From d479dd1aab1c1cb907932c6595b0ef33523fc797 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rg=20Frings-F=C3=BCrst?= Date: Fri, 6 Nov 2015 07:14:47 +0100 Subject: Imported Upstream version 1.8.3 --- jpeg/djpeg.1 | 252 ----------------------------------------------------------- 1 file changed, 252 deletions(-) delete mode 100755 jpeg/djpeg.1 (limited to 'jpeg/djpeg.1') diff --git a/jpeg/djpeg.1 b/jpeg/djpeg.1 deleted file mode 100755 index f3722d1..0000000 --- a/jpeg/djpeg.1 +++ /dev/null @@ -1,252 +0,0 @@ -.TH DJPEG 1 "3 October 2009" -.SH NAME -djpeg \- decompress a JPEG file to an image file -.SH SYNOPSIS -.B djpeg -[ -.I options -] -[ -.I filename -] -.LP -.SH DESCRIPTION -.LP -.B djpeg -decompresses the named JPEG file, or the standard input if no file is named, -and produces an image file on the standard output. PBMPLUS (PPM/PGM), BMP, -GIF, Targa, or RLE (Utah Raster Toolkit) output format can be selected. -(RLE is supported only if the URT library is available.) -.SH OPTIONS -All switch names may be abbreviated; for example, -.B \-grayscale -may be written -.B \-gray -or -.BR \-gr . -Most of the "basic" switches can be abbreviated to as little as one letter. -Upper and lower case are equivalent (thus -.B \-BMP -is the same as -.BR \-bmp ). -British spellings are also accepted (e.g., -.BR \-greyscale ), -though for brevity these are not mentioned below. -.PP -The basic switches are: -.TP -.BI \-colors " N" -Reduce image to at most N colors. This reduces the number of colors used in -the output image, so that it can be displayed on a colormapped display or -stored in a colormapped file format. For example, if you have an 8-bit -display, you'd need to reduce to 256 or fewer colors. -.TP -.BI \-quantize " N" -Same as -.BR \-colors . -.B \-colors -is the recommended name, -.B \-quantize -is provided only for backwards compatibility. -.TP -.B \-fast -Select recommended processing options for fast, low quality output. (The -default options are chosen for highest quality output.) Currently, this is -equivalent to \fB\-dct fast \-nosmooth \-onepass \-dither ordered\fR. -.TP -.B \-grayscale -Force gray-scale output even if JPEG file is color. Useful for viewing on -monochrome displays; also, -.B djpeg -runs noticeably faster in this mode. -.TP -.BI \-scale " M/N" -Scale the output image by a factor M/N. Currently supported scale factors are -M/N with all M from 1 to 16, where N is the source DCT size, which is 8 for -baseline JPEG. If the /N part is omitted, then M specifies the DCT scaled -size to be applied on the given input. For baseline JPEG this is equivalent -to M/8 scaling, since the source DCT size for baseline JPEG is 8. -Scaling is handy if the image is larger than your screen; also, -.B djpeg -runs much faster when scaling down the output. -.TP -.B \-bmp -Select BMP output format (Windows flavor). 8-bit colormapped format is -emitted if -.B \-colors -or -.B \-grayscale -is specified, or if the JPEG file is gray-scale; otherwise, 24-bit full-color -format is emitted. -.TP -.B \-gif -Select GIF output format. Since GIF does not support more than 256 colors, -.B \-colors 256 -is assumed (unless you specify a smaller number of colors). -.TP -.B \-os2 -Select BMP output format (OS/2 1.x flavor). 8-bit colormapped format is -emitted if -.B \-colors -or -.B \-grayscale -is specified, or if the JPEG file is gray-scale; otherwise, 24-bit full-color -format is emitted. -.TP -.B \-pnm -Select PBMPLUS (PPM/PGM) output format (this is the default format). -PGM is emitted if the JPEG file is gray-scale or if -.B \-grayscale -is specified; otherwise PPM is emitted. -.TP -.B \-rle -Select RLE output format. (Requires URT library.) -.TP -.B \-targa -Select Targa output format. Gray-scale format is emitted if the JPEG file is -gray-scale or if -.B \-grayscale -is specified; otherwise, colormapped format is emitted if -.B \-colors -is specified; otherwise, 24-bit full-color format is emitted. -.PP -Switches for advanced users: -.TP -.B \-dct int -Use integer DCT method (default). -.TP -.B \-dct fast -Use fast integer DCT (less accurate). -.TP -.B \-dct float -Use floating-point DCT method. -The float method is very slightly more accurate than the int method, but is -much slower unless your machine has very fast floating-point hardware. Also -note that results of the floating-point method may vary slightly across -machines, while the integer methods should give the same results everywhere. -The fast integer method is much less accurate than the other two. -.TP -.B \-dither fs -Use Floyd-Steinberg dithering in color quantization. -.TP -.B \-dither ordered -Use ordered dithering in color quantization. -.TP -.B \-dither none -Do not use dithering in color quantization. -By default, Floyd-Steinberg dithering is applied when quantizing colors; this -is slow but usually produces the best results. Ordered dither is a compromise -between speed and quality; no dithering is fast but usually looks awful. Note -that these switches have no effect unless color quantization is being done. -Ordered dither is only available in -.B \-onepass -mode. -.TP -.BI \-map " file" -Quantize to the colors used in the specified image file. This is useful for -producing multiple files with identical color maps, or for forcing a -predefined set of colors to be used. The -.I file -must be a GIF or PPM file. This option overrides -.B \-colors -and -.BR \-onepass . -.TP -.B \-nosmooth -Don't use high-quality upsampling. -.TP -.B \-onepass -Use one-pass instead of two-pass color quantization. The one-pass method is -faster and needs less memory, but it produces a lower-quality image. -.B \-onepass -is ignored unless you also say -.B \-colors -.IR N . -Also, the one-pass method is always used for gray-scale output (the two-pass -method is no improvement then). -.TP -.BI \-maxmemory " N" -Set limit for amount of memory to use in processing large images. Value is -in thousands of bytes, or millions of bytes if "M" is attached to the -number. For example, -.B \-max 4m -selects 4000000 bytes. If more space is needed, temporary files will be used. -.TP -.BI \-outfile " name" -Send output image to the named file, not to standard output. -.TP -.B \-verbose -Enable debug printout. More -.BR \-v 's -give more output. Also, version information is printed at startup. -.TP -.B \-debug -Same as -.BR \-verbose . -.SH EXAMPLES -.LP -This example decompresses the JPEG file foo.jpg, quantizes it to -256 colors, and saves the output in 8-bit BMP format in foo.bmp: -.IP -.B djpeg \-colors 256 \-bmp -.I foo.jpg -.B > -.I foo.bmp -.SH HINTS -To get a quick preview of an image, use the -.B \-grayscale -and/or -.B \-scale -switches. -.B \-grayscale \-scale 1/8 -is the fastest case. -.PP -Several options are available that trade off image quality to gain speed. -.B \-fast -turns on the recommended settings. -.PP -.B \-dct fast -and/or -.B \-nosmooth -gain speed at a small sacrifice in quality. -When producing a color-quantized image, -.B \-onepass \-dither ordered -is fast but much lower quality than the default behavior. -.B \-dither none -may give acceptable results in two-pass mode, but is seldom tolerable in -one-pass mode. -.PP -If you are fortunate enough to have very fast floating point hardware, -\fB\-dct float\fR may be even faster than \fB\-dct fast\fR. But on most -machines \fB\-dct float\fR is slower than \fB\-dct int\fR; in this case it is -not worth using, because its theoretical accuracy advantage is too small to be -significant in practice. -.SH ENVIRONMENT -.TP -.B JPEGMEM -If this environment variable is set, its value is the default memory limit. -The value is specified as described for the -.B \-maxmemory -switch. -.B JPEGMEM -overrides the default value specified when the program was compiled, and -itself is overridden by an explicit -.BR \-maxmemory . -.SH SEE ALSO -.BR cjpeg (1), -.BR jpegtran (1), -.BR rdjpgcom (1), -.BR wrjpgcom (1) -.br -.BR ppm (5), -.BR pgm (5) -.br -Wallace, Gregory K. "The JPEG Still Picture Compression Standard", -Communications of the ACM, April 1991 (vol. 34, no. 4), pp. 30-44. -.SH AUTHOR -Independent JPEG Group -.SH BUGS -To avoid the Unisys LZW patent, -.B djpeg -produces uncompressed GIF files. These are larger than they should be, but -are readable by standard GIF decoders. -- cgit v1.2.3