LayoutTests/fast/canvas/canvas-resetTransform_t01.dart

/*
 * Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 * for details. All rights reserved. Use of this source code is governed by a
 * BSD-style license that can be found in the LICENSE file.
 */
/** 
 * @description This test checks resetTransform in canvas v5
 */
import "dart:html";
import "../../testcommon.dart";
import "../../../Utils/async_utils.dart";

main() {
  var canvas = document.createElement('canvas');
  document.body.append(canvas);
  canvas.setAttribute('width', '100');
  canvas.setAttribute('height', '100');
  var ctx = canvas.getContext('2d');

  debug("resetTransform should reset other transforms.");
  ctx.save();
  ctx.scale(0.5, 0.5);
  ctx.resetTransform();
  ctx.fillStyle = 'green';
  ctx.fillRect(0, 0, 100, 100);
  ctx.restore();

  var imageData = ctx.getImageData(98, 98, 1, 1);
  var imgdata = imageData.data;
  shouldBe(imgdata[0], 0);
  shouldBe(imgdata[1], 128);
  shouldBe(imgdata[2], 0);

  debug("resetTransform should not affect CTM outside of save() and restore().");
  ctx.save();
  ctx.scale(0.5, 0.5);
  ctx.save();
  ctx.resetTransform();
  ctx.fillStyle = 'green';
  ctx.fillRect(0, 0, 100, 100);
  ctx.restore();
  ctx.fillStyle = 'red';
  ctx.fillRect(0, 0, 100, 100);
  ctx.restore();

  imageData = ctx.getImageData(98, 98, 1, 1);
  imgdata = imageData.data;
  shouldBe(imgdata[0], 0);
  shouldBe(imgdata[1], 128);
  shouldBe(imgdata[2], 0);

  imageData = ctx.getImageData(48, 48, 1, 1);
  imgdata = imageData.data;
  shouldBe(imgdata[0], 255);
  shouldBe(imgdata[1], 0);
  shouldBe(imgdata[2], 0);

  debug("resetTransform should restore the path transform to identity.");
  /* This should draw a green rectangle on on top of a red one. The red should not be visible. */
  ctx.save();
  ctx.beginPath();
  ctx.moveTo(0, 0);
  ctx.lineTo(100, 0);
  ctx.lineTo(100, 100);
  ctx.lineTo(0, 100);
  ctx.fillStyle = 'red';
  ctx.fill();
  ctx.translate(200, 0);
  ctx.resetTransform();
  ctx.fillStyle = 'green';
  ctx.fill();
  ctx.restore();

  imageData = ctx.getImageData(50, 50, 1, 1);
  imgdata = imageData.data;
  shouldBe(imgdata[0], 0);
  shouldBe(imgdata[1], 128);
  shouldBe(imgdata[2], 0);

  debug("resetTransform should resolve the non-invertible CTM state.");
  ctx.save();
  ctx.fillStyle = 'red';
  ctx.fillRect(0, 0, 100, 100);
  ctx.beginPath();
  ctx.moveTo(0, 0);
  ctx.lineTo(100, 0);
  ctx.lineTo(100, 100);
  ctx.lineTo(0, 100);
  ctx.scale(0, 0);
  ctx.resetTransform();
  ctx.fillStyle = 'green';
  ctx.fill();
  ctx.restore();

  imageData = ctx.getImageData(98, 98, 1, 1);
  imgdata = imageData.data;
  shouldBe(imgdata[0], 0);
  shouldBe(imgdata[1], 128);
  shouldBe(imgdata[2], 0);

  debug("The path object should not be updated on the non-invertible CTM state.");
  debug("resetTransform should restore the path object just before CTM became non-invertible.");
  ctx.save();
  ctx.fillStyle = 'red';
  ctx.fillRect(0, 0, 100, 100);
  ctx.beginPath();
  ctx.moveTo(0, 0);
  ctx.lineTo(100, 0);
  ctx.lineTo(100, 50);
  ctx.scale(0, 0);
  ctx.lineTo(100, 100);
  ctx.resetTransform();
  ctx.lineTo(0, 100);
  ctx.fillStyle = 'green';
  ctx.fill();
  ctx.restore();

  imageData = ctx.getImageData(98, 98, 1, 1);
  imgdata = imageData.data;
  shouldBe(imgdata[0], 255);
  shouldBe(imgdata[1], 0);
  shouldBe(imgdata[2], 0);

  imageData = ctx.getImageData(98, 48, 1, 1);
  imgdata = imageData.data;
  shouldBe(imgdata[0], 0);
  shouldBe(imgdata[1], 128);
  shouldBe(imgdata[2], 0);
}