Run results for: drawing pixels: putImageData vs fillRect

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.6 Safari/605.1.15

Browser: Safari 18

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 8 months ago

putImageData

2K/s

fillRect

33/s

View exact numbers

Test name	Executions per second
✓ putImageData	2,248 Ops/sec
fillRect	33 Ops/sec

HTML Preparation code:

<canvas id='aa' width='320' height='180'></canvas>
<canvas id='bb' width='320' height='180'></canvas>

Script Preparation code:

var aa = document.getElementById('aa').getContext('2d');
var bb = document.getElementById('bb').getContext('2d');

var pixels = new Uint8ClampedArray(320 * 180 * 4);
var imgdata = new ImageData(pixels, 320, 180);

Tests:

putImageData
for (var y = 0; y < 180; y++) { for (var x = 0; x < 320; x++) { var i = y * 180 * 4 + x * 4; pixels[i + 0] = Math.floor(Math.random() * 256); pixels[i + 1] = Math.floor(Math.random() * 256); pixels[i + 2] = Math.floor(Math.random() * 256); pixels[i + 3] = 255; } } aa.putImageData(imgdata, 0, 0);
fillRect
for (var y = 0; y < 180; y++) { for (var x = 0; x < 320; x++) { var r = Math.floor(Math.random() * 256); var g = Math.floor(Math.random() * 256); var b = Math.floor(Math.random() * 256); bb.fillStyle = `rgb(${r},${g},${b})`; bb.fillRect(x, y, 1, 1); } }