1TIFFReadRGBAStrip(3TIFF)                              TIFFReadRGBAStrip(3TIFF)
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NAME

6       TIFFReadRGBAStrip  - read and decode an image strip into a fixed-format
7       raster
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SYNOPSIS

10       #include <tiffio.h>
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12       #define TIFFGetR(abgr) ((abgr) & 0xff)
13       #define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)
14       #define TIFFGetB(abgr) (((abgr) >> 16) & 0xff)
15       #define TIFFGetA(abgr) (((abgr) >> 24) & 0xff)
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17       int TIFFReadRGBAStrip(TIFF *tif, uint32 row, uint32 *raster)
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DESCRIPTION

20       TIFFReadRGBAStrip reads a single strip of a strip-based image into mem‐
21       ory,  storing  the result in the user supplied RGBA raster.  The raster
22       is assumed to be an array of width times rowsperstrip  32-bit  entries,
23       where width is the width of the image (TIFFTAG_IMAGEWIDTH) and rowsper‐
24       strip is the maximum lines in a strip (TIFFTAG_ROWSPERSTRIP).
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27       The row value should be the row of the first row in the strip (strip  *
28       rowsperstrip, zero based).
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31       Note  that  the raster is assume to be organized such that the pixel at
32       location (x,y) is raster[y*width+x]; with  the  raster  origin  in  the
33       lower-left  hand  corner  of the strip. That is bottom to top organiza‐
34       tion.  When reading a partial last strip in the file the last  line  of
35       the image will begin at the beginning of the buffer.
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37
38       Raster  pixels  are  8-bit  packed red, green, blue, alpha samples. The
39       macros TIFFGetR, TIFFGetG, TIFFGetB, and TIFFGetA  should  be  used  to
40       access  individual  samples.  Images  without  Associated Alpha matting
41       information have a constant Alpha of 1.0 (255).
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43       See the TIFFRGBAImage(3TIFF) page for more details on how various image
44       types are converted to RGBA values.
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NOTES

47       Samples  must  be  either  1,  2,  4,  8, or 16 bits. Colorimetric sam‐
48       ples/pixel must be either 1,  3,  or  4  (i.e.   SamplesPerPixel  minus
49       ExtraSamples).
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51       Palette  image colormaps that appear to be incorrectly written as 8-bit
52       values are automatically scaled to 16-bits.
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54       TIFFReadRGBAStrip is just a wrapper around the more general TIFFRGBAIm‐
55       age(3TIFF)  facilities.  It's main advantage over the similar TIFFRead‐
56       RGBAImage() function is that for large images a single  buffer  capable
57       of  holding  the  whole image doesn't need to be allocated, only enough
58       for one strip.  The TIFFReadRGBATile() function does a  similar  opera‐
59       tion for tiled images.
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RETURN VALUES

62       1 is returned if the image was successfully read and converted.  Other‐
63       wise, 0 is returned if an error was encountered.
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DIAGNOSTICS

66       All error messages are directed to the TIFFError(3TIFF) routine.
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68       Sorry, can not handle %d-bit pictures.   The  image  had  BitsPerSample
69       other than 1, 2, 4, 8, or 16.
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71       Sorry, can not handle %d-channel images.  The image had SamplesPerPixel
72       other than 1, 3, or 4.
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74       Missing needed "PhotometricInterpretation" tag.  The image did not have
75       a tag that describes how to display the data.
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77       No  "PhotometricInterpretation" tag, assuming RGB.  The image was miss‐
78       ing a tag that describes how to display it, but because it has 3  or  4
79       samples/pixel, it is assumed to be RGB.
80
81       No  "PhotometricInterpretation"  tag,  assuming min-is-black. The image
82       was missing a tag that describes how to display it, but because it  has
83       1 sample/pixel, it is assumed to be a grayscale or bilevel image.
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85       No space for photometric conversion table.  There was insufficient mem‐
86       ory for a table used to convert image samples to 8-bit RGB.
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88       Missing required "Colormap" tag.   A  Palette  image  did  not  have  a
89       required Colormap tag.
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91       No space for tile buffer.  There was insufficient memory to allocate an
92       i/o buffer.
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94       No space for strip buffer.  There was insufficient memory  to  allocate
95       an i/o buffer.
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97       Can not handle format.  The image has a format (combination of BitsPer‐
98       Sample, SamplesPerPixel, and PhotometricInterpretation) that  TIFFRead‐
99       RGBAImage can not handle.
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101       No space for B&W mapping table.  There was insufficient memory to allo‐
102       cate a table used to map grayscale data to RGB.
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104       No space for Palette mapping table.  There was insufficient  memory  to
105       allocate a table used to map data to 8-bit RGB.
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SEE ALSO

108       TIFFOpen(3TIFF),  TIFFRGBAImage(3TIFF), TIFFReadRGBAImage(3TIFF), TIFF‐
109       ReadRGBATile(3TIFF), libtiff(3TIFF)
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111       Libtiff library home page: http://www.simplesystems.org/libtiff/
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116libtiff                        December 10, 1998      TIFFReadRGBAStrip(3TIFF)