Title: [188148] trunk
Revision
188148
Author
[email protected]
Date
2015-08-07 12:40:45 -0700 (Fri, 07 Aug 2015)

Log Message

Shadows don't draw on fillText when using a gradient fill
https://bugs.webkit.org/show_bug.cgi?id=147758
<rdar://problem/20860912>

Reviewed by Myles Maxfield.

Source/WebCore:

Since we use a mask to render a pattern or gradient
into text, any shadow was being clipped out. Change
this to draw the shadow before the mask + fill operation,
using a technique similar to text-shadow.

Test: fast/canvas/gradient-text-with-shadow.html

* html/canvas/CanvasRenderingContext2D.cpp:
(WebCore::CanvasRenderingContext2D::drawTextInternal): Get the current shadow
style, paint the text with a transformed shadow offset so that we only
see the shadow and not the text, then combine with the existing pattern/gradient
fill.

LayoutTests:

New test that exercises shadows on gradient fills. This really
should be a ref test, but there is a very small rendering difference
caused by masking, so instead it uses JS to look for pixels of
the correct color.

* fast/canvas/gradient-text-with-shadow-expected.txt: Added.
* fast/canvas/gradient-text-with-shadow.html: Added.

Modified Paths

Added Paths

Diff

Modified: trunk/LayoutTests/ChangeLog (188147 => 188148)


--- trunk/LayoutTests/ChangeLog	2015-08-07 19:34:13 UTC (rev 188147)
+++ trunk/LayoutTests/ChangeLog	2015-08-07 19:40:45 UTC (rev 188148)
@@ -1,3 +1,19 @@
+2015-08-06  Dean Jackson  <[email protected]>
+
+        Shadows don't draw on fillText when using a gradient fill
+        https://bugs.webkit.org/show_bug.cgi?id=147758
+        <rdar://problem/20860912>
+
+        Reviewed by Myles Maxfield.
+
+        New test that exercises shadows on gradient fills. This really
+        should be a ref test, but there is a very small rendering difference
+        caused by masking, so instead it uses JS to look for pixels of
+        the correct color.
+
+        * fast/canvas/gradient-text-with-shadow-expected.txt: Added.
+        * fast/canvas/gradient-text-with-shadow.html: Added.
+
 2015-08-07  Myles C. Maxfield  <[email protected]>
 
         Implement font-feature-settings

Added: trunk/LayoutTests/fast/canvas/gradient-text-with-shadow-expected.txt (0 => 188148)


--- trunk/LayoutTests/fast/canvas/gradient-text-with-shadow-expected.txt	                        (rev 0)
+++ trunk/LayoutTests/fast/canvas/gradient-text-with-shadow-expected.txt	2015-08-07 19:40:45 UTC (rev 188148)
@@ -0,0 +1 @@
+PASSED
Property changes on: trunk/LayoutTests/fast/canvas/gradient-text-with-shadow-expected.txt
___________________________________________________________________

Added: svn:mime-type

Added: svn:keywords

Added: svn:eol-style

Added: trunk/LayoutTests/fast/canvas/gradient-text-with-shadow.html (0 => 188148)


--- trunk/LayoutTests/fast/canvas/gradient-text-with-shadow.html	                        (rev 0)
+++ trunk/LayoutTests/fast/canvas/gradient-text-with-shadow.html	2015-08-07 19:40:45 UTC (rev 188148)
@@ -0,0 +1,43 @@
+<script>
+
+if (window.testRunner)
+    testRunner.dumpAsText();
+
+function runTest() {
+
+    var canvas = document.querySelector("canvas");
+    var context = canvas.getContext('2d');
+
+    context.shadowOffsetX = 0;
+    context.shadowOffsetY = 10;
+    context.shadowBlur = 0;
+    context.shadowColor = "rgb(255, 0, 0)";
+
+    context.font = "80px sans-serif";
+
+    var gradient = context.createLinearGradient(0, 0, 0, 100);
+    gradient.addColorStop(0, "blue");
+    gradient.addColorStop(1, "blue");
+
+    context.fillStyle = gradient;
+    context.fillText("hello", 10, 95);
+
+    // If we correctly drew the shadow, there will be some
+    // red pixels along the bottom line of the canvas.
+
+    var buffer = context.getImageData(0, canvas.height - 1, canvas.width, 1);
+    var passed = false;
+    for (var i = 0; i < canvas.width; ++i) {
+        if (buffer.data[i * 4] > 0) {
+            passed = true;
+            break;
+        }
+    }
+    document.querySelector("p").textContent = passed ? "PASSED" : "FAILED";
+}
+
+window.addEventListener("load", runTest, false);
+
+</script>
+<canvas width="200" height="100"></canvas>
+<p></p>
\ No newline at end of file
Property changes on: trunk/LayoutTests/fast/canvas/gradient-text-with-shadow.html
___________________________________________________________________

Added: svn:mime-type

Added: svn:keywords

Added: svn:eol-style

Modified: trunk/Source/WebCore/ChangeLog (188147 => 188148)


--- trunk/Source/WebCore/ChangeLog	2015-08-07 19:34:13 UTC (rev 188147)
+++ trunk/Source/WebCore/ChangeLog	2015-08-07 19:40:45 UTC (rev 188148)
@@ -1,3 +1,24 @@
+2015-08-06  Dean Jackson  <[email protected]>
+
+        Shadows don't draw on fillText when using a gradient fill
+        https://bugs.webkit.org/show_bug.cgi?id=147758
+        <rdar://problem/20860912>
+
+        Reviewed by Myles Maxfield.
+
+        Since we use a mask to render a pattern or gradient
+        into text, any shadow was being clipped out. Change
+        this to draw the shadow before the mask + fill operation,
+        using a technique similar to text-shadow.
+
+        Test: fast/canvas/gradient-text-with-shadow.html
+
+        * html/canvas/CanvasRenderingContext2D.cpp:
+        (WebCore::CanvasRenderingContext2D::drawTextInternal): Get the current shadow
+        style, paint the text with a transformed shadow offset so that we only
+        see the shadow and not the text, then combine with the existing pattern/gradient
+        fill.
+
 2015-08-07  Myles C. Maxfield  <[email protected]>
 
         Implement font-feature-settings

Modified: trunk/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp (188147 => 188148)


--- trunk/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp	2015-08-07 19:34:13 UTC (rev 188147)
+++ trunk/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp	2015-08-07 19:40:45 UTC (rev 188148)
@@ -2357,8 +2357,40 @@
 #if USE(CG)
     const CanvasStyle& drawStyle = fill ? state().m_fillStyle : state().m_strokeStyle;
     if (drawStyle.canvasGradient() || drawStyle.canvasPattern()) {
+
         IntRect maskRect = enclosingIntRect(textRect);
 
+        // If we have a shadow, we need to draw it before the mask operation.
+        // Follow a procedure similar to paintTextWithShadows in TextPainter.
+
+        if (shouldDrawShadows()) {
+            GraphicsContextStateSaver stateSaver(*c);
+
+            FloatSize offset = FloatSize(0, 2 * maskRect.height());
+
+            FloatSize shadowOffset;
+            float shadowRadius;
+            Color shadowColor;
+            ColorSpace shadowColorSpace;
+            c->getShadow(shadowOffset, shadowRadius, shadowColor, shadowColorSpace);
+
+            FloatRect shadowRect(maskRect);
+            shadowRect.inflate(shadowRadius * 1.4);
+            shadowRect.move(shadowOffset * -1);
+            c->clip(shadowRect);
+
+            shadowOffset += offset;
+
+            c->setLegacyShadow(shadowOffset, shadowRadius, shadowColor, shadowColorSpace);
+
+            if (fill)
+                c->setFillColor(Color::black, ColorSpaceDeviceRGB);
+            else
+                c->setStrokeColor(Color::black, ColorSpaceDeviceRGB);
+
+            c->drawBidiText(font, textRun, location + offset, FontCascade::UseFallbackIfFontNotReady);
+        }
+
         std::unique_ptr<ImageBuffer> maskImage = c->createCompatibleBuffer(maskRect.size());
 
         GraphicsContext* maskImageContext = maskImage->context();
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