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 up algorithm.
34: *
35: * <code>Up(i,j) = Raw(i,j) - Raw(i,j-1)</code>
36: *
37: * <code>Raw(i,j) = Up(i,j) + Raw(i,j-1)</code>
38: *
39: * @author xylifyx@yahoo.co.uk
40: * @version $Revision: 1.3 $
41: */
42: public class Up 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: // case: y = 0;
50: if (srcOffset - srcDy < 0) {
51: if (0 < getHeight()) {
52: for (int x = 0; x < bpl; x++) {
53: dest[destOffset + x] = src[srcOffset + x];
54: }
55: }
56: } else {
57: for (int x = 0; x < bpl; x++) {
58: dest[destOffset + x] = (byte) (src[srcOffset + x] - src[srcOffset
59: + x - srcDy]);
60: }
61: }
62: }
63:
64: /**
65: * {@inheritDoc}
66: */
67: public void decodeLine(byte[] src, byte[] dest, int srcDy,
68: int srcOffset, int destDy, int destOffset) {
69: // case: y = 0;
70: int bpl = getWidth() * getBpp();
71: if (destOffset - destDy < 0) {
72: if (0 < getHeight()) {
73: for (int x = 0; x < bpl; x++) {
74: dest[destOffset + x] = src[srcOffset + x];
75: }
76: }
77: } else {
78: for (int x = 0; x < bpl; x++) {
79: dest[destOffset + x] = (byte) (src[srcOffset + x] + dest[destOffset
80: + x - destDy]);
81: }
82: }
83: }
84: }
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