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/*
* Copyright (C) 2011 University of Szeged
* Copyright (C) 2011 Renata Hodovan <reni@webkit.org>
* 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 UNIVERSITY OF SZEGED ``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 UNIVERSITY OF SZEGED 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/svg/LayoutSVGRect.h"
#include "core/svg/SVGRectElement.h"
#include "wtf/MathExtras.h"
namespace blink {
LayoutSVGRect::LayoutSVGRect(SVGRectElement* node)
: LayoutSVGShape(node), m_usePathFallback(false) {}
LayoutSVGRect::~LayoutSVGRect() {}
void LayoutSVGRect::updateShapeFromElement() {
// Before creating a new object we need to clear the cached bounding box
// to avoid using garbage.
m_fillBoundingBox = FloatRect();
m_strokeBoundingBox = FloatRect();
m_usePathFallback = false;
SVGRectElement* rect = toSVGRectElement(element());
ASSERT(rect);
SVGLengthContext lengthContext(rect);
FloatSize boundingBoxSize(
lengthContext.valueForLength(styleRef().width(), styleRef(),
SVGLengthMode::Width),
lengthContext.valueForLength(styleRef().height(), styleRef(),
SVGLengthMode::Height));
// Spec: "A negative value is an error."
if (boundingBoxSize.width() < 0 || boundingBoxSize.height() < 0)
return;
// Spec: "A value of zero disables rendering of the element."
if (!boundingBoxSize.isEmpty()) {
// Fallback to LayoutSVGShape and path-based hit detection if the rect
// has rounded corners or a non-scaling or non-simple stroke.
if (lengthContext.valueForLength(styleRef().svgStyle().rx(), styleRef(),
SVGLengthMode::Width) > 0 ||
lengthContext.valueForLength(styleRef().svgStyle().ry(), styleRef(),
SVGLengthMode::Height) > 0 ||
hasNonScalingStroke() || !definitelyHasSimpleStroke()) {
LayoutSVGShape::updateShapeFromElement();
m_usePathFallback = true;
return;
}
}
m_fillBoundingBox = FloatRect(
FloatPoint(
lengthContext.valueForLength(styleRef().svgStyle().x(), styleRef(),
SVGLengthMode::Width),
lengthContext.valueForLength(styleRef().svgStyle().y(), styleRef(),
SVGLengthMode::Height)),
boundingBoxSize);
m_strokeBoundingBox = m_fillBoundingBox;
if (style()->svgStyle().hasStroke())
m_strokeBoundingBox.inflate(strokeWidth() / 2);
if (element())
element()->setNeedsResizeObserverUpdate();
}
bool LayoutSVGRect::shapeDependentStrokeContains(const FloatPoint& point) {
// The optimized code below does not support non-simple strokes so we need
// to fall back to LayoutSVGShape::shapeDependentStrokeContains in these
// cases.
if (m_usePathFallback || !definitelyHasSimpleStroke()) {
if (!hasPath())
LayoutSVGShape::updateShapeFromElement();
return LayoutSVGShape::shapeDependentStrokeContains(point);
}
const float halfStrokeWidth = strokeWidth() / 2;
const float halfWidth = m_fillBoundingBox.width() / 2;
const float halfHeight = m_fillBoundingBox.height() / 2;
const FloatPoint fillBoundingBoxCenter = FloatPoint(
m_fillBoundingBox.x() + halfWidth, m_fillBoundingBox.y() + halfHeight);
const float absDeltaX = std::abs(point.x() - fillBoundingBoxCenter.x());
const float absDeltaY = std::abs(point.y() - fillBoundingBoxCenter.y());
if (!(absDeltaX <= halfWidth + halfStrokeWidth &&
absDeltaY <= halfHeight + halfStrokeWidth))
return false;
return (halfWidth - halfStrokeWidth <= absDeltaX) ||
(halfHeight - halfStrokeWidth <= absDeltaY);
}
bool LayoutSVGRect::shapeDependentFillContains(const FloatPoint& point,
const WindRule fillRule) const {
if (m_usePathFallback)
return LayoutSVGShape::shapeDependentFillContains(point, fillRule);
return m_fillBoundingBox.contains(point.x(), point.y());
}
// Returns true if the stroke is continuous and definitely uses miter joins.
bool LayoutSVGRect::definitelyHasSimpleStroke() const {
const SVGComputedStyle& svgStyle = style()->svgStyle();
// The four angles of a rect are 90 degrees. Using the formula at:
// http://www.w3.org/TR/SVG/painting.html#StrokeMiterlimitProperty
// when the join style of the rect is "miter", the ratio of the miterLength
// to the stroke-width is found to be
// miterLength / stroke-width = 1 / sin(45 degrees)
// = 1 / (1 / sqrt(2))
// = sqrt(2)
// = 1.414213562373095...
// When sqrt(2) exceeds the miterlimit, then the join style switches to
// "bevel". When the miterlimit is greater than or equal to sqrt(2) then
// the join style remains "miter".
//
// An approximation of sqrt(2) is used here because at certain precise
// miterlimits, the join style used might not be correct (e.g. a miterlimit
// of 1.4142135 should result in bevel joins, but may be drawn using miter
// joins).
return svgStyle.strokeDashArray()->isEmpty() &&
svgStyle.joinStyle() == MiterJoin &&
svgStyle.strokeMiterLimit() >= 1.5;
}
} // namespace blink
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