TIFFReadRGBAStrip.3tiff 5.6 KB

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  1. .\"
  2. .\" Copyright (c) 1991-1997 Sam Leffler
  3. .\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
  4. .\"
  5. .\" Permission to use, copy, modify, distribute, and sell this software and
  6. .\" its documentation for any purpose is hereby granted without fee, provided
  7. .\" that (i) the above copyright notices and this permission notice appear in
  8. .\" all copies of the software and related documentation, and (ii) the names of
  9. .\" Sam Leffler and Silicon Graphics may not be used in any advertising or
  10. .\" publicity relating to the software without the specific, prior written
  11. .\" permission of Sam Leffler and Silicon Graphics.
  12. .\"
  13. .\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  14. .\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  15. .\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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  17. .\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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  24. .if n .po 0
  25. .TH TIFFReadRGBAStrip 3TIFF "December 10, 1998" "libtiff"
  26. .SH NAME
  27. TIFFReadRGBAStrip \- read and decode an image strip into a fixed-format raster
  28. .SH SYNOPSIS
  29. .B "#include <tiffio.h>"
  30. .sp
  31. .B "#define TIFFGetR(abgr) ((abgr) & 0xff)"
  32. .br
  33. .B "#define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)"
  34. .br
  35. .B "#define TIFFGetB(abgr) (((abgr) >> 16) & 0xff)"
  36. .br
  37. .B "#define TIFFGetA(abgr) (((abgr) >> 24) & 0xff)"
  38. .sp
  39. .BI "int TIFFReadRGBAStrip(TIFF *" tif ", uint32_t " row ", uint32_t *" raster ")"
  40. .SH DESCRIPTION
  41. .IR TIFFReadRGBAStrip
  42. reads a single strip of a strip-based image into memory, storing the result in
  43. the user supplied RGBA
  44. .IR raster .
  45. The raster is assumed to be an array of width times rowsperstrip 32-bit
  46. entries, where width is the width of the image (TIFFTAG_IMAGEWIDTH) and
  47. rowsperstrip is the maximum lines in a strip (TIFFTAG_ROWSPERSTRIP).
  48. .PP
  49. The
  50. .IR row
  51. value should be the row of the first row in the strip (strip * rowsperstrip,
  52. zero based).
  53. .PP
  54. Note that the raster is assume to be organized such that the pixel at location
  55. (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP]; with the
  56. raster origin in the
  57. .I lower-left hand corner
  58. of the strip. That is bottom to top organization. When reading a partial last
  59. strip in the file the last line of the image will begin at the beginning of
  60. the buffer.
  61. .PP
  62. Raster pixels are 8-bit packed red, green, blue, alpha samples. The macros
  63. .IR TIFFGetR ,
  64. .IR TIFFGetG ,
  65. .IR TIFFGetB ,
  66. and
  67. .I TIFFGetA
  68. should be used to access individual samples. Images without Associated Alpha
  69. matting information have a constant Alpha of 1.0 (255).
  70. .PP
  71. See the
  72. .IR TIFFRGBAImage (3TIFF)
  73. page for more details on how various image types are converted to RGBA values.
  74. .SH NOTES
  75. Samples must be either 1, 2, 4, 8, or 16 bits. Colorimetric samples/pixel must
  76. be either 1, 3, or 4 (i.e.
  77. .I SamplesPerPixel
  78. minus
  79. .IR ExtraSamples ).
  80. .PP
  81. Palette image colormaps that appear to be incorrectly written as 8-bit values
  82. are automatically scaled to 16-bits.
  83. .PP
  84. .I TIFFReadRGBAStrip
  85. is just a wrapper around the more general
  86. .IR TIFFRGBAImage (3TIFF)
  87. facilities. It's main advantage over the similar
  88. .IR TIFFReadRGBAImage()
  89. function is that for large images a single buffer capable of holding the whole
  90. image doesn't need to be allocated, only enough for one strip. The
  91. .IR TIFFReadRGBATile()
  92. function does a similar operation for tiled images.
  93. .SH "RETURN VALUES"
  94. 1 is returned if the image was successfully read and converted.
  95. Otherwise, 0 is returned if an error was encountered.
  96. .SH DIAGNOSTICS
  97. All error messages are directed to the
  98. .IR TIFFError (3TIFF)
  99. routine.
  100. .PP
  101. .BR "Sorry, can not handle %d-bit pictures" .
  102. The image had
  103. .I BitsPerSample
  104. other than 1, 2, 4, 8, or 16.
  105. .PP
  106. .BR "Sorry, can not handle %d-channel images" .
  107. The image had
  108. .I SamplesPerPixel
  109. other than 1, 3, or 4.
  110. .PP
  111. \fBMissing needed "PhotometricInterpretation" tag\fP.
  112. The image did not have a tag that describes how to display the data.
  113. .PP
  114. \fBNo "PhotometricInterpretation" tag, assuming RGB\fP.
  115. The image was missing a tag that describes how to display it, but because it
  116. has 3 or 4 samples/pixel, it is assumed to be
  117. .SM RGB.
  118. .PP
  119. \fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP. The image was
  120. missing a tag that describes how to display it, but because it has 1
  121. sample/pixel, it is assumed to be a grayscale or bilevel image.
  122. .PP
  123. .BR "No space for photometric conversion table" .
  124. There was insufficient memory for a table used to convert image samples to
  125. 8-bit
  126. .SM RGB.
  127. .PP
  128. \fBMissing required "Colormap" tag\fP.
  129. A Palette image did not have a required
  130. .I Colormap
  131. tag.
  132. .PP
  133. .BR "No space for tile buffer" .
  134. There was insufficient memory to allocate an i/o buffer.
  135. .PP
  136. .BR "No space for strip buffer" .
  137. There was insufficient memory to allocate an i/o buffer.
  138. .PP
  139. .BR "Can not handle format" .
  140. The image has a format (combination of
  141. .IR BitsPerSample ,
  142. .IR SamplesPerPixel ,
  143. and
  144. .IR PhotometricInterpretation )
  145. that
  146. .I TIFFReadRGBAImage
  147. can not handle.
  148. .PP
  149. .BR "No space for B&W mapping table" .
  150. There was insufficient memory to allocate a table used to map grayscale data
  151. to
  152. .SM RGB.
  153. .PP
  154. .BR "No space for Palette mapping table" .
  155. There was insufficient memory to allocate a table used to map data to 8-bit
  156. .SM RGB.
  157. .SH "SEE ALSO"
  158. .BR TIFFOpen (3TIFF),
  159. .BR TIFFRGBAImage (3TIFF),
  160. .BR TIFFReadRGBAImage (3TIFF),
  161. .BR TIFFReadRGBATile (3TIFF),
  162. .BR libtiff (3TIFF)
  163. .PP
  164. Libtiff library home page:
  165. .BR http://www.simplesystems.org/libtiff/