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 17 package android.graphics; 18 19 import com.android.ide.common.rendering.api.LayoutLog; 20 import com.android.layoutlib.bridge.Bridge; 21 import com.android.layoutlib.bridge.impl.DelegateManager; 22 import com.android.tools.layoutlib.annotations.LayoutlibDelegate; 23 24 import android.graphics.Shader.TileMode; 25 26 /** 27 * Delegate implementing the native methods of android.graphics.LinearGradient 28 * 29 * Through the layoutlib_create tool, the original native methods of LinearGradient have been 30 * replaced by calls to methods of the same name in this delegate class. 31 * 32 * This class behaves like the original native implementation, but in Java, keeping previously 33 * native data into its own objects and mapping them to int that are sent back and forth between 34 * it and the original LinearGradient class. 35 * 36 * Because this extends {@link Shader_Delegate}, there's no need to use a {@link DelegateManager}, 37 * as all the Shader classes will be added to the manager owned by {@link Shader_Delegate}. 38 * 39 * @see Shader_Delegate 40 * 41 */ 42 public final class LinearGradient_Delegate extends Gradient_Delegate { 43 44 // ---- delegate data ---- 45 private java.awt.Paint mJavaPaint; 46 47 // ---- Public Helper methods ---- 48 49 @Override 50 public java.awt.Paint getJavaPaint() { 51 return mJavaPaint; 52 } 53 54 // ---- native methods ---- 55 56 @LayoutlibDelegate 57 /*package*/ static long nativeCreate1(LinearGradient thisGradient, 58 float x0, float y0, float x1, float y1, 59 int colors[], float positions[], int tileMode) { 60 LinearGradient_Delegate newDelegate = new LinearGradient_Delegate(x0, y0, x1, y1, 61 colors, positions, Shader_Delegate.getTileMode(tileMode)); 62 return sManager.addNewDelegate(newDelegate); 63 } 64 65 @LayoutlibDelegate 66 /*package*/ static long nativeCreate2(LinearGradient thisGradient, 67 float x0, float y0, float x1, float y1, 68 int color0, int color1, int tileMode) { 69 return nativeCreate1(thisGradient, 70 x0, y0, x1, y1, new int[] { color0, color1}, null /*positions*/, 71 tileMode); 72 } 73 74 // ---- Private delegate/helper methods ---- 75 76 /** 77 * Create a shader that draws a linear gradient along a line. 78 * 79 * @param x0 The x-coordinate for the start of the gradient line 80 * @param y0 The y-coordinate for the start of the gradient line 81 * @param x1 The x-coordinate for the end of the gradient line 82 * @param y1 The y-coordinate for the end of the gradient line 83 * @param colors The colors to be distributed along the gradient line 84 * @param positions May be null. The relative positions [0..1] of each 85 * corresponding color in the colors array. If this is null, the 86 * the colors are distributed evenly along the gradient line. 87 * @param tile The Shader tiling mode 88 */ 89 private LinearGradient_Delegate(float x0, float y0, float x1, float y1, 90 int colors[], float positions[], TileMode tile) { 91 super(colors, positions); 92 mJavaPaint = new LinearGradientPaint(x0, y0, x1, y1, mColors, mPositions, tile); 93 } 94 95 // ---- Custom Java Paint ---- 96 /** 97 * Linear Gradient (Java) Paint able to handle more than 2 points, as 98 * {@link java.awt.GradientPaint} only supports 2 points and does not support Android's tile 99 * modes. 100 */ 101 private class LinearGradientPaint extends GradientPaint { 102 103 private final float mX0; 104 private final float mY0; 105 private final float mDx; 106 private final float mDy; 107 private final float mDSize2; 108 109 public LinearGradientPaint(float x0, float y0, float x1, float y1, int colors[], 110 float positions[], TileMode tile) { 111 super(colors, positions, tile); 112 mX0 = x0; 113 mY0 = y0; 114 mDx = x1 - x0; 115 mDy = y1 - y0; 116 mDSize2 = mDx * mDx + mDy * mDy; 117 } 118 119 @Override 120 public java.awt.PaintContext createContext( 121 java.awt.image.ColorModel colorModel, 122 java.awt.Rectangle deviceBounds, 123 java.awt.geom.Rectangle2D userBounds, 124 java.awt.geom.AffineTransform xform, 125 java.awt.RenderingHints hints) { 126 precomputeGradientColors(); 127 128 java.awt.geom.AffineTransform canvasMatrix; 129 try { 130 canvasMatrix = xform.createInverse(); 131 } catch (java.awt.geom.NoninvertibleTransformException e) { 132 Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE, 133 "Unable to inverse matrix in LinearGradient", e, null /*data*/); 134 canvasMatrix = new java.awt.geom.AffineTransform(); 135 } 136 137 java.awt.geom.AffineTransform localMatrix = getLocalMatrix(); 138 try { 139 localMatrix = localMatrix.createInverse(); 140 } catch (java.awt.geom.NoninvertibleTransformException e) { 141 Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE, 142 "Unable to inverse matrix in LinearGradient", e, null /*data*/); 143 localMatrix = new java.awt.geom.AffineTransform(); 144 } 145 146 return new LinearGradientPaintContext(canvasMatrix, localMatrix, colorModel); 147 } 148 149 private class LinearGradientPaintContext implements java.awt.PaintContext { 150 151 private final java.awt.geom.AffineTransform mCanvasMatrix; 152 private final java.awt.geom.AffineTransform mLocalMatrix; 153 private final java.awt.image.ColorModel mColorModel; 154 155 private LinearGradientPaintContext( 156 java.awt.geom.AffineTransform canvasMatrix, 157 java.awt.geom.AffineTransform localMatrix, 158 java.awt.image.ColorModel colorModel) { 159 mCanvasMatrix = canvasMatrix; 160 mLocalMatrix = localMatrix; 161 mColorModel = colorModel; 162 } 163 164 @Override 165 public void dispose() { 166 } 167 168 @Override 169 public java.awt.image.ColorModel getColorModel() { 170 return mColorModel; 171 } 172 173 @Override 174 public java.awt.image.Raster getRaster(int x, int y, int w, int h) { 175 java.awt.image.BufferedImage image = new java.awt.image.BufferedImage(w, h, 176 java.awt.image.BufferedImage.TYPE_INT_ARGB); 177 178 int[] data = new int[w*h]; 179 180 int index = 0; 181 float[] pt1 = new float[2]; 182 float[] pt2 = new float[2]; 183 for (int iy = 0 ; iy < h ; iy++) { 184 for (int ix = 0 ; ix < w ; ix++) { 185 // handle the canvas transform 186 pt1[0] = x + ix; 187 pt1[1] = y + iy; 188 mCanvasMatrix.transform(pt1, 0, pt2, 0, 1); 189 190 // handle the local matrix. 191 pt1[0] = pt2[0]; 192 pt1[1] = pt2[1]; 193 mLocalMatrix.transform(pt1, 0, pt2, 0, 1); 194 195 data[index++] = getColor(pt2[0], pt2[1]); 196 } 197 } 198 199 image.setRGB(0 /*startX*/, 0 /*startY*/, w, h, data, 0 /*offset*/, w /*scansize*/); 200 201 return image.getRaster(); 202 } 203 } 204 205 /** 206 * Returns a color for an arbitrary point. 207 */ 208 private int getColor(float x, float y) { 209 float pos; 210 if (mDx == 0) { 211 pos = (y - mY0) / mDy; 212 } else if (mDy == 0) { 213 pos = (x - mX0) / mDx; 214 } else { 215 // find the x position on the gradient vector. 216 float _x = (mDx*mDy*(y-mY0) + mDy*mDy*mX0 + mDx*mDx*x) / mDSize2; 217 // from it get the position relative to the vector 218 pos = (_x - mX0) / mDx; 219 } 220 221 return getGradientColor(pos); 222 } 223 } 224 } 225
