Merge WebKit at r75315: Initial merge by git.

Change-Id: I570314b346ce101c935ed22a626b48c2af266b84

1 files changed, 833 insertions, 0 deletions

diff --git a/Source/WebCore/css/CSSGradientValue.cpp b/Source/WebCore/css/CSSGradientValue.cpp
new file mode 100644
index 0000000..8040c6c
--- /dev/null
+++ b/Source/WebCore/css/CSSGradientValue.cpp
@@ -0,0 +1,833 @@
+/*
+ * Copyright (C) 2008 Apple Inc.  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 "CSSGradientValue.h"
+
+#include "CSSValueKeywords.h"
+#include "CSSStyleSelector.h"
+#include "GeneratedImage.h"
+#include "Gradient.h"
+#include "Image.h"
+#include "IntSize.h"
+#include "IntSizeHash.h"
+#include "NodeRenderStyle.h"
+#include "PlatformString.h"
+#include "RenderObject.h"
+
+using namespace std;
+
+namespace WebCore {
+
+Image* CSSGradientValue::image(RenderObject* renderer, const IntSize& size)
+{
+    ASSERT(m_clients.contains(renderer));
+
+    // Need to look up our size.  Create a string of width*height to use as a hash key.
+    // FIXME: hashing based only on size is not sufficient. Color stops may use context-sensitive units (like em)
+    // that should force the color stop positions to be recomputed.
+    Image* result = getImage(renderer, size);
+    if (result)
+        return result;
+
+    if (size.isEmpty())
+        return 0;
+
+    // We need to create an image.
+    RefPtr<Image> newImage = GeneratedImage::create(createGradient(renderer, size), size);
+    result = newImage.get();
+    putImage(size, newImage.release());
+
+    return result;
+}
+
+// Should only ever be called for deprecated gradients.
+static inline bool compareStops(const CSSGradientColorStop& a, const CSSGradientColorStop& b)
+{
+    double aVal = a.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER);
+    double bVal = b.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER);
+    
+    return aVal < bVal;
+}
+
+void CSSGradientValue::sortStopsIfNeeded()
+{
+    ASSERT(m_deprecatedType);
+    if (!m_stopsSorted) {
+        if (m_stops.size())
+            std::stable_sort(m_stops.begin(), m_stops.end(), compareStops);
+        m_stopsSorted = true;
+    }
+}
+
+static inline int blend(int from, int to, float progress)
+{  
+    return int(from + (to - from) * progress);
+}
+
+static inline Color blend(const Color& from, const Color& to, float progress)
+{
+    // FIXME: when we interpolate gradients using premultiplied colors, this should also do premultiplication.
+    return Color(blend(from.red(), to.red(), progress),
+        blend(from.green(), to.green(), progress),
+        blend(from.blue(), to.blue(), progress),
+        blend(from.alpha(), to.alpha(), progress));
+}
+
+struct GradientStop {
+    Color color;
+    float offset;
+    bool specified;
+    
+    GradientStop()
+        : offset(0)
+        , specified(false)
+    { }
+};
+
+void CSSGradientValue::addStops(Gradient* gradient, RenderObject* renderer, RenderStyle* rootStyle, float maxLengthForRepeat)
+{
+    RenderStyle* style = renderer->style();
+    
+    if (m_deprecatedType) {
+        sortStopsIfNeeded();
+
+        // We have to resolve colors.
+        for (unsigned i = 0; i < m_stops.size(); i++) {
+            const CSSGradientColorStop& stop = m_stops[i];
+            Color color = renderer->document()->styleSelector()->getColorFromPrimitiveValue(stop.m_color.get());
+
+            float offset;
+            if (stop.m_position->primitiveType() == CSSPrimitiveValue::CSS_PERCENTAGE)
+                offset = stop.m_position->getFloatValue(CSSPrimitiveValue::CSS_PERCENTAGE) / 100;
+            else
+                offset = stop.m_position->getFloatValue(CSSPrimitiveValue::CSS_NUMBER);
+            
+            gradient->addColorStop(offset, color);
+        }
+
+        // The back end already sorted the stops.
+        gradient->setStopsSorted(true);
+        return;
+    }
+
+    size_t numStops = m_stops.size();
+    
+    Vector<GradientStop> stops(numStops);
+    
+    float gradientLength = 0;
+    bool computedGradientLength = false;
+    
+    FloatPoint gradientStart = gradient->p0();
+    FloatPoint gradientEnd;
+    if (isLinearGradient())
+        gradientEnd = gradient->p1();
+    else if (isRadialGradient())
+        gradientEnd = gradientStart + FloatSize(gradient->endRadius(), 0);
+        
+    for (size_t i = 0; i < numStops; ++i) {
+        const CSSGradientColorStop& stop = m_stops[i];
+
+        stops[i].color = renderer->document()->styleSelector()->getColorFromPrimitiveValue(stop.m_color.get());
+
+        if (stop.m_position) {
+            int type = stop.m_position->primitiveType();
+            if (type == CSSPrimitiveValue::CSS_PERCENTAGE)
+                stops[i].offset = stop.m_position->getFloatValue(CSSPrimitiveValue::CSS_PERCENTAGE) / 100;
+            else if (CSSPrimitiveValue::isUnitTypeLength(type)) {
+                float length = stop.m_position->computeLengthFloat(style, rootStyle, style->effectiveZoom());
+                if (!computedGradientLength) {
+                    FloatSize gradientSize(gradientStart - gradientEnd);
+                    gradientLength = gradientSize.diagonalLength();
+                }
+                stops[i].offset = (gradientLength > 0) ? length / gradientLength : 0;
+            } else {
+                ASSERT_NOT_REACHED();
+                stops[i].offset = 0;
+            }
+            stops[i].specified = true;
+        } else {
+            // If the first color-stop does not have a position, its position defaults to 0%.
+            // If the last color-stop does not have a position, its position defaults to 100%.
+            if (!i) {
+                stops[i].offset = 0;
+                stops[i].specified = true;
+            } else if (numStops > 1 && i == numStops - 1) {
+                stops[i].offset = 1;
+                stops[i].specified = true;
+            }
+        }
+
+        // If a color-stop has a position that is less than the specified position of any
+        // color-stop before it in the list, its position is changed to be equal to the
+        // largest specified position of any color-stop before it.
+        if (stops[i].specified && i > 0) {
+            size_t prevSpecifiedIndex;
+            for (prevSpecifiedIndex = i - 1; prevSpecifiedIndex; --prevSpecifiedIndex) {
+                if (stops[prevSpecifiedIndex].specified)
+                    break;
+            }
+            
+            if (stops[i].offset < stops[prevSpecifiedIndex].offset)
+                stops[i].offset = stops[prevSpecifiedIndex].offset;
+        }
+    }
+
+    ASSERT(stops[0].specified && stops[numStops - 1].specified);
+    
+    // If any color-stop still does not have a position, then, for each run of adjacent
+    // color-stops without positions, set their positions so that they are evenly spaced
+    // between the preceding and following color-stops with positions.
+    if (numStops > 2) {
+        size_t unspecifiedRunStart = 0;
+        bool inUnspecifiedRun = false;
+
+        for (size_t i = 0; i < numStops; ++i) {
+            if (!stops[i].specified && !inUnspecifiedRun) {
+                unspecifiedRunStart = i;
+                inUnspecifiedRun = true;
+            } else if (stops[i].specified && inUnspecifiedRun) {
+                size_t unspecifiedRunEnd = i;
+
+                if (unspecifiedRunStart < unspecifiedRunEnd) {
+                    float lastSpecifiedOffset = stops[unspecifiedRunStart - 1].offset;
+                    float nextSpecifiedOffset = stops[unspecifiedRunEnd].offset;
+                    float delta = (nextSpecifiedOffset - lastSpecifiedOffset) / (unspecifiedRunEnd - unspecifiedRunStart + 1);
+                    
+                    for (size_t j = unspecifiedRunStart; j < unspecifiedRunEnd; ++j)
+                        stops[j].offset = lastSpecifiedOffset + (j - unspecifiedRunStart + 1) * delta;
+                }
+
+                inUnspecifiedRun = false;
+            }
+        }
+    }
+
+    // If the gradient is repeating, repeat the color stops.
+    // We can't just push this logic down into the platform-specific Gradient code,
+    // because we have to know the extent of the gradient, and possible move the end points.
+    if (m_repeating && numStops > 1) {
+        float maxExtent = 1;
+
+        // Radial gradients may need to extend further than the endpoints, because they have
+        // to repeat out to the corners of the box.
+        if (isRadialGradient()) {
+            if (!computedGradientLength) {
+                FloatSize gradientSize(gradientStart - gradientEnd);
+                gradientLength = gradientSize.diagonalLength();
+            }
+            
+            if (maxLengthForRepeat > gradientLength)
+                maxExtent = maxLengthForRepeat / gradientLength;
+        }
+
+        size_t originalNumStops = numStops;
+        size_t originalFirstStopIndex = 0;
+
+        // Work backwards from the first, adding stops until we get one before 0.
+        float firstOffset = stops[0].offset;
+        if (firstOffset > 0) {
+            float currOffset = firstOffset;
+            size_t srcStopOrdinal = originalNumStops - 1;
+            
+            while (true) {
+                GradientStop newStop = stops[originalFirstStopIndex + srcStopOrdinal];
+                newStop.offset = currOffset;
+                stops.prepend(newStop);
+                ++originalFirstStopIndex;
+                if (currOffset < 0)
+                    break;
+
+                if (srcStopOrdinal)
+                    currOffset -= stops[originalFirstStopIndex + srcStopOrdinal].offset - stops[originalFirstStopIndex + srcStopOrdinal - 1].offset;
+                srcStopOrdinal = (srcStopOrdinal + originalNumStops - 1) % originalNumStops;
+            }
+        }
+        
+        // Work forwards from the end, adding stops until we get one after 1.
+        float lastOffset = stops[stops.size() - 1].offset;
+        if (lastOffset < maxExtent) {
+            float currOffset = lastOffset;
+            size_t srcStopOrdinal = 0;
+
+            while (true) {
+                GradientStop newStop = stops[srcStopOrdinal];
+                newStop.offset = currOffset;
+                stops.append(newStop);
+                if (currOffset > maxExtent)
+                    break;
+                if (srcStopOrdinal < originalNumStops - 1)
+                    currOffset += stops[originalFirstStopIndex + srcStopOrdinal + 1].offset - stops[originalFirstStopIndex + srcStopOrdinal].offset;
+                srcStopOrdinal = (srcStopOrdinal + 1) % originalNumStops;
+            }
+        }
+    }
+    
+    numStops = stops.size();
+    
+    // If the gradient goes outside the 0-1 range, normalize it by moving the endpoints, and adjusting the stops.
+    if (numStops > 1 && (stops[0].offset < 0 || stops[numStops - 1].offset > 1)) {
+        if (isLinearGradient()) {
+            float firstOffset = stops[0].offset;
+            float lastOffset = stops[numStops - 1].offset;
+            float scale = lastOffset - firstOffset;
+
+            for (size_t i = 0; i < numStops; ++i)
+                stops[i].offset = (stops[i].offset - firstOffset) / scale;
+
+            FloatPoint p0 = gradient->p0();
+            FloatPoint p1 = gradient->p1();
+            gradient->setP0(FloatPoint(p0.x() + firstOffset * (p1.x() - p0.x()), p0.y() + firstOffset * (p1.y() - p0.y())));
+            gradient->setP1(FloatPoint(p1.x() + (lastOffset - 1) * (p1.x() - p0.x()), p1.y() + (lastOffset - 1) * (p1.y() - p0.y())));
+        } else if (isRadialGradient()) {
+            // Rather than scaling the points < 0, we truncate them, so only scale according to the largest point.
+            float firstOffset = 0;
+            float lastOffset = stops[numStops - 1].offset;
+            float scale = lastOffset - firstOffset;
+
+            // Reset points below 0 to the first visible color.
+            size_t firstZeroOrGreaterIndex = numStops;
+            for (size_t i = 0; i < numStops; ++i) {
+                if (stops[i].offset >= 0) {
+                    firstZeroOrGreaterIndex = i;
+                    break;
+                }
+            }
+            
+            if (firstZeroOrGreaterIndex > 0) {
+                if (firstZeroOrGreaterIndex < numStops && stops[firstZeroOrGreaterIndex].offset > 0) {
+                    float prevOffset = stops[firstZeroOrGreaterIndex - 1].offset;
+                    float nextOffset = stops[firstZeroOrGreaterIndex].offset;
+                    
+                    float interStopProportion = -prevOffset / (nextOffset - prevOffset);
+                    Color blendedColor = blend(stops[firstZeroOrGreaterIndex - 1].color, stops[firstZeroOrGreaterIndex].color, interStopProportion);
+
+                    // Clamp the positions to 0 and set the color.
+                    for (size_t i = 0; i < firstZeroOrGreaterIndex; ++i) {
+                        stops[i].offset = 0;
+                        stops[i].color = blendedColor;
+                    }
+                } else {
+                    // All stops are below 0; just clamp them.
+                    for (size_t i = 0; i < firstZeroOrGreaterIndex; ++i)
+                        stops[i].offset = 0;
+                }
+            }
+            
+            for (size_t i = 0; i < numStops; ++i)
+                stops[i].offset /= scale;
+            
+            gradient->setStartRadius(gradient->startRadius() * scale);
+            gradient->setEndRadius(gradient->endRadius() * scale);
+        }
+    }
+    
+    for (unsigned i = 0; i < numStops; i++)
+        gradient->addColorStop(stops[i].offset, stops[i].color);
+
+    gradient->setStopsSorted(true);
+}
+
+static float positionFromValue(CSSPrimitiveValue* value, RenderStyle* style, RenderStyle* rootStyle, const IntSize& size, bool isHorizontal)
+{
+    float zoomFactor = style->effectiveZoom();
+
+    switch (value->primitiveType()) {
+    case CSSPrimitiveValue::CSS_NUMBER:
+        return value->getFloatValue() * zoomFactor;
+
+    case CSSPrimitiveValue::CSS_PERCENTAGE:
+        return value->getFloatValue() / 100.f * (isHorizontal ? size.width() : size.height());
+
+    case CSSPrimitiveValue::CSS_IDENT:
+        switch (value->getIdent()) {
+            case CSSValueTop:
+                ASSERT(!isHorizontal);
+                return 0;
+            case CSSValueLeft:
+                ASSERT(isHorizontal);
+                return 0;
+            case CSSValueBottom:
+                ASSERT(!isHorizontal);
+                return size.height();
+            case CSSValueRight:
+                ASSERT(isHorizontal);
+                return size.width();
+        }
+
+    default:
+        return value->computeLengthFloat(style, rootStyle, zoomFactor);
+    }
+}
+
+FloatPoint CSSGradientValue::computeEndPoint(CSSPrimitiveValue* first, CSSPrimitiveValue* second, RenderStyle* style, RenderStyle* rootStyle, const IntSize& size)
+{
+    FloatPoint result;
+
+    if (first)
+        result.setX(positionFromValue(first, style, rootStyle, size, true));
+
+    if (second)
+        result.setY(positionFromValue(second, style, rootStyle, size, false));
+        
+    return result;
+}
+
+String CSSLinearGradientValue::cssText() const
+{
+    String result;
+    if (m_deprecatedType) {
+        result = "-webkit-gradient(linear, ";
+        result += m_firstX->cssText() + " ";
+        result += m_firstY->cssText() + ", ";
+        result += m_secondX->cssText() + " ";
+        result += m_secondY->cssText();
+
+        for (unsigned i = 0; i < m_stops.size(); i++) {
+            const CSSGradientColorStop& stop = m_stops[i];
+            result += ", ";
+            if (stop.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER) == 0)
+                result += "from(" + stop.m_color->cssText() + ")";
+            else if (stop.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER) == 1)
+                result += "to(" + stop.m_color->cssText() + ")";
+            else
+                result += "color-stop(" + String::number(stop.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER)) + ", " + stop.m_color->cssText() + ")";
+        }
+    } else {
+        result = m_repeating ? "-webkit-repeating-linear-gradient(" : "-webkit-linear-gradient(";
+        if (m_angle)
+            result += m_angle->cssText();
+        else {
+            if (m_firstX && m_firstY)
+                result += m_firstX->cssText() + " " + m_firstY->cssText();
+            else if (m_firstX || m_firstY) {
+                if (m_firstX)
+                    result += m_firstX->cssText();
+
+                if (m_firstY)
+                    result += m_firstY->cssText();
+            }
+        }
+
+        for (unsigned i = 0; i < m_stops.size(); i++) {
+            const CSSGradientColorStop& stop = m_stops[i];
+            result += ", ";
+            result += stop.m_color->cssText();
+            if (stop.m_position)
+                result += " " + stop.m_position->cssText();
+        }
+    }
+
+    result += ")";
+    return result;
+}
+
+// Compute the endpoints so that a gradient of the given angle covers a box of the given size.
+static void endPointsFromAngle(float angleDeg, const IntSize& size, FloatPoint& firstPoint, FloatPoint& secondPoint)
+{
+    angleDeg = fmodf(angleDeg, 360);
+    if (angleDeg < 0)
+        angleDeg += 360;
+    
+    if (!angleDeg) {
+        firstPoint.set(0, 0);
+        secondPoint.set(size.width(), 0);
+        return;
+    }
+    
+    if (angleDeg == 90) {
+        firstPoint.set(0, size.height());
+        secondPoint.set(0, 0);
+        return;
+    }
+
+    if (angleDeg == 180) {
+        firstPoint.set(size.width(), 0);
+        secondPoint.set(0, 0);
+        return;
+    }
+
+    float slope = tan(deg2rad(angleDeg));
+
+    // We find the endpoint by computing the intersection of the line formed by the slope,
+    // and a line perpendicular to it that intersects the corner.
+    float perpendicularSlope = -1 / slope;
+    
+    // Compute start corner relative to center.
+    float halfHeight = size.height() / 2;
+    float halfWidth = size.width() / 2;
+    FloatPoint endCorner;
+    if (angleDeg < 90)
+        endCorner.set(halfWidth, halfHeight);
+    else if (angleDeg < 180)
+        endCorner.set(-halfWidth, halfHeight);
+    else if (angleDeg < 270)
+        endCorner.set(-halfWidth, -halfHeight);
+    else
+        endCorner.set(halfWidth, -halfHeight);
+
+    // Compute c (of y = mx + c) using the corner point.
+    float c = endCorner.y() - perpendicularSlope * endCorner.x();
+    float endX = c / (slope - perpendicularSlope);
+    float endY = perpendicularSlope * endX + c;
+    
+    // We computed the end point, so set the second point, flipping the Y to account for angles going anticlockwise.
+    secondPoint.set(halfWidth + endX, size.height() - (halfHeight + endY));
+    // Reflect around the center for the start point.
+    firstPoint.set(size.width() - secondPoint.x(), size.height() - secondPoint.y());
+}
+
+PassRefPtr<Gradient> CSSLinearGradientValue::createGradient(RenderObject* renderer, const IntSize& size)
+{
+    ASSERT(!size.isEmpty());
+    
+    RenderStyle* rootStyle = renderer->document()->documentElement()->renderStyle();
+
+    FloatPoint firstPoint;
+    FloatPoint secondPoint;
+    if (m_angle) {
+        float angle = m_angle->getFloatValue(CSSPrimitiveValue::CSS_DEG);
+        endPointsFromAngle(angle, size, firstPoint, secondPoint);
+    } else {
+        firstPoint = computeEndPoint(m_firstX.get(), m_firstY.get(), renderer->style(), rootStyle, size);
+        
+        if (m_secondX || m_secondY)
+            secondPoint = computeEndPoint(m_secondX.get(), m_secondY.get(), renderer->style(), rootStyle, size);
+        else {
+            if (m_firstX)
+                secondPoint.setX(size.width() - firstPoint.x());
+            if (m_firstY)
+                secondPoint.setY(size.height() - firstPoint.y());
+        }
+    }
+
+    RefPtr<Gradient> gradient = Gradient::create(firstPoint, secondPoint);
+
+    // Now add the stops.
+    addStops(gradient.get(), renderer, rootStyle, 1);
+
+    return gradient.release();
+}
+
+String CSSRadialGradientValue::cssText() const
+{
+    String result;
+
+    if (m_deprecatedType) {
+        result = "-webkit-gradient(radial, ";
+
+        result += m_firstX->cssText() + " ";
+        result += m_firstY->cssText() + ", ";
+        result += m_firstRadius->cssText() + ", ";
+        result += m_secondX->cssText() + " ";
+        result += m_secondY->cssText();
+        result += ", ";
+        result += m_secondRadius->cssText();
+
+        // FIXME: share?
+        for (unsigned i = 0; i < m_stops.size(); i++) {
+            const CSSGradientColorStop& stop = m_stops[i];
+            result += ", ";
+            if (stop.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER) == 0)
+                result += "from(" + stop.m_color->cssText() + ")";
+            else if (stop.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER) == 1)
+                result += "to(" + stop.m_color->cssText() + ")";
+            else
+                result += "color-stop(" + String::number(stop.m_position->getDoubleValue(CSSPrimitiveValue::CSS_NUMBER)) + ", " + stop.m_color->cssText() + ")";
+        }
+    } else {
+
+        result = m_repeating ? "-webkit-repeating-radial-gradient(" : "-webkit-radial-gradient(";
+        if (m_firstX && m_firstY) {
+            result += m_firstX->cssText() + " " + m_firstY->cssText();
+        } else if (m_firstX)
+            result += m_firstX->cssText();
+         else if (m_firstY)
+            result += m_firstY->cssText();
+        else
+            result += "center";
+
+
+        if (m_shape || m_sizingBehavior) {
+            result += ", ";
+            if (m_shape)
+                result += m_shape->cssText() + " ";
+            else
+                result += "ellipse ";
+
+            if (m_sizingBehavior)
+                result += m_sizingBehavior->cssText();
+            else
+                result += "cover";
+
+        } else if (m_endHorizontalSize && m_endVerticalSize) {
+            result += ", ";
+            result += m_endHorizontalSize->cssText() + " " + m_endVerticalSize->cssText();
+        }
+
+        for (unsigned i = 0; i < m_stops.size(); i++) {
+            const CSSGradientColorStop& stop = m_stops[i];
+            result += ", ";
+            result += stop.m_color->cssText();
+            if (stop.m_position)
+                result += " " + stop.m_position->cssText();
+        }
+    }
+
+    result += ")";
+    return result;
+}
+
+float CSSRadialGradientValue::resolveRadius(CSSPrimitiveValue* radius, RenderStyle* style, RenderStyle* rootStyle, float* widthOrHeight)
+{
+    float zoomFactor = style->effectiveZoom();
+
+    float result = 0;
+    if (radius->primitiveType() == CSSPrimitiveValue::CSS_NUMBER)  // Can the radius be a percentage?
+        result = radius->getFloatValue() * zoomFactor;
+    else if (widthOrHeight && radius->primitiveType() == CSSPrimitiveValue::CSS_PERCENTAGE)
+        result = *widthOrHeight * radius->getFloatValue() / 100;
+    else
+        result = radius->computeLengthFloat(style, rootStyle, zoomFactor);
+ 
+    return result;
+}
+
+static float distanceToClosestCorner(const FloatPoint& p, const FloatSize& size, FloatPoint& corner)
+{
+    FloatPoint topLeft;
+    float topLeftDistance = FloatSize(p - topLeft).diagonalLength();
+
+    FloatPoint topRight(size.width(), 0);
+    float topRightDistance = FloatSize(p - topRight).diagonalLength();
+
+    FloatPoint bottomLeft(0, size.height());
+    float bottomLeftDistance = FloatSize(p - bottomLeft).diagonalLength();
+
+    FloatPoint bottomRight(size.width(), size.height());
+    float bottomRightDistance = FloatSize(p - bottomRight).diagonalLength();
+
+    corner = topLeft;
+    float minDistance = topLeftDistance;
+    if (topRightDistance < minDistance) {
+        minDistance = topRightDistance;
+        corner = topRight;
+    }
+
+    if (bottomLeftDistance < minDistance) {
+        minDistance = bottomLeftDistance;
+        corner = bottomLeft;
+    }
+
+    if (bottomRightDistance < minDistance) {
+        minDistance = bottomRightDistance;
+        corner = bottomRight;
+    }
+    return minDistance;
+}
+
+static float distanceToFarthestCorner(const FloatPoint& p, const FloatSize& size, FloatPoint& corner)
+{
+    FloatPoint topLeft;
+    float topLeftDistance = FloatSize(p - topLeft).diagonalLength();
+
+    FloatPoint topRight(size.width(), 0);
+    float topRightDistance = FloatSize(p - topRight).diagonalLength();
+
+    FloatPoint bottomLeft(0, size.height());
+    float bottomLeftDistance = FloatSize(p - bottomLeft).diagonalLength();
+
+    FloatPoint bottomRight(size.width(), size.height());
+    float bottomRightDistance = FloatSize(p - bottomRight).diagonalLength();
+
+    corner = topLeft;
+    float maxDistance = topLeftDistance;
+    if (topRightDistance > maxDistance) {
+        maxDistance = topRightDistance;
+        corner = topRight;
+    }
+
+    if (bottomLeftDistance > maxDistance) {
+        maxDistance = bottomLeftDistance;
+        corner = bottomLeft;
+    }
+
+    if (bottomRightDistance > maxDistance) {
+        maxDistance = bottomRightDistance;
+        corner = bottomRight;
+    }
+    return maxDistance;
+}
+
+// Compute horizontal radius of ellipse with center at 0,0 which passes through p, and has
+// width/height given by aspectRatio.
+static inline float horizontalEllipseRadius(const FloatSize& p, float aspectRatio)
+{
+    // x^2/a^2 + y^2/b^2 = 1
+    // a/b = aspectRatio, b = a/aspectRatio
+    // a = sqrt(x^2 + y^2/(1/r^2))
+    return sqrtf(p.width() * p.width() + (p.height() * p.height()) / (1 / (aspectRatio * aspectRatio)));
+}
+
+// FIXME: share code with the linear version
+PassRefPtr<Gradient> CSSRadialGradientValue::createGradient(RenderObject* renderer, const IntSize& size)
+{
+    ASSERT(!size.isEmpty());
+    
+    RenderStyle* rootStyle = renderer->document()->documentElement()->renderStyle();
+
+    FloatPoint firstPoint = computeEndPoint(m_firstX.get(), m_firstY.get(), renderer->style(), rootStyle, size);
+    if (!m_firstX)
+        firstPoint.setX(size.width() / 2);
+    if (!m_firstY)
+        firstPoint.setY(size.height() / 2);
+
+    FloatPoint secondPoint = computeEndPoint(m_secondX.get(), m_secondY.get(), renderer->style(), rootStyle, size);
+    if (!m_secondX)
+        secondPoint.setX(size.width() / 2);
+    if (!m_secondY)
+        secondPoint.setY(size.height() / 2);
+    
+    float firstRadius = 0;
+    if (m_firstRadius)
+        firstRadius = resolveRadius(m_firstRadius.get(), renderer->style(), rootStyle);
+
+    float secondRadius = 0;
+    float aspectRatio = 1; // width / height.
+    if (m_secondRadius)
+        secondRadius = resolveRadius(m_secondRadius.get(), renderer->style(), rootStyle);
+    else if (m_endHorizontalSize || m_endVerticalSize) {
+        float width = size.width();
+        float height = size.height();
+        secondRadius = resolveRadius(m_endHorizontalSize.get(), renderer->style(), rootStyle, &width);
+        aspectRatio = secondRadius / resolveRadius(m_endVerticalSize.get(), renderer->style(), rootStyle, &height);
+    } else {
+        enum GradientShape { Circle, Ellipse };
+        GradientShape shape = Ellipse;
+        if (m_shape && m_shape->primitiveType() == CSSPrimitiveValue::CSS_IDENT && m_shape->getIdent() == CSSValueCircle)
+            shape = Circle;
+        
+        enum GradientFill { ClosestSide, ClosestCorner, FarthestSide, FarthestCorner };
+        GradientFill fill = FarthestCorner;
+        
+        if (m_sizingBehavior && m_sizingBehavior->primitiveType() == CSSPrimitiveValue::CSS_IDENT) {
+            switch (m_sizingBehavior->getIdent()) {
+            case CSSValueContain:
+            case CSSValueClosestSide:
+                fill = ClosestSide;
+                break;
+            case CSSValueClosestCorner:
+                fill = ClosestCorner;
+                break;
+            case CSSValueFarthestSide:
+                fill = FarthestSide;
+                break;
+            case CSSValueCover:
+            case CSSValueFarthestCorner:
+                fill = FarthestCorner;
+                break;
+            }
+        }
+        
+        // Now compute the end radii based on the second point, shape and fill.
+        
+        // Horizontal
+        switch (fill) {
+        case ClosestSide: {
+            float xDist = min(secondPoint.x(), size.width() - secondPoint.x());
+            float yDist = min(secondPoint.y(), size.height() - secondPoint.y());
+            if (shape == Circle) {
+                float smaller = min(xDist, yDist);
+                xDist = smaller;
+                yDist = smaller;
+            }
+            secondRadius = xDist;
+            aspectRatio = xDist / yDist;
+            break;
+        }
+        case FarthestSide: {
+            float xDist = max(secondPoint.x(), size.width() - secondPoint.x());
+            float yDist = max(secondPoint.y(), size.height() - secondPoint.y());
+            if (shape == Circle) {
+                float larger = max(xDist, yDist);
+                xDist = larger;
+                yDist = larger;
+            }
+            secondRadius = xDist;
+            aspectRatio = xDist / yDist;
+            break;
+        }
+        case ClosestCorner: {
+            FloatPoint corner;
+            float distance = distanceToClosestCorner(secondPoint, size, corner);
+            if (shape == Circle)
+                secondRadius = distance;
+            else {
+                // If <shape> is ellipse, the gradient-shape has the same ratio of width to height
+                // that it would if closest-side or farthest-side were specified, as appropriate.
+                float xDist = min(secondPoint.x(), size.width() - secondPoint.x());
+                float yDist = min(secondPoint.y(), size.height() - secondPoint.y());
+                
+                secondRadius = horizontalEllipseRadius(corner - secondPoint, xDist / yDist);
+                aspectRatio = xDist / yDist;
+            }
+            break;
+        }
+
+        case FarthestCorner: {
+            FloatPoint corner;
+            float distance = distanceToFarthestCorner(secondPoint, size, corner);
+            if (shape == Circle)
+                secondRadius = distance;
+            else {
+                // If <shape> is ellipse, the gradient-shape has the same ratio of width to height
+                // that it would if closest-side or farthest-side were specified, as appropriate.
+                float xDist = max(secondPoint.x(), size.width() - secondPoint.x());
+                float yDist = max(secondPoint.y(), size.height() - secondPoint.y());
+                
+                secondRadius = horizontalEllipseRadius(corner - secondPoint, xDist / yDist);
+                aspectRatio = xDist / yDist;
+            }
+            break;
+        }
+        }
+    }
+
+    RefPtr<Gradient> gradient = Gradient::create(firstPoint, firstRadius, secondPoint, secondRadius, aspectRatio);
+
+    // addStops() only uses maxExtent for repeating gradients.
+    float maxExtent = 0;
+    if (m_repeating) {
+        FloatPoint corner;
+        maxExtent = distanceToFarthestCorner(secondPoint, size, corner);
+    }
+
+    // Now add the stops.
+    addStops(gradient.get(), renderer, rootStyle, maxExtent);
+
+    return gradient.release();
+}
+
+} // namespace WebCore