The theme's chrome is worked out once, not per grapheme; still post passes let the GUI rest; a perf gate

somtrmsz's contrast floors made ChromeTheme.fromTheme run its focus-tint
and separator searches (pow calls each), and Output's RowDecoration.styleAt
called it for every grapheme of every highlighted row: the 50k-line file's
render went from 0.11 ms to 13 ms. Pardes.bodyChrome now keeps the theme's
chrome, worked out again only when the theme differs; recolorSyntax asks
for it once a decorated row, and a plain row (nearly every row of a file)
never asks. ReleaseFast, medium fixture, median us, before -> after (main):
render 13150 -> 76 (111), key-down 14658 -> 79 (110), wheel 13589 -> 76
(109), open 14891 -> 2095 (2055), edit-char 16703 -> 3006 (1251; the rest of
that gap is editing and tree-sitter, not this).

Post.animating asked for frames whenever the window had focus and any pass
was ready, so a still pass kept the GUI drawing at the display's rate
(Bloom: 49% of a core idle, in a hidden test window). A pass now says
whether it moves on its own: the CRT (its hum and dither) and a Shadertoy
file whose source reads iTime, iFrame or iDate (shader_build.readsTime; the
flag rides the wire's post message); Bloom, Vignette and Grain are still.
Bloom idle: 49% -> 1.2%, as with no pass.

zig build perf-gate: the 50k-line file's gestures, each's fastest sample
within 3x of the recorded baseline's (test/perf-baseline-<platform>-
<optimize>.json, recorded from this build), run with every unit-test. On
the regressed code it fails at 180x for render.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/File.zig b/src/File.zig
index 5f6d7097..1d838c4f 100644
--- a/src/File.zig
+++ b/src/File.zig
@@ -1293,6 +1293,7 @@ pub fn recolorSyntax(p: *Pardes, s: *Surface, pane: *Pane, f: *State, r: pardes.
         const row_index: usize = @intCast(@max(0, pane.wrapAt(vr).line));
         const metadata: ?locations.Row = if (row_index < f.location_rows.len) f.location_rows[row_index] else null;
         const decoration = Output.decorateRow(f.output, line, metadata);
+        const chrome: ?*const pardes.ChromeTheme = if (decoration.plain()) null else p.bodyChrome();
         var c: usize = 0;
         var screen_c: usize = 0;
         while (hs + c < limit and prefix_width + screen_c < tw) {
@@ -1315,7 +1316,7 @@ pub fn recolorSyntax(p: *Pardes, s: *Surface, pane: *Pane, f: *State, r: pardes.
             }
             // Results keep their exact live text. Only the location,
             // matched source range and diagnostic label gain emphasis.
-            if (decoration.styleAt(p, hs + c)) |style| {
+            if (if (chrome) |ch| decoration.styleAt(ch, hs + c) else null) |style| {
                 var fill: usize = 0;
                 while (fill < cells and prefix_width + screen_c + fill < tw) : (fill += 1) {
                     const cell = s.at(tx + @as(u16, @intCast(prefix_width + screen_c + fill)), body_y + vr);