Add attributesEqual and underline diff APIs

Fixes #3440
2026-02-06 16:21:25 -08:00
parent 452ee50c81
commit cc8e680790
10 changed files with 253 additions and 23 deletions
@@ -0,0 +1,65 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+import { Attributes, BgFlags, FgFlags, UnderlineStyle } from 'common/buffer/Constants';
+import { CellData } from 'common/buffer/CellData';
+import { assert } from 'chai';
+
+function createStyledCell(char: string, underlineStyle: UnderlineStyle, underlineColor: number): CellData {
+  const cell = new CellData();
+  const fg = Attributes.CM_P256 | 12 | FgFlags.BOLD | FgFlags.UNDERLINE;
+  cell.setFromCharData([fg, char, 1, char.charCodeAt(0)]);
+  cell.bg = Attributes.CM_P16 | 2 | BgFlags.ITALIC;
+  cell.extended.underlineStyle = underlineStyle;
+  cell.extended.underlineColor = Attributes.CM_P256 | underlineColor;
+  cell.updateExtended();
+  return cell;
+}
+
+describe('CellData', () => {
+  describe('attributesEquals', () => {
+    it('returns true for same attributes with different chars', () => {
+      const cellA = createStyledCell('A', UnderlineStyle.DOUBLE, 45);
+      const cellB = createStyledCell('B', UnderlineStyle.DOUBLE, 45);
+
+      assert.equal(cellA.attributesEquals(cellB), true);
+    });
+
+    it('detects underline style changes', () => {
+      const cellA = createStyledCell('A', UnderlineStyle.DOUBLE, 45);
+      const cellB = createStyledCell('B', UnderlineStyle.SINGLE, 45);
+
+      assert.equal(cellA.attributesEquals(cellB), false);
+    });
+
+    it('detects underline color changes', () => {
+      const cellA = createStyledCell('A', UnderlineStyle.SINGLE, 45);
+      const cellB = createStyledCell('B', UnderlineStyle.SINGLE, 46);
+
+      assert.equal(cellA.attributesEquals(cellB), false);
+    });
+
+    it('ignores underline variant offsets', () => {
+      const cellA = createStyledCell('A', UnderlineStyle.SINGLE, 45);
+      const cellB = createStyledCell('B', UnderlineStyle.SINGLE, 45);
+      cellA.extended.underlineVariantOffset = 1;
+      cellB.extended.underlineVariantOffset = 3;
+      cellA.updateExtended();
+      cellB.updateExtended();
+
+      assert.equal(cellA.attributesEquals(cellB), true);
+    });
+
+    it('ignores url ids', () => {
+      const cellA = createStyledCell('A', UnderlineStyle.SINGLE, 45);
+      const cellB = createStyledCell('B', UnderlineStyle.SINGLE, 45);
+      cellA.extended.urlId = 1;
+      cellB.extended.urlId = 2;
+      cellA.updateExtended();
+      cellB.updateExtended();
+
+      assert.equal(cellA.attributesEquals(cellB), true);
+    });
+  });
+});