For the integration tests we prefer non-linked test cases because those
PDF files are directly checked into the Git repository and thus don't
need a separate download step that linked test cases do.
However, for the freetext and ink integration tests we currently use
`aboutstacks.pdf` which is a linked test case. Fortunately we don't need
to use it because for most tests we don't actually use any properties of
it: we only create editors on top of the canvas, but for that any PDF
file works, so we can simply use the non-linked `empty.pdf` file instead.
The only exception is the "aria-owns" test that needs a line of text from
the PDF file, so we move that particular test to a dedicated `describe`
block and adapt it to use the non-linked `attachment.pdf` file that just
contains a single line of text that can be used for this purpose.
The changes combined make 12 more integration tests run out-of-the-box
after a Git clone, which also simplifies running on GitHub Actions.
But keep a lower quality when enableOptimizedPartialRendering is true because we need to compensate the time
used to compute the bboxes and since subsequent rendering are faster it's more acceptable to see
a lower quality image for few tenths of seconds.
This PR serializes font data into an ArrayBuffer
that is then transfered from the worker to the
main thread. It's more efficient than the current
solution which clones the "export data" object
which includes the font data as a Uint8Array.
It prepares us to switch to a SharedArrayBuffer
in the future, which would allow us to share
the font data with multiple agents, which would be
crucial for the upcoming "renderer" worker.
The size of the canvas has significant impact on the rendering
performance. If we are going to render a high-res detail
view on top of the full-page canvas, we can further
reduce the full-page canvas resolution to improve
rendering time without affecting the resolution seen by
the user.
Users will se the lower resolution when quickly scrolling around the
page, but it will then be replaced with the high-res
detail view.
This PR changes the way we store bounding boxes so that they use less
memory and can be more easily shared across threads in the future.
Instead of storing the bounding box and list of dependencies for each
operation that renders _something_, we now only store the bounding box
of _every_ operation and no dependencies list. The bounding box of
each operation covers the bounding box of all the operations affected
by it that render something. For example, the bounding box of a
`setFont` operation will be the bounding box of all the `showText`
operations that use that font.
This affects the debugging experience in pdfBug, since now the bounding
box of an operation may be larger than what it renders itself. To help
with this, now when hovering on an operation we also highlight (in red)
all its dependents. We highlight with white stripes operations that do
not affect any part of the page (i.e. with an empty bbox).
To save memory, we now save bounding box x/y coordinates as uint8
rather than float64. This effectively gives us a 256x256 uniform grid
that covers the page, which is high enough resolution for the usecase.
