WebCore/rendering/RenderPath.cpp - WebKit - Git at Google

 /*
     Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
                   2004, 2005, 2008 Rob Buis <buis@kde.org>
                   2005, 2007 Eric Seidel <eric@webkit.org>
                   2009 Google, Inc.

     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.

     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.

     You should have received a copy of the GNU Library General Public License
     aint with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */

 #include "config.h"

 #if ENABLE(SVG)
 #include "RenderPath.h"

 #include "FloatPoint.h"
 #include "FloatQuad.h"
 #include "GraphicsContext.h"
 #include "PointerEventsHitRules.h"
 #include "RenderSVGContainer.h"
 #include "StrokeStyleApplier.h"
 #include "SVGPaintServer.h"
 #include "SVGRenderSupport.h"
 #include "SVGResourceFilter.h"
 #include "SVGResourceMarker.h"
 #include "SVGResourceMasker.h"
 #include "SVGStyledTransformableElement.h"
 #include "SVGTransformList.h"
 #include "SVGURIReference.h"
 #include <wtf/MathExtras.h>

 namespace WebCore {

 class BoundingRectStrokeStyleApplier : public StrokeStyleApplier {
 public:
     BoundingRectStrokeStyleApplier(const RenderObject* object, RenderStyle* style)
         : m_object(object)
         , m_style(style)
     {
         ASSERT(style);
         ASSERT(object);
     }

     void strokeStyle(GraphicsContext* gc)
     {
         applyStrokeStyleToContext(gc, m_style, m_object);
     }

 private:
     const RenderObject* m_object;
     RenderStyle* m_style;
 };

 RenderPath::RenderPath(SVGStyledTransformableElement* node)
     : RenderSVGModelObject(node)
 {
 }

 TransformationMatrix RenderPath::localToParentTransform() const
 {
     return m_localTransform;
 }

 TransformationMatrix RenderPath::localTransform() const
 {
     return m_localTransform;
 }

 bool RenderPath::fillContains(const FloatPoint& point, bool requiresFill) const
 {
     if (m_path.isEmpty())
         return false;

     if (requiresFill && !SVGPaintServer::fillPaintServer(style(), this))
         return false;

     return m_path.contains(point, style()->svgStyle()->fillRule());
 }

 bool RenderPath::strokeContains(const FloatPoint& point, bool requiresStroke) const
 {
     if (m_path.isEmpty())
         return false;

     if (requiresStroke && !SVGPaintServer::strokePaintServer(style(), this))
         return false;

     BoundingRectStrokeStyleApplier strokeStyle(this, style());
     return m_path.strokeContains(&strokeStyle, point);
 }

 FloatRect RenderPath::objectBoundingBox() const
 {
     if (m_path.isEmpty())
         return FloatRect();

     if (m_cachedLocalFillBBox.isEmpty())
         m_cachedLocalFillBBox = m_path.boundingRect();

     return m_cachedLocalFillBBox;
 }

 FloatRect RenderPath::repaintRectInLocalCoordinates() const
 {
     if (m_path.isEmpty())
         return FloatRect();

     // If we already have a cached repaint rect, return that
     if (!m_cachedLocalRepaintRect.isEmpty())
         return m_cachedLocalRepaintRect;

     if (!style()->svgStyle()->hasStroke())
         m_cachedLocalRepaintRect = objectBoundingBox();
     else {
         BoundingRectStrokeStyleApplier strokeStyle(this, style());
         m_cachedLocalRepaintRect = m_path.strokeBoundingRect(&strokeStyle);
     }

     // Markers and filters can paint outside of the stroke path
     m_cachedLocalRepaintRect.unite(m_markerBounds);
     m_cachedLocalRepaintRect.unite(filterBoundingBoxForRenderer(this));

     return m_cachedLocalRepaintRect;
 }

 void RenderPath::setPath(const Path& newPath)
 {
     m_path = newPath;
     m_cachedLocalRepaintRect = FloatRect();
     m_cachedLocalFillBBox = FloatRect();
 }

 const Path& RenderPath::path() const
 {
     return m_path;
 }

 void RenderPath::layout()
 {
     LayoutRepainter repainter(*this, checkForRepaintDuringLayout() && selfNeedsLayout());

     SVGStyledTransformableElement* element = static_cast<SVGStyledTransformableElement*>(node());
     m_localTransform = element->animatedLocalTransform();
     setPath(element->toPathData());

     repainter.repaintAfterLayout();
     setNeedsLayout(false);
 }

 static inline void fillAndStrokePath(const Path& path, GraphicsContext* context, RenderStyle* style, RenderPath* object)
 {
     context->beginPath();

     SVGPaintServer* fillPaintServer = SVGPaintServer::fillPaintServer(style, object);
     if (fillPaintServer) {
         context->addPath(path);
         fillPaintServer->draw(context, object, ApplyToFillTargetType);
     }

     SVGPaintServer* strokePaintServer = SVGPaintServer::strokePaintServer(style, object);
     if (strokePaintServer) {
         context->addPath(path); // path is cleared when filled.
         strokePaintServer->draw(context, object, ApplyToStrokeTargetType);
     }
 }

 void RenderPath::paint(PaintInfo& paintInfo, int, int)
 {
     if (paintInfo.context->paintingDisabled() || style()->visibility() == HIDDEN || m_path.isEmpty())
         return;

     paintInfo.context->save();
     paintInfo.context->concatCTM(localToParentTransform());

     SVGResourceFilter* filter = 0;

     FloatRect boundingBox = repaintRectInLocalCoordinates();
     if (paintInfo.phase == PaintPhaseForeground) {
         PaintInfo savedInfo(paintInfo);

         prepareToRenderSVGContent(this, paintInfo, boundingBox, filter);
         if (style()->svgStyle()->shapeRendering() == SR_CRISPEDGES)
             paintInfo.context->setShouldAntialias(false);
         fillAndStrokePath(m_path, paintInfo.context, style(), this);

         if (static_cast<SVGStyledElement*>(node())->supportsMarkers())
             m_markerBounds = drawMarkersIfNeeded(paintInfo.context, paintInfo.rect, m_path);

         finishRenderSVGContent(this, paintInfo, filter, savedInfo.context);
     }

     if ((paintInfo.phase == PaintPhaseOutline || paintInfo.phase == PaintPhaseSelfOutline) && style()->outlineWidth())
         paintOutline(paintInfo.context, static_cast<int>(boundingBox.x()), static_cast<int>(boundingBox.y()),
             static_cast<int>(boundingBox.width()), static_cast<int>(boundingBox.height()), style());

     paintInfo.context->restore();
 }

 // This method is called from inside paintOutline() since we call paintOutline()
 // while transformed to our coord system, return local coords
 void RenderPath::addFocusRingRects(GraphicsContext* graphicsContext, int, int)
 {
     graphicsContext->addFocusRingRect(enclosingIntRect(repaintRectInLocalCoordinates()));
 }

 bool RenderPath::nodeAtFloatPoint(const HitTestRequest&, HitTestResult& result, const FloatPoint& pointInParent, HitTestAction hitTestAction)
 {
     // We only draw in the forground phase, so we only hit-test then.
     if (hitTestAction != HitTestForeground)
         return false;

     FloatPoint localPoint = localToParentTransform().inverse().mapPoint(pointInParent);

     PointerEventsHitRules hitRules(PointerEventsHitRules::SVG_PATH_HITTESTING, style()->pointerEvents());

     bool isVisible = (style()->visibility() == VISIBLE);
     if (isVisible || !hitRules.requireVisible) {
         if ((hitRules.canHitStroke && (style()->svgStyle()->hasStroke() || !hitRules.requireStroke) && strokeContains(localPoint, hitRules.requireStroke))
             || (hitRules.canHitFill && (style()->svgStyle()->hasFill() || !hitRules.requireFill) && fillContains(localPoint, hitRules.requireFill))) {
             updateHitTestResult(result, roundedIntPoint(localPoint));
             return true;
         }
     }

     return false;
 }

 enum MarkerType {
     Start,
     Mid,
     End
 };

 struct MarkerData {
     FloatPoint origin;
     FloatPoint subpathStart;
     double strokeWidth;
     FloatPoint inslopePoints[2];
     FloatPoint outslopePoints[2];
     MarkerType type;
     SVGResourceMarker* marker;
 };

 struct DrawMarkersData {
     DrawMarkersData(GraphicsContext*, SVGResourceMarker* startMarker, SVGResourceMarker* midMarker, double strokeWidth);
     GraphicsContext* context;
     int elementIndex;
     MarkerData previousMarkerData;
     SVGResourceMarker* midMarker;
 };

 DrawMarkersData::DrawMarkersData(GraphicsContext* c, SVGResourceMarker *start, SVGResourceMarker *mid, double strokeWidth)
     : context(c)
     , elementIndex(0)
     , midMarker(mid)
 {
     previousMarkerData.origin = FloatPoint();
     previousMarkerData.subpathStart = FloatPoint();
     previousMarkerData.strokeWidth = strokeWidth;
     previousMarkerData.marker = start;
     previousMarkerData.type = Start;
 }

 static void drawMarkerWithData(GraphicsContext* context, MarkerData &data)
 {
     if (!data.marker)
         return;

     FloatPoint inslopeChange = data.inslopePoints[1] - FloatSize(data.inslopePoints[0].x(), data.inslopePoints[0].y());
     FloatPoint outslopeChange = data.outslopePoints[1] - FloatSize(data.outslopePoints[0].x(), data.outslopePoints[0].y());

     double inslope = rad2deg(atan2(inslopeChange.y(), inslopeChange.x()));
     double outslope = rad2deg(atan2(outslopeChange.y(), outslopeChange.x()));

     double angle = 0.0;
     switch (data.type) {
         case Start:
             angle = outslope;
             break;
         case Mid:
             angle = (inslope + outslope) / 2;
             break;
         case End:
             angle = inslope;
     }

     data.marker->draw(context, FloatRect(), data.origin.x(), data.origin.y(), data.strokeWidth, angle);
 }

 static inline void updateMarkerDataForElement(MarkerData& previousMarkerData, const PathElement* element)
 {
     FloatPoint* points = element->points;

     switch (element->type) {
     case PathElementAddQuadCurveToPoint:
         // TODO
         previousMarkerData.origin = points[1];
         break;
     case PathElementAddCurveToPoint:
         previousMarkerData.inslopePoints[0] = points[1];
         previousMarkerData.inslopePoints[1] = points[2];
         previousMarkerData.origin = points[2];
         break;
     case PathElementMoveToPoint:
         previousMarkerData.subpathStart = points[0];
     case PathElementAddLineToPoint:
         previousMarkerData.inslopePoints[0] = previousMarkerData.origin;
         previousMarkerData.inslopePoints[1] = points[0];
         previousMarkerData.origin = points[0];
         break;
     case PathElementCloseSubpath:
         previousMarkerData.inslopePoints[0] = previousMarkerData.origin;
         previousMarkerData.inslopePoints[1] = points[0];
         previousMarkerData.origin = previousMarkerData.subpathStart;
         previousMarkerData.subpathStart = FloatPoint();
     }
 }

 static void drawStartAndMidMarkers(void* info, const PathElement* element)
 {
     DrawMarkersData& data = *reinterpret_cast<DrawMarkersData*>(info);

     int elementIndex = data.elementIndex;
     MarkerData& previousMarkerData = data.previousMarkerData;

     FloatPoint* points = element->points;

     // First update the outslope for the previous element
     previousMarkerData.outslopePoints[0] = previousMarkerData.origin;
     previousMarkerData.outslopePoints[1] = points[0];

     // Draw the marker for the previous element
     if (elementIndex != 0)
         drawMarkerWithData(data.context, previousMarkerData);

     // Update our marker data for this element
     updateMarkerDataForElement(previousMarkerData, element);

     if (elementIndex == 1) {
         // After drawing the start marker, switch to drawing mid markers
         previousMarkerData.marker = data.midMarker;
         previousMarkerData.type = Mid;
     }

     data.elementIndex++;
 }

 FloatRect RenderPath::drawMarkersIfNeeded(GraphicsContext* context, const FloatRect&, const Path& path) const
 {
     Document* doc = document();

     SVGElement* svgElement = static_cast<SVGElement*>(node());
     ASSERT(svgElement && svgElement->document() && svgElement->isStyled());

     SVGStyledElement* styledElement = static_cast<SVGStyledElement*>(svgElement);
     const SVGRenderStyle* svgStyle = style()->svgStyle();

     AtomicString startMarkerId(svgStyle->startMarker());
     AtomicString midMarkerId(svgStyle->midMarker());
     AtomicString endMarkerId(svgStyle->endMarker());

     SVGResourceMarker* startMarker = getMarkerById(doc, startMarkerId);
     SVGResourceMarker* midMarker = getMarkerById(doc, midMarkerId);
     SVGResourceMarker* endMarker = getMarkerById(doc, endMarkerId);

     if (!startMarker && !startMarkerId.isEmpty())
         svgElement->document()->accessSVGExtensions()->addPendingResource(startMarkerId, styledElement);
     else if (startMarker)
         startMarker->addClient(styledElement);

     if (!midMarker && !midMarkerId.isEmpty())
         svgElement->document()->accessSVGExtensions()->addPendingResource(midMarkerId, styledElement);
     else if (midMarker)
         midMarker->addClient(styledElement);

     if (!endMarker && !endMarkerId.isEmpty())
         svgElement->document()->accessSVGExtensions()->addPendingResource(endMarkerId, styledElement);
     else if (endMarker)
         endMarker->addClient(styledElement);

     if (!startMarker && !midMarker && !endMarker)
         return FloatRect();

     double strokeWidth = SVGRenderStyle::cssPrimitiveToLength(this, svgStyle->strokeWidth(), 1.0f);
     DrawMarkersData data(context, startMarker, midMarker, strokeWidth);

     path.apply(&data, drawStartAndMidMarkers);

     data.previousMarkerData.marker = endMarker;
     data.previousMarkerData.type = End;
     drawMarkerWithData(context, data.previousMarkerData);

     // We know the marker boundaries, only after they're drawn!
     // Otherwhise we'd need to do all the marker calculation twice
     // once here (through paint()) and once in absoluteClippedOverflowRect().
     FloatRect bounds;

     if (startMarker)
         bounds.unite(startMarker->cachedBounds());

     if (midMarker)
         bounds.unite(midMarker->cachedBounds());

     if (endMarker)
         bounds.unite(endMarker->cachedBounds());

     return bounds;
 }

 }

 #endif // ENABLE(SVG)
	/*
	Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
	2004, 2005, 2008 Rob Buis <buis@kde.org>
	2005, 2007 Eric Seidel <eric@webkit.org>
	2009 Google, Inc.

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Library General Public
	License as published by the Free Software Foundation; either
	version 2 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	Library General Public License for more details.

	You should have received a copy of the GNU Library General Public License
	aint with this library; see the file COPYING.LIB. If not, write to
	the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	Boston, MA 02110-1301, USA.
	*/

	#include "config.h"

	#if ENABLE(SVG)
	#include "RenderPath.h"

	#include "FloatPoint.h"
	#include "FloatQuad.h"
	#include "GraphicsContext.h"
	#include "PointerEventsHitRules.h"
	#include "RenderSVGContainer.h"
	#include "StrokeStyleApplier.h"
	#include "SVGPaintServer.h"
	#include "SVGRenderSupport.h"
	#include "SVGResourceFilter.h"
	#include "SVGResourceMarker.h"
	#include "SVGResourceMasker.h"
	#include "SVGStyledTransformableElement.h"
	#include "SVGTransformList.h"
	#include "SVGURIReference.h"
	#include <wtf/MathExtras.h>

	namespace WebCore {

	class BoundingRectStrokeStyleApplier : public StrokeStyleApplier {
	public:
	BoundingRectStrokeStyleApplier(const RenderObject* object, RenderStyle* style)
	: m_object(object)
	, m_style(style)
	{
	ASSERT(style);
	ASSERT(object);
	}

	void strokeStyle(GraphicsContext* gc)
	{
	applyStrokeStyleToContext(gc, m_style, m_object);
	}

	private:
	const RenderObject* m_object;
	RenderStyle* m_style;
	};

	RenderPath::RenderPath(SVGStyledTransformableElement* node)
	: RenderSVGModelObject(node)
	{
	}

	TransformationMatrix RenderPath::localToParentTransform() const
	{
	return m_localTransform;
	}

	TransformationMatrix RenderPath::localTransform() const
	{
	return m_localTransform;
	}

	bool RenderPath::fillContains(const FloatPoint& point, bool requiresFill) const
	{
	if (m_path.isEmpty())
	return false;

	if (requiresFill && !SVGPaintServer::fillPaintServer(style(), this))
	return false;

	return m_path.contains(point, style()->svgStyle()->fillRule());
	}

	bool RenderPath::strokeContains(const FloatPoint& point, bool requiresStroke) const
	{
	if (m_path.isEmpty())
	return false;

	if (requiresStroke && !SVGPaintServer::strokePaintServer(style(), this))
	return false;

	BoundingRectStrokeStyleApplier strokeStyle(this, style());
	return m_path.strokeContains(&strokeStyle, point);
	}

	FloatRect RenderPath::objectBoundingBox() const
	{
	if (m_path.isEmpty())
	return FloatRect();

	if (m_cachedLocalFillBBox.isEmpty())
	m_cachedLocalFillBBox = m_path.boundingRect();

	return m_cachedLocalFillBBox;
	}

	FloatRect RenderPath::repaintRectInLocalCoordinates() const
	{
	if (m_path.isEmpty())
	return FloatRect();

	// If we already have a cached repaint rect, return that
	if (!m_cachedLocalRepaintRect.isEmpty())
	return m_cachedLocalRepaintRect;

	if (!style()->svgStyle()->hasStroke())
	m_cachedLocalRepaintRect = objectBoundingBox();
	else {
	BoundingRectStrokeStyleApplier strokeStyle(this, style());
	m_cachedLocalRepaintRect = m_path.strokeBoundingRect(&strokeStyle);
	}

	// Markers and filters can paint outside of the stroke path
	m_cachedLocalRepaintRect.unite(m_markerBounds);
	m_cachedLocalRepaintRect.unite(filterBoundingBoxForRenderer(this));

	return m_cachedLocalRepaintRect;
	}

	void RenderPath::setPath(const Path& newPath)
	{
	m_path = newPath;
	m_cachedLocalRepaintRect = FloatRect();
	m_cachedLocalFillBBox = FloatRect();
	}

	const Path& RenderPath::path() const
	{
	return m_path;
	}

	void RenderPath::layout()
	{
	LayoutRepainter repainter(*this, checkForRepaintDuringLayout() && selfNeedsLayout());

	SVGStyledTransformableElement* element = static_cast<SVGStyledTransformableElement*>(node());
	m_localTransform = element->animatedLocalTransform();
	setPath(element->toPathData());

	repainter.repaintAfterLayout();
	setNeedsLayout(false);
	}

	static inline void fillAndStrokePath(const Path& path, GraphicsContext* context, RenderStyle* style, RenderPath* object)
	{
	context->beginPath();

	SVGPaintServer* fillPaintServer = SVGPaintServer::fillPaintServer(style, object);
	if (fillPaintServer) {
	context->addPath(path);
	fillPaintServer->draw(context, object, ApplyToFillTargetType);
	}

	SVGPaintServer* strokePaintServer = SVGPaintServer::strokePaintServer(style, object);
	if (strokePaintServer) {
	context->addPath(path); // path is cleared when filled.
	strokePaintServer->draw(context, object, ApplyToStrokeTargetType);
	}
	}

	void RenderPath::paint(PaintInfo& paintInfo, int, int)
	{
	if (paintInfo.context->paintingDisabled() \|\| style()->visibility() == HIDDEN \|\| m_path.isEmpty())
	return;

	paintInfo.context->save();
	paintInfo.context->concatCTM(localToParentTransform());

	SVGResourceFilter* filter = 0;

	FloatRect boundingBox = repaintRectInLocalCoordinates();
	if (paintInfo.phase == PaintPhaseForeground) {
	PaintInfo savedInfo(paintInfo);

	prepareToRenderSVGContent(this, paintInfo, boundingBox, filter);
	if (style()->svgStyle()->shapeRendering() == SR_CRISPEDGES)
	paintInfo.context->setShouldAntialias(false);
	fillAndStrokePath(m_path, paintInfo.context, style(), this);

	if (static_cast<SVGStyledElement*>(node())->supportsMarkers())
	m_markerBounds = drawMarkersIfNeeded(paintInfo.context, paintInfo.rect, m_path);

	finishRenderSVGContent(this, paintInfo, filter, savedInfo.context);
	}

	if ((paintInfo.phase == PaintPhaseOutline \|\| paintInfo.phase == PaintPhaseSelfOutline) && style()->outlineWidth())
	paintOutline(paintInfo.context, static_cast<int>(boundingBox.x()), static_cast<int>(boundingBox.y()),
	static_cast<int>(boundingBox.width()), static_cast<int>(boundingBox.height()), style());

	paintInfo.context->restore();
	}

	// This method is called from inside paintOutline() since we call paintOutline()
	// while transformed to our coord system, return local coords
	void RenderPath::addFocusRingRects(GraphicsContext* graphicsContext, int, int)
	{
	graphicsContext->addFocusRingRect(enclosingIntRect(repaintRectInLocalCoordinates()));
	}

	bool RenderPath::nodeAtFloatPoint(const HitTestRequest&, HitTestResult& result, const FloatPoint& pointInParent, HitTestAction hitTestAction)
	{
	// We only draw in the forground phase, so we only hit-test then.
	if (hitTestAction != HitTestForeground)
	return false;

	FloatPoint localPoint = localToParentTransform().inverse().mapPoint(pointInParent);

	PointerEventsHitRules hitRules(PointerEventsHitRules::SVG_PATH_HITTESTING, style()->pointerEvents());

	bool isVisible = (style()->visibility() == VISIBLE);
	if (isVisible \|\| !hitRules.requireVisible) {
	if ((hitRules.canHitStroke && (style()->svgStyle()->hasStroke() \|\| !hitRules.requireStroke) && strokeContains(localPoint, hitRules.requireStroke))
	\|\| (hitRules.canHitFill && (style()->svgStyle()->hasFill() \|\| !hitRules.requireFill) && fillContains(localPoint, hitRules.requireFill))) {
	updateHitTestResult(result, roundedIntPoint(localPoint));
	return true;
	}
	}

	return false;
	}

	enum MarkerType {
	Start,
	Mid,
	End
	};

	struct MarkerData {
	FloatPoint origin;
	FloatPoint subpathStart;
	double strokeWidth;
	FloatPoint inslopePoints[2];
	FloatPoint outslopePoints[2];
	MarkerType type;
	SVGResourceMarker* marker;
	};

	struct DrawMarkersData {
	DrawMarkersData(GraphicsContext, SVGResourceMarker startMarker, SVGResourceMarker* midMarker, double strokeWidth);
	GraphicsContext* context;
	int elementIndex;
	MarkerData previousMarkerData;
	SVGResourceMarker* midMarker;
	};

	DrawMarkersData::DrawMarkersData(GraphicsContext* c, SVGResourceMarker start, SVGResourceMarker mid, double strokeWidth)
	: context(c)
	, elementIndex(0)
	, midMarker(mid)
	{
	previousMarkerData.origin = FloatPoint();
	previousMarkerData.subpathStart = FloatPoint();
	previousMarkerData.strokeWidth = strokeWidth;
	previousMarkerData.marker = start;
	previousMarkerData.type = Start;
	}

	static void drawMarkerWithData(GraphicsContext* context, MarkerData &data)
	{
	if (!data.marker)
	return;

	FloatPoint inslopeChange = data.inslopePoints[1] - FloatSize(data.inslopePoints[0].x(), data.inslopePoints[0].y());
	FloatPoint outslopeChange = data.outslopePoints[1] - FloatSize(data.outslopePoints[0].x(), data.outslopePoints[0].y());

	double inslope = rad2deg(atan2(inslopeChange.y(), inslopeChange.x()));
	double outslope = rad2deg(atan2(outslopeChange.y(), outslopeChange.x()));

	double angle = 0.0;
	switch (data.type) {
	case Start:
	angle = outslope;
	break;
	case Mid:
	angle = (inslope + outslope) / 2;
	break;
	case End:
	angle = inslope;
	}

	data.marker->draw(context, FloatRect(), data.origin.x(), data.origin.y(), data.strokeWidth, angle);
	}

	static inline void updateMarkerDataForElement(MarkerData& previousMarkerData, const PathElement* element)
	{
	FloatPoint* points = element->points;

	switch (element->type) {
	case PathElementAddQuadCurveToPoint:
	// TODO
	previousMarkerData.origin = points[1];
	break;
	case PathElementAddCurveToPoint:
	previousMarkerData.inslopePoints[0] = points[1];
	previousMarkerData.inslopePoints[1] = points[2];
	previousMarkerData.origin = points[2];
	break;
	case PathElementMoveToPoint:
	previousMarkerData.subpathStart = points[0];
	case PathElementAddLineToPoint:
	previousMarkerData.inslopePoints[0] = previousMarkerData.origin;
	previousMarkerData.inslopePoints[1] = points[0];
	previousMarkerData.origin = points[0];
	break;
	case PathElementCloseSubpath:
	previousMarkerData.inslopePoints[0] = previousMarkerData.origin;
	previousMarkerData.inslopePoints[1] = points[0];
	previousMarkerData.origin = previousMarkerData.subpathStart;
	previousMarkerData.subpathStart = FloatPoint();
	}
	}

	static void drawStartAndMidMarkers(void* info, const PathElement* element)
	{
	DrawMarkersData& data = reinterpret_cast<DrawMarkersData>(info);

	int elementIndex = data.elementIndex;
	MarkerData& previousMarkerData = data.previousMarkerData;

	FloatPoint* points = element->points;

	// First update the outslope for the previous element
	previousMarkerData.outslopePoints[0] = previousMarkerData.origin;
	previousMarkerData.outslopePoints[1] = points[0];

	// Draw the marker for the previous element
	if (elementIndex != 0)
	drawMarkerWithData(data.context, previousMarkerData);

	// Update our marker data for this element
	updateMarkerDataForElement(previousMarkerData, element);

	if (elementIndex == 1) {
	// After drawing the start marker, switch to drawing mid markers
	previousMarkerData.marker = data.midMarker;
	previousMarkerData.type = Mid;
	}

	data.elementIndex++;
	}

	FloatRect RenderPath::drawMarkersIfNeeded(GraphicsContext* context, const FloatRect&, const Path& path) const
	{
	Document* doc = document();

	SVGElement* svgElement = static_cast<SVGElement*>(node());
	ASSERT(svgElement && svgElement->document() && svgElement->isStyled());

	SVGStyledElement* styledElement = static_cast<SVGStyledElement*>(svgElement);
	const SVGRenderStyle* svgStyle = style()->svgStyle();

	AtomicString startMarkerId(svgStyle->startMarker());
	AtomicString midMarkerId(svgStyle->midMarker());
	AtomicString endMarkerId(svgStyle->endMarker());

	SVGResourceMarker* startMarker = getMarkerById(doc, startMarkerId);
	SVGResourceMarker* midMarker = getMarkerById(doc, midMarkerId);
	SVGResourceMarker* endMarker = getMarkerById(doc, endMarkerId);

	if (!startMarker && !startMarkerId.isEmpty())
	svgElement->document()->accessSVGExtensions()->addPendingResource(startMarkerId, styledElement);
	else if (startMarker)
	startMarker->addClient(styledElement);

	if (!midMarker && !midMarkerId.isEmpty())
	svgElement->document()->accessSVGExtensions()->addPendingResource(midMarkerId, styledElement);
	else if (midMarker)
	midMarker->addClient(styledElement);

	if (!endMarker && !endMarkerId.isEmpty())
	svgElement->document()->accessSVGExtensions()->addPendingResource(endMarkerId, styledElement);
	else if (endMarker)
	endMarker->addClient(styledElement);

	if (!startMarker && !midMarker && !endMarker)
	return FloatRect();

	double strokeWidth = SVGRenderStyle::cssPrimitiveToLength(this, svgStyle->strokeWidth(), 1.0f);
	DrawMarkersData data(context, startMarker, midMarker, strokeWidth);

	path.apply(&data, drawStartAndMidMarkers);

	data.previousMarkerData.marker = endMarker;
	data.previousMarkerData.type = End;
	drawMarkerWithData(context, data.previousMarkerData);

	// We know the marker boundaries, only after they're drawn!
	// Otherwhise we'd need to do all the marker calculation twice
	// once here (through paint()) and once in absoluteClippedOverflowRect().
	FloatRect bounds;

	if (startMarker)
	bounds.unite(startMarker->cachedBounds());

	if (midMarker)
	bounds.unite(midMarker->cachedBounds());

	if (endMarker)
	bounds.unite(endMarker->cachedBounds());

	return bounds;
	}

	}

	#endif // ENABLE(SVG)