SVGLinearGradientElement.cpp revision 635860845790a19bf50bbc51ba8fb66a96dde068 
1/*
2    Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
3                  2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
4                  2008 Eric Seidel <eric@webkit.org>
5                  2008 Dirk Schulze <krit@webkit.org>
6
7    This library is free software; you can redistribute it and/or
8    modify it under the terms of the GNU Library General Public
9    License as published by the Free Software Foundation; either
10    version 2 of the License, or (at your option) any later version.
11
12    This library is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15    Library General Public License for more details.
16
17    You should have received a copy of the GNU Library General Public License
18    along with this library; see the file COPYING.LIB.  If not, write to
19    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20    Boston, MA 02110-1301, USA.
21*/
22
23#include "config.h"
24
25#if ENABLE(SVG)
26#include "SVGLinearGradientElement.h"
27
28#include "Document.h"
29#include "FloatPoint.h"
30#include "LinearGradientAttributes.h"
31#include "SVGLength.h"
32#include "SVGNames.h"
33#include "SVGPaintServerLinearGradient.h"
34#include "SVGTransform.h"
35#include "SVGTransformList.h"
36#include "SVGUnitTypes.h"
37
38namespace WebCore {
39
40SVGLinearGradientElement::SVGLinearGradientElement(const QualifiedName& tagName, Document* doc)
41    : SVGGradientElement(tagName, doc)
42    , m_x1(this, SVGNames::x1Attr, LengthModeWidth)
43    , m_y1(this, SVGNames::y1Attr, LengthModeHeight)
44    , m_x2(this, SVGNames::x2Attr, LengthModeWidth, "100%")
45    , m_y2(this, SVGNames::y2Attr, LengthModeHeight)
46{
47    // Spec: If the x2 attribute is not specified, the effect is as if a value of "100%" were specified.
48}
49
50SVGLinearGradientElement::~SVGLinearGradientElement()
51{
52}
53
54void SVGLinearGradientElement::parseMappedAttribute(MappedAttribute* attr)
55{
56    if (attr->name() == SVGNames::x1Attr)
57        setX1BaseValue(SVGLength(LengthModeWidth, attr->value()));
58    else if (attr->name() == SVGNames::y1Attr)
59        setY1BaseValue(SVGLength(LengthModeHeight, attr->value()));
60    else if (attr->name() == SVGNames::x2Attr)
61        setX2BaseValue(SVGLength(LengthModeWidth, attr->value()));
62    else if (attr->name() == SVGNames::y2Attr)
63        setY2BaseValue(SVGLength(LengthModeHeight, attr->value()));
64    else
65        SVGGradientElement::parseMappedAttribute(attr);
66}
67
68void SVGLinearGradientElement::svgAttributeChanged(const QualifiedName& attrName)
69{
70    SVGGradientElement::svgAttributeChanged(attrName);
71
72    if (!m_resource)
73        return;
74
75    if (attrName == SVGNames::x1Attr || attrName == SVGNames::y1Attr ||
76        attrName == SVGNames::x2Attr || attrName == SVGNames::y2Attr)
77        m_resource->invalidate();
78}
79
80void SVGLinearGradientElement::buildGradient() const
81{
82    LinearGradientAttributes attributes = collectGradientProperties();
83
84    RefPtr<SVGPaintServerLinearGradient> linearGradient = WTF::static_pointer_cast<SVGPaintServerLinearGradient>(m_resource);
85
86    FloatPoint startPoint = FloatPoint::narrowPrecision(attributes.x1(), attributes.y1());
87    FloatPoint endPoint = FloatPoint::narrowPrecision(attributes.x2(), attributes.y2());
88
89    RefPtr<Gradient> gradient = Gradient::create(startPoint, endPoint);
90
91    Vector<SVGGradientStop> m_stops = attributes.stops();
92    float previousOffset = 0.0f;
93    for (unsigned i = 0; i < m_stops.size(); ++i) {
94        float offset = std::min(std::max(previousOffset, m_stops[i].first), 1.0f);
95        previousOffset = offset;
96        gradient->addColorStop(offset, m_stops[i].second);
97    }
98
99    linearGradient->setGradient(gradient);
100
101    if (attributes.stops().isEmpty())
102        return;
103
104    // This code should go away.  PaintServers should go away too.
105    // Only this code should care about bounding boxes
106    linearGradient->setBoundingBoxMode(attributes.boundingBoxMode());
107    linearGradient->setGradientStops(attributes.stops());
108
109    // These should possibly be supported on Gradient
110    linearGradient->setGradientSpreadMethod(attributes.spreadMethod());
111    linearGradient->setGradientTransform(attributes.gradientTransform());
112    linearGradient->setGradientStart(startPoint);
113    linearGradient->setGradientEnd(endPoint);
114}
115
116LinearGradientAttributes SVGLinearGradientElement::collectGradientProperties() const
117{
118    LinearGradientAttributes attributes;
119    HashSet<const SVGGradientElement*> processedGradients;
120
121    bool isLinear = true;
122    const SVGGradientElement* current = this;
123
124    while (current) {
125        if (!attributes.hasSpreadMethod() && current->hasAttribute(SVGNames::spreadMethodAttr))
126            attributes.setSpreadMethod((GradientSpreadMethod) current->spreadMethod());
127
128        if (!attributes.hasBoundingBoxMode() && current->hasAttribute(SVGNames::gradientUnitsAttr))
129            attributes.setBoundingBoxMode(current->gradientUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX);
130
131        if (!attributes.hasGradientTransform() && current->hasAttribute(SVGNames::gradientTransformAttr))
132            attributes.setGradientTransform(current->gradientTransform()->consolidate().matrix());
133
134        if (!attributes.hasStops()) {
135            const Vector<SVGGradientStop>& stops(current->buildStops());
136            if (!stops.isEmpty())
137                attributes.setStops(stops);
138        }
139
140        if (isLinear) {
141            const SVGLinearGradientElement* linear = static_cast<const SVGLinearGradientElement*>(current);
142
143            if (!attributes.hasX1() && current->hasAttribute(SVGNames::x1Attr))
144                attributes.setX1(linear->x1().valueAsPercentage());
145
146            if (!attributes.hasY1() && current->hasAttribute(SVGNames::y1Attr))
147                attributes.setY1(linear->y1().valueAsPercentage());
148
149            if (!attributes.hasX2() && current->hasAttribute(SVGNames::x2Attr))
150                attributes.setX2(linear->x2().valueAsPercentage());
151
152            if (!attributes.hasY2() && current->hasAttribute(SVGNames::y2Attr))
153                attributes.setY2(linear->y2().valueAsPercentage());
154        }
155
156        processedGradients.add(current);
157
158        // Respect xlink:href, take attributes from referenced element
159        Node* refNode = ownerDocument()->getElementById(SVGURIReference::getTarget(current->href()));
160        if (refNode && (refNode->hasTagName(SVGNames::linearGradientTag) || refNode->hasTagName(SVGNames::radialGradientTag))) {
161            current = static_cast<const SVGGradientElement*>(const_cast<const Node*>(refNode));
162
163            // Cycle detection
164            if (processedGradients.contains(current))
165                return LinearGradientAttributes();
166
167            isLinear = current->gradientType() == LinearGradientPaintServer;
168        } else
169            current = 0;
170    }
171
172    return attributes;
173}
174
175}
176
177#endif // ENABLE(SVG)
178