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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/