Shader.java revision ab87983a11e0bd2e08d752d86d5e945ea7d39a04 
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.graphics;
18
19/**
20 * Shader is the based class for objects that return horizontal spans of colors
21 * during drawing. A subclass of Shader is installed in a Paint calling
22 * paint.setShader(shader). After that any object (other than a bitmap) that is
23 * drawn with that paint will get its color(s) from the shader.
24 */
25public class Shader {
26    /**
27     * This is set by subclasses, but don't make it public.
28     *
29     * @hide
30     */
31    public long native_instance;
32
33    private Matrix mLocalMatrix;
34
35    public enum TileMode {
36        /**
37         * replicate the edge color if the shader draws outside of its
38         * original bounds
39         */
40        CLAMP   (0),
41        /**
42         * repeat the shader's image horizontally and vertically
43         */
44        REPEAT  (1),
45        /**
46         * repeat the shader's image horizontally and vertically, alternating
47         * mirror images so that adjacent images always seam
48         */
49        MIRROR  (2);
50
51        TileMode(int nativeInt) {
52            this.nativeInt = nativeInt;
53        }
54        final int nativeInt;
55    }
56
57    /**
58     * Return true if the shader has a non-identity local matrix.
59     * @param localM If not null, it is set to the shader's local matrix.
60     * @return true if the shader has a non-identity local matrix
61     */
62    public boolean getLocalMatrix(Matrix localM) {
63        if (mLocalMatrix != null) {
64            localM.set(mLocalMatrix);
65            return !mLocalMatrix.isIdentity();
66        }
67        return false;
68    }
69
70    /**
71     * Set the shader's local matrix. Passing null will reset the shader's
72     * matrix to identity.
73     *
74     * Starting with {@link android.os.Build.VERSION_CODES#L}, this does not
75     * modify any Paints which use this Shader. In order to modify the Paint,
76     * you need to call {@link Paint#setShader} again.
77     *
78     * @param localM The shader's new local matrix, or null to specify identity
79     */
80    public void setLocalMatrix(Matrix localM) {
81        mLocalMatrix = localM;
82        native_instance = nativeSetLocalMatrix(native_instance,
83                localM == null ? 0 : localM.native_instance);
84    }
85
86    protected void finalize() throws Throwable {
87        try {
88            super.finalize();
89        } finally {
90            nativeDestructor(native_instance);
91        }
92    }
93
94    /**
95     * @hide
96     */
97    protected Shader copy() {
98        final Shader copy = new Shader();
99        copyLocalMatrix(copy);
100        return copy;
101    }
102
103    /**
104     * @hide
105     */
106    protected void copyLocalMatrix(Shader dest) {
107        if (mLocalMatrix != null) {
108            final Matrix lm = new Matrix();
109            getLocalMatrix(lm);
110            dest.setLocalMatrix(lm);
111        } else {
112            dest.setLocalMatrix(null);
113        }
114    }
115
116    private static native void nativeDestructor(long native_shader);
117    private static native long nativeSetLocalMatrix(long native_shader,
118            long matrix_instance);
119}
120