1/*
2 * Copyright (C) 2011 Igalia S.L.
3 * Copyright (c) 2008, Google Inc. All rights reserved.
4 * Copyright (c) 2012, Intel Corporation
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
23 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include "config.h"
29#include "PlatformContextCairo.h"
30
31#if USE(CAIRO)
32
33#include "CairoUtilities.h"
34#include "Gradient.h"
35#include "GraphicsContext.h"
36#include "Pattern.h"
37#include <cairo.h>
38
39namespace WebCore {
40
41// In Cairo image masking is immediate, so to emulate image clipping we must save masking
42// details as part of the context state and apply them during platform restore.
43class ImageMaskInformation {
44public:
45 void update(cairo_surface_t* maskSurface, const FloatRect& maskRect)
46 {
47 m_maskSurface = maskSurface;
48 m_maskRect = maskRect;
49 }
50
51 bool isValid() const { return m_maskSurface; }
52 cairo_surface_t* maskSurface() const { return m_maskSurface.get(); }
53 const FloatRect& maskRect() const { return m_maskRect; }
54
55private:
56 RefPtr<cairo_surface_t> m_maskSurface;
57 FloatRect m_maskRect;
58};
59
60
61// Encapsulates the additional painting state information we store for each
62// pushed graphics state.
63class PlatformContextCairo::State {
64public:
65 State() = default;
66
67 ImageMaskInformation m_imageMaskInformation;
68};
69
70PlatformContextCairo::PlatformContextCairo(cairo_t* cr)
71 : m_cr(cr)
72{
73 m_stateStack.append(State());
74 m_state = &m_stateStack.last();
75}
76
77void PlatformContextCairo::restore()
78{
79 const ImageMaskInformation& maskInformation = m_state->m_imageMaskInformation;
80 if (maskInformation.isValid()) {
81 const FloatRect& maskRect = maskInformation.maskRect();
82 cairo_pop_group_to_source(m_cr.get());
83 cairo_mask_surface(m_cr.get(), maskInformation.maskSurface(), maskRect.x(), maskRect.y());
84 }
85
86 m_stateStack.removeLast();
87 ASSERT(!m_stateStack.isEmpty());
88 m_state = &m_stateStack.last();
89
90 cairo_restore(m_cr.get());
91}
92
93PlatformContextCairo::~PlatformContextCairo() = default;
94
95void PlatformContextCairo::save()
96{
97 m_stateStack.append(State());
98 m_state = &m_stateStack.last();
99
100 cairo_save(m_cr.get());
101}
102
103void PlatformContextCairo::pushImageMask(cairo_surface_t* surface, const FloatRect& rect)
104{
105 // We must call savePlatformState at least once before we can use image masking,
106 // since we actually apply the mask in restorePlatformState.
107 ASSERT(!m_stateStack.isEmpty());
108 m_state->m_imageMaskInformation.update(surface, rect);
109
110 // Cairo doesn't support the notion of an image clip, so we push a group here
111 // and then paint it to the surface with an image mask (which is an immediate
112 // operation) during restorePlatformState.
113
114 // We want to allow the clipped elements to composite with the surface as it
115 // is now, but they are isolated in another group. To make this work, we're
116 // going to blit the current surface contents onto the new group once we push it.
117 cairo_surface_t* currentTarget = cairo_get_target(m_cr.get());
118 cairo_surface_flush(currentTarget);
119
120 // Pushing a new group ensures that only things painted after this point are clipped.
121 cairo_push_group(m_cr.get());
122 cairo_set_operator(m_cr.get(), CAIRO_OPERATOR_SOURCE);
123
124 // To avoid the limit of Pixman backend, we need to reduce the size of pattern matrix
125 // See https://bugs.webkit.org/show_bug.cgi?id=154283
126 cairo_set_source_surface(m_cr.get(), currentTarget, rect.x(), rect.y());
127 cairo_translate(m_cr.get(), rect.x(), rect.y());
128 cairo_rectangle(m_cr.get(), 0, 0, rect.width(), rect.height());
129 cairo_fill(m_cr.get());
130 cairo_translate(m_cr.get(), -rect.x(), -rect.y());
131}
132
133} // namespace WebCore
134
135#endif // USE(CAIRO)
136