1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
|
<!-- Creator : groff version 1.22.4 -->
<!-- CreationDate: Sat Jun 4 16:23:27 2022 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
p { margin-top: 0; margin-bottom: 0; vertical-align: top }
pre { margin-top: 0; margin-bottom: 0; vertical-align: top }
table { margin-top: 0; margin-bottom: 0; vertical-align: top }
h1 { text-align: center }
</style>
<title>TIFFReadRGBATile</title>
</head>
<body>
<h1 align="center">TIFFReadRGBATile</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#NOTES">NOTES</a><br>
<a href="#RETURN VALUES">RETURN VALUES</a><br>
<a href="#DIAGNOSTICS">DIAGNOSTICS</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<hr>
<h2>NAME
<a name="NAME"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">TIFFReadRGBATile
− read and decode an image tile into a fixed-format
raster</p>
<h2>SYNOPSIS
<a name="SYNOPSIS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<tiffio.h></b></p>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="-3%">
<p><b>#define TIFFGetR(abgr)</b></p></td>
<td width="30%"></td>
<td width="8%"></td>
<td width="54%">
<p><b>((abgr) & 0xff)</b></p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="-3%">
<p><b>#define TIFFGetG(abgr)</b></p></td>
<td width="30%"></td>
<td width="8%"></td>
<td width="54%">
<p><b>(((abgr) >> 8) & 0xff)</b></p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="-3%">
<p><b>#define TIFFGetB(abgr)</b></p></td>
<td width="30%"></td>
<td width="8%"></td>
<td width="54%">
<p><b>(((abgr) >> 16) & 0xff)</b></p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="-3%">
<p><b>#define TIFFGetA(abgr)</b></p></td>
<td width="30%"></td>
<td width="8%"></td>
<td width="54%">
<p><b>(((abgr) >> 24) & 0xff)</b></p></td></tr>
</table>
<p style="margin-left:11%; margin-top: 1em"><b>int
TIFFReadRGBATile(TIFF *</b><i>tif</i><b>, uint32_t</b>
<i>x</i><b>, uint32_t</b> <i>y</i><b>, uint32_t
*</b><i>raster</i><b>)</b></p>
<h2>DESCRIPTION
<a name="DESCRIPTION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b><i>TIFFReadRGBATile</i></b>
reads a single tile of a tile-based image into memory,
storing the result in the user supplied RGBA <i>raster</i>.
The raster is assumed to be an array of width times length
32-bit entries, where width is the width of a tile
(TIFFTAG_TILEWIDTH) and length is the height of a tile
(TIFFTAG_TILELENGTH).</p>
<p style="margin-left:11%; margin-top: 1em">The <i>x</i>
and <i>y</i> values are the offsets from the top left corner
to the top left corner of the tile to be read. They must be
an exact multiple of the tile width and length.</p>
<p style="margin-left:11%; margin-top: 1em">Note that the
raster is assume to be organized such that the pixel at
location (<i>x</i>,<i>y</i>) is
<i>raster</i>[<i>y</i>*<i>width</i>+<i>x</i>]; with the
raster origin in the <i>lower-left hand corner</i> of the
tile. That is bottom to top organization. Edge tiles which
partly fall off the image will be filled out with
appropriate zeroed areas.</p>
<p style="margin-left:11%; margin-top: 1em">Raster pixels
are 8-bit packed red, green, blue, alpha samples. The macros
<i>TIFFGetR</i>, <i>TIFFGetG</i>, <i>TIFFGetB</i>, and
<i>TIFFGetA</i> should be used to access individual samples.
Images without Associated Alpha matting information have a
constant Alpha of 1.0 (255).</p>
<p style="margin-left:11%; margin-top: 1em">See the
<i>TIFFRGBAImage</i>(3TIFF) page for more details on how
various image types are converted to RGBA values.</p>
<h2>NOTES
<a name="NOTES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">Samples must be
either 1, 2, 4, 8, or 16 bits. Colorimetric samples/pixel
must be either 1, 3, or 4 (i.e. <i>SamplesPerPixel</i> minus
<i>ExtraSamples</i>).</p>
<p style="margin-left:11%; margin-top: 1em">Palette image
colormaps that appear to be incorrectly written as 8-bit
values are automatically scaled to 16-bits.</p>
<p style="margin-left:11%; margin-top: 1em"><i>TIFFReadRGBATile</i>
is just a wrapper around the more general
<i>TIFFRGBAImage</i>(3TIFF) facilities. It’s main
advantage over the similar <i>TIFFReadRGBAImage()</i>
function is that for large images a single buffer capable of
holding the whole image doesn’t need to be allocated,
only enough for one tile. The <i>TIFFReadRGBAStrip()</i>
function does a similar operation for stripped images.</p>
<h2>RETURN VALUES
<a name="RETURN VALUES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">1 is returned
if the image was successfully read and converted. Otherwise,
0 is returned if an error was encountered.</p>
<h2>DIAGNOSTICS
<a name="DIAGNOSTICS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">All error
messages are directed to the <i>TIFFError</i>(3TIFF)
routine.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Sorry, can
not handle %d-bit pictures</b>. The image had
<i>BitsPerSample</i> other than 1, 2, 4, 8, or 16.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Sorry, can
not handle %d-channel images</b>. The image had
<i>SamplesPerPixel</i> other than 1, 3, or 4.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Missing
needed "PhotometricInterpretation" tag</b>. The
image did not have a tag that describes how to display the
data.</p>
<p style="margin-left:11%; margin-top: 1em"><b>No
"PhotometricInterpretation" tag, assuming RGB</b>.
The image was missing a tag that describes how to display
it, but because it has 3 or 4 samples/pixel, it is assumed
to be <small>RGB.</small></p>
<p style="margin-left:11%; margin-top: 1em"><b>No
"PhotometricInterpretation" tag, assuming
min-is-black</b>. The image was missing a tag that describes
how to display it, but because it has 1 sample/pixel, it is
assumed to be a grayscale or bilevel image.</p>
<p style="margin-left:11%; margin-top: 1em"><b>No space for
photometric conversion table</b>. There was insufficient
memory for a table used to convert image samples to 8-bit
<small>RGB.</small></p>
<p style="margin-left:11%; margin-top: 1em"><b>Missing
required "Colormap" tag</b>. A Palette image did
not have a required <i>Colormap</i> tag.</p>
<p style="margin-left:11%; margin-top: 1em"><b>No space for
tile buffer</b>. There was insufficient memory to allocate
an i/o buffer.</p>
<p style="margin-left:11%; margin-top: 1em"><b>No space for
strip buffer</b>. There was insufficient memory to allocate
an i/o buffer.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Can not
handle format</b>. The image has a format (combination of
<i>BitsPerSample</i>, <i>SamplesPerPixel</i>, and
<i>PhotometricInterpretation</i>) that
<i>TIFFReadRGBAImage</i> can not handle.</p>
<p style="margin-left:11%; margin-top: 1em"><b>No space for
B&W mapping table</b>. There was insufficient memory to
allocate a table used to map grayscale data to
<small>RGB.</small></p>
<p style="margin-left:11%; margin-top: 1em"><b>No space for
Palette mapping table</b>. There was insufficient memory to
allocate a table used to map data to 8-bit
<small>RGB.</small></p>
<h2>SEE ALSO
<a name="SEE ALSO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>TIFFOpen</b>(3TIFF),
<b>TIFFRGBAImage</b>(3TIFF),
<b>TIFFReadRGBAImage</b>(3TIFF),
<b>TIFFReadRGBAStrip</b>(3TIFF), <b>libtiff</b>(3TIFF)</p>
<p style="margin-left:11%; margin-top: 1em">Libtiff library
home page: <b>http://www.simplesystems.org/libtiff/</b></p>
<hr>
</body>
</html>
|
