testing/web-platform/tests/html/canvas/offscreen/filters/2d.filter.canvasFilterObject.componentTransfer.gamma.tentative.html

   1 <!DOCTYPE html>
   2 <!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
   3 <title>OffscreenCanvas test: 2d.filter.canvasFilterObject.componentTransfer.gamma.tentative</title>
   4 <script src="/resources/testharness.js"></script>
   5 <script src="/resources/testharnessreport.js"></script>
   6 <script src="/html/canvas/resources/canvas-tests.js"></script>
   7
   8 <h1>2d.filter.canvasFilterObject.componentTransfer.gamma.tentative</h1>
   9 <p class="desc">Test pixels on CanvasFilter() componentTransfer with gamma type</p>
  10
  11
  12 <script>
  13 var t = async_test("Test pixels on CanvasFilter() componentTransfer with gamma type");
  14 var t_pass = t.done.bind(t);
  15 var t_fail = t.step_func(function(reason) {
  16     throw reason;
  17 });
  18 t.step(async function() {
  19
  20 var canvas = new OffscreenCanvas(100, 50);
  21 var ctx = canvas.getContext('2d');
  22
  23 await (function(canvas, ctx) {
  24 // From https://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement
  25 function getColor(inputColor, amplitude, exponent, offset) {
  26     return [
  27         Math.max(0, Math.min(1, Math.pow(inputColor[0]/255, exponent[0]) * amplitude[0] + offset[0])) * 255,
  28         Math.max(0, Math.min(1, Math.pow(inputColor[1]/255, exponent[1]) * amplitude[1] + offset[1])) * 255,
  29         Math.max(0, Math.min(1, Math.pow(inputColor[2]/255, exponent[2]) * amplitude[2] + offset[2])) * 255,
  30     ];
  31 }
  32
  33 const amplitudes = [2, 1.1, 0.5];
  34 const exponents = [5, 3, 1];
  35 const offsets = [0.25, 0, 0.5];
  36 ctx.filter = new CanvasFilter({filter: 'componentTransfer',
  37     funcR: {type: 'gamma', amplitude: amplitudes[0], exponent: exponents[0], offset: offsets[0]},
  38     funcG: {type: 'gamma', amplitude: amplitudes[1], exponent: exponents[1], offset: offsets[1]},
  39     funcB: {type: 'gamma', amplitude: amplitudes[2], exponent: exponents[2], offset: offsets[2]},
  40 });
  41
  42 const inputColors = [
  43     [255, 255, 255],
  44     [0, 0, 0],
  45     [127, 0, 34],
  46     [252, 186, 3],
  47     [50, 68, 87],
  48 ];
  49
  50 for (const color of inputColors) {
  51     let outputColor = getColor(color, amplitudes, exponents, offsets);
  52     ctx.fillStyle = `rgb(${color[0]}, ${color[1]}, ${color[2]})`;
  53     ctx.fillRect(0, 0, 10, 10);
  54     _assertPixelApprox(canvas, 5, 5, outputColor[0],outputColor[1],outputColor[2],255, 2);
  55 }
  56 })(canvas, ctx);
  57 t.done();
  58
  59 });
  60 </script>