Changeset 74328 in webkit

Timestamp:

Dec 19, 2010 5:02:20 PM (13 years ago)

Author:

commit-queue@webkit.org

Message:

2010-12-19 Helder Correia <​helder@sencha.com>

Reviewed by Ariya Hidayat.

[Qt] Blur distance should not be affected by transformations
​https://bugs.webkit.org/show_bug.cgi?id=51161

From the spec at ​http://dev.w3.org/html5/2dcontext/#dom-context-2d-shadowblur:
"The shadowBlur attribute specifies the level of the blurring effect.
(The units do not map to coordinate space units, and are not affected
by the current transformation matrix.)"

Add test to ensure that the blur radius is not affected by the CTM.

• fast/canvas/canvas-scale-shadowBlur-expected.txt: Added.
• fast/canvas/canvas-scale-shadowBlur.html: Added.
• fast/canvas/canvas-scale-strokePath-shadow-expected.txt: Increase shadowBlur and test tolerance to ease testing and support the different blurring algorithms.
• fast/canvas/script-tests/canvas-scale-shadowBlur.js: Added.
• fast/canvas/script-tests/canvas-scale-strokePath-shadow.js:

2010-12-19 Helder Correia <​helder@sencha.com>

Reviewed by Ariya Hidayat.

[Qt] Blur distance should not be affected by transformations
​https://bugs.webkit.org/show_bug.cgi?id=51161

From the spec at ​http://dev.w3.org/html5/2dcontext/#dom-context-2d-shadowblur:
"The shadowBlur attribute specifies the level of the blurring effect.
(The units do not map to coordinate space units, and are not affected
by the current transformation matrix.)"

Test: fast/canvas/canvas-scale-shadowBlur.html

• platform/graphics/ContextShadow.cpp: (WebCore::ContextShadow::adjustBlurDistance):
• platform/graphics/ContextShadow.h:
• platform/graphics/cairo/ContextShadowCairo.cpp: (WebCore::ContextShadow::beginShadowLayer):
• platform/graphics/qt/ContextShadowQt.cpp: (WebCore::ContextShadow::beginShadowLayer):

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/canvas/canvas-scale-shadowBlur-expected.txt (added)
• LayoutTests/fast/canvas/canvas-scale-shadowBlur.html (added)
• LayoutTests/fast/canvas/canvas-scale-strokePath-shadow-expected.txt (modified) (1 diff)
• LayoutTests/fast/canvas/script-tests/canvas-scale-shadowBlur.js (added)
• LayoutTests/fast/canvas/script-tests/canvas-scale-strokePath-shadow.js (modified) (2 diffs)
• WebCore/ChangeLog (modified) (1 diff)
• WebCore/platform/graphics/ContextShadow.cpp (modified) (2 diffs)
• WebCore/platform/graphics/ContextShadow.h (modified) (1 diff)
• WebCore/platform/graphics/cairo/ContextShadowCairo.cpp (modified) (1 diff)
• WebCore/platform/graphics/qt/ContextShadowQt.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2010-12-19  Helder Correia  <helder@sencha.com>
+
+        Reviewed by Ariya Hidayat.
+
+        [Qt] Blur distance should not be affected by transformations
+        https://bugs.webkit.org/show_bug.cgi?id=51161
+
+        From the spec at http://dev.w3.org/html5/2dcontext/#dom-context-2d-shadowblur:
+        "The shadowBlur attribute specifies the level of the blurring effect.
+        (The units do not map to coordinate space units, and are not affected
+        by the current transformation matrix.)"
+
+        Add test to ensure that the blur radius is not affected by the CTM.
+
+        * fast/canvas/canvas-scale-shadowBlur-expected.txt: Added.
+        * fast/canvas/canvas-scale-shadowBlur.html: Added.
+        * fast/canvas/canvas-scale-strokePath-shadow-expected.txt: Increase
+          shadowBlur and test tolerance to ease testing and support the
+          different blurring algorithms.
+        * fast/canvas/script-tests/canvas-scale-shadowBlur.js: Added.
+        * fast/canvas/script-tests/canvas-scale-strokePath-shadow.js:
+
 2010-12-19  Dan Bernstein  <mitz@apple.com>
 

trunk/LayoutTests/fast/canvas/canvas-scale-strokePath-shadow-expected.txt

@@ -31 +31 @@
 PASS d[1] is 0
 PASS d[2] is 0
-PASS d[3] is around 149
+PASS d[3] is around 200
 PASS d[0] is 255
 PASS d[1] is 0
 PASS d[2] is 0
-PASS d[3] is around 116
+PASS d[3] is around 49
 PASS d[0] is 255
 PASS d[1] is 0
 PASS d[2] is 0
-PASS d[3] is around 115
+PASS d[3] is around 199
 PASS d[0] is 255
 PASS d[1] is 0

trunk/LayoutTests/fast/canvas/script-tests/canvas-scale-strokePath-shadow.js

@@ -28 +28 @@
 var canvas = document.createElement('canvas');
 document.body.appendChild(canvas);
-canvas.setAttribute('width', '1000');
-canvas.setAttribute('height', '1000');
+canvas.setAttribute('width', '600');
+canvas.setAttribute('height', '600');
 var ctx = canvas.getContext('2d');
 
@@ -116 +116 @@
 
 // Verify blurry shadow.
-d = ctx.getImageData(404, 210, 1, 1).data;
+d = ctx.getImageData(398, 210, 1, 1).data;
 shouldBe('d[0]', '255');
 shouldBe('d[1]', '0');
 shouldBe('d[2]', '0');
-shouldBeAround('d[3]', '149');
+shouldBeAround('d[3]', '200');
 
-d = ctx.getImageData(505, 250, 1, 1).data;
+d = ctx.getImageData(508, 250, 1, 1).data;
 shouldBe('d[0]', '255');
 shouldBe('d[1]', '0');
 shouldBe('d[2]', '0');
-shouldBeAround('d[3]', '116');
+shouldBeAround('d[3]', '49');
 
-d = ctx.getImageData(450, 205, 1, 1).data;
+d = ctx.getImageData(450, 198, 1, 1).data;
 shouldBe('d[0]', '255');
 shouldBe('d[1]', '0');
 shouldBe('d[2]', '0');
-shouldBeAround('d[3]', '115');
+shouldBeAround('d[3]', '199');
 
 // Verify blurry alpha shadow.

trunk/WebCore/ChangeLog

@@ +1 @@
+2010-12-19  Helder Correia  <helder@sencha.com>
+
+        Reviewed by Ariya Hidayat.
+
+        [Qt] Blur distance should not be affected by transformations
+        https://bugs.webkit.org/show_bug.cgi?id=51161
+
+        From the spec at http://dev.w3.org/html5/2dcontext/#dom-context-2d-shadowblur:
+        "The shadowBlur attribute specifies the level of the blurring effect.
+        (The units do not map to coordinate space units, and are not affected
+        by the current transformation matrix.)"
+
+        Test: fast/canvas/canvas-scale-shadowBlur.html
+
+        * platform/graphics/ContextShadow.cpp:
+        (WebCore::ContextShadow::adjustBlurDistance):
+        * platform/graphics/ContextShadow.h:
+        * platform/graphics/cairo/ContextShadowCairo.cpp:
+        (WebCore::ContextShadow::beginShadowLayer):
+        * platform/graphics/qt/ContextShadowQt.cpp:
+        (WebCore::ContextShadow::beginShadowLayer):
+
 2010-12-19  Dan Bernstein  <mitz@apple.com>
 

trunk/WebCore/platform/graphics/ContextShadow.cpp

@@ -31 +31 @@
 
 #include "FloatQuad.h"
+#include <cmath>
 #include <wtf/MathExtras.h>
 #include <wtf/Noncopyable.h>
@@ -170 +171 @@
 }
 
+void ContextShadow::adjustBlurDistance(const PlatformContext context)
+{
+    // Adjust blur if we're scaling, since the radius must not be affected by transformations.
+    const TransformationMatrix transform(getTransformationMatrixFromContext(context));
+
+    if (transform.isIdentity())
+        return;
+
+    // Calculale transformed unit vectors.
+    const FloatQuad unitQuad(FloatPoint(0, 0), FloatPoint(1, 0),
+                             FloatPoint(0, 1), FloatPoint(1, 1));
+    const FloatQuad transformedUnitQuad = transform.mapQuad(unitQuad);
+
+    // Calculate X axis scale factor.
+    const FloatSize xUnitChange = transformedUnitQuad.p2() - transformedUnitQuad.p1();
+    const float xAxisScale = sqrtf(xUnitChange.width() * xUnitChange.width()
+                                   + xUnitChange.height() * xUnitChange.height());
+
+    // Calculate Y axis scale factor.
+    const FloatSize yUnitChange = transformedUnitQuad.p3() - transformedUnitQuad.p1();
+    const float yAxisScale = sqrtf(yUnitChange.width() * yUnitChange.width()
+                                   + yUnitChange.height() * yUnitChange.height());
+
+    // blurLayerImage() does not support per-axis blurring, so calculate a balanced scaling.
+    const float scale = sqrtf(xAxisScale * yAxisScale);
+    m_blurDistance = roundf(static_cast<float>(m_blurDistance) / scale);
+}
+
 IntRect ContextShadow::calculateLayerBoundingRect(const PlatformContext context, const FloatRect& layerArea, const IntRect& clipRect)
 {

trunk/WebCore/platform/graphics/ContextShadow.h

@@ -127 +127 @@
     bool m_shadowsIgnoreTransforms;
 
+    void adjustBlurDistance(const PlatformContext);
     void blurLayerImage(unsigned char*, const IntSize& imageSize, int stride);
     IntRect calculateLayerBoundingRect(const PlatformContext, const FloatRect& layerArea, const IntRect& clipRect);

trunk/WebCore/platform/graphics/cairo/ContextShadowCairo.cpp

@@ -93 +93 @@
 PlatformContext ContextShadow::beginShadowLayer(PlatformContext context, const FloatRect& layerArea)
 {
+    adjustBlurDistance(context);
+
     double x1, x2, y1, y2;
     cairo_clip_extents(context, &x1, &y1, &x2, &y2);

trunk/WebCore/platform/graphics/qt/ContextShadowQt.cpp

@@ -112 +112 @@
 PlatformContext ContextShadow::beginShadowLayer(PlatformContext p, const FloatRect& layerArea)
 {
+    // Set m_blurDistance.
+    adjustBlurDistance(p);
+
     QRect clipRect;
     if (p->hasClipping())