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1   /*
2    * Copyright (c) 1996, 2004, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
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7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
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19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
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25  
26  package java.awt.image;
27  
28  import java.awt.image.ImageConsumer;
29  import java.awt.image.ColorModel;
30  import java.util.Hashtable;
31  import java.awt.Rectangle;
32  
33  /**
34   * An ImageFilter class for scaling images using the simplest algorithm.
35   * This class extends the basic ImageFilter Class to scale an existing
36   * image and provide a source for a new image containing the resampled
37   * image.  The pixels in the source image are sampled to produce pixels
38   * for an image of the specified size by replicating rows and columns of
39   * pixels to scale up or omitting rows and columns of pixels to scale
40   * down.
41   * <p>It is meant to be used in conjunction with a FilteredImageSource
42   * object to produce scaled versions of existing images.  Due to
43   * implementation dependencies, there may be differences in pixel values
44   * of an image filtered on different platforms.
45   *
46   * @see FilteredImageSource
47   * @see ImageFilter
48   *
49   * @author      Jim Graham
50   */
51  public class ReplicateScaleFilter extends ImageFilter {
52  
53      /**
54       * The width of the source image.
55       */
56      protected int srcWidth;
57  
58      /**
59       * The height of the source image.
60       */
61      protected int srcHeight;
62  
63      /**
64       * The target width to scale the image.
65       */
66      protected int destWidth;
67  
68      /**
69       * The target height to scale the image.
70       */
71      protected int destHeight;
72  
73      /**
74       * An <code>int</code> array containing information about a
75       * row of pixels.
76       */
77      protected int srcrows[];
78  
79      /**
80       * An <code>int</code> array containing information about a
81       * column of pixels.
82       */
83      protected int srccols[];
84  
85      /**
86       * A <code>byte</code> array initialized with a size of
87       * {@link #destWidth} and used to deliver a row of pixel
88       * data to the {@link ImageConsumer}.
89       */
90      protected Object outpixbuf;
91  
92      /**
93       * Constructs a ReplicateScaleFilter that scales the pixels from
94       * its source Image as specified by the width and height parameters.
95       * @param width the target width to scale the image
96       * @param height the target height to scale the image
97       * @throws IllegalArgumentException if <code>width</code> equals
98       *         zero or <code>height</code> equals zero
99       */
100     public ReplicateScaleFilter(int width, int height) {
101         if (width == 0 || height == 0) {
102             throw new IllegalArgumentException("Width ("+width+
103                                                 ") and height ("+height+
104                                                 ") must be non-zero");
105         }
106         destWidth = width;
107         destHeight = height;
108     }
109 
110     /**
111      * Passes along the properties from the source object after adding a
112      * property indicating the scale applied.
113      * This method invokes <code>super.setProperties</code>,
114      * which might result in additional properties being added.
115      * <p>
116      * Note: This method is intended to be called by the
117      * <code>ImageProducer</code> of the <code>Image</code> whose pixels
118      * are being filtered. Developers using
119      * this class to filter pixels from an image should avoid calling
120      * this method directly since that operation could interfere
121      * with the filtering operation.
122      */
123     public void setProperties(Hashtable<?,?> props) {
124         Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();
125         String key = "rescale";
126         String val = destWidth + "x" + destHeight;
127         Object o = p.get(key);
128         if (o != null && o instanceof String) {
129             val = ((String) o) + ", " + val;
130         }
131         p.put(key, val);
132         super.setProperties(p);
133     }
134 
135     /**
136      * Override the dimensions of the source image and pass the dimensions
137      * of the new scaled size to the ImageConsumer.
138      * <p>
139      * Note: This method is intended to be called by the
140      * <code>ImageProducer</code> of the <code>Image</code> whose pixels
141      * are being filtered. Developers using
142      * this class to filter pixels from an image should avoid calling
143      * this method directly since that operation could interfere
144      * with the filtering operation.
145      * @see ImageConsumer
146      */
147     public void setDimensions(int w, int h) {
148         srcWidth = w;
149         srcHeight = h;
150         if (destWidth < 0) {
151             if (destHeight < 0) {
152                 destWidth = srcWidth;
153                 destHeight = srcHeight;
154             } else {
155                 destWidth = srcWidth * destHeight / srcHeight;
156             }
157         } else if (destHeight < 0) {
158             destHeight = srcHeight * destWidth / srcWidth;
159         }
160         consumer.setDimensions(destWidth, destHeight);
161     }
162 
163     private void calculateMaps() {
164         srcrows = new int[destHeight + 1];
165         for (int y = 0; y <= destHeight; y++) {
166             srcrows[y] = (2 * y * srcHeight + srcHeight) / (2 * destHeight);
167         }
168         srccols = new int[destWidth + 1];
169         for (int x = 0; x <= destWidth; x++) {
170             srccols[x] = (2 * x * srcWidth + srcWidth) / (2 * destWidth);
171         }
172     }
173 
174     /**
175      * Choose which rows and columns of the delivered byte pixels are
176      * needed for the destination scaled image and pass through just
177      * those rows and columns that are needed, replicated as necessary.
178      * <p>
179      * Note: This method is intended to be called by the
180      * <code>ImageProducer</code> of the <code>Image</code> whose pixels
181      * are being filtered. Developers using
182      * this class to filter pixels from an image should avoid calling
183      * this method directly since that operation could interfere
184      * with the filtering operation.
185      */
186     public void setPixels(int x, int y, int w, int h,
187                           ColorModel model, byte pixels[], int off,
188                           int scansize) {
189         if (srcrows == null || srccols == null) {
190             calculateMaps();
191         }
192         int sx, sy;
193         int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
194         int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
195         byte outpix[];
196         if (outpixbuf != null && outpixbuf instanceof byte[]) {
197             outpix = (byte[]) outpixbuf;
198         } else {
199             outpix = new byte[destWidth];
200             outpixbuf = outpix;
201         }
202         for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
203             int srcoff = off + scansize * (sy - y);
204             int dx;
205             for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
206                 outpix[dx] = pixels[srcoff + sx - x];
207             }
208             if (dx > dx1) {
209                 consumer.setPixels(dx1, dy, dx - dx1, 1,
210                                    model, outpix, dx1, destWidth);
211             }
212         }
213     }
214 
215     /**
216      * Choose which rows and columns of the delivered int pixels are
217      * needed for the destination scaled image and pass through just
218      * those rows and columns that are needed, replicated as necessary.
219      * <p>
220      * Note: This method is intended to be called by the
221      * <code>ImageProducer</code> of the <code>Image</code> whose pixels
222      * are being filtered. Developers using
223      * this class to filter pixels from an image should avoid calling
224      * this method directly since that operation could interfere
225      * with the filtering operation.
226      */
227     public void setPixels(int x, int y, int w, int h,
228                           ColorModel model, int pixels[], int off,
229                           int scansize) {
230         if (srcrows == null || srccols == null) {
231             calculateMaps();
232         }
233         int sx, sy;
234         int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
235         int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
236         int outpix[];
237         if (outpixbuf != null && outpixbuf instanceof int[]) {
238             outpix = (int[]) outpixbuf;
239         } else {
240             outpix = new int[destWidth];
241             outpixbuf = outpix;
242         }
243         for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
244             int srcoff = off + scansize * (sy - y);
245             int dx;
246             for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
247                 outpix[dx] = pixels[srcoff + sx - x];
248             }
249             if (dx > dx1) {
250                 consumer.setPixels(dx1, dy, dx - dx1, 1,
251                                    model, outpix, dx1, destWidth);
252             }
253         }
254     }
255 }