Bug 142119 – fast/canvas/canvas-ellipse-zero-lineto.html failing on Apple Windows

• Component: Canvas
• Status: RESOLVED MOVED

[Dean Jackson]

This test is reproducibly failing on Windows.

fast/canvas/canvas-ellipse-zero-lineto.html

[Radar WebKit Bug Importer]

<rdar://problem/19993919>

[Myles C. Maxfield]

*** Bug 142120 has been marked as a duplicate of this bug. ***

[Brent Fulgham]

Failure looks like the following:

--- /cygdrive/c/Projects/WebKit/OpenSource/WebKitBuild/Release/bin32/layout-test-results/fast/canvas/canvas-ellipse-zero-lineto-expected.txt
+++ /cygdrive/c/Projects/WebKit/OpenSource/WebKitBuild/Release/bin32/layout-test-results/fast/canvas/canvas-ellipse-zero-lineto-actual.txt
@@ -57,7 +57,7 @@
 PASS imageData.data[1] is 0
 PASS imageData.data[1] is 0
  2. sweepAngle < PI
-PASS imageData.data[1] is 0
+FAIL imageData.data[1] should be 0. Was 7.
 PASS imageData.data[1] is 255
 PASS imageData.data[1] is 0
 PASS imageData.data[1] is 0

[Brent Fulgham]

Here is the failing sequence of commands:

debug(" 2. sweepAngle < PI");
ctx.translate(0, 30);
ctx.save();
ctx.beginPath();
ctx.lineTo(10, 0);
ctx.ellipse(20, 0, 20, zero, Math.PI / 6, -Math.PI / 4, Math.PI / 2, false);
ctx.lineTo(80, 0);
ctx.stroke();
ctx.restore();

imageData = ctx.getImageData(232, 69, 1, 1);
shouldBe("imageData.data[1]", "0");
imageData = ctx.getImageData(238, 72, 1, 1);
shouldBe("imageData.data[1]", "255");
imageData = ctx.getImageData(228, 65, 1, 1);
shouldBe("imageData.data[1]", "0");
imageData = ctx.getImageData(242, 61, 1, 1);
shouldBe("imageData.data[1]", "0");

[Brent Fulgham]

See the screenshot "Comparison" to see the slight differences between the two drawing libraries. The top "arrow" is the Mac version, the bottom is the WIndows one.

Antialiasing seems different on the two platforms.

The drawing commands are identical:

ctx.beginPath();
ctx.lineTo(10, 0);
ctx.ellipse(20, 0, 20, zero, Math.PI / 6, -Math.PI / 4, Math.PI / 2, false);
ctx.lineTo(80, 0);
ctx.stroke();
ctx.restore();

imageData = ctx.getImageData(232, 69, 1, 1); // Should be black, but WIndows is '7' (not '0')
imageData = ctx.getImageData(238, 72, 1, 1); // Should be White, and both are.
imageData = ctx.getImageData(228, 65, 1, 1); // Should be black, and both are.
imageData = ctx.getImageData(242, 61, 1, 1); // Should be black, and both are.

This might be a drawing difference in the rendering libraries used on the two platforms.

[Brent Fulgham]

Unskipped and rebaselined test in r180895 <https://trac.webkit.org/changeset/180895>.

[Brent Fulgham]

The fix for this issue was needed outside the WebKit project, therefore this is being resolved as 'Moved'.

This should now be fixed in shipping software.