1/*
2 * Copyright (C) 2007 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
17package android.graphics;
18
19/** A subclass of shader that returns the composition of two other shaders, combined by
20    an {@link android.graphics.Xfermode} subclass.
21*/
22public class ComposeShader extends Shader {
23
24    private static final int TYPE_XFERMODE = 1;
25    private static final int TYPE_PORTERDUFFMODE = 2;
26
27    /**
28     * Type of the ComposeShader: can be either TYPE_XFERMODE or TYPE_PORTERDUFFMODE
29     */
30    private int mType;
31
32    private Xfermode mXferMode;
33    private PorterDuff.Mode mPorterDuffMode;
34
35    /**
36     * Hold onto the shaders to avoid GC.
37     */
38    @SuppressWarnings({"UnusedDeclaration"})
39    private final Shader mShaderA;
40    @SuppressWarnings({"UnusedDeclaration"})
41    private final Shader mShaderB;
42
43    /** Create a new compose shader, given shaders A, B, and a combining mode.
44        When the mode is applied, it will be given the result from shader A as its
45        "dst", and the result from shader B as its "src".
46        @param shaderA  The colors from this shader are seen as the "dst" by the mode
47        @param shaderB  The colors from this shader are seen as the "src" by the mode
48        @param mode     The mode that combines the colors from the two shaders. If mode
49                        is null, then SRC_OVER is assumed.
50    */
51    public ComposeShader(Shader shaderA, Shader shaderB, Xfermode mode) {
52        mType = TYPE_XFERMODE;
53        mShaderA = shaderA;
54        mShaderB = shaderB;
55        mXferMode = mode;
56        native_instance = nativeCreate1(shaderA.native_instance, shaderB.native_instance,
57                (mode != null) ? mode.native_instance : 0);
58        if (mode instanceof PorterDuffXfermode) {
59            PorterDuff.Mode pdMode = ((PorterDuffXfermode) mode).mode;
60            native_shader = nativePostCreate2(native_instance, shaderA.native_shader,
61                    shaderB.native_shader, pdMode != null ? pdMode.nativeInt : 0);
62        } else {
63            native_shader = nativePostCreate1(native_instance, shaderA.native_shader,
64                    shaderB.native_shader, mode != null ? mode.native_instance : 0);
65        }
66    }
67
68    /** Create a new compose shader, given shaders A, B, and a combining PorterDuff mode.
69        When the mode is applied, it will be given the result from shader A as its
70        "dst", and the result from shader B as its "src".
71        @param shaderA  The colors from this shader are seen as the "dst" by the mode
72        @param shaderB  The colors from this shader are seen as the "src" by the mode
73        @param mode     The PorterDuff mode that combines the colors from the two shaders.
74    */
75    public ComposeShader(Shader shaderA, Shader shaderB, PorterDuff.Mode mode) {
76        mType = TYPE_PORTERDUFFMODE;
77        mShaderA = shaderA;
78        mShaderB = shaderB;
79        mPorterDuffMode = mode;
80        native_instance = nativeCreate2(shaderA.native_instance, shaderB.native_instance,
81                mode.nativeInt);
82        native_shader = nativePostCreate2(native_instance, shaderA.native_shader,
83                shaderB.native_shader, mode.nativeInt);
84    }
85
86    /**
87     * @hide
88     */
89    @Override
90    protected Shader copy() {
91        final ComposeShader copy;
92        switch (mType) {
93            case TYPE_XFERMODE:
94                copy = new ComposeShader(mShaderA.copy(), mShaderB.copy(), mXferMode);
95                break;
96            case TYPE_PORTERDUFFMODE:
97                copy = new ComposeShader(mShaderA.copy(), mShaderB.copy(), mPorterDuffMode);
98                break;
99            default:
100                throw new IllegalArgumentException(
101                        "ComposeShader should be created with either Xfermode or PorterDuffMode");
102        }
103        copyLocalMatrix(copy);
104        return copy;
105    }
106
107    private static native int nativeCreate1(int native_shaderA, int native_shaderB,
108            int native_mode);
109    private static native int nativeCreate2(int native_shaderA, int native_shaderB,
110            int porterDuffMode);
111    private static native int nativePostCreate1(int native_shader, int native_skiaShaderA,
112            int native_skiaShaderB, int native_mode);
113    private static native int nativePostCreate2(int native_shader, int native_skiaShaderA,
114            int native_skiaShaderB, int porterDuffMode);
115}
116