Fixes#1037
Renderers must convert the internal Kitty graphics state to a GPU
texture for rendering. For performance reasons, renderers cache the GPU
state by image ID. Unfortunately, this meant that if an image was
replaced with the same ID and was already cached, it would never be
updated on the GPU.
This PR adds the transmission time to the cache. If the transmission
time differs, we assume the image changed and replace the image.
Fixes#882
We previously had a hardcoded limit of 16 codepoints. In #882, a user
pointed out that in Chinese, is reasonable for a preedit input to be
longer than this.
To avoid any future issues, this commit moves to a heap-allocated
variant. Preedits aren't that common, they aren't high throughput, and
they're generally pretty small, so using a heap allocation is fine. The
memory is owned by the person who set it.
Fixes#895
Every loaded font face calculates metrics for itself. One of the
important metrics is the baseline to "sit" the glyph on top of. Prior to
this commit, each rasterized glyph would sit on its own calculated
baseline. However, this leads to off-center rendering when the font
being rasterized isn't the font that defines the terminal grid.
This commit passes in the font metrics for the font defining the
terminal grid to all font rasterization requests. This can then be used
by non-primary fonts to sit the glyph according to the primary grid.
This uses WCAG2 algorithms with a minimum ratio hardcoded of 3:1. This
is not shippable in its current state because we want the ratio to be
configurable and I'm not happy with the way data is being sent to the
shader.
Fixes#932
We have to do this for Metal as well (this code is copied from Metal)
since Metal doesnt even allow RGB textures. I couldn't figure out a way
to get the A value to be "255" (byte), it seems to always be set to 1
which gets normalized to 1/255, so lets just manually convert.
