RadialGradient.java revision 8a985d24ce9a38f40ed88fecbdcd0e75e3a68f44 
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
19public class RadialGradient extends Shader {
20
21    private static final int TYPE_COLORS_AND_POSITIONS = 1;
22    private static final int TYPE_COLOR_CENTER_AND_COLOR_EDGE = 2;
23
24    /**
25     * Type of the RadialGradient: can be either TYPE_COLORS_AND_POSITIONS or
26     * TYPE_COLOR_CENTER_AND_COLOR_EDGE.
27     */
28    private int mType;
29
30    private float mX;
31    private float mY;
32    private float mRadius;
33    private int[] mColors;
34    private float[] mPositions;
35    private int mColor0;
36    private int mColor1;
37
38    private TileMode mTileMode;
39
40    /** Create a shader that draws a radial gradient given the center and radius.
41        @param x        The x-coordinate of the center of the radius
42        @param y        The y-coordinate of the center of the radius
43        @param radius   Must be positive. The radius of the circle for this gradient
44        @param colors   The colors to be distributed between the center and edge of the circle
45        @param positions May be NULL. The relative position of
46                        each corresponding color in the colors array. If this is NULL,
47                        the the colors are distributed evenly between the center and edge of the circle.
48        @param  tile    The Shader tiling mode
49    */
50    public RadialGradient(float x, float y, float radius,
51                          int colors[], float positions[], TileMode tile) {
52        if (radius <= 0) {
53            throw new IllegalArgumentException("radius must be > 0");
54        }
55        if (colors.length < 2) {
56            throw new IllegalArgumentException("needs >= 2 number of colors");
57        }
58        if (positions != null && colors.length != positions.length) {
59            throw new IllegalArgumentException("color and position arrays must be of equal length");
60        }
61        mType = TYPE_COLORS_AND_POSITIONS;
62        mX = x;
63        mY = y;
64        mRadius = radius;
65        mColors = colors;
66        mPositions = positions;
67        mTileMode = tile;
68        native_instance = nativeCreate1(x, y, radius, colors, positions, tile.nativeInt);
69        native_shader = nativePostCreate1(native_instance, x, y, radius, colors, positions,
70                tile.nativeInt);
71    }
72
73    /** Create a shader that draws a radial gradient given the center and radius.
74        @param x        The x-coordinate of the center of the radius
75        @param y        The y-coordinate of the center of the radius
76        @param radius   Must be positive. The radius of the circle for this gradient
77        @param color0   The color at the center of the circle.
78        @param color1   The color at the edge of the circle.
79        @param tile     The Shader tiling mode
80    */
81    public RadialGradient(float x, float y, float radius,
82                          int color0, int color1, TileMode tile) {
83        if (radius <= 0) {
84            throw new IllegalArgumentException("radius must be > 0");
85        }
86        mType = TYPE_COLOR_CENTER_AND_COLOR_EDGE;
87        mX = x;
88        mY = y;
89        mRadius = radius;
90        mColor0 = color0;
91        mColor1 = color1;
92        mTileMode = tile;
93        native_instance = nativeCreate2(x, y, radius, color0, color1, tile.nativeInt);
94        native_shader = nativePostCreate2(native_instance, x, y, radius, color0, color1,
95                tile.nativeInt);
96    }
97
98    /**
99     * @hide
100     */
101    @Override
102    protected Shader copy() {
103        final RadialGradient copy;
104        switch (mType) {
105            case TYPE_COLORS_AND_POSITIONS:
106                copy = new RadialGradient(mX, mY, mRadius, mColors.clone(),
107                        mPositions != null ? mPositions.clone() : null, mTileMode);
108                break;
109            case TYPE_COLOR_CENTER_AND_COLOR_EDGE:
110                copy = new RadialGradient(mX, mY, mRadius, mColor0, mColor1, mTileMode);
111                break;
112            default:
113                throw new IllegalArgumentException("RadialGradient should be created with either " +
114                        "colors and positions or center color and edge color");
115        }
116        copyLocalMatrix(copy);
117        return copy;
118    }
119
120    private static native long nativeCreate1(float x, float y, float radius,
121            int colors[], float positions[], int tileMode);
122    private static native long nativeCreate2(float x, float y, float radius,
123            int color0, int color1, int tileMode);
124
125    private static native long nativePostCreate1(long native_shader, float x, float y, float radius,
126            int colors[], float positions[], int tileMode);
127    private static native long nativePostCreate2(long native_shader, float x, float y, float radius,
128            int color0, int color1, int tileMode);
129}
130
131