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 import java.awt.image.ColorModel; 27 import java.awt.image.DataBufferInt; 28 import java.awt.image.Raster; 29 import java.awt.image.SampleModel; 30 31 /** 32 * Delegate implementing the native methods of android.graphics.LinearGradient 33 * 34 * Through the layoutlib_create tool, the original native methods of LinearGradient have been 35 * replaced by calls to methods of the same name in this delegate class. 36 * 37 * This class behaves like the original native implementation, but in Java, keeping previously 38 * native data into its own objects and mapping them to int that are sent back and forth between 39 * it and the original LinearGradient class. 40 * 41 * Because this extends {@link Shader_Delegate}, there's no need to use a {@link DelegateManager}, 42 * as all the Shader classes will be added to the manager owned by {@link Shader_Delegate}. 43 * 44 * @see Shader_Delegate 45 * 46 */ 47 public final class LinearGradient_Delegate extends Gradient_Delegate { 48 49 // ---- delegate data ---- 50 private java.awt.Paint mJavaPaint; 51 52 // ---- Public Helper methods ---- 53 54 @Override 55 public java.awt.Paint getJavaPaint() { 56 return mJavaPaint; 57 } 58 59 // ---- native methods ---- 60 61 @LayoutlibDelegate 62 /*package*/ static long nativeCreate1(LinearGradient thisGradient, long matrix, 63 float x0, float y0, float x1, float y1, 64 int colors[], float positions[], int tileMode) { 65 LinearGradient_Delegate newDelegate = new LinearGradient_Delegate(matrix, x0, y0, 66 x1, y1, colors, positions, Shader_Delegate.getTileMode(tileMode)); 67 return sManager.addNewDelegate(newDelegate); 68 } 69 70 @LayoutlibDelegate 71 /*package*/ static long nativeCreate2(LinearGradient thisGradient, long matrix, 72 float x0, float y0, float x1, float y1, 73 int color0, int color1, int tileMode) { 74 return nativeCreate1(thisGradient, matrix, x0, y0, x1, y1, new int[] { color0, color1}, 75 null /*positions*/, tileMode); 76 } 77 78 // ---- Private delegate/helper methods ---- 79 80 /** 81 * Create a shader that draws a linear gradient along a line. 82 * 83 * @param nativeMatrix reference to the shader's native transformation matrix 84 * @param x0 The x-coordinate for the start of the gradient line 85 * @param y0 The y-coordinate for the start of the gradient line 86 * @param x1 The x-coordinate for the end of the gradient line 87 * @param y1 The y-coordinate for the end of the gradient line 88 * @param colors The colors to be distributed along the gradient line 89 * @param positions May be null. The relative positions [0..1] of each 90 * corresponding color in the colors array. If this is null, the 91 * the colors are distributed evenly along the gradient line. 92 * @param tile The Shader tiling mode 93 */ 94 private LinearGradient_Delegate(long nativeMatrix, float x0, float y0, float x1, 95 float y1, int colors[], float positions[], TileMode tile) { 96 super(nativeMatrix, colors, positions); 97 mJavaPaint = new LinearGradientPaint(x0, y0, x1, y1, mColors, mPositions, tile); 98 } 99 100 // ---- Custom Java Paint ---- 101 /** 102 * Linear Gradient (Java) Paint able to handle more than 2 points, as 103 * {@link java.awt.GradientPaint} only supports 2 points and does not support Android's tile 104 * modes. 105 */ 106 private class LinearGradientPaint extends GradientPaint { 107 108 private final float mX0; 109 private final float mY0; 110 private final float mDx; 111 private final float mDy; 112 private final float mDSize2; 113 114 public LinearGradientPaint(float x0, float y0, float x1, float y1, int colors[], 115 float positions[], TileMode tile) { 116 super(colors, positions, tile); 117 mX0 = x0; 118 mY0 = y0; 119 mDx = x1 - x0; 120 mDy = y1 - y0; 121 mDSize2 = mDx * mDx + mDy * mDy; 122 } 123 124 @Override 125 public java.awt.PaintContext createContext( 126 java.awt.image.ColorModel colorModel, 127 java.awt.Rectangle deviceBounds, 128 java.awt.geom.Rectangle2D userBounds, 129 java.awt.geom.AffineTransform xform, 130 java.awt.RenderingHints hints) { 131 precomputeGradientColors(); 132 133 java.awt.geom.AffineTransform canvasMatrix; 134 try { 135 canvasMatrix = xform.createInverse(); 136 } catch (java.awt.geom.NoninvertibleTransformException e) { 137 Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE, 138 "Unable to inverse matrix in LinearGradient", e, null /*data*/); 139 canvasMatrix = new java.awt.geom.AffineTransform(); 140 } 141 142 java.awt.geom.AffineTransform localMatrix = getLocalMatrix(); 143 try { 144 localMatrix = localMatrix.createInverse(); 145 } catch (java.awt.geom.NoninvertibleTransformException e) { 146 Bridge.getLog().fidelityWarning(LayoutLog.TAG_MATRIX_INVERSE, 147 "Unable to inverse matrix in LinearGradient", e, null /*data*/); 148 localMatrix = new java.awt.geom.AffineTransform(); 149 } 150 151 return new LinearGradientPaintContext(canvasMatrix, localMatrix, colorModel); 152 } 153 154 private class LinearGradientPaintContext implements java.awt.PaintContext { 155 156 private final java.awt.geom.AffineTransform mCanvasMatrix; 157 private final java.awt.geom.AffineTransform mLocalMatrix; 158 private final java.awt.image.ColorModel mColorModel; 159 160 private LinearGradientPaintContext( 161 java.awt.geom.AffineTransform canvasMatrix, 162 java.awt.geom.AffineTransform localMatrix, 163 java.awt.image.ColorModel colorModel) { 164 mCanvasMatrix = canvasMatrix; 165 mLocalMatrix = localMatrix; 166 mColorModel = colorModel.hasAlpha() ? colorModel : ColorModel.getRGBdefault(); 167 } 168 169 @Override 170 public void dispose() { 171 } 172 173 @Override 174 public java.awt.image.ColorModel getColorModel() { 175 return mColorModel; 176 } 177 178 @Override 179 public java.awt.image.Raster getRaster(int x, int y, int w, int h) { 180 int[] data = new int[w*h]; 181 182 int index = 0; 183 float[] pt1 = new float[2]; 184 float[] pt2 = new float[2]; 185 for (int iy = 0 ; iy < h ; iy++) { 186 for (int ix = 0 ; ix < w ; ix++) { 187 // handle the canvas transform 188 pt1[0] = x + ix; 189 pt1[1] = y + iy; 190 mCanvasMatrix.transform(pt1, 0, pt2, 0, 1); 191 192 // handle the local matrix. 193 pt1[0] = pt2[0]; 194 pt1[1] = pt2[1]; 195 mLocalMatrix.transform(pt1, 0, pt2, 0, 1); 196 197 data[index++] = getColor(pt2[0], pt2[1]); 198 } 199 } 200 201 DataBufferInt dataBuffer = new DataBufferInt(data, data.length); 202 SampleModel colorModel = mColorModel.createCompatibleSampleModel(w, h); 203 return Raster.createWritableRaster(colorModel, dataBuffer, null); 204 } 205 } 206 207 /** 208 * Returns a color for an arbitrary point. 209 */ 210 private int getColor(float x, float y) { 211 float pos; 212 if (mDx == 0) { 213 pos = (y - mY0) / mDy; 214 } else if (mDy == 0) { 215 pos = (x - mX0) / mDx; 216 } else { 217 // find the x position on the gradient vector. 218 float _x = (mDx*mDy*(y-mY0) + mDy*mDy*mX0 + mDx*mDx*x) / mDSize2; 219 // from it get the position relative to the vector 220 pos = (_x - mX0) / mDx; 221 } 222 223 return getGradientColor(pos); 224 } 225 } 226 } 227
