Run results for: Setting Canvas Pixel

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 26_2_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) FxiOS/145.3 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 26

Operating system: iOS 26.2.1

Device Platform: Mobile

Date tested: 5 months ago

fillRect/concat

3K/s

fillRect/join

3K/s

1×1 Image Data

1K/s

View exact numbers

Test name	Executions per second
✓ fillRect/concat	2,898 Ops/sec
fillRect/join	2,773 Ops/sec
1×1 Image Data	1,390 Ops/sec

HTML Preparation code:

<canvas id="c" width="800" height="300"></canvas>

Script Preparation code:

$c = document.getElementById('c');
$ctx = $c.getContext('2d');
$ctx.clearRect(0, 0, 800, 300);
$px = $ctx.createImageData(1, 1);
$pxls = [];
for (var i=0; i<10000; ++i) $pxls.push({
   x: Math.random() * 800 << 0,
   y: Math.random() * 300 << 0,
   r: Math.random() * 255 << 0,
   g: Math.random() * 255 << 0,
   b: Math.random() * 255 << 0,
   a: Math.random() * 128 << 0 + 128
});
$i = 0;

Tests:

fillRect/concat
for (var i=500;i--;){ var px = $pxls[$i++ % 10000]; $ctx.fillStyle = 'rgba(' + px.r + ',' + px.g + ',' + px.b + ',' + (px.a / 255) + ')'; $ctx.fillRect(px.x, px.y, 1, 1); }
fillRect/join
for (var i=500;i--;){ var px = $pxls[$i++ % 10000]; $ctx.fillStyle = 'rgba(' + [px.r,px.g,px.b,px.a/255].join() + ')'; $ctx.fillRect(px.x, px.y, 1, 1); }
1×1 Image Data
for (var i=500;i--;){ var px=$pxls[$i++ % 10000], d=$px.data; d[0] = px.r; d[1] = px.g; d[2] = px.b; d[3] = px.a; $ctx.putImageData($px, px.x, px.y); }