loading the PDF.
[object Promise],[object Promise]
```
With this patch we'll again get proper output, e.g. something with this format:
```
An error occurred while loading the PDF.
PDF.js v? (build: ?)
Message: unknown encryption method
```
Since the very early days of the viewer, it's been possible to pass in a `scale` when opening a PDF file. However, most of the time it was/is actually being ignored, which limits its usefulness considerably.
In older versions of the viewer, if a document hash was present (i.e. `PDFViewerApplication.initialBookmark` being set) or if the document existed in the `ViewHistory`, the `scale` passed to `PDFViewerApplication.open` would thus always be ignored.
In addition to the above, in the current viewer there's even more cases where the `scale` parameter will be ignored: if a (valid) browser history entry exists on document load, or if the `defaultZoomValue` preference is set to a non-default value.
Hence the result is that in most situation, a `scale` passed to `PDFViewerApplication.open` will be completely ignored.
A much better, not to mention supported, way of setting the initial scale is by using the `defaultZoomLevel` preference. In comparision, this also has the advantage of being used in situations where the `scale` would be ignored.
All in all this leads to the current situation where we have code which is essentially dead, since no part of the viewer (by default) relies on it.
To clean up this code, and to avoid having to pass (basically) unused parameters around, I'd thus like to remove the ability to pass a `scale` to `PDFViewerApplication.open`.
The method signature was improved in PR 7440, which has now been present in a number of releases (starting with `v1.6.210`).
Hence we should be able to remove this now, and just print an error message if the old format is used.
This was added in PR 7793, which has now been present in a number of PDF.js releases (from version `v1.7.225`).
Hence we should be able to remove it now, considering that the migration code was only intended as a best effort solution to avoid wiping out all existing user data at once. Also, keep in mind that `ViewHistory` is already limited with regards to the number of documents it will simultaneous store data for.
As discussed in PR 8673, we cannot solve the general issue (since that would require parsing every single page). However, we can mitigate the effect somewhat, by waiting for the FileAttachment annotations of the initially rendered page.
Rather than duplicating initialization code, we can just call `this.reset()` instead (which is also similar to other existing code, e.g. `PDFViewer`). This will also help ensure that the DOM is completely reset, before any outline items or attachments are displayed.
At this point, the default viewer is already not usable in older browsers in `gulp server` mode, since we only run the code through Babel as part of the build step.
Hence there shouldn't be much point in manually loading `compatibility.js` in `viewer.html` the way that we've been doing, especially considering that it's already being loaded by `src/shared/util.js`.
Note that the PageMode, as specified in the API, will only be honoured when either: the user hasn't set the `sidebarViewOnLoad` preference to a non-default value, or a non-default `sidebarView` entry doesn't exist in the view history, or the "pagemode" hash parameter is included in the URL.
Since this is new functionality, the patch also includes a preference (`disablePageMode`), to make it easy to opt-out of this functionality if the user/implementor so wishes.
Add UI for the cursorToolOnLoad pref in the UI of the Chrome extension.
Add logic to migrate the enableHandToolOnLoad pref to cursorToolOnLoad.
For past values in the mutable extension storage area:
1. If enableHandToolOnLoad=true, save cursorToolOnLoad=1.
2. Remove enableHandToolOnLoad.
For the managed extension storage, which is immutable since it is based
on administrative policies, use the following logic:
1. If enableHandToolOnLoad=true and cursorToolOnLoad=0 (default).
set cursorToolOnLoad=0 and assume enableHandToolOnLoad=false.
2. As usual, managed preferences can (and will) be overridden by the user.
The first migration logic is in extensions/chromium/options/migration.js
and can be removed after a few months / less than many years.
The second migration logic is in web/chromecom.js, and should be kept
around for a long while (many years).
The need for this migration logic arises from the change by:
https://github.com/mozilla/pdf.js/pull/7635
* Check for undefined
new URL(file, window.location.href) throws the following error in IE11 + iPad Safari:
Unable to get property 'replace' of undefined or null reference
* Adapting previous change to pdf.js code standards
Added curly braces
* Moved check for undefined above try/catch
`__pdfjsdev_webpack__` was used to skip evaluating part of an AST,
in order to not mangle some `require` symbols.
This commit removes `__pdfjsdev_webpack__`, and:
- Uses `__non_webpack_require__` when one wants the output to
contain `require` instead of `__webpack_require__`.
- Adds options to the webpack config to prevent "polyfills" for
some Node.js-specific APIs to be added.
- Use `// eslint-disable-next-line no-undef` instead of `/* globals ... */`
for variables that are not meant to be used globally.
Since we no longer, after PR 8555, allow changing the scale until the document is loaded, that hack is no longer necessary. Furthermore, no part of that event handling function needs to run unless a document is loaded.
The reason that this hack was initially added, is that previously the `ViewHistory` might be updated *before* `PDFViewerApplication.setInitialView` had run (in some cases leading to incorrect inital document scale). Since that is no longer possible, this is now dead code.
Don't allow setting various properties, such as `currentPageNumber`/`currentScale`/`currentScaleValue`/`pagesRotation`, before `{PDFViewer, PDFThumbnailViewer}.setDocument` has been called
After PR 8394, where the l10n service was converted to be asynchronous, we're no longer calling `_adjustWidth` after updating the `findMsg` label. Hence it's currently possible that the width of the findbar won't be correct. The solution is simple though, just call `_adjustWidth` after the `findMsg` label has been (asynchronously) updated.
Another existing issue, which was an oversight in PR 8132, is that `PDFFindBar.updateResultsCount` may be called directly from `PDFFindController`. In that case, we're not calling `_adjustWidth` at all, which means that the findbar may also not have the correct width.
The simple solution here is to always call `_adjustWidth` at the end of `updateResultsCount` (which is why we no longer need the `_adjustWidth` call at the end of `updateUIState`).
Currently we're *only* hiding the label, but not actually resetting it until a new match is found.
Obviously it's being hidden, but it seems that it really ought to be completely reset as well (since e.g. `PDFFindBar.reset` won't technically reset *all* state otherwise).
Note that these files were among the first to be converted to ES6 classes, so it probably makes sense to do another pass to bring them inline with the most recent ES6 conversions.
These changes consists mainly of replacing `var` with `let`/`const`, adding a couple of default parameters to function signatures, and finally converting `EventBus`/`ProgressBar` to proper classes.
After PR 8510, we now always lookup the localized `page_scale_percent` string to prevent any possible ordering issues. Since the scaleSelect dropdown is updated asynchronous, there's really no point in having a helper function any more, hence this code can rather be placed inline in `Toolbar._updateUIState`.
*This is an existing issue that I noticed while testing PR 8552.*
When zooming or rotation occurs, we'll try to use the current canvas as a (CSS transformed) preview until the page has been completely re-drawn.
If you manage to change the scale (or rotation) *very* quickly, it's possible that `PDFPageView.update` can be called *before* a previous `render` operation has progressed far enough to remove the `hidden` property from the canvas.
The result is thus that a page may be *entirely* black during zooming or rotation, which doesn't look very good. This effect can be a bit difficult to spot, but it does manifest even in the default viewer.
Part of the rotation handling code, in what's now `web/app.js`, hasn't really changed since before the viewer was split into multiple files/components.
Similar to other properties, such as current page/scale, we should probably avoid tracking state in multiple places. Hence I'm suggesting that we don't store the rotation in `PDFViewerApplication`, and access the value in `PDFViewer` instead.
Since `PDFViewerApplication.pageRotation` has existed for a very long time, a getter was added to avoid outright breaking third-party code that may depend on it.
Currently a number of these properties do not work correctly if set *before* calling `setDocument`; please refer to the discussion starting in https://github.com/mozilla/pdf.js/pull/8539#issuecomment-309706629.
Rather than trying to have *some* of these methods working, but not others, it seems much more consistent to simply always require that `setDocument` has been called.
