Usage : imscale [options...] infilename outfilename Copyright (c) 1989-1995 San Diego Supercomputer Center (SDSC), CA, USA imscale scales input images by a selected scale factor, or scales them up or down to a desired size. Input and output files may have different image file formats. -bilinear Use bilinear interpolation -feedback Generate a feedback form (bug report) -fullhelp Display a full-length help message -help Give help about specific options -indpi dots_per_inch Specify the dpi of the incoming file -infile image_filename Specify an input image file name -infilecompression scheme Specify compression for the -infile -informat format_name Specify the format of the -infile -inmap channel_map Read one channel into another one -inpageheight inches Specify the page height of an image -inpagewidth inches Specify the page width of an image -outalpha Force output of alpha plane with image -outchandepth no_bits Force output of # of bits/channel/pixel -outclt Force output of a CLT with the image -outcompress comp_type Force output of compressed image -outfile image_filename Specify an output image file name -outfilecompression scheme Specify compression for the -outfile -outformat format_name Specify the format of the -outfile -outgroup group_type Force output of grouped image -outindex Force output as a color indexed image -outinterleave inter_type Force output of interleaved RGB image -outmap channel_map Write one channel into another one -outnchan no_channels Force output of # of channels/pixel -outnoalpha Block output of alpha plane with image -outnoclt Block output of a CLT with the image -outquality whole_number Force quality of compression -outrgb Force output as an RGB image -outtransparency Force single-color transparency -outtransparencyindex index Force single-color transparency -outtransparencyrgb r g b Force single-color transparency -pixelrep Use pixel replication -register Generate a user registration form -scale xy Specify XY scale factor -verbose Be verbose -version Display the command's version numbers -xscale x Specify X scale factor -xsize x Specify desired width in pixels -yscale y Specify Y scale factor -ysize y Specify desired height in pixels Typical Invocations: Scale a 640x480 image up to 1280x1024 (non-uniform scaling): imscale small.pix -xscale 2.0 -yscale 2.133 large.pix imscale small.pix -xsize 1280 -ysize 1024 large.pix Reduce an image to 1/3 its original size: imscale large.pix -scale 0.33 small.pix imscale large.pix -xscale 0.33 -yscale 0.33 small.pix Double an image with pixel replication instead of bilinear interpolation: imscale begin.pix -scale 2 double.pix -pixelrep imscale begin.pix -xscale 2 -yscale 2 double.pix -pixelrep Files: -infile selects the file whose images are to be scaled. -outfile selects the file into which to write the resulting scaled images. The input file is unaltered. Image Resizing: -scale, -xscale and -yscale specify floating point scale factors. To increase the size of an image, use a scale factor greater than 1.0. To decrease an image's size, use a scale factor less than 1.0. Default is 1.0. -xsize and -ysize specify desired image size in pixels. The scale factor needed to enlarge or reduce the incoming image to the desired size is automatically computed and applied. Default is the input image size. -xsize, -ysize, -xscale, and -yscale may be used together as long as at most one of -xsize and -xscale are used, and at most one of -ysize and -yscale are used. -scale may not be used with -xsize, -ysize, -xscale or -yscale. Scaling Algorithm: -bilinear uses bilinear interpolation to increase or decrease the image size. This is the default. -pixelrep uses pixel replication to increase the image size. Input File Options ------------------ It is possible to remap the channels of a file when it is read in by using the options above of the form '-...map'. For more information about how to do this, see the help page for such an option. For a list of the image formats that are supported, see the help page for an option of the form '-...format', or use the 'imformats' command. By default, input file's image file formats are determined by the file's magic number or the filename extension (like .hdf for HDF files). To override the default, explicit format names may be given using a flag of the form -...format. For instance, -informat hdf to read an hdf file. A single dash ('-') for an input filename indicates stdin. When using stdin, an explicit format name is necessary. Output File Options ------------------- There are a wide variety of options for customizing an output file. In addition to specifying the format, you can specify whether or not the output file has a color lookup table (CLT), whether or not the output file has an alpha channel, the compression method of the output file, the number of channels in the output file, the size of each channel in the output file, and various other characteristics. Refer to the list of options above for all such output file parameters. If you'd like more information about any one of these, type 'imscale -help -