Run results for: OffsetScreenCanvas.measureText VS. Canvas.measureText

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:147.0) Gecko/20100101 Firefox/147.0

Browser: Firefox 147

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one month ago

Test name	Executions per second
measureText via Canvas	94310.7 Ops/sec
measureText via OffsetScreenCanvas	94034.7 Ops/sec

Script Preparation code:

const font = '12px sans-serif';
const testTexts = window.testTexts = '国口永水〇0o123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('');

window.measureText = (() => {
  const canvas = document.createElement('canvas');
  const ctx = canvas.getContext('2d');
  ctx.font = font;
  return (txt) => ctx.measureText(txt);
})();

window.oscMeasureText = (() => {
  const canvas = new window.OffscreenCanvas(0, 0);
  const ctx = canvas.getContext('2d');
  ctx.font = font;
  return (txt) => ctx.measureText(txt);
})();

Tests:

measureText via Canvas
testTexts.map(txt => measureText(txt))
measureText via OffsetScreenCanvas
testTexts.map(txt => oscMeasureText(txt))

Run results for: OffsetScreenCanvas.measureText VS. Canvas.measureText

measureText via Canvas

measureText via OffsetScreenCanvas