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1 | .\" $Id: TIFFReadRGBAStrip.3tiff,v 1.3 2005/11/02 11:07:18 dron Exp $ |
2 | .\" | |
3 | .\" Copyright (c) 1991-1997 Sam Leffler | |
4 | .\" Copyright (c) 1991-1997 Silicon Graphics, Inc. | |
5 | .\" | |
6 | .\" Permission to use, copy, modify, distribute, and sell this software and | |
7 | .\" its documentation for any purpose is hereby granted without fee, provided | |
8 | .\" that (i) the above copyright notices and this permission notice appear in | |
9 | .\" all copies of the software and related documentation, and (ii) the names of | |
10 | .\" Sam Leffler and Silicon Graphics may not be used in any advertising or | |
11 | .\" publicity relating to the software without the specific, prior written | |
12 | .\" permission of Sam Leffler and Silicon Graphics. | |
13 | .\" | |
14 | .\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, | |
15 | .\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY | |
16 | .\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. | |
17 | .\" | |
18 | .\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR | |
19 | .\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, | |
20 | .\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, | |
21 | .\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF | |
22 | .\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE | |
23 | .\" OF THIS SOFTWARE. | |
24 | .\" | |
25 | .if n .po 0 | |
26 | .TH TIFFReadRGBAStrip 3TIFF "December 10, 1998" "libtiff" | |
27 | .SH NAME | |
28 | TIFFReadRGBAStrip \- read and decode an image strip into a fixed-format raster | |
29 | .SH SYNOPSIS | |
30 | .B "#include <tiffio.h>" | |
31 | .sp | |
32 | .B "#define TIFFGetR(abgr) ((abgr) & 0xff)" | |
33 | .br | |
34 | .B "#define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)" | |
35 | .br | |
36 | .B "#define TIFFGetB(abgr) (((abgr) >> 16) & 0xff)" | |
37 | .br | |
38 | .B "#define TIFFGetA(abgr) (((abgr) >> 24) & 0xff)" | |
39 | .sp | |
40 | .BI "int TIFFReadRGBAStrip(TIFF *" tif ", uint32 " row ", uint32 *" raster ")" | |
41 | .SH DESCRIPTION | |
42 | .IR TIFFReadRGBAStrip | |
43 | reads a single strip of a strip-based image into memory, storing the result in | |
44 | the user supplied RGBA | |
45 | .IR raster . | |
46 | The raster is assumed to be an array of width times rowsperstrip 32-bit | |
47 | entries, where width is the width of the image (TIFFTAG_IMAGEWIDTH) and | |
48 | rowsperstrip is the maximum lines in a strip (TIFFTAG_ROWSPERSTRIP). | |
49 | ||
50 | .PP | |
51 | The | |
52 | .IR row | |
53 | value should be the row of the first row in the strip (strip * rowsperstrip, | |
54 | zero based). | |
55 | ||
56 | .PP | |
57 | Note that the raster is assume to be organized such that the pixel at location | |
58 | (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP]; with the | |
59 | raster origin in the | |
60 | .I lower-left hand corner | |
61 | of the strip. That is bottom to top organization. When reading a partial last | |
62 | strip in the file the last line of the image will begin at the beginning of | |
63 | the buffer. | |
64 | ||
65 | .PP | |
66 | Raster pixels are 8-bit packed red, green, blue, alpha samples. The macros | |
67 | .IR TIFFGetR , | |
68 | .IR TIFFGetG , | |
69 | .IR TIFFGetB , | |
70 | and | |
71 | .I TIFFGetA | |
72 | should be used to access individual samples. Images without Associated Alpha | |
73 | matting information have a constant Alpha of 1.0 (255). | |
74 | .PP | |
75 | See the | |
76 | .IR TIFFRGBAImage (3TIFF) | |
77 | page for more details on how various image types are converted to RGBA values. | |
78 | .SH NOTES | |
79 | Samples must be either 1, 2, 4, 8, or 16 bits. Colorimetric samples/pixel must | |
80 | be either 1, 3, or 4 (i.e. | |
81 | .I SamplesPerPixel | |
82 | minus | |
83 | .IR ExtraSamples ). | |
84 | .PP | |
85 | Palette image colormaps that appear to be incorrectly written as 8-bit values | |
86 | are automatically scaled to 16-bits. | |
87 | .PP | |
88 | .I TIFFReadRGBAStrip | |
89 | is just a wrapper around the more general | |
90 | .IR TIFFRGBAImage (3TIFF) | |
91 | facilities. It's main advantage over the similar | |
92 | .IR TIFFReadRGBAImage() | |
93 | function is that for large images a single buffer capable of holding the whole | |
94 | image doesn't need to be allocated, only enough for one strip. The | |
95 | .IR TIFFReadRGBATile() | |
96 | function does a similar operation for tiled images. | |
97 | .SH "RETURN VALUES" | |
98 | 1 is returned if the image was successfully read and converted. | |
99 | Otherwise, 0 is returned if an error was encountered. | |
100 | .SH DIAGNOSTICS | |
101 | All error messages are directed to the | |
102 | .IR TIFFError (3TIFF) | |
103 | routine. | |
104 | .PP | |
105 | .BR "Sorry, can not handle %d-bit pictures" . | |
106 | The image had | |
107 | .I BitsPerSample | |
108 | other than 1, 2, 4, 8, or 16. | |
109 | .PP | |
110 | .BR "Sorry, can not handle %d-channel images" . | |
111 | The image had | |
112 | .I SamplesPerPixel | |
113 | other than 1, 3, or 4. | |
114 | .PP | |
115 | \fBMissing needed "PhotometricInterpretation" tag\fP. | |
116 | The image did not have a tag that describes how to display the data. | |
117 | .PP | |
118 | \fBNo "PhotometricInterpretation" tag, assuming RGB\fP. | |
119 | The image was missing a tag that describes how to display it, but because it | |
120 | has 3 or 4 samples/pixel, it is assumed to be | |
121 | .SM RGB. | |
122 | .PP | |
123 | \fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP. The image was | |
124 | missing a tag that describes how to display it, but because it has 1 | |
125 | sample/pixel, it is assumed to be a grayscale or bilevel image. | |
126 | .PP | |
127 | .BR "No space for photometric conversion table" . | |
128 | There was insufficient memory for a table used to convert image samples to | |
129 | 8-bit | |
130 | .SM RGB. | |
131 | .PP | |
132 | \fBMissing required "Colormap" tag\fP. | |
133 | A Palette image did not have a required | |
134 | .I Colormap | |
135 | tag. | |
136 | .PP | |
137 | .BR "No space for tile buffer" . | |
138 | There was insufficient memory to allocate an i/o buffer. | |
139 | .PP | |
140 | .BR "No space for strip buffer" . | |
141 | There was insufficient memory to allocate an i/o buffer. | |
142 | .PP | |
143 | .BR "Can not handle format" . | |
144 | The image has a format (combination of | |
145 | .IR BitsPerSample , | |
146 | .IR SamplesPerPixel , | |
147 | and | |
148 | .IR PhotometricInterpretation ) | |
149 | that | |
150 | .I TIFFReadRGBAImage | |
151 | can not handle. | |
152 | .PP | |
153 | .BR "No space for B&W mapping table" . | |
154 | There was insufficient memory to allocate a table used to map grayscale data | |
155 | to | |
156 | .SM RGB. | |
157 | .PP | |
158 | .BR "No space for Palette mapping table" . | |
159 | There was insufficient memory to allocate a table used to map data to 8-bit | |
160 | .SM RGB. | |
161 | .SH "SEE ALSO" | |
162 | .BR TIFFOpen (3TIFF), | |
163 | .BR TIFFRGBAImage (3TIFF), | |
164 | .BR TIFFReadRGBAImage (3TIFF), | |
165 | .BR TIFFReadRGBATile (3TIFF), | |
166 | .BR libtiff (3TIFF) | |
167 | .PP | |
168 | Libtiff library home page: | |
169 | .BR http://www.remotesensing.org/libtiff/ | |
170 |