third_party/WebKit/LayoutTests/fast/canvas/canvas-getImageData-rounding.html

   1 <!DOCTYPE html>
   2 <html>
   3 <head>
   4 <script src="../../resources/js-test.js"></script>
   5 </head>
   6 <body>
   7 <script>
   8 description("Test the handling of non-integer source coordinates in getImageData().");
   9
  10 ctx = document.createElement('canvas').getContext('2d');
  11
  12 function dimensionsShouldBe(sx, sy, sw, sh, width, height)
  13 {
  14     imageData = ctx.getImageData(sx, sy, sw, sh);
  15     debug('getImageData(' + sx + ', ' + sy + ', ' + sw + ', ' + sh + ')');
  16     shouldBe('imageData.width', width + '');
  17     shouldBe('imageData.height', height + '');
  18 }
  19
  20 // Basic integer values
  21 dimensionsShouldBe(   0,  0,   20,  10,     20, 10);
  22
  23 // Source point is not an integer
  24 dimensionsShouldBe(  .1, .2,   20,  10,     21, 11);
  25 dimensionsShouldBe(  .9, .8,   20,  10,     21, 11);
  26
  27 // Size is not an integer
  28 dimensionsShouldBe(   0,  0, 19.9, 9.9,     20, 10);
  29 dimensionsShouldBe(   0,  0, 19.1, 9.1,     20, 10);
  30
  31 // Width straddles a pixel boundary
  32 dimensionsShouldBe(  .9,  0,   .2,  10,      2, 10);
  33
  34 // Basic integer negative values
  35 dimensionsShouldBe(  -1, -1,   20,  10,     20, 10);
  36
  37 // Non-integer negative values
  38 dimensionsShouldBe(-1.1,  0,   20,  10,     21, 10);
  39 dimensionsShouldBe(-1.9,  0,   20,  10,     21, 10);
  40 </script>
  41 </body>
  42 </html>