Source for gnu.java.awt.java2d.TexturePaintContext

   1: /* TexturePaintContext.java -- PaintContext impl for TexturePaint
   2:    Copyright (C) 2006 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.java.awt.java2d;
  40: 
  41: import java.awt.AWTError;
  42: import java.awt.PaintContext;
  43: import java.awt.Rectangle;
  44: import java.awt.TexturePaint;
  45: import java.awt.geom.AffineTransform;
  46: import java.awt.geom.NoninvertibleTransformException;
  47: import java.awt.geom.Rectangle2D;
  48: import java.awt.image.BufferedImage;
  49: import java.awt.image.ColorModel;
  50: import java.awt.image.Raster;
  51: import java.awt.image.WritableRaster;
  52: 
  53: /**
  54:  * A {@link PaintContext} implementation for {@link TexturePaint}, done in
  55:  * pure Java.
  56:  *
  57:  * @author Roman Kennke (kennke@aicas.com)
  58:  */
  59: public class TexturePaintContext
  60:   implements PaintContext
  61: {
  62: 
  63:   /**
  64:    * The TexturePaint object.
  65:    */
  66:   private BufferedImage image;
  67: 
  68:   /**
  69:    * The Raster that holds the texture.
  70:    */
  71:   private WritableRaster paintRaster;
  72: 
  73:   /**
  74:    * The transform from userspace into device space.
  75:    */
  76:   private AffineTransform transform;
  77: 
  78:   /**
  79:    * Creates a new TexturePaintContext for the specified TexturePaint object.
  80:    * This initializes the Raster which is returned by
  81:    * {@link #getRaster(int, int, int, int)}.
  82:    *
  83:    * @param t the texture paint object
  84:    * @param db the bounds of the target raster in device space
  85:    * @param ub the bounds of the target raster in user space
  86:    * @param xform the transformation from user space to device space
  87:    */
  88:   public TexturePaintContext(TexturePaint t, Rectangle db,
  89:                              Rectangle2D ub, AffineTransform xform)
  90:   {
  91:     image = t.getImage();
  92: 
  93:     try
  94:       {
  95:         // Prepare transform for mapping from device space into image space.
  96:         // In order to achieve this we take the transform for userspace->
  97:         // devicespace, append the correct scale and translation according
  98:         // to the anchor (which gives us the image->userspace->devicespace
  99:         // transform), and invert that (which gives use the device->user->image
 100:         // transform).
 101:         Rectangle2D anchor = t.getAnchorRect();
 102:         BufferedImage image = t.getImage();
 103:         double scaleX = anchor.getWidth() / image.getWidth();
 104:         double scaleY = anchor.getHeight() / image.getHeight();
 105:         transform = (AffineTransform) xform.clone();
 106:         transform.scale(scaleX, scaleY);
 107:         transform.translate(-anchor.getMinX(), -anchor.getMinY());
 108:         transform = transform.createInverse();
 109:       }
 110:     catch (NoninvertibleTransformException ex)
 111:       {
 112:         AWTError err =
 113:           new AWTError("Unexpected NoninvertibleTransformException");
 114:         err.initCause(ex);
 115:         throw err;
 116:       }
 117:   }
 118: 
 119:   /**
 120:    * Disposes the PaintContext. Nothing is to do here, since we don't use
 121:    * any native resources in that implementation.
 122:    */
 123:   public void dispose()
 124:   {
 125:     // Nothing to do here.
 126:   }
 127: 
 128:   /**
 129:    * Returns the color model of this PaintContext. This implementation returnes
 130:    * the color model used by the BufferedImage in the TexturePaint object,
 131:    * this avoids costly color model transformations (at least at this point).
 132:    *
 133:    * @return the color model of this PaintContext
 134:    */
 135:   public ColorModel getColorModel()
 136:   {
 137:     return image.getColorModel();
 138:   }
 139: 
 140:   /**
 141:    * Returns the Raster that is used for painting.
 142:    *
 143:    * @param x1 the x location of the raster inside the user bounds of this paint
 144:    *        context
 145:    * @param y1 the y location of the raster inside the user bounds of this paint
 146:    *        context
 147:    * @param w the width
 148:    * @param h the height
 149:    *
 150:    * @return the Raster that is used for painting
 151:    *
 152:    */
 153:   public Raster getRaster(int x1, int y1, int w, int h)
 154:   {
 155:     ensureRasterSize(w, h);
 156:     int x2 = x1 + w;
 157:     int y2 = y1 + h;
 158:     float[] src = new float[2];
 159:     float[] dest = new float[2];
 160:     Raster source = image.getData();
 161:     int minX = source.getMinX();
 162:     int width = source.getWidth();
 163:     int minY = source.getMinY();
 164:     int height = source.getHeight();
 165:     Object pixel = null;
 166:     for (int y = y1; y < y2; y++)
 167:       {
 168:         for (int x = x1; x < x2; x++)
 169:           {
 170:             // Transform the coordinates from device space into image space.
 171:             src[0] = x;
 172:             src[1] = y;
 173:             transform.transform(src, 0, dest, 0, 1);
 174:             int dx = (int) dest[0];
 175:             int dy = (int) dest[1];
 176: 
 177:             // The modulo operation gives us the replication effect.
 178:             dx = ((dx - minX) % width) + minX;
 179:             dy = ((dy - minY) % height) + minY;
 180: 
 181:             // Handle possible negative values (replicating above the top-left)
 182:             if (dx < 0)
 183:               dx += width;
 184:             if (dy < 0)
 185:               dy += height;
 186: 
 187:             // Copy the pixel.
 188:             pixel = source.getDataElements(dx, dy, pixel);
 189:             paintRaster.setDataElements(x - x1, y - y1, pixel);
 190:           }
 191:       }
 192:     return paintRaster;
 193:   }
 194: 
 195:   /**
 196:    * Ensures that the target raster exists and has at least the specified
 197:    * size.
 198:    *
 199:    * @param w the requested target width
 200:    * @param h the requested target height
 201:    */
 202:   private void ensureRasterSize(int w, int h)
 203:   {
 204:     if (paintRaster == null || paintRaster.getWidth() < w
 205:         || paintRaster.getHeight() < h)
 206:       {
 207:         Raster s = image.getData();
 208:         paintRaster = s.createCompatibleWritableRaster(w, h);
 209:       }
 210:   }
 211: }