third_party/WebKit/Source/core/layout/shapes/Shape.cpp - chromium/src - Git at Google

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "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 THE
  * COPYRIGHT HOLDER 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 "core/layout/shapes/Shape.h"

 #include "core/css/BasicShapeFunctions.h"
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/dom/DOMTypedArray.h"
 #include "core/fetch/ImageResource.h"
 #include "core/layout/shapes/BoxShape.h"
 #include "core/layout/shapes/PolygonShape.h"
 #include "core/layout/shapes/RasterShape.h"
 #include "core/layout/shapes/RectangleShape.h"
 #include "core/style/ComputedStyle.h"
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/LengthFunctions.h"
 #include "platform/geometry/FloatRoundedRect.h"
 #include "platform/geometry/FloatSize.h"
 #include "platform/graphics/GraphicsTypes.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "wtf/MathExtras.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/typed_arrays/ArrayBufferContents.h"
 #include <memory>

 namespace blink {

 static std::unique_ptr<Shape> createInsetShape(const FloatRoundedRect& bounds) {
   ASSERT(bounds.rect().width() >= 0 && bounds.rect().height() >= 0);
   return wrapUnique(new BoxShape(bounds));
 }

 static std::unique_ptr<Shape> createCircleShape(const FloatPoint& center,
                                                 float radius) {
   ASSERT(radius >= 0);
   return wrapUnique(
       new RectangleShape(FloatRect(center.x() - radius, center.y() - radius,
                                    radius * 2, radius * 2),
                          FloatSize(radius, radius)));
 }

 static std::unique_ptr<Shape> createEllipseShape(const FloatPoint& center,
                                                  const FloatSize& radii) {
   ASSERT(radii.width() >= 0 && radii.height() >= 0);
   return wrapUnique(new RectangleShape(
       FloatRect(center.x() - radii.width(), center.y() - radii.height(),
                 radii.width() * 2, radii.height() * 2),
       radii));
 }

 static std::unique_ptr<Shape> createPolygonShape(
     std::unique_ptr<Vector<FloatPoint>> vertices,
     WindRule fillRule) {
   return wrapUnique(new PolygonShape(std::move(vertices), fillRule));
 }

 static inline FloatRect physicalRectToLogical(const FloatRect& rect,
                                               float logicalBoxHeight,
                                               WritingMode writingMode) {
   if (isHorizontalWritingMode(writingMode))
     return rect;
   if (isFlippedBlocksWritingMode(writingMode))
     return FloatRect(rect.y(), logicalBoxHeight - rect.maxX(), rect.height(),
                      rect.width());
   return rect.transposedRect();
 }

 static inline FloatPoint physicalPointToLogical(const FloatPoint& point,
                                                 float logicalBoxHeight,
                                                 WritingMode writingMode) {
   if (isHorizontalWritingMode(writingMode))
     return point;
   if (isFlippedBlocksWritingMode(writingMode))
     return FloatPoint(point.y(), logicalBoxHeight - point.x());
   return point.transposedPoint();
 }

 static inline FloatSize physicalSizeToLogical(const FloatSize& size,
                                               WritingMode writingMode) {
   if (isHorizontalWritingMode(writingMode))
     return size;
   return size.transposedSize();
 }

 std::unique_ptr<Shape> Shape::createShape(const BasicShape* basicShape,
                                           const LayoutSize& logicalBoxSize,
                                           WritingMode writingMode,
                                           float margin) {
   ASSERT(basicShape);

   bool horizontalWritingMode = isHorizontalWritingMode(writingMode);
   float boxWidth = horizontalWritingMode ? logicalBoxSize.width().toFloat()
                                          : logicalBoxSize.height().toFloat();
   float boxHeight = horizontalWritingMode ? logicalBoxSize.height().toFloat()
                                           : logicalBoxSize.width().toFloat();
   std::unique_ptr<Shape> shape;

   switch (basicShape->type()) {
     case BasicShape::BasicShapeCircleType: {
       const BasicShapeCircle* circle = toBasicShapeCircle(basicShape);
       FloatPoint center = floatPointForCenterCoordinate(
           circle->centerX(), circle->centerY(), FloatSize(boxWidth, boxHeight));
       float radius =
           circle->floatValueForRadiusInBox(FloatSize(boxWidth, boxHeight));
       FloatPoint logicalCenter = physicalPointToLogical(
           center, logicalBoxSize.height().toFloat(), writingMode);

       shape = createCircleShape(logicalCenter, radius);
       break;
     }

     case BasicShape::BasicShapeEllipseType: {
       const BasicShapeEllipse* ellipse = toBasicShapeEllipse(basicShape);
       FloatPoint center =
           floatPointForCenterCoordinate(ellipse->centerX(), ellipse->centerY(),
                                         FloatSize(boxWidth, boxHeight));
       float radiusX = ellipse->floatValueForRadiusInBox(ellipse->radiusX(),
                                                         center.x(), boxWidth);
       float radiusY = ellipse->floatValueForRadiusInBox(ellipse->radiusY(),
                                                         center.y(), boxHeight);
       FloatPoint logicalCenter = physicalPointToLogical(
           center, logicalBoxSize.height().toFloat(), writingMode);

       shape = createEllipseShape(logicalCenter, FloatSize(radiusX, radiusY));
       break;
     }

     case BasicShape::BasicShapePolygonType: {
       const BasicShapePolygon* polygon = toBasicShapePolygon(basicShape);
       const Vector<Length>& values = polygon->values();
       size_t valuesSize = values.size();
       ASSERT(!(valuesSize % 2));
       std::unique_ptr<Vector<FloatPoint>> vertices =
           wrapUnique(new Vector<FloatPoint>(valuesSize / 2));
       for (unsigned i = 0; i < valuesSize; i += 2) {
         FloatPoint vertex(floatValueForLength(values.at(i), boxWidth),
                           floatValueForLength(values.at(i + 1), boxHeight));
         (*vertices)[i / 2] = physicalPointToLogical(
             vertex, logicalBoxSize.height().toFloat(), writingMode);
       }
       shape = createPolygonShape(std::move(vertices), polygon->getWindRule());
       break;
     }

     case BasicShape::BasicShapeInsetType: {
       const BasicShapeInset& inset = *toBasicShapeInset(basicShape);
       float left = floatValueForLength(inset.left(), boxWidth);
       float top = floatValueForLength(inset.top(), boxHeight);
       float right = floatValueForLength(inset.right(), boxWidth);
       float bottom = floatValueForLength(inset.bottom(), boxHeight);
       FloatRect rect(left, top, std::max<float>(boxWidth - left - right, 0),
                      std::max<float>(boxHeight - top - bottom, 0));
       FloatRect logicalRect = physicalRectToLogical(
           rect, logicalBoxSize.height().toFloat(), writingMode);

       FloatSize boxSize(boxWidth, boxHeight);
       FloatSize topLeftRadius = physicalSizeToLogical(
           floatSizeForLengthSize(inset.topLeftRadius(), boxSize), writingMode);
       FloatSize topRightRadius = physicalSizeToLogical(
           floatSizeForLengthSize(inset.topRightRadius(), boxSize), writingMode);
       FloatSize bottomLeftRadius = physicalSizeToLogical(
           floatSizeForLengthSize(inset.bottomLeftRadius(), boxSize),
           writingMode);
       FloatSize bottomRightRadius = physicalSizeToLogical(
           floatSizeForLengthSize(inset.bottomRightRadius(), boxSize),
           writingMode);
       FloatRoundedRect::Radii cornerRadii(topLeftRadius, topRightRadius,
                                           bottomLeftRadius, bottomRightRadius);

       FloatRoundedRect finalRect(logicalRect, cornerRadii);
       finalRect.constrainRadii();

       shape = createInsetShape(finalRect);
       break;
     }

     default:
       ASSERT_NOT_REACHED();
   }

   shape->m_writingMode = writingMode;
   shape->m_margin = margin;

   return shape;
 }

 std::unique_ptr<Shape> Shape::createEmptyRasterShape(WritingMode writingMode,
                                                      float margin) {
   std::unique_ptr<RasterShapeIntervals> intervals =
       wrapUnique(new RasterShapeIntervals(0, 0));
   std::unique_ptr<RasterShape> rasterShape =
       wrapUnique(new RasterShape(std::move(intervals), IntSize()));
   rasterShape->m_writingMode = writingMode;
   rasterShape->m_margin = margin;
   return std::move(rasterShape);
 }

 std::unique_ptr<Shape> Shape::createRasterShape(Image* image,
                                                 float threshold,
                                                 const LayoutRect& imageR,
                                                 const LayoutRect& marginR,
                                                 WritingMode writingMode,
                                                 float margin) {
   IntRect imageRect = pixelSnappedIntRect(imageR);
   IntRect marginRect = pixelSnappedIntRect(marginR);

   std::unique_ptr<RasterShapeIntervals> intervals = wrapUnique(
       new RasterShapeIntervals(marginRect.height(), -marginRect.y()));
   std::unique_ptr<ImageBuffer> imageBuffer =
       ImageBuffer::create(imageRect.size());

   if (image && imageBuffer) {
     // FIXME: This is not totally correct but it is needed to prevent shapes
     // that loads SVG Images during paint invalidations to mark layoutObjects
     // for layout, which is not allowed. See https://crbug.com/429346
     ImageObserverDisabler disabler(image);
     SkPaint paint;
     IntRect imageSourceRect(IntPoint(), image->size());
     IntRect imageDestRect(IntPoint(), imageRect.size());
     image->draw(imageBuffer->canvas(), paint, imageDestRect, imageSourceRect,
                 DoNotRespectImageOrientation,
                 Image::DoNotClampImageToSourceRect);

     WTF::ArrayBufferContents contents;
     imageBuffer->getImageData(Unmultiplied,
                               IntRect(IntPoint(), imageRect.size()), contents);
     DOMArrayBuffer* arrayBuffer = DOMArrayBuffer::create(contents);
     DOMUint8ClampedArray* pixelArray =
         DOMUint8ClampedArray::create(arrayBuffer, 0, arrayBuffer->byteLength());
     unsigned pixelArrayOffset = 3;  // Each pixel is four bytes: RGBA.
     uint8_t alphaPixelThreshold = threshold * 255;

     ASSERT(static_cast<unsigned>(imageRect.width() * imageRect.height() * 4) ==
            pixelArray->length());

     int minBufferY = std::max(0, marginRect.y() - imageRect.y());
     int maxBufferY =
         std::min(imageRect.height(), marginRect.maxY() - imageRect.y());

     for (int y = minBufferY; y < maxBufferY; ++y) {
       int startX = -1;
       for (int x = 0; x < imageRect.width(); ++x, pixelArrayOffset += 4) {
         uint8_t alpha = pixelArray->item(pixelArrayOffset);
         bool alphaAboveThreshold = alpha > alphaPixelThreshold;
         if (startX == -1 && alphaAboveThreshold) {
           startX = x;
         } else if (startX != -1 &&
                    (!alphaAboveThreshold || x == imageRect.width() - 1)) {
           int endX = alphaAboveThreshold ? x + 1 : x;
           intervals->intervalAt(y + imageRect.y())
               .unite(IntShapeInterval(startX + imageRect.x(),
                                       endX + imageRect.x()));
           startX = -1;
         }
       }
     }
   }

   std::unique_ptr<RasterShape> rasterShape =
       wrapUnique(new RasterShape(std::move(intervals), marginRect.size()));
   rasterShape->m_writingMode = writingMode;
   rasterShape->m_margin = margin;
   return std::move(rasterShape);
 }

 std::unique_ptr<Shape> Shape::createLayoutBoxShape(
     const FloatRoundedRect& roundedRect,
     WritingMode writingMode,
     float margin) {
   FloatRect rect(0, 0, roundedRect.rect().width(), roundedRect.rect().height());
   FloatRoundedRect bounds(rect, roundedRect.getRadii());
   std::unique_ptr<Shape> shape = createInsetShape(bounds);
   shape->m_writingMode = writingMode;
   shape->m_margin = margin;

   return shape;
 }

 }  // namespace blink
	/*
	* Copyright (C) 2012 Adobe Systems Incorporated. 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "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 THE
	* COPYRIGHT HOLDER 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 "core/layout/shapes/Shape.h"

	#include "core/css/BasicShapeFunctions.h"
	#include "core/dom/DOMArrayBuffer.h"
	#include "core/dom/DOMTypedArray.h"
	#include "core/fetch/ImageResource.h"
	#include "core/layout/shapes/BoxShape.h"
	#include "core/layout/shapes/PolygonShape.h"
	#include "core/layout/shapes/RasterShape.h"
	#include "core/layout/shapes/RectangleShape.h"
	#include "core/style/ComputedStyle.h"
	#include "core/svg/graphics/SVGImage.h"
	#include "platform/LengthFunctions.h"
	#include "platform/geometry/FloatRoundedRect.h"
	#include "platform/geometry/FloatSize.h"
	#include "platform/graphics/GraphicsTypes.h"
	#include "platform/graphics/ImageBuffer.h"
	#include "wtf/MathExtras.h"
	#include "wtf/PtrUtil.h"
	#include "wtf/typed_arrays/ArrayBufferContents.h"
	#include <memory>

	namespace blink {

	static std::unique_ptr<Shape> createInsetShape(const FloatRoundedRect& bounds) {
	ASSERT(bounds.rect().width() >= 0 && bounds.rect().height() >= 0);
	return wrapUnique(new BoxShape(bounds));
	}

	static std::unique_ptr<Shape> createCircleShape(const FloatPoint& center,
	float radius) {
	ASSERT(radius >= 0);
	return wrapUnique(
	new RectangleShape(FloatRect(center.x() - radius, center.y() - radius,
	radius * 2, radius * 2),
	FloatSize(radius, radius)));
	}

	static std::unique_ptr<Shape> createEllipseShape(const FloatPoint& center,
	const FloatSize& radii) {
	ASSERT(radii.width() >= 0 && radii.height() >= 0);
	return wrapUnique(new RectangleShape(
	FloatRect(center.x() - radii.width(), center.y() - radii.height(),
	radii.width() * 2, radii.height() * 2),
	radii));
	}

	static std::unique_ptr<Shape> createPolygonShape(
	std::unique_ptr<Vector<FloatPoint>> vertices,
	WindRule fillRule) {
	return wrapUnique(new PolygonShape(std::move(vertices), fillRule));
	}

	static inline FloatRect physicalRectToLogical(const FloatRect& rect,
	float logicalBoxHeight,
	WritingMode writingMode) {
	if (isHorizontalWritingMode(writingMode))
	return rect;
	if (isFlippedBlocksWritingMode(writingMode))
	return FloatRect(rect.y(), logicalBoxHeight - rect.maxX(), rect.height(),
	rect.width());
	return rect.transposedRect();
	}

	static inline FloatPoint physicalPointToLogical(const FloatPoint& point,
	float logicalBoxHeight,
	WritingMode writingMode) {
	if (isHorizontalWritingMode(writingMode))
	return point;
	if (isFlippedBlocksWritingMode(writingMode))
	return FloatPoint(point.y(), logicalBoxHeight - point.x());
	return point.transposedPoint();
	}

	static inline FloatSize physicalSizeToLogical(const FloatSize& size,
	WritingMode writingMode) {
	if (isHorizontalWritingMode(writingMode))
	return size;
	return size.transposedSize();
	}

	std::unique_ptr<Shape> Shape::createShape(const BasicShape* basicShape,
	const LayoutSize& logicalBoxSize,
	WritingMode writingMode,
	float margin) {
	ASSERT(basicShape);

	bool horizontalWritingMode = isHorizontalWritingMode(writingMode);
	float boxWidth = horizontalWritingMode ? logicalBoxSize.width().toFloat()
	: logicalBoxSize.height().toFloat();
	float boxHeight = horizontalWritingMode ? logicalBoxSize.height().toFloat()
	: logicalBoxSize.width().toFloat();
	std::unique_ptr<Shape> shape;

	switch (basicShape->type()) {
	case BasicShape::BasicShapeCircleType: {
	const BasicShapeCircle* circle = toBasicShapeCircle(basicShape);
	FloatPoint center = floatPointForCenterCoordinate(
	circle->centerX(), circle->centerY(), FloatSize(boxWidth, boxHeight));
	float radius =
	circle->floatValueForRadiusInBox(FloatSize(boxWidth, boxHeight));
	FloatPoint logicalCenter = physicalPointToLogical(
	center, logicalBoxSize.height().toFloat(), writingMode);

	shape = createCircleShape(logicalCenter, radius);
	break;
	}

	case BasicShape::BasicShapeEllipseType: {
	const BasicShapeEllipse* ellipse = toBasicShapeEllipse(basicShape);
	FloatPoint center =
	floatPointForCenterCoordinate(ellipse->centerX(), ellipse->centerY(),
	FloatSize(boxWidth, boxHeight));
	float radiusX = ellipse->floatValueForRadiusInBox(ellipse->radiusX(),
	center.x(), boxWidth);
	float radiusY = ellipse->floatValueForRadiusInBox(ellipse->radiusY(),
	center.y(), boxHeight);
	FloatPoint logicalCenter = physicalPointToLogical(
	center, logicalBoxSize.height().toFloat(), writingMode);

	shape = createEllipseShape(logicalCenter, FloatSize(radiusX, radiusY));
	break;
	}

	case BasicShape::BasicShapePolygonType: {
	const BasicShapePolygon* polygon = toBasicShapePolygon(basicShape);
	const Vector<Length>& values = polygon->values();
	size_t valuesSize = values.size();
	ASSERT(!(valuesSize % 2));
	std::unique_ptr<Vector<FloatPoint>> vertices =
	wrapUnique(new Vector<FloatPoint>(valuesSize / 2));
	for (unsigned i = 0; i < valuesSize; i += 2) {
	FloatPoint vertex(floatValueForLength(values.at(i), boxWidth),
	floatValueForLength(values.at(i + 1), boxHeight));
	(*vertices)[i / 2] = physicalPointToLogical(
	vertex, logicalBoxSize.height().toFloat(), writingMode);
	}
	shape = createPolygonShape(std::move(vertices), polygon->getWindRule());
	break;
	}

	case BasicShape::BasicShapeInsetType: {
	const BasicShapeInset& inset = *toBasicShapeInset(basicShape);
	float left = floatValueForLength(inset.left(), boxWidth);
	float top = floatValueForLength(inset.top(), boxHeight);
	float right = floatValueForLength(inset.right(), boxWidth);
	float bottom = floatValueForLength(inset.bottom(), boxHeight);
	FloatRect rect(left, top, std::max<float>(boxWidth - left - right, 0),
	std::max<float>(boxHeight - top - bottom, 0));
	FloatRect logicalRect = physicalRectToLogical(
	rect, logicalBoxSize.height().toFloat(), writingMode);

	FloatSize boxSize(boxWidth, boxHeight);
	FloatSize topLeftRadius = physicalSizeToLogical(
	floatSizeForLengthSize(inset.topLeftRadius(), boxSize), writingMode);
	FloatSize topRightRadius = physicalSizeToLogical(
	floatSizeForLengthSize(inset.topRightRadius(), boxSize), writingMode);
	FloatSize bottomLeftRadius = physicalSizeToLogical(
	floatSizeForLengthSize(inset.bottomLeftRadius(), boxSize),
	writingMode);
	FloatSize bottomRightRadius = physicalSizeToLogical(
	floatSizeForLengthSize(inset.bottomRightRadius(), boxSize),
	writingMode);
	FloatRoundedRect::Radii cornerRadii(topLeftRadius, topRightRadius,
	bottomLeftRadius, bottomRightRadius);

	FloatRoundedRect finalRect(logicalRect, cornerRadii);
	finalRect.constrainRadii();

	shape = createInsetShape(finalRect);
	break;
	}

	default:
	ASSERT_NOT_REACHED();
	}

	shape->m_writingMode = writingMode;
	shape->m_margin = margin;

	return shape;
	}

	std::unique_ptr<Shape> Shape::createEmptyRasterShape(WritingMode writingMode,
	float margin) {
	std::unique_ptr<RasterShapeIntervals> intervals =
	wrapUnique(new RasterShapeIntervals(0, 0));
	std::unique_ptr<RasterShape> rasterShape =
	wrapUnique(new RasterShape(std::move(intervals), IntSize()));
	rasterShape->m_writingMode = writingMode;
	rasterShape->m_margin = margin;
	return std::move(rasterShape);
	}

	std::unique_ptr<Shape> Shape::createRasterShape(Image* image,
	float threshold,
	const LayoutRect& imageR,
	const LayoutRect& marginR,
	WritingMode writingMode,
	float margin) {
	IntRect imageRect = pixelSnappedIntRect(imageR);
	IntRect marginRect = pixelSnappedIntRect(marginR);

	std::unique_ptr<RasterShapeIntervals> intervals = wrapUnique(
	new RasterShapeIntervals(marginRect.height(), -marginRect.y()));
	std::unique_ptr<ImageBuffer> imageBuffer =
	ImageBuffer::create(imageRect.size());

	if (image && imageBuffer) {
	// FIXME: This is not totally correct but it is needed to prevent shapes
	// that loads SVG Images during paint invalidations to mark layoutObjects
	// for layout, which is not allowed. See https://crbug.com/429346
	ImageObserverDisabler disabler(image);
	SkPaint paint;
	IntRect imageSourceRect(IntPoint(), image->size());
	IntRect imageDestRect(IntPoint(), imageRect.size());
	image->draw(imageBuffer->canvas(), paint, imageDestRect, imageSourceRect,
	DoNotRespectImageOrientation,
	Image::DoNotClampImageToSourceRect);

	WTF::ArrayBufferContents contents;
	imageBuffer->getImageData(Unmultiplied,
	IntRect(IntPoint(), imageRect.size()), contents);
	DOMArrayBuffer* arrayBuffer = DOMArrayBuffer::create(contents);
	DOMUint8ClampedArray* pixelArray =
	DOMUint8ClampedArray::create(arrayBuffer, 0, arrayBuffer->byteLength());
	unsigned pixelArrayOffset = 3; // Each pixel is four bytes: RGBA.
	uint8_t alphaPixelThreshold = threshold * 255;

	ASSERT(static_cast<unsigned>(imageRect.width() * imageRect.height() * 4) ==
	pixelArray->length());

	int minBufferY = std::max(0, marginRect.y() - imageRect.y());
	int maxBufferY =
	std::min(imageRect.height(), marginRect.maxY() - imageRect.y());

	for (int y = minBufferY; y < maxBufferY; ++y) {
	int startX = -1;
	for (int x = 0; x < imageRect.width(); ++x, pixelArrayOffset += 4) {
	uint8_t alpha = pixelArray->item(pixelArrayOffset);
	bool alphaAboveThreshold = alpha > alphaPixelThreshold;
	if (startX == -1 && alphaAboveThreshold) {
	startX = x;
	} else if (startX != -1 &&
	(!alphaAboveThreshold \|\| x == imageRect.width() - 1)) {
	int endX = alphaAboveThreshold ? x + 1 : x;
	intervals->intervalAt(y + imageRect.y())
	.unite(IntShapeInterval(startX + imageRect.x(),
	endX + imageRect.x()));
	startX = -1;
	}
	}
	}
	}

	std::unique_ptr<RasterShape> rasterShape =
	wrapUnique(new RasterShape(std::move(intervals), marginRect.size()));
	rasterShape->m_writingMode = writingMode;
	rasterShape->m_margin = margin;
	return std::move(rasterShape);
	}

	std::unique_ptr<Shape> Shape::createLayoutBoxShape(
	const FloatRoundedRect& roundedRect,
	WritingMode writingMode,
	float margin) {
	FloatRect rect(0, 0, roundedRect.rect().width(), roundedRect.rect().height());
	FloatRoundedRect bounds(rect, roundedRect.getRadii());
	std::unique_ptr<Shape> shape = createInsetShape(bounds);
	shape->m_writingMode = writingMode;
	shape->m_margin = margin;

	return shape;
	}

	} // namespace blink