Merge pull request #261 from pmndrs/feat/span-publication-profile

perf(glyph): reuse unchanged span alignment for color updates

Author: thejustinwalsh

.agents/docs/attestations/2026-10-09-glyph-4d68221c.md

@@ -19,6 +19,7 @@ on:
           - measure
           - glyphs
           - publication
+          - spans
           - batch
           - style
           - reflow

.agents/docs/attestations/2026-10-09-glyph-benchmarks-5a1b1122.md

@@ -0,0 +1,74 @@
+import {
+  borrowedChecksum,
+  createLabels,
+  disposeLabels,
+  inspectDraws,
+  inspectGlyphPaint,
+  span,
+  txt,
+} from './fixture.ts';
+
+function formattedLabel(text: string) {
+  return txt`${span({ color: '#ffffff', decoration: { underline: true } })`${text.slice(0, 5)}`}${text.slice(5)}`;
+}
+
+function trailingSpanLabel(text: string, trailingColor: string): ReturnType<typeof formattedLabel> {
+  const content = `${text} alpha beta gamma delta epsilon`;
+  const literal = formattedLabel(content);
+  const spanCount = 8;
+  return {
+    ...literal,
+    spans: Array.from({ length: spanCount }, (_, index) => ({
+      start: Math.floor((content.length * index) / spanCount),
+      end: Math.floor((content.length * (index + 1)) / spanCount),
+      style: { color: index === spanCount - 1 ? trailingColor : '#ffffff' },
+    })),
+  };
+}
+
+/** Exact trailing-span publication workload shared by Labs timing and attribution. */
+export function createTrailingSpanPublicationWorkload(count = 1_000) {
+  const created = createLabels(count);
+  const desired = ['#ff2f00', '#2f7fff'].map((trailingColor) =>
+    created.labels.map((label) => ({ text: trailingSpanLabel(label.text, trailingColor) })),
+  );
+  let selected = 0;
+
+  const setNext = () => {
+    selected = selected === 0 ? 1 : 0;
+    const next = desired[selected]!;
+    for (let index = 0; index < created.labels.length; index++) {
+      created.labels[index]!.set(next[index]!);
+    }
+  };
+  const commit = () => {
+    created.scene.updateMatrixWorld(true);
+    if (created.textGroup.error !== undefined) throw created.textGroup.error;
+    return created.textGroup.textCount;
+  };
+  const update = () => {
+    setNext();
+    return commit();
+  };
+  const inspect = () => {
+    const paint = inspectGlyphPaint(created.scene);
+    return {
+      checksum: borrowedChecksum(created.labels),
+      draws: inspectDraws(created.scene),
+      paint,
+      paintMatchesSelected:
+        selected === 0
+          ? paint.redDominant > 0 && paint.blueDominant === 0
+          : paint.blueDominant > 0 && paint.redDominant === 0,
+      textCount: created.textGroup.textCount,
+    };
+  };
+
+  return {
+    commit,
+    dispose: () => disposeLabels(created),
+    inspect,
+    setNext,
+    update,
+  };
+}

.agents/docs/log/2026-10-08-reused-unchanged-span-alignment.md

@@ -1,24 +1,7 @@
 import { assert, bench, group } from '@pmndrs/labs';
 
-import { borrowedChecksum, createLabels, disposeLabels, inspectDraws, span, txt } from './fixture.ts';
-
-function formattedLabel(text: string) {
-  return txt`${span({ color: '#ffffff', decoration: { underline: true } })`${text.slice(0, 5)}`}${text.slice(5)}`;
-}
-
-function trailingSpanLabel(text: string, trailingColor: string): ReturnType<typeof formattedLabel> {
-  const content = `${text} alpha beta gamma delta epsilon`;
-  const literal = formattedLabel(content);
-  const spanCount = 8;
-  return {
-    ...literal,
-    spans: Array.from({ length: spanCount }, (_, index) => ({
-      start: Math.floor((content.length * index) / spanCount),
-      end: Math.floor((content.length * (index + 1)) / spanCount),
-      style: { color: index === spanCount - 1 ? trailingColor : '#ffffff' },
-    })),
-  };
-}
+import { createTrailingSpanPublicationWorkload } from './adapter-publication-workload.ts';
+import { borrowedChecksum, createLabels, disposeLabels, inspectDraws } from './fixture.ts';
 
 group('allocation-light adapter publication @publication', () => {
   bench('normalize 1000 equivalent retained label updates @cached', function* () {
@@ -46,32 +29,17 @@ group('allocation-light adapter publication @publication', () => {
   });
 
   bench('mutate one trailing span across 1000 formatted labels @spans', function* () {
-    const count = 1_000;
-    const created = createLabels(count);
-    const desired = ['#ff2f00', '#2f7fff'].map((trailingColor) =>
-      created.labels.map((label) => ({ text: trailingSpanLabel(label.text, trailingColor) })),
-    );
-    let selected = 0;
-
-    const update = () => {
-      selected = selected === 0 ? 1 : 0;
-      const next = desired[selected]!;
-      for (let index = 0; index < created.labels.length; index++) {
-        created.labels[index]!.set(next[index]!);
-      }
-      created.scene.updateMatrixWorld(true);
-      if (created.textGroup.error !== undefined) throw created.textGroup.error;
-      return created.textGroup.textCount;
-    };
-    update();
-    const expectedChecksum = borrowedChecksum(created.labels);
-    const expectedDraws = inspectDraws(created.textGroup);
-    const textCount = yield update;
-    assert.equal(textCount, count);
-    assert.equal(borrowedChecksum(created.labels), expectedChecksum);
-    assert.equal(inspectDraws(created.textGroup).glyphs, expectedDraws.glyphs);
-    assert.equal(inspectDraws(created.textGroup).draws, expectedDraws.draws);
-
-    disposeLabels(created);
+    const workload = createTrailingSpanPublicationWorkload();
+    workload.update();
+    const expected = workload.inspect();
+    const textCount = yield workload.update;
+    const actual = workload.inspect();
+    assert.equal(textCount, 1_000);
+    assert.equal(actual.checksum, expected.checksum);
+    assert.equal(actual.draws.glyphs, expected.draws.glyphs);
+    assert.equal(actual.draws.draws, expected.draws.draws);
+    assert.equal(actual.paintMatchesSelected, true);
+
+    workload.dispose();
   });
 });