Run results for: Canvas clearing performance v3

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:122.0) Gecko/20100101 Firefox/122.0

Browser: Firefox 122

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

Clear only

139K/s

Save transform Clear restore

53K/s

Canvas w with memo

4K/s

fillRect

1K/s

w=w

785/s

w+=0

782/s

createImageData

99/s

View exact numbers

Test name	Executions per second
✓ Clear only	138,865 Ops/sec
Save transform Clear restore	52,614 Ops/sec
Canvas w with memo	3,914 Ops/sec
fillRect	1,346 Ops/sec
w=w	785 Ops/sec
w+=0	782 Ops/sec
createImageData	99 Ops/sec

HTML Preparation code:

<canvas id="canvasOne" width="1600" height="800"></canvas>
<canvas id="canvasTwo" width="1600" height="800"></canvas>
<canvas id="canvasThree" width="1600" height="800"></canvas>
<canvas id="canvasFour" width="1600" height="800"></canvas>

Script Preparation code:

var canvasOne = document.getElementById("canvasOne");
var ctx = canvasOne.getContext("2d", {desynchronized: true, alpha: true, preserveDrawingBuffer: true});

var canvasTwo = document.getElementById("canvasTwo");
var ctxTwo = canvasTwo.getContext("2d");

var canvasThree = document.getElementById("canvasThree");
var ctxThree = canvasThree.getContext("2d");

var canvasFour = document.getElementById("canvasFour");
var ctxFour = canvasFour.getContext("2d");

Tests:

Clear only
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); ctx.clearRect(0,0,ctx.canvas.width,ctx.canvas.height); ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();
Save transform Clear restore
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); ctx.save(); ctx.setTransform(1,0,0,1,0,0); ctx.clearRect(0,0,ctx.canvas.width,ctx.canvas.height); ctx.restore(); ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();
Canvas w with memo
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); var w = ctx.canvas.width; ctx.canvas.width = 1; ctx.canvas.width = w; ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();
w=w
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); ctx.canvas.width = ctx.canvas.width; ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();
w+=0
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); ctx.canvas.width += 0; ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();
fillRect
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); ctx.fillStyle = 'rgba(0, 0, 0, 1)'; ctx.fillRect(0,0,ctx.canvas.width, ctx.canvas.height); ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();
createImageData
ctx.fillStyle = 'rgba(255, 255, 255, 0.3)'; ctx.fillRect(0, 0, 400, 400); var i = ctx.createImageData(ctx.canvas.width, ctx.canvas.height); ctx.putImageData(i, 0, 0); // clear context by putting empty image data ctx.beginPath(); ctx.fillStyle = 'rgba(231, 76, 60, 0.1)'; ctx.arc(200, 200, 100, 0, Math.PI * 2, true); ctx.fill();