Source/WebCore/svg/SVGLengthContext.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  * Copyright (C) 2014 Adobe Systems Incorporated. All rights reserved.
  *
  * 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
  * along 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"
 #include "SVGLengthContext.h"

 #include "CSSHelper.h"
 #include "FontMetrics.h"
 #include "Frame.h"
 #include "LengthFunctions.h"
 #include "RenderSVGRoot.h"
 #include "RenderSVGViewportContainer.h"
 #include "RenderView.h"
 #include "SVGSVGElement.h"

 namespace WebCore {

 SVGLengthContext::SVGLengthContext(const SVGElement* context)
     : m_context(context)
 {
 }

 SVGLengthContext::SVGLengthContext(const SVGElement* context, const FloatRect& viewport)
     : m_context(context)
     , m_overridenViewport(viewport)
 {
 }

 FloatRect SVGLengthContext::resolveRectangle(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const FloatRect& viewport, const SVGLengthValue& x, const SVGLengthValue& y, const SVGLengthValue& width, const SVGLengthValue& height)
 {
     ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
     if (type == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
         SVGLengthContext lengthContext(context);
         return FloatRect(x.value(lengthContext), y.value(lengthContext), width.value(lengthContext), height.value(lengthContext));
     }

     SVGLengthContext lengthContext(context, viewport);
     return FloatRect(x.value(lengthContext) + viewport.x(),
                      y.value(lengthContext) + viewport.y(),
                      width.value(lengthContext),
                      height.value(lengthContext));
 }

 FloatPoint SVGLengthContext::resolvePoint(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const SVGLengthValue& x, const SVGLengthValue& y)
 {
     ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
     if (type == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
         SVGLengthContext lengthContext(context);
         return FloatPoint(x.value(lengthContext), y.value(lengthContext));
     }

     // FIXME: valueAsPercentage() won't be correct for eg. cm units. They need to be resolved in user space and then be considered in objectBoundingBox space.
     return FloatPoint(x.valueAsPercentage(), y.valueAsPercentage());
 }

 float SVGLengthContext::resolveLength(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const SVGLengthValue& x)
 {
     ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
     if (type == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
         SVGLengthContext lengthContext(context);
         return x.value(lengthContext);
     }

     // FIXME: valueAsPercentage() won't be correct for eg. cm units. They need to be resolved in user space and then be considered in objectBoundingBox space.
     return x.valueAsPercentage();
 }

 float SVGLengthContext::valueForLength(const Length& length, SVGLengthMode mode)
 {
     if (length.isPercent()) {
         auto result = convertValueFromPercentageToUserUnits(length.value() / 100, mode);
         if (result.hasException())
             return 0;
         return result.releaseReturnValue();
     }
     if (length.isAuto() || !length.isSpecified())
         return 0;

     FloatSize viewportSize;
     determineViewport(viewportSize);

     switch (mode) {
     case LengthModeWidth:
         return floatValueForLength(length, viewportSize.width());
     case LengthModeHeight:
         return floatValueForLength(length, viewportSize.height());
     case LengthModeOther:
         return floatValueForLength(length, std::sqrt(viewportSize.diagonalLengthSquared() / 2));
     };
     return 0;
 }

 ExceptionOr<float> SVGLengthContext::convertValueToUserUnits(float value, SVGLengthMode mode, SVGLengthType fromUnit) const
 {
     // If the SVGLengthContext carries a custom viewport, force resolving against it.
     if (!m_overridenViewport.isEmpty()) {
         // 100% = 100.0 instead of 1.0 for historical reasons, this could eventually be changed
         if (fromUnit == LengthTypePercentage)
             value /= 100;
         return convertValueFromPercentageToUserUnits(value, mode);
     }

     switch (fromUnit) {
     case LengthTypeUnknown:
         return Exception { NotSupportedError };
     case LengthTypeNumber:
         return value;
     case LengthTypePX:
         return value;
     case LengthTypePercentage:
         return convertValueFromPercentageToUserUnits(value / 100, mode);
     case LengthTypeEMS:
         return convertValueFromEMSToUserUnits(value);
     case LengthTypeEXS:
         return convertValueFromEXSToUserUnits(value);
     case LengthTypeCM:
         return value * cssPixelsPerInch / 2.54f;
     case LengthTypeMM:
         return value * cssPixelsPerInch / 25.4f;
     case LengthTypeIN:
         return value * cssPixelsPerInch;
     case LengthTypePT:
         return value * cssPixelsPerInch / 72;
     case LengthTypePC:
         return value * cssPixelsPerInch / 6;
     }

     ASSERT_NOT_REACHED();
     return 0;
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromUserUnits(float value, SVGLengthMode mode, SVGLengthType toUnit) const
 {
     switch (toUnit) {
     case LengthTypeUnknown:
         return Exception { NotSupportedError };
     case LengthTypeNumber:
         return value;
     case LengthTypePercentage:
         return convertValueFromUserUnitsToPercentage(value * 100, mode);
     case LengthTypeEMS:
         return convertValueFromUserUnitsToEMS(value);
     case LengthTypeEXS:
         return convertValueFromUserUnitsToEXS(value);
     case LengthTypePX:
         return value;
     case LengthTypeCM:
         return value * 2.54f / cssPixelsPerInch;
     case LengthTypeMM:
         return value * 25.4f / cssPixelsPerInch;
     case LengthTypeIN:
         return value / cssPixelsPerInch;
     case LengthTypePT:
         return value * 72 / cssPixelsPerInch;
     case LengthTypePC:
         return value * 6 / cssPixelsPerInch;
     }

     ASSERT_NOT_REACHED();
     return 0;
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromUserUnitsToPercentage(float value, SVGLengthMode mode) const
 {
     FloatSize viewportSize;
     if (!determineViewport(viewportSize))
         return Exception { NotSupportedError };

     switch (mode) {
     case LengthModeWidth:
         return value / viewportSize.width() * 100;
     case LengthModeHeight:
         return value / viewportSize.height() * 100;
     case LengthModeOther:
         return value / (std::sqrt(viewportSize.diagonalLengthSquared() / 2)) * 100;
     };

     ASSERT_NOT_REACHED();
     return 0;
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromPercentageToUserUnits(float value, SVGLengthMode mode) const
 {
     FloatSize viewportSize;
     if (!determineViewport(viewportSize))
         return Exception { NotSupportedError };

     switch (mode) {
     case LengthModeWidth:
         return value * viewportSize.width();
     case LengthModeHeight:
         return value * viewportSize.height();
     case LengthModeOther:
         return value * std::sqrt(viewportSize.diagonalLengthSquared() / 2);
     };

     ASSERT_NOT_REACHED();
     return 0;
 }

 static inline const RenderStyle* renderStyleForLengthResolving(const SVGElement* context)
 {
     if (!context)
         return nullptr;

     const ContainerNode* currentContext = context;
     do {
         if (currentContext->renderer())
             return &currentContext->renderer()->style();
         currentContext = currentContext->parentNode();
     } while (currentContext);

     // There must be at least a RenderSVGRoot renderer, carrying a style.
     ASSERT_NOT_REACHED();
     return nullptr;
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromUserUnitsToEMS(float value) const
 {
     auto* style = renderStyleForLengthResolving(m_context);
     if (!style)
         return Exception { NotSupportedError };

     float fontSize = style->computedFontPixelSize();
     if (!fontSize)
         return Exception { NotSupportedError };

     return value / fontSize;
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromEMSToUserUnits(float value) const
 {
     auto* style = renderStyleForLengthResolving(m_context);
     if (!style)
         return Exception { NotSupportedError };

     return value * style->computedFontPixelSize();
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromUserUnitsToEXS(float value) const
 {
     auto* style = renderStyleForLengthResolving(m_context);
     if (!style)
         return Exception { NotSupportedError };

     // Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
     // if this causes problems in real world cases maybe it would be best to remove this
     float xHeight = std::ceil(style->fontMetrics().xHeight());
     if (!xHeight)
         return Exception { NotSupportedError };

     return value / xHeight;
 }

 ExceptionOr<float> SVGLengthContext::convertValueFromEXSToUserUnits(float value) const
 {
     auto* style = renderStyleForLengthResolving(m_context);
     if (!style)
         return Exception { NotSupportedError };

     // Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
     // if this causes problems in real world cases maybe it would be best to remove this
     return value * std::ceil(style->fontMetrics().xHeight());
 }

 bool SVGLengthContext::determineViewport(FloatSize& viewportSize) const
 {
     if (!m_context)
         return false;

     // If an overriden viewport is given, it has precedence.
     if (!m_overridenViewport.isEmpty()) {
         viewportSize = m_overridenViewport.size();
         return true;
     }

     // Root <svg> element lengths are resolved against the top level viewport.
     if (m_context->isOutermostSVGSVGElement()) {
         viewportSize = downcast<SVGSVGElement>(*m_context).currentViewportSize();
         return true;
     }

     // Take size from nearest viewport element.
     auto viewportElement = makeRefPtr(m_context->viewportElement());
     if (!is<SVGSVGElement>(viewportElement))
         return false;

     const SVGSVGElement& svg = downcast<SVGSVGElement>(*viewportElement);
     viewportSize = svg.currentViewBoxRect().size();
     if (viewportSize.isEmpty())
         viewportSize = svg.currentViewportSize();

     return true;
 }

 }
	/*
	* Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
	* Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
	* Copyright (C) 2007 Apple Inc. All rights reserved.
	* Copyright (C) Research In Motion Limited 2011. All rights reserved.
	* Copyright (C) 2014 Adobe Systems Incorporated. All rights reserved.
	*
	* 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
	* along 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"
	#include "SVGLengthContext.h"

	#include "CSSHelper.h"
	#include "FontMetrics.h"
	#include "Frame.h"
	#include "LengthFunctions.h"
	#include "RenderSVGRoot.h"
	#include "RenderSVGViewportContainer.h"
	#include "RenderView.h"
	#include "SVGSVGElement.h"

	namespace WebCore {

	SVGLengthContext::SVGLengthContext(const SVGElement* context)
	: m_context(context)
	{
	}

	SVGLengthContext::SVGLengthContext(const SVGElement* context, const FloatRect& viewport)
	: m_context(context)
	, m_overridenViewport(viewport)
	{
	}

	FloatRect SVGLengthContext::resolveRectangle(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const FloatRect& viewport, const SVGLengthValue& x, const SVGLengthValue& y, const SVGLengthValue& width, const SVGLengthValue& height)
	{
	ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
	if (type == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
	SVGLengthContext lengthContext(context);
	return FloatRect(x.value(lengthContext), y.value(lengthContext), width.value(lengthContext), height.value(lengthContext));
	}

	SVGLengthContext lengthContext(context, viewport);
	return FloatRect(x.value(lengthContext) + viewport.x(),
	y.value(lengthContext) + viewport.y(),
	width.value(lengthContext),
	height.value(lengthContext));
	}

	FloatPoint SVGLengthContext::resolvePoint(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const SVGLengthValue& x, const SVGLengthValue& y)
	{
	ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
	if (type == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
	SVGLengthContext lengthContext(context);
	return FloatPoint(x.value(lengthContext), y.value(lengthContext));
	}

	// FIXME: valueAsPercentage() won't be correct for eg. cm units. They need to be resolved in user space and then be considered in objectBoundingBox space.
	return FloatPoint(x.valueAsPercentage(), y.valueAsPercentage());
	}

	float SVGLengthContext::resolveLength(const SVGElement* context, SVGUnitTypes::SVGUnitType type, const SVGLengthValue& x)
	{
	ASSERT(type != SVGUnitTypes::SVG_UNIT_TYPE_UNKNOWN);
	if (type == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
	SVGLengthContext lengthContext(context);
	return x.value(lengthContext);
	}

	// FIXME: valueAsPercentage() won't be correct for eg. cm units. They need to be resolved in user space and then be considered in objectBoundingBox space.
	return x.valueAsPercentage();
	}

	float SVGLengthContext::valueForLength(const Length& length, SVGLengthMode mode)
	{
	if (length.isPercent()) {
	auto result = convertValueFromPercentageToUserUnits(length.value() / 100, mode);
	if (result.hasException())
	return 0;
	return result.releaseReturnValue();
	}
	if (length.isAuto() \|\| !length.isSpecified())
	return 0;

	FloatSize viewportSize;
	determineViewport(viewportSize);

	switch (mode) {
	case LengthModeWidth:
	return floatValueForLength(length, viewportSize.width());
	case LengthModeHeight:
	return floatValueForLength(length, viewportSize.height());
	case LengthModeOther:
	return floatValueForLength(length, std::sqrt(viewportSize.diagonalLengthSquared() / 2));
	};
	return 0;
	}

	ExceptionOr<float> SVGLengthContext::convertValueToUserUnits(float value, SVGLengthMode mode, SVGLengthType fromUnit) const
	{
	// If the SVGLengthContext carries a custom viewport, force resolving against it.
	if (!m_overridenViewport.isEmpty()) {
	// 100% = 100.0 instead of 1.0 for historical reasons, this could eventually be changed
	if (fromUnit == LengthTypePercentage)
	value /= 100;
	return convertValueFromPercentageToUserUnits(value, mode);
	}

	switch (fromUnit) {
	case LengthTypeUnknown:
	return Exception { NotSupportedError };
	case LengthTypeNumber:
	return value;
	case LengthTypePX:
	return value;
	case LengthTypePercentage:
	return convertValueFromPercentageToUserUnits(value / 100, mode);
	case LengthTypeEMS:
	return convertValueFromEMSToUserUnits(value);
	case LengthTypeEXS:
	return convertValueFromEXSToUserUnits(value);
	case LengthTypeCM:
	return value * cssPixelsPerInch / 2.54f;
	case LengthTypeMM:
	return value * cssPixelsPerInch / 25.4f;
	case LengthTypeIN:
	return value * cssPixelsPerInch;
	case LengthTypePT:
	return value * cssPixelsPerInch / 72;
	case LengthTypePC:
	return value * cssPixelsPerInch / 6;
	}

	ASSERT_NOT_REACHED();
	return 0;
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromUserUnits(float value, SVGLengthMode mode, SVGLengthType toUnit) const
	{
	switch (toUnit) {
	case LengthTypeUnknown:
	return Exception { NotSupportedError };
	case LengthTypeNumber:
	return value;
	case LengthTypePercentage:
	return convertValueFromUserUnitsToPercentage(value * 100, mode);
	case LengthTypeEMS:
	return convertValueFromUserUnitsToEMS(value);
	case LengthTypeEXS:
	return convertValueFromUserUnitsToEXS(value);
	case LengthTypePX:
	return value;
	case LengthTypeCM:
	return value * 2.54f / cssPixelsPerInch;
	case LengthTypeMM:
	return value * 25.4f / cssPixelsPerInch;
	case LengthTypeIN:
	return value / cssPixelsPerInch;
	case LengthTypePT:
	return value * 72 / cssPixelsPerInch;
	case LengthTypePC:
	return value * 6 / cssPixelsPerInch;
	}

	ASSERT_NOT_REACHED();
	return 0;
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromUserUnitsToPercentage(float value, SVGLengthMode mode) const
	{
	FloatSize viewportSize;
	if (!determineViewport(viewportSize))
	return Exception { NotSupportedError };

	switch (mode) {
	case LengthModeWidth:
	return value / viewportSize.width() * 100;
	case LengthModeHeight:
	return value / viewportSize.height() * 100;
	case LengthModeOther:
	return value / (std::sqrt(viewportSize.diagonalLengthSquared() / 2)) * 100;
	};

	ASSERT_NOT_REACHED();
	return 0;
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromPercentageToUserUnits(float value, SVGLengthMode mode) const
	{
	FloatSize viewportSize;
	if (!determineViewport(viewportSize))
	return Exception { NotSupportedError };

	switch (mode) {
	case LengthModeWidth:
	return value * viewportSize.width();
	case LengthModeHeight:
	return value * viewportSize.height();
	case LengthModeOther:
	return value * std::sqrt(viewportSize.diagonalLengthSquared() / 2);
	};

	ASSERT_NOT_REACHED();
	return 0;
	}

	static inline const RenderStyle* renderStyleForLengthResolving(const SVGElement* context)
	{
	if (!context)
	return nullptr;

	const ContainerNode* currentContext = context;
	do {
	if (currentContext->renderer())
	return &currentContext->renderer()->style();
	currentContext = currentContext->parentNode();
	} while (currentContext);

	// There must be at least a RenderSVGRoot renderer, carrying a style.
	ASSERT_NOT_REACHED();
	return nullptr;
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromUserUnitsToEMS(float value) const
	{
	auto* style = renderStyleForLengthResolving(m_context);
	if (!style)
	return Exception { NotSupportedError };

	float fontSize = style->computedFontPixelSize();
	if (!fontSize)
	return Exception { NotSupportedError };

	return value / fontSize;
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromEMSToUserUnits(float value) const
	{
	auto* style = renderStyleForLengthResolving(m_context);
	if (!style)
	return Exception { NotSupportedError };

	return value * style->computedFontPixelSize();
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromUserUnitsToEXS(float value) const
	{
	auto* style = renderStyleForLengthResolving(m_context);
	if (!style)
	return Exception { NotSupportedError };

	// Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
	// if this causes problems in real world cases maybe it would be best to remove this
	float xHeight = std::ceil(style->fontMetrics().xHeight());
	if (!xHeight)
	return Exception { NotSupportedError };

	return value / xHeight;
	}

	ExceptionOr<float> SVGLengthContext::convertValueFromEXSToUserUnits(float value) const
	{
	auto* style = renderStyleForLengthResolving(m_context);
	if (!style)
	return Exception { NotSupportedError };

	// Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
	// if this causes problems in real world cases maybe it would be best to remove this
	return value * std::ceil(style->fontMetrics().xHeight());
	}

	bool SVGLengthContext::determineViewport(FloatSize& viewportSize) const
	{
	if (!m_context)
	return false;

	// If an overriden viewport is given, it has precedence.
	if (!m_overridenViewport.isEmpty()) {
	viewportSize = m_overridenViewport.size();
	return true;
	}

	// Root <svg> element lengths are resolved against the top level viewport.
	if (m_context->isOutermostSVGSVGElement()) {
	viewportSize = downcast<SVGSVGElement>(*m_context).currentViewportSize();
	return true;
	}

	// Take size from nearest viewport element.
	auto viewportElement = makeRefPtr(m_context->viewportElement());
	if (!is<SVGSVGElement>(viewportElement))
	return false;

	const SVGSVGElement& svg = downcast<SVGSVGElement>(*viewportElement);
	viewportSize = svg.currentViewBoxRect().size();
	if (viewportSize.isEmpty())
	viewportSize = svg.currentViewportSize();

	return true;
	}

	}