01: /**
02: * Copyright (c) 2005, www.pdfbox.org
03: * All rights reserved.
04: *
05: * Redistribution and use in source and binary forms, with or without
06: * modification, are permitted provided that the following conditions are met:
07: *
08: * 1. Redistributions of source code must retain the above copyright notice,
09: * this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright notice,
11: * this list of conditions and the following disclaimer in the documentation
12: * and/or other materials provided with the distribution.
13: * 3. Neither the name of pdfbox; nor the names of its
14: * contributors may be used to endorse or promote products derived from this
15: * software without specific prior written permission.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20: * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
21: * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22: * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23: * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
24: * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27: *
28: * http://www.pdfbox.org
29: *
30: */package org.pdfbox.pdmodel.graphics.predictor;
31:
32: /**
33: * The sub algorithm.
34: *
35: * <code>Sub(i,j) = Raw(i,j) - Raw(i-1,j)</code>
36: *
37: * <code>Raw(i,j) = Sub(i,j) + Raw(i-1,j)</code>
38: *
39: * @author xylifyx@yahoo.co.uk
40: * @version $Revision: 1.3 $
41: */
42: public class Sub extends PredictorAlgorithm {
43: /**
44: * {@inheritDoc}
45: */
46: public void encodeLine(byte[] src, byte[] dest, int srcDy,
47: int srcOffset, int destDy, int destOffset) {
48: int bpl = getWidth() * getBpp();
49: int bpp = getBpp();
50: // case: x < bpp
51: for (int x = 0; x < bpl && x < bpp; x++) {
52: dest[x + destOffset] = src[x + srcOffset];
53: }
54: // otherwise
55: for (int x = getBpp(); x < bpl; x++) {
56: dest[x + destOffset] = (byte) (src[x + srcOffset] - src[x
57: + srcOffset - bpp]);
58: }
59: }
60:
61: /**
62: * {@inheritDoc}
63: */
64: public void decodeLine(byte[] src, byte[] dest, int srcDy,
65: int srcOffset, int destDy, int destOffset) {
66: int bpl = getWidth() * getBpp();
67: int bpp = getBpp();
68: // case: x < bpp
69: for (int x = 0; x < bpl && x < bpp; x++) {
70: dest[x + destOffset] = src[x + srcOffset];
71: }
72: // otherwise
73: for (int x = getBpp(); x < bpl; x++) {
74: dest[x + destOffset] = (byte) (src[x + srcOffset] + dest[x
75: + destOffset - bpp]);
76: }
77: }
78: }
|