This optimizes `RenderState.update`, the per-frame call that snapshots
terminal state for the renderer and is the main reason the renderer
thread holds the terminal lock.
Lock hold time is reduced ~2.7x to ~11x depending on the frame.
## The changes
1. iterate page chunks instead of rows in `update`
2. classify cells with masked vector compares.
3. split the update into `beginUpdate`/`endUpdate` phases. There's a
lot to be gained by accumulating data with the lock held and then
processing it out of the lock.
4. generalize the masked-compare scans into `page.Mask`. This is just
a really common pattern we're doing now and it yields a ton of great
value. Its error prone so lets make it a tested helper.
## Benchmarks
Measured with the new `ghostty-bench +screen-clone` modes (`render`,
`render-locked`, `render-clean`, `render-partial`), 120x80 terminal, M4
Max, macOS 26, ReleaseFast, hyperfine means of 10+ runs, per-update
times derived from fixed-count update loops with process startup
subtracted. "Lock held" is the time the terminal lock must be held per
update; "before" held the lock for the entire update.
| scenario | before (lock held) | after (lock held) | after (total) | lock change |
|----------|--------------------|-------------------|---------------|-------------|
| clean frame (nothing dirty) | 202 ns | 19 ns | 19 ns | 10.9x |
| partial frame (1 dirty row) | 290 ns | 54 ns | 54 ns | 5.4x |
| full rebuild, lightly styled | 6.9 µs | 2.5 µs | 3.0 µs | 2.7x |
| full rebuild, fully styled | 9.3 µs | 2.4 µs | 8.0 µs | 3.8x |
| full rebuild, fully styled, 250x150 | 49.9 µs | 9.4 µs | 31.6 µs | 5.3x |
| full rebuild, plain text | 1.9 µs | 1.9 µs | 1.9 µs | 1.0x (memcpy floor) |
The clean and partial cases are the steady-state frame costs (cursor
blink, mouse movement, typing). The full-rebuild cases are the contended
ones: colored scrolling output (build logs, htop, vim) moves the
viewport pin every frame, forcing a full rebuild exactly when the IO
thread is busiest, so that row of the table is where lock contention
actually hurts. Plain text was already at the memcpy floor and is
unchanged.
## LLM Notes
This work was driven by Fable 5: benchmarks, optimizations, the property
test, and the measurements above. I reviewed every line, simplified the
design in a few places (API naming, the Mask helper shape), and re-ran
the verifications myself.
Fixes#11705
Add bg_color and fg_color options to GhosttyRenderStateRowCellsData
that resolve the final RGB color for a cell, flattening the multiple
possible sources. For background, this handles content-tag bg_color_rgb,
content-tag bg_color_palette (looked up in the palette), and the
style bg_color. For foreground, this resolves palette indices through
the palette; bold color handling is not applied and is left to the
caller.
Both return GHOSTTY_INVALID_VALUE when no explicit color is set, in
which case the caller should fall back to whatever default color it
wants (e.g. the terminal background/foreground).
Specifically:
iCurrentCursorStyle
iPreviousCursorStyle
iCurrentCursorVisible
iPreviousCursorVisible
Visibility calculated and updated independently from the typical cursor
unifrom updates to preserve cursor style even when not in the viewport
or set to be hidden
Fixes#10680
The image state is used for drawing, so when we update it, we need to
acquire the draw mutex. All our other state updates already acquire the
draw mutex but Kitty images are odd in that they happen in the critical
area (due to their size).
Discussed in https://github.com/ghostty-org/ghostty/discussions/10739
## Summary
Remove the hardcoded opaque background (alpha=255) from IME preedit
cells so they respect `background-opacity` like all other cells.
When `background-opacity` is less than 1, preedit (composition) text was
rendered with a fully opaque background, causing the text to appear
highlighted and hard to read. This change removes the explicit per-cell
background from `addPreeditCell`, letting preedit cells fall through to
the global background. The underline indicator is preserved to mark the
preedit region.
---
`background-opacity` が 1
未満のとき、IME入力中（preedit）のセルが完全不透明な背景で描画され、ハイライトされたように見えて読みづらくなる問題を修正しました。
`addPreeditCell` のセル背景描画を削除し、グローバル背景に委ねることで通常セルと同じ透過表示になります。
preedit領域のアンダーラインは維持されます。
## Test plan
- Set `background-opacity` to a value less than 1 (e.g. 0.5)
- Type Japanese (or other IME input) to trigger preedit
- Verify preedit text no longer appears highlighted
- Verify the underline indicator is still drawn under preedit text
AI disclosure: I used Claude Code to investigate the source code and
generate code changes in this PR.
Fixes#10424
Replaces #10431
The issue is that when the row where preedit was wasn't dirty, we were
layering more preedit cells (identical ones) on top, so it'd appear to
get "thicker".
Fixes#10522
This also fixes possible runtime safety crashes. Whenever the underlying
size information doesn't match what our renderer or grid see, then we
should deinit and reinit.
This extracts all our image renderer state into a separate struct,
blandly named `renderer.image.State`. This structure owns all the
storage of images and placements and exposes a limited public API
to manage them.
One motivation was to limit state access by our Kitty graphics functions
within the generic renderer. Another was to limit our own generic
renderer from getting our image system into an incoherent state. This is
prevented now on both sides due to some encapsulation.
This currently only supports Kitty images, since that's the only image
protocol we support. But I intend to add additional image types to this,
namely the ability to add overlay images for debug information.
**There are no plans to add new image protocols to the terminal,** the
extraction is purely to support some internal features. But, it could be
used for other protocols one day.
Adds palette and color scheme uniforms to custom shaders, allowing
custom shaders to access terminal color information:
- iPalette[256]: Full 256-color terminal palette (RGB)
- iBackgroundColor, iForegroundColor: Terminal colors (RGB)
- iCursorColor, iCursorText: Cursor colors (RGB)
- iSelectionBackgroundColor, iSelectionForegroundColor: Selection
colors (RGB)
Colors are normalized to [0.0, 1.0] range and update when the palette
changes via OSC sequences or configuration changes. The palette_dirty
flag tracks when colors need to be refreshed, initialized to true to
ensure correct colors on new surfaces.
This makes `cursorStyle` utilize `RenderState` to determine the
appropriate cursor style. This moves the cursor style logic outside the
critical area, although it was cheap to begin with.
This always removes `viewport_is_bottom` which had no practical use.
