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1 <!-- Creator : groff version 1.18.1 --> |
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2 <!-- CreationDate: Mon Mar 13 18:03:08 2006 --> |
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3 <html> |
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4 <head> |
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5 <meta name="generator" content="groff -Thtml, see www.gnu.org"> |
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6 <meta name="Content-Style" content="text/css"> |
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7 <title>TIFFOpen</title> |
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8 </head> |
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9 <body> |
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10 |
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11 <h1 align=center>TIFFOpen</h1> |
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12 <a href="#NAME">NAME</a><br> |
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13 <a href="#SYNOPSIS">SYNOPSIS</a><br> |
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14 <a href="#DESCRIPTION">DESCRIPTION</a><br> |
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15 <a href="#OPTIONS">OPTIONS</a><br> |
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16 <a href="#BYTE ORDER">BYTE ORDER</a><br> |
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17 <a href="#RETURN VALUES">RETURN VALUES</a><br> |
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18 <a href="#DIAGNOSTICS">DIAGNOSTICS</a><br> |
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19 <a href="#SEE ALSO">SEE ALSO</a><br> |
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20 |
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21 <hr> |
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22 <a name="NAME"></a> |
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23 <h2>NAME</h2> |
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24 <!-- INDENTATION --> |
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25 <table width="100%" border=0 rules="none" frame="void" |
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26 cols="2" cellspacing="0" cellpadding="0"> |
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27 <tr valign="top" align="left"> |
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28 <td width="8%"></td> |
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29 <td width="91%"> |
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30 <p>TIFFOpen, TIFFFdOpen, TIFFClientOpen − open a |
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31 <small>TIFF</small> file for reading or writing</p> |
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32 </td> |
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33 </table> |
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34 <a name="SYNOPSIS"></a> |
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35 <h2>SYNOPSIS</h2> |
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36 <!-- INDENTATION --> |
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37 <table width="100%" border=0 rules="none" frame="void" |
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38 cols="2" cellspacing="0" cellpadding="0"> |
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39 <tr valign="top" align="left"> |
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40 <td width="8%"></td> |
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41 <td width="91%"> |
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42 <p><b>#include <tiffio.h></b></p> |
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43 <!-- INDENTATION --> |
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44 <p><b>TIFF* TIFFOpen(const char *</b><i>filename</i><b>, |
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45 const char *</b><i>mode</i><b>)<br> |
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46 TIFF* TIFFFdOpen(const int</b> <i>fd</i><b>, const char |
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47 *</b><i>filename</i><b>, const char |
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48 *</b><i>mode</i><b>)</b></p> |
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49 <!-- INDENTATION --> |
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50 <p><b>typedef tsize_t (*TIFFReadWriteProc)(thandle_t, |
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51 tdata_t, tsize_t);<br> |
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52 typedef toff_t (*TIFFSeekProc)(thandle_t, toff_t, int);<br> |
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53 typedef int (*TIFFCloseProc)(thandle_t);<br> |
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54 typedef toff_t (*TIFFSizeProc)(thandle_t);<br> |
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55 typedef int (*TIFFMapFileProc)(thandle_t, tdata_t*, |
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56 toff_t*);<br> |
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57 typedef void (*TIFFUnmapFileProc)(thandle_t, tdata_t, |
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58 toff_t);</b></p> |
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59 <!-- INDENTATION --> |
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60 <p><b>TIFF* TIFFClientOpen(const char |
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61 *</b><i>filename</i><b>, const char *</b><i>mode</i><b>, |
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62 thandle_t</b> <i>clientdata</i><b>, TIFFReadWriteProc</b> |
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63 <i>readproc</i><b>, TIFFReadWriteProc</b> |
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64 <i>writeproc</i><b>, TIFFSeekProc</b> <i>seekproc</i><b>, |
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65 TIFFCloseProc</b> <i>closeproc</i><b>, TIFFSizeProc</b> |
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66 <i>sizeproc</i><b>, TIFFMapFileProc</b> <i>mapproc</i><b>, |
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67 TIFFUnmapFileProc</b> <i>unmapproc</i><b>)</b></p> |
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68 </td> |
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69 </table> |
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70 <a name="DESCRIPTION"></a> |
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71 <h2>DESCRIPTION</h2> |
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72 <!-- INDENTATION --> |
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73 <table width="100%" border=0 rules="none" frame="void" |
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74 cols="2" cellspacing="0" cellpadding="0"> |
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75 <tr valign="top" align="left"> |
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76 <td width="8%"></td> |
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77 <td width="91%"> |
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78 <p><i>TIFFOpen</i> opens a <small>TIFF</small> file whose |
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79 name is <i>filename</i> and returns a handle to be used in |
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80 subsequent calls to routines in <i>libtiff</i>. If the open |
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81 operation fails, then zero is returned. The <i>mode</i> |
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82 parameter specifies if the file is to be opened for reading |
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83 (‘‘r’’), writing |
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84 (‘‘w’’), or appending |
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85 (‘‘a’’) and, optionally, whether to |
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86 override certain default aspects of library operation (see |
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87 below). When a file is opened for appending, existing data |
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88 will not be touched; instead new data will be written as |
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89 additional subfiles. If an existing file is opened for |
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90 writing, all previous data is overwritten.</p> |
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91 <!-- INDENTATION --> |
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92 <p>If a file is opened for reading, the first |
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93 <small>TIFF</small> directory in the file is automatically |
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94 read (also see <i>TIFFSetDirectory</i>(3TIFF) for reading |
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95 directories other than the first). If a file is opened for |
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96 writing or appending, a default directory is automatically |
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97 created for writing subsequent data. This directory has all |
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98 the default values specified in <small>TIFF</small> Revision |
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99 6.0: <i>BitsPerSample</i>=1, <i>ThreshHolding</i>=bilevel |
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100 art scan, <i>FillOrder</i>=1 (most significant bit of each |
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101 data byte is filled first), <i>Orientation</i>=1 (the 0th |
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102 row represents the visual top of the image, and the 0th |
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103 column represents the visual left hand side), |
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104 <i>SamplesPerPixel</i>=1, <i>RowsPerStrip</i>=infinity, |
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105 <i>ResolutionUnit</i>=2 (inches), and <i>Compression</i>=1 |
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106 (no compression). To alter these values, or to define values |
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107 for additional fields, <i>TIFFSetField</i>(3TIFF) must be |
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108 used.</p> |
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109 <!-- INDENTATION --> |
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110 <p><i>TIFFFdOpen</i> is like <i>TIFFOpen</i> except that it |
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111 opens a <small>TIFF</small> file given an open file |
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112 descriptor <i>fd</i>. The file’s name and mode must |
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113 reflect that of the open descriptor. The object associated |
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114 with the file descriptor <b>must support random |
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115 access</b>.</p> |
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116 <!-- INDENTATION --> |
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117 <p><i>TIFFClientOpen</i> is like <i>TIFFOpen</i> except that |
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118 the caller supplies a collection of functions that the |
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119 library will use to do <small>UNIX</small> -like I/O |
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120 operations. The <i>readproc</i> and <i>writeproc</i> are |
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121 called to read and write data at the current file position. |
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122 <i>seekproc</i> is called to change the current file |
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123 position a la <i>lseek</i>(2). <i>closeproc</i> is invoked |
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124 to release any resources associated with an open file. |
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125 <i>sizeproc</i> is invoked to obtain the size in bytes of a |
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126 file. <i>mapproc</i> and <i>unmapproc</i> are called to map |
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127 and unmap a file’s contents in memory; c.f. |
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128 <i>mmap</i>(2) and <i>munmap</i>(2). The <i>clientdata</i> |
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129 parameter is an opaque ‘‘handle’’ |
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130 passed to the client-specified routines passed as parameters |
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131 to <i>TIFFClientOpen</i>.</p> |
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132 </td> |
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133 </table> |
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134 <a name="OPTIONS"></a> |
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135 <h2>OPTIONS</h2> |
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136 <!-- INDENTATION --> |
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137 <table width="100%" border=0 rules="none" frame="void" |
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138 cols="2" cellspacing="0" cellpadding="0"> |
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139 <tr valign="top" align="left"> |
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140 <td width="8%"></td> |
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141 <td width="91%"> |
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142 <p>The open mode parameter can include the following flags |
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143 in addition to the ‘‘r’’, |
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144 ‘‘w’’, and |
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145 ‘‘a’’ flags. Note however that |
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146 option flags must follow the read-write-append |
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147 specification.</p> |
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148 </td> |
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149 </table> |
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150 <!-- TABS --> |
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151 <table width="100%" border=0 rules="none" frame="void" |
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152 cols="5" cellspacing="0" cellpadding="0"> |
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153 <tr valign="top" align="left"> |
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154 <td width="10%"></td> |
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155 <td width="2%"> |
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156 |
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157 <p><b>l</b></p> |
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158 </td> |
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159 <td width="6%"></td> |
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160 <td width="80%"> |
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161 |
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162 <p>When creating a new file force information be written |
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163 with Little-Endian byte order (but see below). By default |
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164 the library will create new files using the native |
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165 <small>CPU</small> byte order.</p> |
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166 </td> |
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167 <td width="0%"> |
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168 </td> |
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169 <tr valign="top" align="left"> |
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170 <td width="10%"></td> |
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171 <td width="2%"> |
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172 |
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173 <p><b>b</b></p> |
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174 </td> |
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175 <td width="6%"></td> |
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176 <td width="80%"> |
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177 |
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178 <p>When creating a new file force information be written |
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179 with Big-Endian byte order (but see below). By default the |
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180 library will create new files using the native |
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181 <small>CPU</small> byte order.</p> |
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182 </td> |
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183 <td width="0%"> |
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184 </td> |
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185 <tr valign="top" align="left"> |
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186 <td width="10%"></td> |
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187 <td width="2%"> |
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188 |
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189 <p><b>L</b></p> |
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190 </td> |
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191 <td width="6%"></td> |
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192 <td width="80%"> |
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193 |
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194 <p>Force image data that is read or written to be treated |
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195 with bits filled from Least Significant Bit ( |
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196 <small>LSB</small> ) to Most Significant Bit ( |
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197 <small>MSB</small> ). Note that this is the opposite to the |
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198 way the library has worked from its inception.</p> |
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199 </td> |
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200 <td width="0%"> |
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201 </td> |
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202 <tr valign="top" align="left"> |
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203 <td width="10%"></td> |
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204 <td width="2%"> |
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205 |
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206 <p><b>B</b></p> |
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207 </td> |
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208 <td width="6%"></td> |
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209 <td width="80%"> |
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210 |
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211 <p>Force image data that is read or written to be treated |
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212 with bits filled from Most Significant Bit ( |
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213 <small>MSB</small> ) to Least Significant Bit ( |
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214 <small>LSB</small> ); this is the default.</p> |
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215 </td> |
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216 <td width="0%"> |
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217 </td> |
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218 <tr valign="top" align="left"> |
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219 <td width="10%"></td> |
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220 <td width="2%"> |
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221 |
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222 <p><b>H</b></p> |
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223 </td> |
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224 <td width="6%"></td> |
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225 <td width="80%"> |
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226 |
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227 <p>Force image data that is read or written to be treated |
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228 with bits filled in the same order as the native |
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229 <small>CPU.</small></p> |
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230 </td> |
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231 <td width="0%"> |
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232 </td> |
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233 <tr valign="top" align="left"> |
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234 <td width="10%"></td> |
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235 <td width="2%"> |
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236 |
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237 <p><b>M</b></p> |
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238 </td> |
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239 <td width="6%"></td> |
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240 <td width="80%"> |
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241 |
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242 <p>Enable the use of memory-mapped files for images opened |
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243 read-only. If the underlying system does not support |
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244 memory-mapped files or if the specific image being opened |
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245 cannot be memory-mapped then the library will fallback to |
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246 using the normal system interface for reading information. |
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247 By default the library will attempt to use memory-mapped |
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248 files.</p> |
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249 </td> |
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250 <td width="0%"> |
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251 </td> |
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252 <tr valign="top" align="left"> |
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253 <td width="10%"></td> |
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254 <td width="2%"> |
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255 |
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256 <p><b>m</b></p> |
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257 </td> |
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258 <td width="6%"></td> |
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259 <td width="80%"> |
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260 |
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261 <p>Disable the use of memory-mapped files.</p> |
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262 </td> |
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263 <td width="0%"> |
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264 </td> |
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265 <tr valign="top" align="left"> |
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266 <td width="10%"></td> |
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267 <td width="2%"> |
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268 |
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269 <p><b>C</b></p> |
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270 </td> |
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271 <td width="6%"></td> |
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272 <td width="80%"> |
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273 |
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274 <p>Enable the use of ‘‘strip |
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275 chopping’’ when reading images that are |
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276 comprised of a single strip or tile of uncompressed data. |
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277 Strip chopping is a mechanism by which the library will |
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278 automatically convert the single-strip image to multiple |
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279 strips, each of which has about 8 Kilobytes of data. This |
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280 facility can be useful in reducing the amount of memory used |
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281 to read an image because the library normally reads each |
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282 strip in its entirety. Strip chopping does however alter the |
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283 apparent contents of the image because when an image is |
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284 divided into multiple strips it looks as though the |
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285 underlying file contains multiple separate strips. Finally, |
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286 note that default handling of strip chopping is a |
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287 compile-time configuration parameter. The default behaviour, |
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288 for backwards compatibility, is to enable strip |
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289 chopping.</p> |
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290 </td> |
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291 <td width="0%"> |
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292 </td> |
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293 <tr valign="top" align="left"> |
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294 <td width="10%"></td> |
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295 <td width="2%"> |
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296 |
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297 <p><b>c</b></p> |
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298 </td> |
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299 <td width="6%"></td> |
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300 <td width="80%"> |
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301 |
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302 <p>Disable the use of strip chopping when reading |
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303 images.</p> |
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304 </td> |
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305 <td width="0%"> |
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306 </td> |
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307 <tr valign="top" align="left"> |
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308 <td width="10%"></td> |
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309 <td width="2%"> |
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310 |
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311 <p><b>h</b></p> |
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312 </td> |
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313 <td width="6%"></td> |
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314 <td width="80%"> |
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315 |
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316 <p>Read TIFF header only, do not load the first image |
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317 directory. That could be useful in case of the broken first |
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318 directory. We can open the file and proceed to the other |
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319 directories.</p> |
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320 </td> |
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321 <td width="0%"> |
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322 </td> |
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323 </table> |
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324 <a name="BYTE ORDER"></a> |
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325 <h2>BYTE ORDER</h2> |
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326 <!-- INDENTATION --> |
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327 <table width="100%" border=0 rules="none" frame="void" |
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328 cols="2" cellspacing="0" cellpadding="0"> |
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329 <tr valign="top" align="left"> |
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330 <td width="8%"></td> |
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331 <td width="91%"> |
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332 <p>The <small>TIFF</small> specification (<b>all |
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333 versions</b>) states that compliant readers <i>must be |
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334 capable of reading images written in either byte order</i>. |
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335 Nonetheless some software that claims to support the reading |
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336 of <small>TIFF</small> images is incapable of reading images |
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337 in anything but the native <small>CPU</small> byte order on |
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338 which the software was written. (Especially notorious are |
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339 applications written to run on Intel-based machines.) By |
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340 default the library will create new files with the native |
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341 byte-order of the <small>CPU</small> on which the |
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342 application is run. This ensures optimal performance and is |
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343 portable to any application that conforms to the TIFF |
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344 specification. To force the library to use a specific |
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345 byte-order when creating a new file the |
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346 ‘‘b’’ and |
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347 ‘‘l’’ option flags may be included |
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348 in the call to open a file; for example, |
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349 ‘‘wb’’ or |
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350 ‘‘wl’’.</p> |
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351 </td> |
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352 </table> |
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353 <a name="RETURN VALUES"></a> |
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354 <h2>RETURN VALUES</h2> |
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355 <!-- INDENTATION --> |
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356 <table width="100%" border=0 rules="none" frame="void" |
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357 cols="2" cellspacing="0" cellpadding="0"> |
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358 <tr valign="top" align="left"> |
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359 <td width="8%"></td> |
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360 <td width="91%"> |
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361 <p>Upon successful completion <i>TIFFOpen</i>, |
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362 <i>TIFFFdOpen</i>, and <i>TIFFClientOpen</i> return a |
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363 <small>TIFF</small> pointer. Otherwise, NULL is |
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364 returned.</p> |
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365 </td> |
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366 </table> |
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367 <a name="DIAGNOSTICS"></a> |
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368 <h2>DIAGNOSTICS</h2> |
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369 <!-- INDENTATION --> |
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370 <table width="100%" border=0 rules="none" frame="void" |
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371 cols="2" cellspacing="0" cellpadding="0"> |
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372 <tr valign="top" align="left"> |
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373 <td width="8%"></td> |
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374 <td width="91%"> |
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375 <p>All error messages are directed to the |
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376 <i>TIFFError</i>(3TIFF) routine. Likewise, warning messages |
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377 are directed to the <i>TIFFWarning</i>(3TIFF) routine.</p> |
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378 <!-- INDENTATION --> |
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379 <p><b>"%s": Bad mode</b>. The specified |
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380 <i>mode</i> parameter was not one of |
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381 ‘‘r’’ (read), |
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382 ‘‘w’’ (write), or |
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383 ‘‘a’’ (append).</p> |
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384 <!-- INDENTATION --> |
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385 <p><b>%s: Cannot open</b>. <i>TIFFOpen</i>() was unable to |
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386 open the specified filename for read/writing.</p> |
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387 <!-- INDENTATION --> |
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388 <p><b>Cannot read TIFF header</b>. An error occurred while |
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389 attempting to read the header information.</p> |
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390 <!-- INDENTATION --> |
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391 <p><b>Error writing TIFF header</b>. An error occurred while |
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392 writing the default header information for a new file.</p> |
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393 <!-- INDENTATION --> |
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394 <p><b>Not a TIFF file, bad magic number %d (0x%x)</b>. The |
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395 magic number in the header was not (hex) 0x4d4d or (hex) |
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396 0x4949.</p> |
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397 <!-- INDENTATION --> |
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398 <p><b>Not a TIFF file, bad version number %d (0x%x)</b>. The |
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399 version field in the header was not 42 (decimal).</p> |
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400 <!-- INDENTATION --> |
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401 <p><b>Cannot append to file that has opposite byte |
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402 ordering</b>. A file with a byte ordering opposite to the |
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403 native byte ordering of the current machine was opened for |
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404 appending (‘‘a’’). This is a |
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405 limitation of the library.</p> |
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406 </td> |
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407 </table> |
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408 <a name="SEE ALSO"></a> |
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409 <h2>SEE ALSO</h2> |
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410 <!-- INDENTATION --> |
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411 <table width="100%" border=0 rules="none" frame="void" |
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412 cols="2" cellspacing="0" cellpadding="0"> |
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413 <tr valign="top" align="left"> |
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414 <td width="8%"></td> |
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415 <td width="91%"> |
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416 <p><i>libtiff</i>(3TIFF), <i>TIFFClose</i>(3TIFF)</p> |
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417 </td> |
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418 </table> |
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419 <hr> |
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420 </body> |
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421 </html> |