src/tiff/man/TIFFReadRGBAImage.3tiff

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