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, 12 insertions, 0 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index 1f136f2b..ae04b4e7 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -4380,6 +4380,8 @@ pub const Pardes = struct {
     tty_filter_palette: panes.Terminal.FilterPalette = .{},
     font_request_taken: bool = false,
     custom_theme: ?Theme = null,
+    /// bodyChrome's: the theme it was worked out for, and it.
+    body_chrome: ?struct { theme: Theme, chrome: ChromeTheme } = null,
     theme_file_path: config.Runtime.Text(limits.host_path_cap) = .{},
     theme_file_generation: u32 = 0,
     theme_file_pane: u8 = 0,
@@ -7063,6 +7065,16 @@ pub const Pardes = struct {
         return &p.chrome_animation.displayed;
     }
 
+    /// The theme's own chrome, not a fade's (`theme()`'s, worked out once
+    /// per theme: its contrast searches take pow calls, too many for a
+    /// grapheme or a row).
+    pub fn bodyChrome(p: *Pardes) *const ChromeTheme {
+        const th = p.theme();
+        if (p.body_chrome) |*cached| if (std.meta.eql(cached.theme, th.*)) return &cached.chrome;
+        p.body_chrome = .{ .theme = th.*, .chrome = ChromeTheme.fromTheme(th) };
+        return &p.body_chrome.?.chrome;
+    }
+
     /// When core animation next needs a frame, on the `stepped_ns`
     /// timeline: a frame from now while anything moves, the end of the
     /// wait while something only waits (a message lingering, a look-hover