fix(text): skip initDimensions in set when a textLayoutProperty value did not change

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## [next]
 
+- fix(text): skip `initDimensions` in `set` when a `textLayoutProperty` value did not change [#11029](https://github.com/fabricjs/fabric.js/pull/11029)
 - chore(deps-dev): bump rolldown from 1.1.0 to 1.1.2 [#11025](https://github.com/fabricjs/fabric.js/pull/11025)
 - fix(sandbox): restore vanilla startup with pnpm [#11012](https://github.com/fabricjs/fabric.js/pull/11012)
 - fix(): nested duplicated clipPath causes infinite recursion [#10774](https://github.com/fabricjs/fabric.js/pull/10774)

src/shapes/Text/Text.spec.ts

@@ -4,7 +4,7 @@ import { config } from '../../config';
 import { Path } from '../Path';
 import { FabricText } from './Text';
 
-import { describe, expect, it, afterEach } from 'vitest';
+import { describe, expect, it, afterEach, vi } from 'vitest';
 import {
   FabricObject,
   getFabricDocument,
@@ -1346,4 +1346,60 @@ describe('FabricText', () => {
       expect(cacheKeys?.next().done).toBe(true);
     });
   });
+
+  describe('set & initDimensions', () => {
+    it('does not call initDimensions when a textLayoutProperty is set to the same value', () => {
+      const text = new FabricText('hello');
+      const initSpy = vi.spyOn(text, 'initDimensions');
+      const setCoordsSpy = vi.spyOn(text, 'setCoords');
+
+      // set to the same value it already has
+      text.set('text', 'hello');
+      expect(
+        initSpy,
+        'initDimensions is not called for a no-op set',
+      ).not.toHaveBeenCalled();
+      expect(setCoordsSpy).not.toHaveBeenCalled();
+
+      // changing the value does trigger it
+      text.set('text', 'world');
+      expect(
+        initSpy,
+        'initDimensions is called when value changes',
+      ).toHaveBeenCalledTimes(1);
+      expect(
+        setCoordsSpy,
+        'setCoords is called when value changes',
+      ).toHaveBeenCalledTimes(1);
+
+      initSpy.mockRestore();
+      setCoordsSpy.mockRestore();
+    });
+
+    it('does not call initDimensions when textLayoutProperties are set to the same values via object', () => {
+      const text = new FabricText('hello', { fontSize: 40, charSpacing: 0 });
+      const initSpy = vi.spyOn(text, 'initDimensions');
+      const setCoordsSpy = vi.spyOn(text, 'setCoords');
+
+      text.set({ text: 'hello', fontSize: 40, charSpacing: 0 });
+      expect(
+        initSpy,
+        'no initDimensions for no-op object set',
+      ).not.toHaveBeenCalled();
+      expect(setCoordsSpy).not.toHaveBeenCalled();
+
+      text.set({ text: 'hello', fontSize: 50, charSpacing: 0 });
+      expect(
+        initSpy,
+        'initDimensions runs when at least one value changes',
+      ).toHaveBeenCalledTimes(1);
+      expect(
+        setCoordsSpy,
+        'setCoords runs when at least one value changes',
+      ).toHaveBeenCalledTimes(1);
+
+      initSpy.mockRestore();
+      setCoordsSpy.mockRestore();
+    });
+  });
 });

src/shapes/Text/Text.ts

@@ -1806,21 +1806,27 @@ export class FabricText<
 
   set(key: string | any, value?: any) {
     const { textLayoutProperties } = this.constructor as typeof FabricText;
-    super.set(key, value);
+    // detect layout-relevant changes before super.set mutates the instance,
+    // so initDimensions is only requested when a value actually changed.
     let needsDims = false;
     let isAddingPath = false;
     if (typeof key === 'object') {
       for (const _key in key) {
-        if (_key === 'path') {
-          this.setPathInfo();
-        }
-        needsDims = needsDims || textLayoutProperties.includes(_key);
         isAddingPath = isAddingPath || _key === 'path';
+        needsDims =
+          needsDims ||
+          (textLayoutProperties.includes(_key) &&
+            this[_key as keyof this] !== key[_key]);
       }
     } else {
-      needsDims = textLayoutProperties.includes(key);
       isAddingPath = key === 'path';
+      needsDims =
+        textLayoutProperties.includes(key) && this[key as keyof this] !== value;
     }
+
+    super.set(key, value);
+
+    // setPathInfo must run after super.set so it reads the new path
     if (isAddingPath) {
       this.setPathInfo();
     }