prevent crash on diacritic marks, close #40

index.js

@@ -61,7 +61,7 @@ export default class TinySDF {
         const width = glyphWidth + 2 * this.buffer;
         const height = glyphHeight + 2 * this.buffer;
 
-        const len = width * height;
+        const len = Math.max(width * height, 0);
         const data = new Uint8ClampedArray(len);
         const glyph = {data, width, height, glyphWidth, glyphHeight, glyphTop, glyphLeft, glyphAdvance};
         if (glyphWidth === 0 || glyphHeight === 0) return glyph;

test/test.js

@@ -8,13 +8,13 @@ import pixelmatch from 'pixelmatch';
 
 const baseUrl = import.meta.url;
 
-test('draws an SDF given a character', (t) => {
-
-    class MockTinySDF extends TinySDF {
-        _createCanvas(size) {
-            return nodeCanvas.createCanvas(size, size);
-        }
+class MockTinySDF extends TinySDF {
+    _createCanvas(size) {
+        return nodeCanvas.createCanvas(size, size);
     }
+}
+
+test('draws an SDF given a character', (t) => {
 
     const rawUrl = new URL('./fixtures/1-raw.png', baseUrl);
     const sdfUrl = new URL('./fixtures/1-sdf.png', baseUrl);
@@ -84,3 +84,9 @@ test('draws an SDF given a character', (t) => {
     t.end();
 });
 
+test('does not crash on diacritic marks', (t) => {
+    const sdf = new MockTinySDF();
+    sdf.draw('í'[1]);
+    sdf.draw('G̱'[1]);
+    t.end();
+});