sdk/tests/html/canvas_test.dart

library CanvasTest;
import '../../pkg/unittest/lib/unittest.dart';
import '../../pkg/unittest/lib/html_config.dart';
import 'dart:html';

main() {
  CanvasElement canvas;
  CanvasRenderingContext2D context;
  int width = 100;
  int height = 100;

  canvas = new CanvasElement(width:width, height:height);
  document.body.nodes.add(canvas);

  context = canvas.context2d;

  useHtmlConfiguration();
  test('CreateImageData', () {
    ImageData image = context.createImageData(canvas.width,
                                              canvas.height);
    List<int> data = image.data;

    expect(data, hasLength(40000));
    checkPixel(data, 0, [0, 0, 0, 0]);
    checkPixel(data, width * height - 1, [0, 0, 0, 0]);

    data[100] = 200;
    expect(data[100], equals(200));
  });

  test('toDataUrl', () {
    var canvas = new CanvasElement(width: 100, height: 100);
    var context = canvas.context2d;
    context.fillStyle = 'red';
    context.fill();

    var url = canvas.toDataUrl('image/png');

    var img = new ImageElement();
    img.onLoad.listen(expectAsync1((_) {
      expect(img.complete, true);
    }));
    img.onError.listen((_) {
      guardAsync(() {
        expect(true, isFalse, reason: 'URL failed to load.');
      });
    });
    img.src = url;
  });
}

void checkPixel(List<int> data, int offset, List<int> rgba)
{
  offset *= 4;
  for (var i = 0; i < 4; ++i) {
    expect(data[offset + i], equals(rgba[i]));
  }
}