1/*
2 * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
3 * Copyright (C) 2013 Intel Corporation. All rights reserved.
4 *
5 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
6 *
7 * Other contributors:
8 *   Robert O'Callahan <roc+@cs.cmu.edu>
9 *   David Baron <dbaron@fas.harvard.edu>
10 *   Christian Biesinger <cbiesinger@web.de>
11 *   Randall Jesup <rjesup@wgate.com>
12 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
13 *   Josh Soref <timeless@mac.com>
14 *   Boris Zbarsky <bzbarsky@mit.edu>
15 *
16 * This library is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU Lesser General Public
18 * License as published by the Free Software Foundation; either
19 * version 2.1 of the License, or (at your option) any later version.
20 *
21 * This library is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24 * Lesser General Public License for more details.
25 *
26 * You should have received a copy of the GNU Lesser General Public
27 * License along with this library; if not, write to the Free Software
28 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
29 *
30 * Alternatively, the contents of this file may be used under the terms
31 * of either the Mozilla Public License Version 1.1, found at
32 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
33 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
34 * (the "GPL"), in which case the provisions of the MPL or the GPL are
35 * applicable instead of those above.  If you wish to allow use of your
36 * version of this file only under the terms of one of those two
37 * licenses (the MPL or the GPL) and not to allow others to use your
38 * version of this file under the LGPL, indicate your decision by
39 * deletingthe provisions above and replace them with the notice and
40 * other provisions required by the MPL or the GPL, as the case may be.
41 * If you do not delete the provisions above, a recipient may use your
42 * version of this file under any of the LGPL, the MPL or the GPL.
43 */
44
45#ifndef RenderLayerClipper_h
46#define RenderLayerClipper_h
47
48#include "core/rendering/ClipRectsCache.h"
49#include "core/rendering/RenderBox.h"
50
51namespace blink {
52
53class RenderLayer;
54
55enum ShouldRespectOverflowClip {
56    IgnoreOverflowClip,
57    RespectOverflowClip
58};
59
60class ClipRectsContext {
61public:
62    ClipRectsContext(const RenderLayer* root, ClipRectsCacheSlot slot, OverlayScrollbarSizeRelevancy relevancy = IgnoreOverlayScrollbarSize, const LayoutSize& accumulation = LayoutSize())
63        : rootLayer(root)
64        , scrollbarRelevancy(relevancy)
65        , cacheSlot(slot)
66        , subPixelAccumulation(accumulation)
67        , respectOverflowClip(slot == PaintingClipRectsIgnoringOverflowClip ? IgnoreOverflowClip : RespectOverflowClip)
68    {
69    }
70
71    void setIgnoreOverflowClip()
72    {
73        ASSERT(!usesCache() || cacheSlot == PaintingClipRects);
74        ASSERT(respectOverflowClip == RespectOverflowClip);
75        if (usesCache())
76            cacheSlot = PaintingClipRectsIgnoringOverflowClip;
77        respectOverflowClip = IgnoreOverflowClip;
78    }
79
80    bool usesCache() const
81    {
82        return cacheSlot != UncachedClipRects;
83    }
84
85    const RenderLayer* const rootLayer;
86    const OverlayScrollbarSizeRelevancy scrollbarRelevancy;
87
88private:
89    friend class RenderLayerClipper;
90
91    ClipRectsCacheSlot cacheSlot;
92    LayoutSize subPixelAccumulation;
93    ShouldRespectOverflowClip respectOverflowClip;
94};
95
96class RenderLayerClipper {
97    WTF_MAKE_NONCOPYABLE(RenderLayerClipper);
98public:
99    explicit RenderLayerClipper(RenderLayerModelObject&);
100
101    void clearClipRectsIncludingDescendants();
102    void clearClipRectsIncludingDescendants(ClipRectsCacheSlot);
103
104    LayoutRect childrenClipRect() const; // Returns the foreground clip rect of the layer in the document's coordinate space.
105    LayoutRect localClipRect() const; // Returns the background clip rect of the layer in the local coordinate space.
106
107    ClipRects* getClipRects(const ClipRectsContext&) const;
108
109    ClipRect backgroundClipRect(const ClipRectsContext&) const;
110
111    // This method figures out our layerBounds in coordinates relative to
112    // |rootLayer|. It also computes our background and foreground clip rects
113    // for painting/event handling.
114    // Pass offsetFromRoot if known.
115    void calculateRects(const ClipRectsContext&, const LayoutRect& paintDirtyRect, LayoutRect& layerBounds,
116        ClipRect& backgroundRect, ClipRect& foregroundRect, ClipRect& outlineRect, const LayoutPoint* offsetFromRoot = 0) const;
117
118private:
119    void calculateClipRects(const ClipRectsContext&, ClipRects&) const;
120
121    ClipRects* clipRectsIfCached(const ClipRectsContext&) const;
122    ClipRects* storeClipRectsInCache(const ClipRectsContext&, ClipRects* parentClipRects, const ClipRects&) const;
123
124    // cachedClipRects looks buggy: It doesn't check whether context.rootLayer and entry.root match.
125    // FIXME: Move callers to clipRectsIfCached, which does the proper checks.
126    ClipRects* cachedClipRects(const ClipRectsContext& context) const
127    {
128        return m_cache ? m_cache->get(context.cacheSlot).clipRects.get() : 0;
129    }
130
131    void getOrCalculateClipRects(const ClipRectsContext&, ClipRects&) const;
132
133    RenderLayer* clippingRootForPainting() const;
134
135    ClipRectsCache& cache() const
136    {
137        if (!m_cache)
138            m_cache = adoptPtr(new ClipRectsCache);
139        return *m_cache;
140    }
141
142    // FIXME: Could this be a RenderBox?
143    RenderLayerModelObject& m_renderer;
144    mutable OwnPtr<ClipRectsCache> m_cache;
145};
146
147} // namespace blink
148
149#endif // RenderLayerClipper_h
150