fix(rendering): ignore unsupported font glyphs

Author: ugcodrr

packages/rendering/src/font/font-renderer.ts

@@ -244,8 +244,10 @@ export class FontRenderer {
     const characterSize =
       sizes[isAscii ? "ascii" : "unicode"][unicode.toUpperCase()];
 
-    const startOffset = characterSize?.start ?? 0;
-    const width = characterSize?.width ?? 0;
+    if (!characterSize?.width) return null;
+
+    const startOffset = characterSize.start ?? 0;
+    const width = characterSize.width;
 
     return {
       x: (startOffset + x * 16) * scale,

packages/rendering/tests/index.spec.tsx

@@ -6,6 +6,8 @@
  * https://github.com/Statsify/statsify/blob/main/LICENSE
  */
 
+import { FontRenderer } from "#font";
+import { createCanvas } from "../src/canvas.js";
 import { createInstructions } from "../src/index.js";
 import { expect, it, suite } from "vitest";
 
@@ -156,3 +158,37 @@ suite("JSX Fragments", () => {
     expect(instructions.children?.length).toBe(2);
   });
 });
+
+suite("FontRenderer", () => {
+  it("ignores unsupported glyphs with a loaded unicode page", () => {
+    const page = createCanvas(256, 256);
+    const pageCtx = page.getContext("2d");
+    const target = createCanvas(16, 16).getContext("2d");
+
+    const renderer = new FontRenderer(false);
+
+    Object.assign(renderer, {
+      images: new Map([["1f", pageCtx]]),
+      canvases: new WeakMap([[pageCtx, page]]),
+      scales: new WeakMap([[pageCtx, 1]]),
+    });
+
+    expect(() => renderer.fillText(target, renderer.lex("🌙"), 0, 0)).not.toThrow();
+  });
+
+  it("ignores zero-width glyph metadata", () => {
+    const page = createCanvas(256, 256);
+    const pageCtx = page.getContext("2d");
+    const target = createCanvas(16, 16).getContext("2d");
+
+    const renderer = new FontRenderer(false);
+
+    Object.assign(renderer, {
+      images: new Map([["12", pageCtx]]),
+      canvases: new WeakMap([[pageCtx, page]]),
+      scales: new WeakMap([[pageCtx, 1]]),
+    });
+
+    expect(() => renderer.fillText(target, renderer.lex("\u1249"), 0, 0)).not.toThrow();
+  });
+});