This should help to avoid artifacts in the case where glyphs
render outside their nominal terminal cell (happens when the
shaper tweaks positioning, and/or when ligatures are involved).
Previously we'd render the layers in z-index order for cell N
before the layers in z-index order for cell N+1.
If N had an image that overlayed the text (nominally z-index 0.5!)
and the glyph in N+1 (z-index 0) was slightly to the left of its
border, then it could layer incorrectly over the cell to the left.
The underlying types in termwiz support 10-bit color, but in our
conversion to the data we pass to the vertex, we were forcing it
into 8-bit and then converting to float.
Simplify this by skipping the intermediate 8-bit representation
and just go directly to float.
This should give the shaper a better chance at using text
presentation in a run that mixes emoji with text and/or
uses presentation selectors.
It also exposes the presentation property to the shaper
so that it could potentially adjust its fallback strategy.
However, it doesn't do that here.
refs: https://github.com/wez/wezterm/issues/997
Make a distinction between default and selected presentation,
and account for that in the cell width.
Add a method to the cell that returns the effective presentation.
refs: https://github.com/wez/wezterm/issues/997
I'm not sure if this is needed now that we have a single draw call, but
based on the history and the nuance of different gl/driver/os quirks it
feels like a good idea to keep this option in the back pocket.
We were actually moving it during placement, and then restoring
the original placement. That could potentially lead to the
screen being scrolled, so we want to avoid that.
refs: #986
As of this commit, `kitty +kitten icat ~/Downloads/fast-parallax.gif`
(wherein the icat kitten decodes the gif into frames and sends them
to the terminal to animate) behaves equivalently in wezterm and kitty.
(There appears to be an issue with the background color/deltas in
the icat kitten in kitty-0.21.1-1.fc33.x86_64 which I have installed,
so both wezterm and kitty have a funky black background for this
particular gif).
refs: #986
These modifiers have the effect of forcing us to consider the grapheme
as being either a single cell (VS15) or two cells (VS16) in the
terminal model.
These don't affect font choice as wezterm doesn't know whether a given
font in the fallback has a textual vs. an emoji version of a given
glyph, or whether a later font in the fallback has one or the other
because we can't know until we fall back, and that has a very high
cost--we perform fallback asynchronously in another thread because
of its high cost.
Depending on the selected glyph, it may or may not render as double
wide.
refs: #997
There are some cases where we can print that status before we've
fully drained the output; it's slightly nicer to ensure that
we have an "atomic" line of its own for that, to minimize
the crappiness of the resulting output.
Since we can now mutate individual frames, we need to avoid
falsely caching across a change; switch from using (image_id, frame_idx)
to frame_hash.
refs: #986
Adds a use_image feature to termwiz that enables an optional
dep on the image crate. This in turn allows decoding of animation
formats (gif, apng) from file data, but more crucially, allows
modeling animation frames at the termwiz layer, which is a pre-req
for enabling kitty img protocol animation support.
refs: #986
This adds a simple garbage collection scheme; when adding an image,
check to see if we're over budget on the total amount of RAM used
by the image data.
If we are, remove unreferenced images (images that are not placed)
until we're below the budget.
refs: #986
Switch to using `xterm` rather than `text` for the name of the
xterm style I-beam mouse cursor, as that appears to be more
compatible across themes; the gnome theme aliases text -> xterm
via a symlink.
Improve error diagnostics in the case that no cursor is found.
refs: https://github.com/wez/wezterm/issues/532
Rather than leaving the frame un-rendered, this commit arranges
to make one last pass but with all image quad assignments skipped.
This should at least make a reasonable effort at displaying text
on the screen.
refs: https://github.com/wez/wezterm/issues/879
I noticed when running the notcurses demo that we're spending a
decent amount of time decoding png data whenever we need to
re-do the texture atlas.
Let's avoid that by allowing for ImageData at the termwiz layer
to represent both the image file format and decoded rgba8 data.
This commit is a bit muddy and also includes some stuff to try
to delete placements from the model. It's not perfect by any
means--more expensive than I want, and there's something funky
that causes a large number of images to build up during some
phases of the demo.
refs: #986
OpenGL will silently let us allocate a texture larger than the GPU can
bind to a sampler, reporting the error status out of band and leaving
the display in a perma-broken state.
This commit deliberately checks against the max texture size and raises
an error in that case.
The recovery story isn't perfect, but at least the texture remains
usable, so the user can clear the screen and still be able to see glyphs
afterwards.
refs: https://github.com/wez/wezterm/issues/879
Previously, we'd use a 1MB buffer both to read the output from the
associated pty (blocking), and the same size buffer again to do the
non-blocking read on top of that.
For pathological cases (eg: cat 100MB+ files), we could build a
resulting `Vec<Action>` with over 1mm entries and it could take as much
as 100ms to apply those actions to the terminal model.
This meant that the output could stutter/lag and appear to be processed
more slowly.
This commit introduces a configuration value for the buffer size for the
second stage, and makes it 10KB in size. This helps to constrain the
size of the Action vec and keeps the incremental processing costs down,
while still managing the same throughput.
Taking further advantage of dynamic quad allocation, we can now
remove the multiple render passes in favor of allocating the quads
and painting them from back to front.
In turn, this means that we can reduce the amount of data that we
store in the vertex, which simplifies the shaders a bit, at the
expense of making the render code in rust a bit more complex.
However, we can take advantage of stretching runs of cells with
background colors in to a single quad.
refs: #986
This was added in 365a68dfb8 to free the
orca from its cage. With the recent dynamic quad allocation changes, we
don't need a distinct 4th pass any more and can simply layer a separate
quad on top of the glyph quad.
refs: #986
This removes the pre-allocated (at resize) number of quads
and replaces it with a dynamic mechanism that tracks how many
quads are needed for a frame and then will re-allocate and
re-render when there weren't enough.
We start with 1024 quads and try to allocate in multiples
of 1024 quads.
refs: #986
