Shader.java revision d1ad5e62fda248c6d185cde3cb6d9f01a223066c 
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     * @param localM The shader's new local matrix, or null to specify identity
74     */
75    public void setLocalMatrix(Matrix localM) {
76        mLocalMatrix = localM;
77        nativeSetLocalMatrix(native_instance,
78                localM == null ? 0 : localM.native_instance);
79    }
80
81    protected void finalize() throws Throwable {
82        try {
83            super.finalize();
84        } finally {
85            nativeDestructor(native_instance);
86        }
87    }
88
89    /**
90     * @hide
91     */
92    protected Shader copy() {
93        final Shader copy = new Shader();
94        copyLocalMatrix(copy);
95        return copy;
96    }
97
98    /**
99     * @hide
100     */
101    protected void copyLocalMatrix(Shader dest) {
102        if (mLocalMatrix != null) {
103            final Matrix lm = new Matrix();
104            getLocalMatrix(lm);
105            dest.setLocalMatrix(lm);
106        } else {
107            dest.setLocalMatrix(null);
108        }
109    }
110
111    private static native void nativeDestructor(long native_shader);
112    private static native void nativeSetLocalMatrix(long native_shader,
113            long matrix_instance);
114}
115