1972885-ref.html (748B)
1 <!DOCTYPE html> 2 <html> 3 <meta charset="utf-8"> 4 <title>Reference for Bug 1972885</title> 5 <style> 6 body { 7 margin: 0; 8 } 9 canvas { 10 /* Rounded up. */ 11 margin-top: 2px; 12 width: 100px; 13 /* Subpixel snapped down. */ 14 height: 100px; 15 } 16 </style> 17 <canvas id="canvas"></canvas> 18 <script> 19 function draw(canvas, width, height) { 20 const ctx = canvas.getContext('2d'); 21 canvas.width = width; 22 canvas.height = height; 23 const imgData = ctx.createImageData(width, height); 24 const u32View = new Uint32Array(imgData.data.buffer); 25 u32View.fill(0xFFFFFFFF); 26 for (let y = 0; y < height; y += 2) { 27 for (let x = 0; x < width; x++) { 28 u32View[y * width + x] = 0xFF000000; 29 } 30 } 31 ctx.putImageData(imgData, 0, 0); 32 } 33 34 draw(canvas, 100, 100); 35 </script>