Merge WebKit at r68651 : Initial merge by git.

Change-Id: I3d6bff59f17eedd6722723354f386fec9be8ad12

1 files changed, 174 insertions, 0 deletions

diff --git a/WebCore/platform/graphics/ContextShadow.cpp b/WebCore/platform/graphics/ContextShadow.cpp
new file mode 100644
index 0000000..1007962
--- /dev/null
+++ b/WebCore/platform/graphics/ContextShadow.cpp
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+/*
+ * Copyright (C) 2010 Sencha, Inc.
+ * Copyright (C) 2010 Igalia S.L.
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "ContextShadow.h"
+
+#include <wtf/MathExtras.h>
+#include <wtf/Noncopyable.h>
+
+using WTF::min;
+using WTF::max;
+
+namespace WebCore {
+
+ContextShadow::ContextShadow()
+    : m_type(NoShadow)
+    , m_blurRadius(0)
+{
+}
+
+ContextShadow::ContextShadow(const Color& color, float radius, const FloatSize& offset)
+    : m_color(color)
+    , m_blurRadius(round(radius))
+    , m_offset(offset)
+{
+    // See comments in http://webkit.org/b/40793, it seems sensible
+    // to follow Skia's limit of 128 pixels of blur radius
+    m_blurRadius = min(m_blurRadius, 128);
+
+    // The type of shadow is decided by the blur radius, shadow offset, and shadow color.
+    if (!m_color.isValid() || !color.alpha()) {
+        // Can't paint the shadow with invalid or invisible color.
+        m_type = NoShadow;
+    } else if (radius > 0) {
+        // Shadow is always blurred, even the offset is zero.
+        m_type = BlurShadow;
+    } else if (!m_offset.width() && !m_offset.height()) {
+        // Without blur and zero offset means the shadow is fully hidden.
+        m_type = NoShadow;
+    } else {
+        m_type = SolidShadow;
+    }
+}
+
+void ContextShadow::clear()
+{
+    m_type = NoShadow;
+    m_color = Color();
+    m_blurRadius = 0;
+    m_offset = FloatSize();
+}
+
+// Instead of integer division, we use 17.15 for fixed-point division.
+static const int BlurSumShift = 15;
+
+// Check http://www.w3.org/TR/SVG/filters.html#feGaussianBlur.
+// As noted in the SVG filter specification, running box blur 3x
+// approximates a real gaussian blur nicely.
+
+void ContextShadow::blurLayerImage(unsigned char* imageData, const IntSize& size, int rowStride)
+{
+    int channels[4] = { 3, 0, 1, 3 };
+    int dmax = m_blurRadius >> 1;
+    int dmin = dmax - 1 + (m_blurRadius & 1);
+    if (dmin < 0)
+        dmin = 0;
+
+    // Two stages: horizontal and vertical
+    for (int k = 0; k < 2; ++k) {
+
+        unsigned char* pixels = imageData;
+        int stride = (!k) ? 4 : rowStride;
+        int delta = (!k) ? rowStride : 4;
+        int jfinal = (!k) ? size.height() : size.width();
+        int dim = (!k) ? size.width() : size.height();
+
+        for (int j = 0; j < jfinal; ++j, pixels += delta) {
+
+            // For each step, we blur the alpha in a channel and store the result
+            // in another channel for the subsequent step.
+            // We use sliding window algorithm to accumulate the alpha values.
+            // This is much more efficient than computing the sum of each pixels
+            // covered by the box kernel size for each x.
+
+            for (int step = 0; step < 3; ++step) {
+                int side1 = (!step) ? dmin : dmax;
+                int side2 = (step == 1) ? dmin : dmax;
+                int pixelCount = side1 + 1 + side2;
+                int invCount = ((1 << BlurSumShift) + pixelCount - 1) / pixelCount;
+                int ofs = 1 + side2;
+                int alpha1 = pixels[channels[step]];
+                int alpha2 = pixels[(dim - 1) * stride + channels[step]];
+                unsigned char* ptr = pixels + channels[step + 1];
+                unsigned char* prev = pixels + stride + channels[step];
+                unsigned char* next = pixels + ofs * stride + channels[step];
+
+                int i;
+                int sum = side1 * alpha1 + alpha1;
+                int limit = (dim < side2 + 1) ? dim : side2 + 1;
+                for (i = 1; i < limit; ++i, prev += stride)
+                    sum += *prev;
+                if (limit <= side2)
+                    sum += (side2 - limit + 1) * alpha2;
+
+                limit = (side1 < dim) ? side1 : dim;
+                for (i = 0; i < limit; ptr += stride, next += stride, ++i, ++ofs) {
+                    *ptr = (sum * invCount) >> BlurSumShift;
+                    sum += ((ofs < dim) ? *next : alpha2) - alpha1;
+                }
+                prev = pixels + channels[step];
+                for (; ofs < dim; ptr += stride, prev += stride, next += stride, ++i, ++ofs) {
+                    *ptr = (sum * invCount) >> BlurSumShift;
+                    sum += (*next) - (*prev);
+                }
+                for (; i < dim; ptr += stride, prev += stride, ++i) {
+                    *ptr = (sum * invCount) >> BlurSumShift;
+                    sum += alpha2 - (*prev);
+                }
+            }
+        }
+    }
+}
+
+void ContextShadow::calculateLayerBoundingRect(const FloatRect& layerArea, const IntRect& clipRect)
+{
+    // Calculate the destination of the blurred layer.
+    FloatRect destinationRect(layerArea);
+    destinationRect.move(m_offset);
+    m_layerRect = enclosingIntRect(destinationRect);
+
+    // We expand the area by the blur radius * 2 to give extra space for the blur transition.
+    m_layerRect.inflate((m_type == BlurShadow) ? ceil(m_blurRadius * 2) : 0);
+
+    if (!clipRect.contains(m_layerRect)) {
+        // No need to have the buffer larger than the clip.
+        m_layerRect.intersect(clipRect);
+
+        // If we are totally outside the clip region, we aren't painting at all.
+        if (m_layerRect.isEmpty())
+            return;
+
+        // We adjust again because the pixels at the borders are still
+        // potentially affected by the pixels outside the buffer.
+        if (m_type == BlurShadow)
+            m_layerRect.inflate((m_type == BlurShadow) ? ceil(m_blurRadius * 2) : 0);
+    }
+}
+
+} // namespace WebCore