Snapshot.h revision 8b55f377655d13a445b08a0a8ed09b6e95c752b0 
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(): invisible(false), 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            invisible(s->invisible),
58            flags(0),
59            previous(s),
60            layer(NULL),
61            fbo(s->fbo),
62            viewport(s->viewport) {
63        if ((s->flags & Snapshot::kFlagClipSet) &&
64                !(s->flags & Snapshot::kFlagDirtyLocalClip)) {
65            localClip.set(s->localClip);
66        } else {
67            flags |= Snapshot::kFlagDirtyLocalClip;
68        }
69    }
70
71    /**
72     * Various flags set on #flags.
73     */
74    enum Flags {
75        /**
76         * Indicates that the clip region was modified. When this
77         * snapshot is restored so must the clip.
78         */
79        kFlagClipSet = 0x1,
80        /**
81         * Indicates that this snapshot was created when saving
82         * a new layer.
83         */
84        kFlagIsLayer = 0x2,
85        /**
86         * Indicates that this snapshot has changed the ortho matrix.
87         */
88        kFlagDirtyOrtho = 0x4,
89        /**
90         * Indicates that the local clip should be recomputed.
91         */
92        kFlagDirtyLocalClip = 0x8,
93    };
94
95    /**
96     * Intersects the current clip with the new clip rectangle.
97     */
98    bool clip(float left, float top, float right, float bottom, SkRegion::Op op) {
99        bool clipped = false;
100
101        Rect r(left, top, right, bottom);
102        transform.mapRect(r);
103
104        switch (op) {
105            case SkRegion::kDifference_Op:
106                break;
107            case SkRegion::kIntersect_Op:
108                clipped = clipRect.intersect(r);
109                break;
110            case SkRegion::kUnion_Op:
111                clipped = clipRect.unionWith(r);
112                break;
113            case SkRegion::kXOR_Op:
114                break;
115            case SkRegion::kReverseDifference_Op:
116                break;
117            case SkRegion::kReplace_Op:
118                clipRect.set(r);
119                clipped = true;
120                break;
121        }
122
123        if (clipped) {
124            flags |= Snapshot::kFlagClipSet | Snapshot::kFlagDirtyLocalClip;
125        }
126
127        return clipped;
128    }
129
130    /**
131     * Sets the current clip.
132     */
133    void setClip(float left, float top, float right, float bottom) {
134        clipRect.set(left, top, right, bottom);
135        flags |= Snapshot::kFlagClipSet | Snapshot::kFlagDirtyLocalClip;
136    }
137
138    const Rect& getLocalClip() {
139        if (flags & Snapshot::kFlagDirtyLocalClip) {
140            mat4 inverse;
141            inverse.loadInverse(transform);
142
143            localClip.set(clipRect);
144            inverse.mapRect(localClip);
145
146            flags &= ~Snapshot::kFlagDirtyLocalClip;
147        }
148        return localClip;
149    }
150
151    /**
152     * Height of the framebuffer the snapshot is rendering into.
153     */
154    int height;
155
156    /**
157     * Local transformation. Holds the current translation, scale and
158     * rotation values.
159     */
160    mat4 transform;
161
162    /**
163     * Current clip region. The clip is stored in canvas-space coordinates,
164     * (screen-space coordinates in the regular case.)
165     */
166    Rect clipRect;
167
168    /**
169     * If true, the layer won't be rendered.
170     */
171    bool invisible;
172
173    /**
174     * Dirty flags.
175     */
176    int flags;
177
178    /**
179     * Previous snapshot.
180     */
181    sp<Snapshot> previous;
182
183    /**
184     * Only set when the flag kFlagIsLayer is set.
185     */
186    Layer* layer;
187    GLuint fbo;
188
189    /**
190     * Current viewport.
191     */
192    Rect viewport;
193
194    /**
195     * Contains the previous ortho matrix.
196     */
197    mat4 orthoMatrix;
198
199private:
200    Rect localClip;
201
202}; // class Snapshot
203
204}; // namespace uirenderer
205}; // namespace android
206
207#endif // ANDROID_UI_SNAPSHOT_H
208