1/*
2 * Copyright (C) 2010 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
19import com.android.ide.common.rendering.api.LayoutLog;
20import com.android.layoutlib.bridge.Bridge;
21import com.android.layoutlib.bridge.impl.DelegateManager;
22import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
23
24import android.graphics.Shader.TileMode;
25
26import java.awt.image.ColorModel;
27
28/**
29 * Delegate implementing the native methods of android.graphics.RadialGradient
30 *
31 * Through the layoutlib_create tool, the original native methods of RadialGradient have been
32 * replaced by calls to methods of the same name in this delegate class.
33 *
34 * This class behaves like the original native implementation, but in Java, keeping previously
35 * native data into its own objects and mapping them to int that are sent back and forth between
36 * it and the original RadialGradient class.
37 *
38 * Because this extends {@link Shader_Delegate}, there's no need to use a {@link DelegateManager},
39 * as all the Shader classes will be added to the manager owned by {@link Shader_Delegate}.
40 *
41 * @see Shader_Delegate
42 *
43 */
44public class RadialGradient_Delegate extends Gradient_Delegate {
45
46    // ---- delegate data ----
47    private java.awt.Paint mJavaPaint;
48
49    // ---- Public Helper methods ----
50
51    @Override
52    public java.awt.Paint getJavaPaint() {
53        return mJavaPaint;
54    }
55
56    // ---- native methods ----
57
58    @LayoutlibDelegate
59    /*package*/ static long nativeCreate1(long matrix, float x, float y, float radius,
60            int colors[], float positions[], int tileMode) {
61        RadialGradient_Delegate newDelegate = new RadialGradient_Delegate(matrix, x, y, radius,
62                colors, positions, Shader_Delegate.getTileMode(tileMode));
63        return sManager.addNewDelegate(newDelegate);
64    }
65
66    @LayoutlibDelegate
67    /*package*/ static long nativeCreate2(long matrix, float x, float y, float radius,
68            int color0, int color1, int tileMode) {
69        return nativeCreate1(matrix, x, y, radius, new int[] { color0, color1 },
70                null /*positions*/, tileMode);
71    }
72
73    // ---- Private delegate/helper methods ----
74
75    /**
76     * Create a shader that draws a radial gradient given the center and radius.
77     *
78     * @param nativeMatrix reference to the shader's native transformation matrix
79     * @param x The x-coordinate of the center of the radius
80     * @param y The y-coordinate of the center of the radius
81     * @param radius Must be positive. The radius of the circle for this
82     *            gradient
83     * @param colors The colors to be distributed between the center and edge of
84     *            the circle
85     * @param positions May be NULL. The relative position of each corresponding
86     *            color in the colors array. If this is NULL, the the colors are
87     *            distributed evenly between the center and edge of the circle.
88     * @param tile The Shader tiling mode
89     */
90    private RadialGradient_Delegate(long nativeMatrix, float x, float y, float radius,
91            int colors[], float positions[], TileMode tile) {
92        super(nativeMatrix, colors, positions);
93        mJavaPaint = new RadialGradientPaint(x, y, radius, mColors, mPositions, tile);
94    }
95
96    private class RadialGradientPaint extends GradientPaint {
97
98        private final float mX;
99        private final float mY;
100        private final float mRadius;
101
102        public RadialGradientPaint(float x, float y, float radius,
103                int[] colors, float[] positions, TileMode mode) {
104            super(colors, positions, mode);
105            mX = x;
106            mY = y;
107            mRadius = radius;
108        }
109
110        @Override
111        public java.awt.PaintContext createContext(
112                java.awt.image.ColorModel     colorModel,
113                java.awt.Rectangle            deviceBounds,
114                java.awt.geom.Rectangle2D     userBounds,
115                java.awt.geom.AffineTransform xform,
116                java.awt.RenderingHints       hints) {
117            precomputeGradientColors();
118
119            java.awt.geom.AffineTransform canvasMatrix;
120            try {
121                canvasMatrix = xform.createInverse();
122            } catch (java.awt.geom.NoninvertibleTransformException e) {
123                Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE,
124                        "Unable to inverse matrix in RadialGradient", e, null /*data*/);
125                canvasMatrix = new java.awt.geom.AffineTransform();
126            }
127
128            java.awt.geom.AffineTransform localMatrix = getLocalMatrix();
129            try {
130                localMatrix = localMatrix.createInverse();
131            } catch (java.awt.geom.NoninvertibleTransformException e) {
132                Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE,
133                        "Unable to inverse matrix in RadialGradient", e, null /*data*/);
134                localMatrix = new java.awt.geom.AffineTransform();
135            }
136
137            return new RadialGradientPaintContext(canvasMatrix, localMatrix, colorModel);
138        }
139
140        private class RadialGradientPaintContext implements java.awt.PaintContext {
141
142            private final java.awt.geom.AffineTransform mCanvasMatrix;
143            private final java.awt.geom.AffineTransform mLocalMatrix;
144            private final java.awt.image.ColorModel mColorModel;
145
146            public RadialGradientPaintContext(
147                    java.awt.geom.AffineTransform canvasMatrix,
148                    java.awt.geom.AffineTransform localMatrix,
149                    java.awt.image.ColorModel colorModel) {
150                mCanvasMatrix = canvasMatrix;
151                mLocalMatrix = localMatrix;
152                mColorModel = colorModel.hasAlpha() ? colorModel : ColorModel.getRGBdefault();
153            }
154
155            @Override
156            public void dispose() {
157            }
158
159            @Override
160            public java.awt.image.ColorModel getColorModel() {
161                return mColorModel;
162            }
163
164            @Override
165            public java.awt.image.Raster getRaster(int x, int y, int w, int h) {
166                java.awt.image.BufferedImage image = new java.awt.image.BufferedImage(
167                    mColorModel, mColorModel.createCompatibleWritableRaster(w, h),
168                    mColorModel.isAlphaPremultiplied(), null);
169
170                int[] data = new int[w*h];
171
172                // compute distance from each point to the center, and figure out the distance from
173                // it.
174                int index = 0;
175                float[] pt1 = new float[2];
176                float[] pt2 = new float[2];
177                for (int iy = 0 ; iy < h ; iy++) {
178                    for (int ix = 0 ; ix < w ; ix++) {
179                        // handle the canvas transform
180                        pt1[0] = x + ix;
181                        pt1[1] = y + iy;
182                        mCanvasMatrix.transform(pt1, 0, pt2, 0, 1);
183
184                        // handle the local matrix
185                        pt1[0] = pt2[0] - mX;
186                        pt1[1] = pt2[1] - mY;
187                        mLocalMatrix.transform(pt1, 0, pt2, 0, 1);
188
189                        float _x = pt2[0];
190                        float _y = pt2[1];
191                        float distance = (float) Math.hypot(_x, _y);
192
193                        data[index++] = getGradientColor(distance / mRadius);
194                    }
195                }
196
197                image.setRGB(0 /*startX*/, 0 /*startY*/, w, h, data, 0 /*offset*/, w /*scansize*/);
198
199                return image.getRaster();
200            }
201
202        }
203    }
204
205}
206