source: trunk/src/3rdparty/libtiff/html/man/TIFFReadRGBAStrip.3tiff.html

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1<!-- Creator : groff version 1.18.1 -->
2<!-- CreationDate: Fri Jul 13 17:43:16 2007 -->
3<html>
4<head>
5<meta name="generator" content="groff -Thtml, see www.gnu.org">
6<meta name="Content-Style" content="text/css">
7<title>TIFFReadRGBAStrip</title>
8</head>
9<body>
10
11<h1 align=center>TIFFReadRGBAStrip</h1>
12<a href="#NAME">NAME</a><br>
13<a href="#SYNOPSIS">SYNOPSIS</a><br>
14<a href="#DESCRIPTION">DESCRIPTION</a><br>
15<a href="#NOTES">NOTES</a><br>
16<a href="#RETURN VALUES">RETURN VALUES</a><br>
17<a href="#DIAGNOSTICS">DIAGNOSTICS</a><br>
18<a href="#SEE ALSO">SEE ALSO</a><br>
19
20<hr>
21<a name="NAME"></a>
22<h2>NAME</h2>
23<!-- INDENTATION -->
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28<td width="91%">
29<p>TIFFReadRGBAStrip &minus; read and decode an image strip
30into a fixed-format raster</p>
31</td>
32</table>
33<a name="SYNOPSIS"></a>
34<h2>SYNOPSIS</h2>
35<!-- INDENTATION -->
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40<td width="91%">
41<p><b>#include &lt;tiffio.h&gt;</b></p>
42<!-- INDENTATION -->
43<p><b>#define TIFFGetR(abgr) ((abgr) &amp; 0xff)<br>
44#define TIFFGetG(abgr) (((abgr) &gt;&gt; 8) &amp; 0xff)<br>
45#define TIFFGetB(abgr) (((abgr) &gt;&gt; 16) &amp; 0xff)<br>
46#define TIFFGetA(abgr) (((abgr) &gt;&gt; 24) &amp;
470xff)</b></p>
48<!-- INDENTATION -->
49<p><b>int TIFFReadRGBAStrip(TIFF *</b><i>tif</i><b>,
50uint32</b> <i>row</i><b>, uint32
51*</b><i>raster</i><b>)</b></p>
52</td>
53</table>
54<a name="DESCRIPTION"></a>
55<h2>DESCRIPTION</h2>
56<!-- INDENTATION -->
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61<td width="91%">
62<p><i>TIFFReadRGBAStrip</i> reads a single strip of a
63strip-based image into memory, storing the result in the
64user supplied RGBA <i>raster</i>. The raster is assumed to
65be an array of width times rowsperstrip 32-bit entries,
66where width is the width of the image (TIFFTAG_IMAGEWIDTH)
67and rowsperstrip is the maximum lines in a strip
68(TIFFTAG_ROWSPERSTRIP).</p>
69<!-- INDENTATION -->
70<p>The <i>row</i> value should be the row of the first row
71in the strip (strip * rowsperstrip, zero based).</p>
72<!-- INDENTATION -->
73<p>Note that the raster is assume to be organized such that
74the pixel at location (<i>x</i>,<i>y</i>) is
75<i>raster</i>[<i>y</i>*<i>width</i>+<i>x</i>]; with the
76raster origin in the <i>lower-left hand corner</i> of the
77strip. That is bottom to top organization. When reading a
78partial last strip in the file the last line of the image
79will begin at the beginning of the buffer.</p>
80<!-- INDENTATION -->
81<p>Raster pixels are 8-bit packed red, green, blue, alpha
82samples. The macros <i>TIFFGetR</i>, <i>TIFFGetG</i>,
83<i>TIFFGetB</i>, and <i>TIFFGetA</i> should be used to
84access individual samples. Images without Associated Alpha
85matting information have a constant Alpha of 1.0 (255).</p>
86<!-- INDENTATION -->
87<p>See the <i>TIFFRGBAImage</i>(3TIFF) page for more details
88on how various image types are converted to RGBA values.</p>
89</td>
90</table>
91<a name="NOTES"></a>
92<h2>NOTES</h2>
93<!-- INDENTATION -->
94<table width="100%" border=0 rules="none" frame="void"
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97<td width="8%"></td>
98<td width="91%">
99<p>Samples must be either 1, 2, 4, 8, or 16 bits.
100Colorimetric samples/pixel must be either 1, 3, or 4 (i.e.
101<i>SamplesPerPixel</i> minus <i>ExtraSamples</i>).</p>
102<!-- INDENTATION -->
103<p>Palette image colormaps that appear to be incorrectly
104written as 8-bit values are automatically scaled to
10516-bits.</p>
106<!-- INDENTATION -->
107<p><i>TIFFReadRGBAStrip</i> is just a wrapper around the
108more general <i>TIFFRGBAImage</i>(3TIFF) facilities.
109It&rsquo;s main advantage over the similar
110<i>TIFFReadRGBAImage()</i> function is that for large images
111a single buffer capable of holding the whole image
112doesn&rsquo;t need to be allocated, only enough for one
113strip. The <i>TIFFReadRGBATile()</i> function does a similar
114operation for tiled images.</p>
115</td>
116</table>
117<a name="RETURN VALUES"></a>
118<h2>RETURN VALUES</h2>
119<!-- INDENTATION -->
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125<p>1 is returned if the image was successfully read and
126converted. Otherwise, 0 is returned if an error was
127encountered.</p>
128</td>
129</table>
130<a name="DIAGNOSTICS"></a>
131<h2>DIAGNOSTICS</h2>
132<!-- INDENTATION -->
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138<p>All error messages are directed to the
139<i>TIFFError</i>(3TIFF) routine.</p>
140<!-- INDENTATION -->
141<p><b>Sorry, can not handle %d-bit pictures</b>. The image
142had <i>BitsPerSample</i> other than 1, 2, 4, 8, or 16.</p>
143<!-- INDENTATION -->
144<p><b>Sorry, can not handle %d-channel images</b>. The image
145had <i>SamplesPerPixel</i> other than 1, 3, or 4.</p>
146<!-- INDENTATION -->
147<p><b>Missing needed &quot;PhotometricInterpretation&quot;
148tag</b>. The image did not have a tag that describes how to
149display the data.</p>
150<!-- INDENTATION -->
151<p><b>No &quot;PhotometricInterpretation&quot; tag, assuming
152RGB</b>. The image was missing a tag that describes how to
153display it, but because it has 3 or 4 samples/pixel, it is
154assumed to be <small>RGB.</small></p>
155<!-- INDENTATION -->
156<p><b>No &quot;PhotometricInterpretation&quot; tag, assuming
157min-is-black</b>. The image was missing a tag that describes
158how to display it, but because it has 1 sample/pixel, it is
159assumed to be a grayscale or bilevel image.</p>
160<!-- INDENTATION -->
161<p><b>No space for photometric conversion table</b>. There
162was insufficient memory for a table used to convert image
163samples to 8-bit <small>RGB.</small></p>
164<!-- INDENTATION -->
165<p><b>Missing required &quot;Colormap&quot; tag</b>. A
166Palette image did not have a required <i>Colormap</i>
167tag.</p>
168<!-- INDENTATION -->
169<p><b>No space for tile buffer</b>. There was insufficient
170memory to allocate an i/o buffer.</p>
171<!-- INDENTATION -->
172<p><b>No space for strip buffer</b>. There was insufficient
173memory to allocate an i/o buffer.</p>
174<!-- INDENTATION -->
175<p><b>Can not handle format</b>. The image has a format
176(combination of <i>BitsPerSample</i>,
177<i>SamplesPerPixel</i>, and
178<i>PhotometricInterpretation</i>) that
179<i>TIFFReadRGBAImage</i> can not handle.</p>
180<!-- INDENTATION -->
181<p><b>No space for B&amp;W mapping table</b>. There was
182insufficient memory to allocate a table used to map
183grayscale data to <small>RGB.</small></p>
184<!-- INDENTATION -->
185<p><b>No space for Palette mapping table</b>. There was
186insufficient memory to allocate a table used to map data to
1878-bit <small>RGB.</small></p>
188</td>
189</table>
190<a name="SEE ALSO"></a>
191<h2>SEE ALSO</h2>
192<!-- INDENTATION -->
193<table width="100%" border=0 rules="none" frame="void"
194 cols="2" cellspacing="0" cellpadding="0">
195<tr valign="top" align="left">
196<td width="8%"></td>
197<td width="91%">
198<p><b>TIFFOpen</b>(3TIFF), <b>TIFFRGBAImage</b>(3TIFF),
199<b>TIFFReadRGBAImage</b>(3TIFF),
200<b>TIFFReadRGBATile</b>(3TIFF), <b>libtiff</b>(3TIFF)</p>
201<!-- INDENTATION -->
202<p>Libtiff library home page:
203<b>http://www.remotesensing.org/libtiff/</b></p>
204</td>
205</table>
206<hr>
207</body>
208</html>
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