Changeset 166746 in webkit

Timestamp:

Apr 3, 2014 2:44:54 PM (10 years ago)

Author:

krit@webkit.org

Message:

[CG] Canvas lineDashOffset does not handle negative numbers correctly
​https://bugs.webkit.org/show_bug.cgi?id=80560

Reviewed by Dean Jackson.

Source/WebCore:

CG ignores negative dash array offsets. Check if we have a negative offset, if yes
then calculate the length of the dash array and modulo the dash array offset with
the dash array length.

Test: fast/canvas/canvas-negative-lineDashOffset.html

• platform/graphics/cg/GraphicsContextCG.cpp:

(WebCore::GraphicsContext::setLineDash):

LayoutTests:

Test correct rendering of negative offset for Canvas dash arrays.

• fast/canvas/canvas-negative-lineDashOffset-expected.txt: Added.
• fast/canvas/canvas-negative-lineDashOffset.html: Added.
• fast/canvas/script-tests/canvas-negative-lineDashOffset.js: Added.

(dataToArray):
(getPixel):
(pixelShouldBe):

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/canvas/canvas-negative-lineDashOffset-expected.txt (added)
• LayoutTests/fast/canvas/canvas-negative-lineDashOffset.html (added)
• LayoutTests/fast/canvas/script-tests/canvas-negative-lineDashOffset.js (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/platform/graphics/cg/GraphicsContextCG.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2014-04-03  Dirk Schulze  <krit@webkit.org>
+
+        [CG] Canvas lineDashOffset does not handle negative numbers correctly
+        https://bugs.webkit.org/show_bug.cgi?id=80560
+
+        Reviewed by Dean Jackson.
+
+        Test correct rendering of negative offset for Canvas dash arrays.
+
+        * fast/canvas/canvas-negative-lineDashOffset-expected.txt: Added.
+        * fast/canvas/canvas-negative-lineDashOffset.html: Added.
+        * fast/canvas/script-tests/canvas-negative-lineDashOffset.js: Added.
+        (dataToArray):
+        (getPixel):
+        (pixelShouldBe):
+
 2014-04-03  David Hyatt  <hyatt@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-04-03  Dirk Schulze  <krit@webkit.org>
+
+        [CG] Canvas lineDashOffset does not handle negative numbers correctly
+        https://bugs.webkit.org/show_bug.cgi?id=80560
+
+        Reviewed by Dean Jackson.
+
+        CG ignores negative dash array offsets. Check if we have a negative offset, if yes
+        then calculate the length of the dash array and modulo the dash array offset with
+        the dash array length.
+
+        Test: fast/canvas/canvas-negative-lineDashOffset.html
+
+        * platform/graphics/cg/GraphicsContextCG.cpp:
+        (WebCore::GraphicsContext::setLineDash):
+
 2014-04-03  David Hyatt  <hyatt@apple.com>
 

trunk/Source/WebCore/platform/graphics/cg/GraphicsContextCG.cpp

@@ -1184 +1184 @@
 void GraphicsContext::setLineDash(const DashArray& dashes, float dashOffset)
 {
+    if (dashOffset < 0) {
+        float length = 0;
+        for (size_t i = 0; i < dashes.size(); ++i)
+            length += static_cast<float>(dashes[i]);
+        if (length)
+            dashOffset = fmod(dashOffset, length) + length;
+    }
     CGContextSetLineDash(platformContext(), dashOffset, dashes.data(), dashes.size());
 }