1/*
2 * Copyright (c) 1996, 2014, 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
6 * under the terms of the GNU General Public License version 2 only, as
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 *
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24 */
25
26package java.awt.image;
27
28import java.awt.image.ImageConsumer;
29import java.awt.image.ColorModel;
30import java.util.Hashtable;
31import 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 */
51public 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} array containing information about a
75     * row of pixels.
76     */
77    protected int srcrows[];
78
79    /**
80     * An {@code int} array containing information about a
81     * column of pixels.
82     */
83    protected int srccols[];
84
85    /**
86     * A {@code byte} 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} equals
98     *         zero or {@code height} 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},
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} of the {@code Image} 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        @SuppressWarnings("unchecked")
125        Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();
126        String key = "rescale";
127        String val = destWidth + "x" + destHeight;
128        Object o = p.get(key);
129        if (o != null && o instanceof String) {
130            val = ((String) o) + ", " + val;
131        }
132        p.put(key, val);
133        super.setProperties(p);
134    }
135
136    /**
137     * Override the dimensions of the source image and pass the dimensions
138     * of the new scaled size to the ImageConsumer.
139     * <p>
140     * Note: This method is intended to be called by the
141     * {@code ImageProducer} of the {@code Image} whose pixels
142     * are being filtered. Developers using
143     * this class to filter pixels from an image should avoid calling
144     * this method directly since that operation could interfere
145     * with the filtering operation.
146     * @see ImageConsumer
147     */
148    public void setDimensions(int w, int h) {
149        srcWidth = w;
150        srcHeight = h;
151        if (destWidth < 0) {
152            if (destHeight < 0) {
153                destWidth = srcWidth;
154                destHeight = srcHeight;
155            } else {
156                destWidth = srcWidth * destHeight / srcHeight;
157            }
158        } else if (destHeight < 0) {
159            destHeight = srcHeight * destWidth / srcWidth;
160        }
161        consumer.setDimensions(destWidth, destHeight);
162    }
163
164    private void calculateMaps() {
165        srcrows = new int[destHeight + 1];
166        for (int y = 0; y <= destHeight; y++) {
167            srcrows[y] = (2 * y * srcHeight + srcHeight) / (2 * destHeight);
168        }
169        srccols = new int[destWidth + 1];
170        for (int x = 0; x <= destWidth; x++) {
171            srccols[x] = (2 * x * srcWidth + srcWidth) / (2 * destWidth);
172        }
173    }
174
175    /**
176     * Choose which rows and columns of the delivered byte pixels are
177     * needed for the destination scaled image and pass through just
178     * those rows and columns that are needed, replicated as necessary.
179     * <p>
180     * Note: This method is intended to be called by the
181     * {@code ImageProducer} of the {@code Image} whose pixels
182     * are being filtered. Developers using
183     * this class to filter pixels from an image should avoid calling
184     * this method directly since that operation could interfere
185     * with the filtering operation.
186     */
187    public void setPixels(int x, int y, int w, int h,
188                          ColorModel model, byte pixels[], int off,
189                          int scansize) {
190        if (srcrows == null || srccols == null) {
191            calculateMaps();
192        }
193        int sx, sy;
194        int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
195        int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
196        byte outpix[];
197        if (outpixbuf != null && outpixbuf instanceof byte[]) {
198            outpix = (byte[]) outpixbuf;
199        } else {
200            outpix = new byte[destWidth];
201            outpixbuf = outpix;
202        }
203        for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
204            int srcoff = off + scansize * (sy - y);
205            int dx;
206            for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
207                outpix[dx] = pixels[srcoff + sx - x];
208            }
209            if (dx > dx1) {
210                consumer.setPixels(dx1, dy, dx - dx1, 1,
211                                   model, outpix, dx1, destWidth);
212            }
213        }
214    }
215
216    /**
217     * Choose which rows and columns of the delivered int pixels are
218     * needed for the destination scaled image and pass through just
219     * those rows and columns that are needed, replicated as necessary.
220     * <p>
221     * Note: This method is intended to be called by the
222     * {@code ImageProducer} of the {@code Image} whose pixels
223     * are being filtered. Developers using
224     * this class to filter pixels from an image should avoid calling
225     * this method directly since that operation could interfere
226     * with the filtering operation.
227     */
228    public void setPixels(int x, int y, int w, int h,
229                          ColorModel model, int pixels[], int off,
230                          int scansize) {
231        if (srcrows == null || srccols == null) {
232            calculateMaps();
233        }
234        int sx, sy;
235        int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
236        int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
237        int outpix[];
238        if (outpixbuf != null && outpixbuf instanceof int[]) {
239            outpix = (int[]) outpixbuf;
240        } else {
241            outpix = new int[destWidth];
242            outpixbuf = outpix;
243        }
244        for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
245            int srcoff = off + scansize * (sy - y);
246            int dx;
247            for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
248                outpix[dx] = pixels[srcoff + sx - x];
249            }
250            if (dx > dx1) {
251                consumer.setPixels(dx1, dy, dx - dx1, 1,
252                                   model, outpix, dx1, destWidth);
253            }
254        }
255    }
256}
257