Currently the viewer uses semi-private `EventBus.prototype.{_on, _off}` methods, to try and ensure that all internal viewer state is updated *before* any "external" listeners are invoked.
For all use-cases outside of the viewer, e.g in the integration-tests, the `EventBus.prototype.{on, off}` methods are supposed to be used instead.
Unfortunately this isn't currently enforced in any way, except (hopefully) during review, and generally speaking it's not really possible to prevent the semi-private methods being used (e.g. by third-party users).
Hence this patch adds a new `INTERNAL_EVT` property which is *not* exposed anywhere (neither in the API nor globally), and whose value is generated at build-time, that the viewer uses to mark its `EventBus` listeners are internal.
This allows us to remove the semi-private `EventBus` methods, which helps to simplify that class a little bit.
Image files dropped on or selected via the thumbnail viewer's
"add file" picker are now accepted alongside PDFs and inserted
as synthetic pages sized to the document's modal page dimensions.
The image-encoding helper previously embedded in StampAnnotation has
moved to src/core/editor/pdf_images.js so it can be shared between
stamp annotations and page synthesis.
Drop an external PDF anywhere in the views-manager thumbnail
sidebar to merge it at the cursor, rather than always inserting
after the current page via the "Add file" button.
The drop reuses the blue separator from page-move drag so the
user can see exactly where the inserted pages will land, and the
merge path is shared with the existing picker so post-merge
selection/current-page behavior stays consistent.
The thumbnails are only available if the first page is ready, and not
awaiting that causes the drag-and-drop action to be performed using
incorrect thumbnail viewer state (see the analysis in #21184 for more
details).
Fixes#21184.
Supersedes #20902.
Unblocks #21173.
When pages carry explicit pageIndices (e.g. after a delete),
resolve insertAfter against that layout instead of the empty
base sequence. Also reject partial pageIndices combined with
insertAfter, which would race against the extraction's auto-fill.
There is generally a small amount of time between the find call being
reported as finished and the find count results text being updated with
the correct number in the DOM, so the integration tests will fail if we
check the find results count text too soon.
This commit fixes the issue by using the `waitForTextToBe` helper
function to wait until the find count results text is what we expect it
to be. Note that we already use this helper function for this exact
purpose in other integration tests (related to reorganizing pages), and
it's also a little bit shorter/easier to read which cannot hurt.
The user has to select some pages and then click on the "Save As" menu item in the Manage menu.
If they modify the structure of the pdf (deleted, moved, copied pages), they have to use the usual
save button.
