1/*
2 * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
3 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "config.h"
28#include "Gradient.h"
29
30#include "Color.h"
31#include "FloatRect.h"
32#include <wtf/HashFunctions.h>
33#include <wtf/StringHasher.h>
34
35using WTF::pairIntHash;
36
37namespace WebCore {
38
39Gradient::Gradient(const FloatPoint& p0, const FloatPoint& p1)
40    : m_radial(false)
41    , m_p0(p0)
42    , m_p1(p1)
43    , m_r0(0)
44    , m_r1(0)
45    , m_aspectRatio(1)
46    , m_stopsSorted(false)
47    , m_spreadMethod(SpreadMethodPad)
48    , m_cachedHash(0)
49{
50    platformInit();
51}
52
53Gradient::Gradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio)
54    : m_radial(true)
55    , m_p0(p0)
56    , m_p1(p1)
57    , m_r0(r0)
58    , m_r1(r1)
59    , m_aspectRatio(aspectRatio)
60    , m_stopsSorted(false)
61    , m_spreadMethod(SpreadMethodPad)
62    , m_cachedHash(0)
63{
64    platformInit();
65}
66
67Gradient::~Gradient()
68{
69    platformDestroy();
70}
71
72void Gradient::adjustParametersForTiledDrawing(FloatSize& size, FloatRect& srcRect)
73{
74    if (m_radial)
75        return;
76
77    if (srcRect.isEmpty())
78        return;
79
80    if (m_p0.x() == m_p1.x()) {
81        size.setWidth(1);
82        srcRect.setWidth(1);
83        srcRect.setX(0);
84        return;
85    }
86    if (m_p0.y() != m_p1.y())
87        return;
88
89    size.setHeight(1);
90    srcRect.setHeight(1);
91    srcRect.setY(0);
92}
93
94void Gradient::addColorStop(float value, const Color& color)
95{
96    float r;
97    float g;
98    float b;
99    float a;
100    color.getRGBA(r, g, b, a);
101    m_stops.append(ColorStop(value, r, g, b, a));
102
103    m_stopsSorted = false;
104    platformDestroy();
105
106    invalidateHash();
107}
108
109void Gradient::addColorStop(const Gradient::ColorStop& stop)
110{
111    m_stops.append(stop);
112
113    m_stopsSorted = false;
114    platformDestroy();
115
116    invalidateHash();
117}
118
119static inline bool compareStops(const Gradient::ColorStop& a, const Gradient::ColorStop& b)
120{
121    return a.stop < b.stop;
122}
123
124void Gradient::sortStopsIfNecessary()
125{
126    if (m_stopsSorted)
127        return;
128
129    m_stopsSorted = true;
130
131    if (!m_stops.size())
132        return;
133
134    std::stable_sort(m_stops.begin(), m_stops.end(), compareStops);
135
136    invalidateHash();
137}
138
139bool Gradient::hasAlpha() const
140{
141    for (size_t i = 0; i < m_stops.size(); i++) {
142        if (m_stops[i].alpha < 1)
143            return true;
144    }
145
146    return false;
147}
148
149void Gradient::setSpreadMethod(GradientSpreadMethod spreadMethod)
150{
151    // FIXME: Should it become necessary, allow calls to this method after m_gradient has been set.
152    ASSERT(m_gradient == 0);
153
154    if (m_spreadMethod == spreadMethod)
155        return;
156
157    m_spreadMethod = spreadMethod;
158
159    invalidateHash();
160}
161
162void Gradient::setGradientSpaceTransform(const AffineTransform& gradientSpaceTransformation)
163{
164    if (m_gradientSpaceTransformation == gradientSpaceTransformation)
165        return;
166
167    m_gradientSpaceTransformation = gradientSpaceTransformation;
168    setPlatformGradientSpaceTransform(gradientSpaceTransformation);
169
170    invalidateHash();
171}
172
173#if !USE(CAIRO)
174void Gradient::setPlatformGradientSpaceTransform(const AffineTransform&)
175{
176}
177#endif
178
179unsigned Gradient::hash() const
180{
181    if (m_cachedHash)
182        return m_cachedHash;
183
184    struct {
185        AffineTransform gradientSpaceTransformation;
186        FloatPoint p0;
187        FloatPoint p1;
188        float r0;
189        float r1;
190        float aspectRatio;
191        GradientSpreadMethod spreadMethod;
192        bool radial;
193    } parameters;
194
195    // StringHasher requires that the memory it hashes be a multiple of two in size.
196    COMPILE_ASSERT(!(sizeof(parameters) % 2), Gradient_parameters_size_should_be_multiple_of_two);
197    COMPILE_ASSERT(!(sizeof(ColorStop) % 2), Color_stop_size_should_be_multiple_of_two);
198
199    // Ensure that any padding in the struct is zero-filled, so it will not affect the hash value.
200    memset(&parameters, 0, sizeof(parameters));
201
202    parameters.gradientSpaceTransformation = m_gradientSpaceTransformation;
203    parameters.p0 = m_p0;
204    parameters.p1 = m_p1;
205    parameters.r0 = m_r0;
206    parameters.r1 = m_r1;
207    parameters.aspectRatio = m_aspectRatio;
208    parameters.spreadMethod = m_spreadMethod;
209    parameters.radial = m_radial;
210
211    unsigned parametersHash = StringHasher::hashMemory(&parameters, sizeof(parameters));
212    unsigned stopHash = StringHasher::hashMemory(m_stops.data(), m_stops.size() * sizeof(ColorStop));
213
214    m_cachedHash = pairIntHash(parametersHash, stopHash);
215
216    return m_cachedHash;
217}
218
219} //namespace
220