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pnmtotiff !!!pnmtotiff NAME SYNOPSIS DESCRIPTION OPTIONS NOTES SEE ALSO AUTHOR ---- !!NAME pnmtotiff - convert a PNM image to a TIFF file !!SYNOPSIS __pnmtotiff__ [[__-none__|__-packbits__|__-lzw__|__-g3__|__-g4__] [[__-2d__] [[__-fill__] [[__-predictor__ ''n''] [[__-msb2lsb__|__-lsb2msb__] [[__-rowsperstrip__ ''n''] [[__-minisblack__] [[''pnmfile''] Minimum unambiguous abbreviations of options are acceptable. !!DESCRIPTION Reads a PNM image as input. Produces a TIFF file as output. The output goes to Standard Output, which must be a seekable file. That means no pipes, but any regular file should work. !!OPTIONS By default, __pnmtotiff__ creates a TIFF file with no compression. This is your best bet most of the time. If you want to try another compression scheme or tweak some of the other even more obscure output options, there are a number of flags to play with. Actually, the best default would be to use LZW compression, which is what __pnmtotiff__ used to do by default. However, the Tiff library no longer does LZW compression due to concerns with violating Unisys's patent on LZW compression. The __-none__, __-packbits__, __-lzw__, __-g3__, and __-g4__ options are used to override the default and set the compression scheme used in creating the output file. The CCITT Group 3 and Group 4 compression algorithms can only be used with bilevel data. __-lzw__ doesn't really work because the Tiff library doesn't do LZW compression. It used to, but its developers removed the function out of concern about violating Unisys's patent. This option remains in case you use a Tiff library that cooperates, now or in the future. The __-2d__ and __-fill__ options are meaningful only with Group 3 compression: __-2d__ requests 2-dimensional encoding, while __-fill__ requests that each encoded scanline be zero-filled to a byte boundry. The __-predictor__ option is only meaningful with LZW compression: a predictor value of 2 causes each scanline of the output image to undergo horizontal differencing before it is encoded; a value of 1 forces each scanline to be encoded without differencing. By default, __pnmtotiff__ creates a TIFF file with msb-to-lsb fill order. The __-msb2lsb__ and __-lsb2msb__ options are used to override the default and set the fill order used in creating the file. The fill order is the order in which pixels are packed into a byte in the Tiff raster, in the case that there are multiple pixels per byte. msb-to-lsb means that the leftmost columns go into the most significant bits of the byte in the Tiff image. However, there is considerable confusion about the meaning of fill order. Some believe it means whether 16 bit sample values in the Tiff image are little-endian or big-endian. This is totally erroneous (The endianness of integers in a Tiff image is designated by the image's magic number). However, !ImageMagick and Netpbm both have been known to implement that interpretation. 2001.09.06. If the image does not have sub-byte pixels, these options have no effect other than to set the value of the FILLORDER tag in the Tiff image (which may be useful for those programs that misinterpret the tag with reference to 16 bit samples). The __-rowsperstrip__ option can be used to set the number of rows (scanlines) in each strip of data in the output file. By default, the output file has the number of rows per strip set to a value that will ensure each strip is no more than 8 kilobytes long. The __-minisblack__ option forces the output image to have a __ Without the __-minisblack__ option, __pnmtotiff__ follows the standard. This usually results in better compression and is generally preferred for bilevel coding. Before February 2001, __pnmtotiff__ always produced __pnmtotiff__ sets the photometric interpretation tag in the TIFF output according to which photometric is actually used. !!NOTES There are myriad variations of the TIFF format, and this program generates only a few of them. __pnmtotiff__ creates a grayscale TIFF file if its input is a PBM (monochrome) or PGM (grayscale) file. __pnmtotiff__ also creates a grayscale file if it input is PPM (color), but there is only one color in the image. If the input is a PPM (color) file and there are 256 colors or fewer, but more than 1, __pnmtotiff__ generates a color palette TIFF file. If there are more colors than that, __pnmtotiff__ generates an RGB (not RGBA) single plane TIFF file. Use __pnmtotiffcmyk__ to generate the cyan-magenta-yellow-black ink color separation TIFF format. The number of bits per sample in the TIFF output is determined by the maxval of the PNM input. If the maxval is less than 256, the bits per sample in the output is the smallest number that can encode the maxval. If the maxval is greater than or equal to 256, there are 16 bits per sample in the output. !!SEE ALSO tifftopnm(1), pnmtotiffcmyk(1), pnmdepth(1), pnm(5) !!AUTHOR Derived by Jef Poskanzer from ras2tiff.c, which is Copyright (c) 1990 by Sun Microsystems, Inc. Author: Patrick J. Naughton (naughton@wind.sun.com). ----
5 pages link to
pnmtotiff(1)
:
pbmfilters(1)
pnmtotiffcmyk(1)
pnm(5)
tifftopnm(1)
Man1p
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