Source for gnu.java.awt.java2d.ImagePaint

   1: /* ImagePaint.java -- Supplies the pixels for image rendering
   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.Paint;
  42: import java.awt.PaintContext;
  43: import java.awt.Rectangle;
  44: import java.awt.RenderingHints;
  45: import java.awt.Transparency;
  46: import java.awt.geom.AffineTransform;
  47: import java.awt.geom.Rectangle2D;
  48: import java.awt.image.ColorModel;
  49: import java.awt.image.Raster;
  50: import java.awt.image.RenderedImage;
  51: import java.awt.image.WritableRaster;
  52: 
  53: /**
  54:  * This class is used as a temporary Paint object to supply the pixel values
  55:  * for image rendering using the normal scanline conversion implementation.
  56:  *
  57:  * @author Roman Kennke (kennke@aicas.com)
  58:  */
  59: public class ImagePaint
  60:   implements Paint
  61: {
  62: 
  63:   /**
  64:    * The PaintContext implementation for the ImagePaint.
  65:    */
  66:   private class ImagePaintContext
  67:     implements PaintContext
  68:   {
  69: 
  70:     /**
  71:      * The target raster.
  72:      */
  73:     private WritableRaster target;
  74: 
  75:     /**
  76:      * Nothing to do here.
  77:      */
  78:     public void dispose()
  79:     {
  80:       // Nothing to do here.
  81:     }
  82: 
  83:     /**
  84:      * Returns the color model.
  85:      *
  86:      * @return the color model
  87:      */
  88:     public ColorModel getColorModel()
  89:     {
  90:       return image.getColorModel();
  91:     }
  92: 
  93:     /**
  94:      * Supplies the pixel to be rendered.
  95:      *
  96:      * @see PaintContext#getRaster(int, int, int, int)
  97:      */
  98:     public Raster getRaster(int x1, int y1, int w, int h)
  99:     {
 100:       ensureRasterSize(w, h);
 101:       int x2 = x1 + w;
 102:       int y2 = y1 + h;
 103:       float[] src = new float[2];
 104:       float[] dest = new float[2];
 105:       Raster source = image.getData();
 106:       int minX = source.getMinX();
 107:       int maxX = source.getWidth() + minX;
 108:       int minY = source.getMinY();
 109:       int maxY = source.getHeight() + minY;
 110:       Object pixel = null;
 111:       for (int y = y1; y < y2; y++)
 112:         {
 113:           for (int x = x1; x < x2; x++)
 114:             {
 115:               src[0] = x;
 116:               src[1] = y;
 117:               transform.transform(src, 0, dest, 0, 1);
 118:               int dx = (int) dest[0];
 119:               int dy = (int) dest[1];
 120:               // Pixels outside the source image are not of interest, skip
 121:               // them.
 122:               if (dx >= minX && dx < maxX && dy >= minY && dy < maxY)
 123:                 {
 124:                   pixel = source.getDataElements(dx, dy, pixel);
 125:                   target.setDataElements(x - x1, y - y1, pixel);
 126:                 }
 127:             }
 128:         }
 129:       return target;
 130:     }
 131: 
 132:     /**
 133:      * Ensures that the target raster exists and has at least the specified
 134:      * size.
 135:      *
 136:      * @param w the requested target width
 137:      * @param h the requested target height
 138:      */
 139:     private void ensureRasterSize(int w, int h)
 140:     {
 141:       if (target == null || target.getWidth() < w || target.getHeight() < h)
 142:         {
 143:           Raster s = image.getData();
 144:           target = s.createCompatibleWritableRaster(w, h);
 145:         }
 146:     }
 147:   }
 148: 
 149:   /**
 150:    * The image to render.
 151:    */
 152:   RenderedImage image;
 153: 
 154:   /**
 155:    * The transform from image space to device space. This is the inversed
 156:    * transform of the concatenated
 157:    * transform image space -> user space -> device space transform.
 158:    */
 159:   AffineTransform transform;
 160: 
 161:   /**
 162:    * Creates a new ImagePaint for rendering the specified image using the
 163:    * specified device space -> image space transform. This transform
 164:    * is the inversed transform of the usual image space -> user space -> device
 165:    * space transform.
 166:    *
 167:    * The ImagePaint will only render the image in the specified area of
 168:    * interest (which is specified in image space).
 169:    *
 170:    * @param i the image to render
 171:    * @param t the device space to user space transform
 172:    */
 173:   ImagePaint(RenderedImage i, AffineTransform t)
 174:   {
 175:     image = i;
 176:     transform = t;
 177:   }
 178: 
 179:   public PaintContext createContext(ColorModel cm, Rectangle deviceBounds,
 180:                                     Rectangle2D userBounds,
 181:                                     AffineTransform xform,
 182:                                     RenderingHints hints)
 183:   {
 184:     return new ImagePaintContext();
 185:   }
 186: 
 187:   public int getTransparency()
 188:   {
 189:     return Transparency.OPAQUE;
 190:   }
 191: 
 192: }