Transformation.java revision 54b6cfa9a9e5b861a9930af873580d6dc20f773c
1/* 2 * Copyright (C) 2006 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.view.animation; 18 19import android.graphics.Matrix; 20 21/** 22 * Defines the transformation to be applied at 23 * one point in time of an Animation. 24 * 25 */ 26public class Transformation { 27 /** 28 * Indicates a transformation that has no effect (alpha = 1 and identity matrix.) 29 */ 30 public static int TYPE_IDENTITY = 0x0; 31 /** 32 * Indicates a transformation that applies an alpha only (uses an identity matrix.) 33 */ 34 public static int TYPE_ALPHA = 0x1; 35 /** 36 * Indicates a transformation that applies a matrix only (alpha = 1.) 37 */ 38 public static int TYPE_MATRIX = 0x2; 39 /** 40 * Indicates a transformation that applies an alpha and a matrix. 41 */ 42 public static int TYPE_BOTH = TYPE_ALPHA | TYPE_MATRIX; 43 44 protected Matrix mMatrix; 45 protected float mAlpha; 46 protected int mTransformationType; 47 48 /** 49 * Creates a new transformation with alpha = 1 and the identity matrix. 50 */ 51 public Transformation() { 52 clear(); 53 } 54 55 /** 56 * Reset the transformation to a state that leaves the object 57 * being animated in an unmodified state. The transformation type is 58 * {@link #TYPE_BOTH} by default. 59 */ 60 public void clear() { 61 if (mMatrix == null) { 62 mMatrix = new Matrix(); 63 } else { 64 mMatrix.reset(); 65 } 66 mAlpha = 1.0f; 67 mTransformationType = TYPE_BOTH; 68 } 69 70 /** 71 * Indicates the nature of this transformation. 72 * 73 * @return {@link #TYPE_ALPHA}, {@link #TYPE_MATRIX}, 74 * {@link #TYPE_BOTH} or {@link #TYPE_IDENTITY}. 75 */ 76 public int getTransformationType() { 77 return mTransformationType; 78 } 79 80 /** 81 * Sets the transformation type. 82 * 83 * @param transformationType One of {@link #TYPE_ALPHA}, 84 * {@link #TYPE_MATRIX}, {@link #TYPE_BOTH} or 85 * {@link #TYPE_IDENTITY}. 86 */ 87 public void setTransformationType(int transformationType) { 88 mTransformationType = transformationType; 89 } 90 91 /** 92 * Clones the specified transformation. 93 * 94 * @param t The transformation to clone. 95 */ 96 public void set(Transformation t) { 97 mAlpha = t.getAlpha(); 98 mMatrix.set(t.getMatrix()); 99 mTransformationType = t.getTransformationType(); 100 } 101 102 /** 103 * Apply this Transformation to an existing Transformation, e.g. apply 104 * a scale effect to something that has already been rotated. 105 * @param t 106 */ 107 public void compose(Transformation t) { 108 mAlpha *= t.getAlpha(); 109 mMatrix.preConcat(t.getMatrix()); 110 } 111 112 /** 113 * @return The 3x3 Matrix representing the trnasformation to apply to the 114 * coordinates of the object being animated 115 */ 116 public Matrix getMatrix() { 117 return mMatrix; 118 } 119 120 /** 121 * Sets the degree of transparency 122 * @param alpha 1.0 means fully opaqe and 0.0 means fully transparent 123 */ 124 public void setAlpha(float alpha) { 125 mAlpha = alpha; 126 } 127 128 /** 129 * @return The degree of transparency 130 */ 131 public float getAlpha() { 132 return mAlpha; 133 } 134 135 @Override 136 public String toString() { 137 return "Transformation{alpha=" + mAlpha + " matrix=" + mMatrix + "}"; 138 } 139} 140