ComposeShader.java revision b3061e82ebfaefdbf33b35f78e5e87de7abd5591 
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 int mPorterDuffMode;
25    final Shader mShaderA;
26    final Shader mShaderB;
27
28    /** Create a new compose shader, given shaders A, B, and a combining mode.
29        When the mode is applied, it will be given the result from shader A as its
30        "dst", and the result from shader B as its "src".
31        @param shaderA  The colors from this shader are seen as the "dst" by the mode
32        @param shaderB  The colors from this shader are seen as the "src" by the mode
33        @param mode     The mode that combines the colors from the two shaders. If mode
34                        is null, then SRC_OVER is assumed.
35    */
36    public ComposeShader(Shader shaderA, Shader shaderB, Xfermode mode) {
37        this(shaderA, shaderB, mode.porterDuffMode);
38    }
39
40    /** Create a new compose shader, given shaders A, B, and a combining PorterDuff mode.
41        When the mode is applied, it will be given the result from shader A as its
42        "dst", and the result from shader B as its "src".
43        @param shaderA  The colors from this shader are seen as the "dst" by the mode
44        @param shaderB  The colors from this shader are seen as the "src" by the mode
45        @param mode     The PorterDuff mode that combines the colors from the two shaders.
46    */
47    public ComposeShader(Shader shaderA, Shader shaderB, PorterDuff.Mode mode) {
48        this(shaderA, shaderB, mode.nativeInt);
49    }
50
51    private ComposeShader(Shader shaderA, Shader shaderB, int nativeMode) {
52        mShaderA = shaderA;
53        mShaderB = shaderB;
54        mPorterDuffMode = nativeMode;
55        init(nativeCreate(shaderA.getNativeInstance(), shaderB.getNativeInstance(),
56                nativeMode));
57    }
58
59    /**
60     * @hide
61     */
62    @Override
63    protected Shader copy() {
64        final ComposeShader copy = new ComposeShader(
65                mShaderA.copy(), mShaderB.copy(), mPorterDuffMode);
66        copyLocalMatrix(copy);
67        return copy;
68    }
69
70    private static native long nativeCreate(long native_shaderA, long native_shaderB,
71            int porterDuffMode);
72}
73