src/tiff/man/TIFFReadRGBAImage.3tiff

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  25 .if n .po 0
  26 .TH TIFFReadRGBAImage 3TIFF "October 13, 2006" "libtiff"
  27 .SH NAME
  28 TIFFReadRGBAImage, TIFFReadRGBAImageOriented \- read and decode an image
  29 into a fixed-format raster
  30 .SH SYNOPSIS
  31 .B "#include <tiffio.h>"
  32 .sp
  33 .B "#define TIFFGetR(abgr) ((abgr) & 0xff)"
  34 .br
  35 .B "#define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)"
  36 .br
  37 .B "#define TIFFGetB(abgr) (((abgr) >> 16) & 0xff)"
  38 .br
  39 .B "#define TIFFGetA(abgr) (((abgr) >> 24) & 0xff)"
  40 .sp
  41 .BI "int TIFFReadRGBAImage(TIFF *" tif ", uint32 " width ", uint32 " height ", uint32 *" raster ", int " stopOnError ")"
  42 .br
  43 .BI "int TIFFReadRGBAImageOriented(TIFF *" tif ", uint32 " width ", uint32 " height ", uint32 *" raster ", int " orientation ", int " stopOnError ")"
  44 .br
  45 .SH DESCRIPTION
  46 .IR TIFFReadRGBAImage
  47 reads a strip- or tile-based image into memory, storing the
  48 result in the user supplied
  49 .IR raster .
  50 The raster is assumed to be an array of
  51 .I width
  52 times
  53 .I height
  54 32-bit entries, where
  55 .I width
  56 must be less than or equal to the width of the image (\c
  57 .I height
  58 may be any non-zero size).
  59 If the raster dimensions are smaller than the image, the image data
  60 is cropped to the raster bounds.
  61 If the raster height is greater than that of the image, then the
  62 image data are placed in the lower part of the raster.
  63 (Note that the raster is assume to be organized such that the pixel
  64 at location (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP];
  65 with the raster origin in the lower-left hand corner.)
  66 .PP
  67 .IR TIFFReadRGBAImageOriented
  68 works like
  69 .IR TIFFReadRGBAImage
  70 with except of that user can specify the raster origin position with the
  71 .I orientation
  72 parameter. Four orientations supported:
  73 .TP
  74 .B ORIENTATION_TOPLEFT
  75 origin in top-left corner,
  76 .TP
  77 .B ORIENTATION_TOPRIGHT
  78 origin in top-right corner,
  79 .TP
  80 .B ORIENTATION_BOTLEFT
  81 origin in bottom-left corner
  82 and
  83 .TP
  84 .B ORIENTATION_BOTRIGHT
  85 origin in bottom-right corner.
  86 .LP
  87 If you choose
  88 .B ORIENTATION_BOTLEFT
  89 result will be the same as returned by the
  90 .IR TIFFReadRGBAImage.
  91 .PP
  92 Raster pixels are 8-bit packed red, green, blue, alpha samples.
  93 The macros
  94 .IR TIFFGetR ,
  95 .IR TIFFGetG ,
  96 .IR TIFFGetB ,
  97 and
  98 .I TIFFGetA
  99 should be used to access individual samples.
 100 Images without Associated Alpha matting information have a constant
 101 Alpha of 1.0 (255).
 102 .PP
 103 .I TIFFReadRGBAImage
 104 converts non-8-bit images by scaling sample values.
 105 Palette, grayscale, bilevel,
 106 .SM CMYK\c
 107 , and YCbCr images are converted to
 108 .SM RGB
 109 transparently.
 110 Raster pixels are returned uncorrected by any colorimetry information
 111 present in the directory.
 112 .PP
 113 The paramater
 114 .I stopOnError
 115 specifies how to act if an error is encountered while reading
 116 the image.
 117 If
 118 .I stopOnError
 119 is non-zero, then an error will terminate the operation; otherwise
 120 .I TIFFReadRGBAImage
 121 will continue processing data until all the possible data in the
 122 image have been requested.
 123 .SH NOTES
 124 In C++ the
 125 .I stopOnError
 126 parameter defaults to 0.
 127 .PP
 128 Samples must be either 1, 2, 4, 8, or 16 bits.
 129 Colorimetric samples/pixel must be either 1, 3, or 4 (i.e.
 130 .I SamplesPerPixel
 131 minus
 132 .IR ExtraSamples ).
 133 .PP
 134 Palettte image colormaps that appear to be incorrectly written
 135 as 8-bit values are automatically scaled to 16-bits.
 136 .PP
 137 .I TIFFReadRGBAImage
 138 is just a wrapper around the more general
 139 .IR TIFFRGBAImage (3TIFF)
 140 facilities.
 141 .SH "RETURN VALUES"
 142 1 is returned if the image was successfully read and converted.
 143 Otherwise, 0 is returned if an error was encountered and
 144 .I stopOnError
 145 is zero.
 146 .SH DIAGNOSTICS
 147 All error messages are directed to the
 148 .IR TIFFError (3TIFF)
 149 routine.
 150 .PP
 151 .BR "Sorry, can not handle %d-bit pictures" .
 152 The image had
 153 .I BitsPerSample
 154 other than 1, 2, 4, 8, or 16.
 155 .PP
 156 .BR "Sorry, can not handle %d-channel images" .
 157 The image had
 158 .I SamplesPerPixel
 159 other than 1, 3, or 4.
 160 .PP
 161 \fBMissing needed "PhotometricInterpretation" tag\fP.
 162 The image did not have a tag that describes how to display
 163 the data.
 164 .PP
 165 \fBNo "PhotometricInterpretation" tag, assuming RGB\fP.
 166 The image was missing a tag that describes how to display it,
 167 but because it has 3 or 4 samples/pixel, it is assumed to be
 168 .SM RGB.
 169 .PP
 170 \fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP.
 171 The image was missing a tag that describes how to display it,
 172 but because it has 1 sample/pixel, it is assumed to be a grayscale
 173 or bilevel image.
 174 .PP
 175 .BR "No space for photometric conversion table" .
 176 There was insufficient memory for a table used to convert
 177 image samples to 8-bit
 178 .SM RGB.
 179 .PP
 180 \fBMissing required "Colormap" tag\fP.
 181 A Palette image did not have a required
 182 .I Colormap
 183 tag.
 184 .PP
 185 .BR "No space for tile buffer" .
 186 There was insufficient memory to allocate an i/o buffer.
 187 .PP
 188 .BR "No space for strip buffer" .
 189 There was insufficient memory to allocate an i/o buffer.
 190 .PP
 191 .BR "Can not handle format" .
 192 The image has a format (combination of
 193 .IR BitsPerSample ,
 194 .IR SamplesPerPixel ,
 195 and
 196 .IR PhotometricInterpretation )
 197 that
 198 .I TIFFReadRGBAImage
 199 can not handle.
 200 .PP
 201 .BR "No space for B&W mapping table" .
 202 There was insufficient memory to allocate a table used to map
 203 grayscale data to
 204 .SM RGB.
 205 .PP
 206 .BR "No space for Palette mapping table" .
 207 There was insufficient memory to allocate a table used to map
 208 data to 8-bit
 209 .SM RGB.
 210 .SH "SEE ALSO"
 211 .BR TIFFOpen (3TIFF),
 212 .BR TIFFRGBAImage (3TIFF),
 213 .BR TIFFReadRGBAStrip (3TIFF),
 214 .BR TIFFReadRGBATile (3TIFF),
 215 .BR libtiff (3TIFF)
 216 .PP
 217 Libtiff library home page:
 218 .BR http://www.remotesensing.org/libtiff/