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1 /*******************************************************************************
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2 * Copyright (c) 2000, 2006 IBM Corporation and others.
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3 * All rights reserved. This program and the accompanying materials
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4 * are made available under the terms of the Eclipse Public License v1.0
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5 * which accompanies this distribution, and is available at
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6 * http://www.eclipse.org/legal/epl-v10.html
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7 *
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8 * Contributors:
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9 * IBM Corporation - initial API and implementation
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10 * Port to the D programming language:
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11 * Frank Benoit <benoit@tionex.de>
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12 *******************************************************************************/
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13 module org.eclipse.swt.internal.image.PngPlteChunk;
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14
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15 import java.lang.all;
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16
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17
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18 import org.eclipse.swt.SWT;
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19 import org.eclipse.swt.graphics.PaletteData;
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20 import org.eclipse.swt.graphics.RGB;
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21 import org.eclipse.swt.internal.image.PngChunk;
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22 import org.eclipse.swt.internal.image.PngFileReadState;
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23 import org.eclipse.swt.internal.image.PngIhdrChunk;
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24
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25
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26 class PngPlteChunk : PngChunk {
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27
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28 int paletteSize;
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29
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30 this(PaletteData palette) {
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31 super(palette.getRGBs().length * 3);
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32 paletteSize = length / 3;
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33 setType(TYPE_PLTE);
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34 setPaletteData(palette);
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35 setCRC(computeCRC());
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36 }
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37
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38 this(byte[] reference){
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39 super(reference);
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40 paletteSize = length / 3;
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41 }
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42
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43 override int getChunkType() {
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44 return CHUNK_PLTE;
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45 }
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46
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47 /**
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48 * Get the number of colors in this palette.
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49 */
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50 int getPaletteSize() {
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51 return paletteSize;
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52 }
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53
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54 /**
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55 * Get a PaletteData object representing the colors
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56 * stored in this PLTE chunk.
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57 * The result should be cached as the PLTE chunk
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58 * does not store the palette data created.
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59 */
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60 PaletteData getPaletteData() {
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61 RGB[] rgbs = new RGB[paletteSize];
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62 // int start = DATA_OFFSET;
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63 // int end = DATA_OFFSET + length;
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64 for (int i = 0; i < rgbs.length; i++) {
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65 int offset = DATA_OFFSET + (i * 3);
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66 int red = reference[offset] & 0xFF;
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67 int green = reference[offset + 1] & 0xFF;
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68 int blue = reference[offset + 2] & 0xFF;
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69 rgbs[i] = new RGB(red, green, blue);
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70 }
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71 return new PaletteData(rgbs);
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72 }
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73
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74 /**
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75 * Set the data of a PLTE chunk to the colors
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76 * stored in the specified PaletteData object.
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77 */
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78 void setPaletteData(PaletteData palette) {
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79 RGB[] rgbs = palette.getRGBs();
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80 for (int i = 0; i < rgbs.length; i++) {
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81 int offset = DATA_OFFSET + (i * 3);
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82 reference[offset] = cast(byte) rgbs[i].red;
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83 reference[offset + 1] = cast(byte) rgbs[i].green;
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84 reference[offset + 2] = cast(byte) rgbs[i].blue;
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85 }
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86 }
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87
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88 /**
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89 * Answer whether the chunk is a valid PLTE chunk.
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90 */
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91 override void validate(PngFileReadState readState, PngIhdrChunk headerChunk) {
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92 // A PLTE chunk is invalid if no IHDR has been read or if any PLTE,
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93 // IDAT, or IEND chunk has been read.
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94 if (!readState.readIHDR
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95 || readState.readPLTE
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96 || readState.readTRNS
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97 || readState.readIDAT
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98 || readState.readIEND)
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99 {
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100 SWT.error(SWT.ERROR_INVALID_IMAGE);
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101 } else {
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102 readState.readPLTE = true;
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103 }
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104
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105 super.validate(readState, headerChunk);
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106
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107 // Palettes cannot be included in grayscale images.
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108 //
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109 // Note: just ignore the palette.
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110 // if (!headerChunk.getCanHavePalette()) SWT.error(SWT.ERROR_INVALID_IMAGE);
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111
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112 // Palette chunks' data fields must be event multiples
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113 // of 3. Each 3-byte group represents an RGB value.
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114 if (getLength() % 3 !is 0) SWT.error(SWT.ERROR_INVALID_IMAGE);
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115
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116 // Palettes cannot have more entries than 2^bitDepth
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117 // where bitDepth is the bit depth of the image given
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118 // in the IHDR chunk.
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119 if (1 << headerChunk.getBitDepth() < paletteSize) {
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120 SWT.error(SWT.ERROR_INVALID_IMAGE);
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121 }
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122
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123 // Palettes cannot have more than 256 entries.
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124 if (256 < paletteSize) SWT.error(SWT.ERROR_INVALID_IMAGE);
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125 }
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126
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127 override String contributeToString() {
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128 return Format("\n\tPalette size:{}", paletteSize );
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129 }
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130
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131 }
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