Snapshot.h revision 1d83e1981c8b89da93dff37a4f8b2b1ad8480b44 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_UI_SNAPSHOT_H
18#define ANDROID_UI_SNAPSHOT_H
19
20#include <GLES2/gl2.h>
21#include <GLES2/gl2ext.h>
22
23#include <utils/RefBase.h>
24
25#include <SkRegion.h>
26
27#include "Layer.h"
28#include "Matrix.h"
29#include "Rect.h"
30
31namespace android {
32namespace uirenderer {
33
34/**
35 * A snapshot holds information about the current state of the rendering
36 * surface. A snapshot is usually created whenever the user calls save()
37 * and discarded when the user calls restore(). Once a snapshot is created,
38 * it can hold information for deferred rendering.
39 *
40 * Each snapshot has a link to a previous snapshot, indicating the previous
41 * state of the renderer.
42 */
43class Snapshot: public LightRefBase<Snapshot> {
44public:
45    Snapshot(): flags(0), previous(NULL), layer(NULL), fbo(0) { }
46
47    /**
48     * Copies the specified snapshot. Only the transform and clip rectangle
49     * are copied. The layer information is set to 0 and the transform is
50     * assumed to be dirty. The specified snapshot is stored as the previous
51     * snapshot.
52     */
53    Snapshot(const sp<Snapshot>& s):
54            height(s->height),
55            transform(s->transform),
56            clipRect(s->clipRect),
57            flags(0),
58            previous(s),
59            layer(NULL),
60            fbo(s->fbo),
61            viewport(s->viewport) {
62        if ((s->flags & Snapshot::kFlagClipSet) &&
63                !(s->flags & Snapshot::kFlagDirtyLocalClip)) {
64            localClip.set(s->localClip);
65        } else {
66            flags |= Snapshot::kFlagDirtyLocalClip;
67        }
68    }
69
70    /**
71     * Various flags set on #flags.
72     */
73    enum Flags {
74        /**
75         * Indicates that the clip region was modified. When this
76         * snapshot is restored so must the clip.
77         */
78        kFlagClipSet = 0x1,
79        /**
80         * Indicates that this snapshot was created when saving
81         * a new layer.
82         */
83        kFlagIsLayer = 0x2,
84        /**
85         * Indicates that this snapshot has changed the ortho matrix.
86         */
87        kFlagDirtyOrtho = 0x4,
88        /**
89         * Indicates that the local clip should be recomputed.
90         */
91        kFlagDirtyLocalClip = 0x8,
92    };
93
94    /**
95     * Intersects the current clip with the new clip rectangle.
96     */
97    bool clip(float left, float top, float right, float bottom, SkRegion::Op op) {
98        bool clipped = false;
99
100        Rect r(left, top, right, bottom);
101        transform.mapRect(r);
102
103        switch (op) {
104            case SkRegion::kDifference_Op:
105                break;
106            case SkRegion::kIntersect_Op:
107                clipped = clipRect.intersect(r);
108                break;
109            case SkRegion::kUnion_Op:
110                clipped = clipRect.unionWith(r);
111                break;
112            case SkRegion::kXOR_Op:
113                break;
114            case SkRegion::kReverseDifference_Op:
115                break;
116            case SkRegion::kReplace_Op:
117                clipRect.set(r);
118                clipped = true;
119                break;
120        }
121
122        if (clipped) {
123            flags |= Snapshot::kFlagClipSet | Snapshot::kFlagDirtyLocalClip;
124        }
125
126        return clipped;
127    }
128
129    /**
130     * Sets the current clip.
131     */
132    void setClip(float left, float top, float right, float bottom) {
133        clipRect.set(left, top, right, bottom);
134        flags |= Snapshot::kFlagClipSet | Snapshot::kFlagDirtyLocalClip;
135    }
136
137    const Rect& getLocalClip() {
138        if (flags & Snapshot::kFlagDirtyLocalClip) {
139            mat4 inverse;
140            inverse.loadInverse(transform);
141
142            localClip.set(clipRect);
143            inverse.mapRect(localClip);
144
145            flags &= ~Snapshot::kFlagDirtyLocalClip;
146        }
147        return localClip;
148    }
149
150    /**
151     * Height of the framebuffer the snapshot is rendering into.
152     */
153    int height;
154
155    /**
156     * Local transformation. Holds the current translation, scale and
157     * rotation values.
158     */
159    mat4 transform;
160
161    /**
162     * Current clip region. The clip is stored in canvas-space coordinates,
163     * (screen-space coordinates in the regular case.)
164     */
165    Rect clipRect;
166
167    /**
168     * Dirty flags.
169     */
170    int flags;
171
172    /**
173     * Previous snapshot.
174     */
175    sp<Snapshot> previous;
176
177    /**
178     * Only set when the flag kFlagIsLayer is set.
179     */
180    Layer* layer;
181    GLuint fbo;
182
183    /**
184     * Current viewport.
185     */
186    Rect viewport;
187
188    /**
189     * Contains the previous ortho matrix.
190     */
191    mat4 orthoMatrix;
192
193private:
194    Rect localClip;
195
196}; // class Snapshot
197
198}; // namespace uirenderer
199}; // namespace android
200
201#endif // ANDROID_UI_SNAPSHOT_H
202