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 17 package android.graphics; 18 19 20 import android.annotation.NonNull; 21 22 /** A subclass of shader that returns the composition of two other shaders, combined by 23 an {@link android.graphics.Xfermode} subclass. 24 */ 25 public class ComposeShader extends Shader { 26 27 Shader mShaderA; 28 private long mNativeInstanceShaderA; 29 Shader mShaderB; 30 private long mNativeInstanceShaderB; 31 private int mPorterDuffMode; 32 33 /** 34 * Create a new compose shader, given shaders A, B, and a combining mode. 35 * When the mode is applied, it will be given the result from shader A as its 36 * "dst", and the result from shader B as its "src". 37 * 38 * @param shaderA The colors from this shader are seen as the "dst" by the mode 39 * @param shaderB The colors from this shader are seen as the "src" by the mode 40 * @param mode The mode that combines the colors from the two shaders. If mode 41 * is null, then SRC_OVER is assumed. 42 */ ComposeShader(@onNull Shader shaderA, @NonNull Shader shaderB, @NonNull Xfermode mode)43 public ComposeShader(@NonNull Shader shaderA, @NonNull Shader shaderB, @NonNull Xfermode mode) { 44 this(shaderA, shaderB, mode.porterDuffMode); 45 } 46 47 /** 48 * Create a new compose shader, given shaders A, B, and a combining PorterDuff mode. 49 * When the mode is applied, it will be given the result from shader A as its 50 * "dst", and the result from shader B as its "src". 51 * 52 * @param shaderA The colors from this shader are seen as the "dst" by the mode 53 * @param shaderB The colors from this shader are seen as the "src" by the mode 54 * @param mode The PorterDuff mode that combines the colors from the two shaders. 55 */ ComposeShader(@onNull Shader shaderA, @NonNull Shader shaderB, @NonNull PorterDuff.Mode mode)56 public ComposeShader(@NonNull Shader shaderA, @NonNull Shader shaderB, 57 @NonNull PorterDuff.Mode mode) { 58 this(shaderA, shaderB, mode.nativeInt); 59 } 60 ComposeShader(Shader shaderA, Shader shaderB, int nativeMode)61 private ComposeShader(Shader shaderA, Shader shaderB, int nativeMode) { 62 if (shaderA == null || shaderB == null) { 63 throw new IllegalArgumentException("Shader parameters must not be null"); 64 } 65 66 mShaderA = shaderA; 67 mShaderB = shaderB; 68 mPorterDuffMode = nativeMode; 69 } 70 71 @Override createNativeInstance(long nativeMatrix)72 long createNativeInstance(long nativeMatrix) { 73 mNativeInstanceShaderA = mShaderA.getNativeInstance(); 74 mNativeInstanceShaderB = mShaderB.getNativeInstance(); 75 return nativeCreate(nativeMatrix, 76 mShaderA.getNativeInstance(), mShaderB.getNativeInstance(), mPorterDuffMode); 77 } 78 79 /** @hide */ 80 @Override verifyNativeInstance()81 protected void verifyNativeInstance() { 82 if (mShaderA.getNativeInstance() != mNativeInstanceShaderA 83 || mShaderB.getNativeInstance() != mNativeInstanceShaderB) { 84 // Child shader native instance has been updated, 85 // so our cached native instance is no longer valid - discard it 86 discardNativeInstance(); 87 } 88 } 89 90 /** 91 * @hide 92 */ 93 @Override copy()94 protected Shader copy() { 95 final ComposeShader copy = new ComposeShader( 96 mShaderA.copy(), mShaderB.copy(), mPorterDuffMode); 97 copyLocalMatrix(copy); 98 return copy; 99 } 100 nativeCreate(long nativeMatrix, long nativeShaderA, long nativeShaderB, int porterDuffMode)101 private static native long nativeCreate(long nativeMatrix, 102 long nativeShaderA, long nativeShaderB, int porterDuffMode); 103 } 104