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       econvert - image converter of the ExactImage toolkit


       econvert [option...] [{-i | --input} input-file...]
                [{-o | --output} output-file...]

       econvert {-h | --help}


       ExactImage is a fast C++ image processing library. Unlike many other
       library frameworks it allows operation in several color spaces and bit
       depths natively, resulting in low memory and computational

       econvert is a command line frontend for the image processing library
       and mimicks ImageMagick's convert. However econvert syntax is not
       compatible with convert.


       -i file, --input file
           Read image from the specified file. Optionally, filenames can be
           prefixed with format name, e.g.  jpg:- or raw:rgb8-dump.

       -o file, --output file
           Save output image to the specified file. Optionally, filenames can
           be prefixed with format name, e.g.  jpg:- or raw:rgb8-dump.

       -a file, --append file
           Append output image to the specified file. Existing image must have
           the same width as the appended one. Optionally, filenames can be
           prefixed with format name, e.g.  jpg:- or raw:rgb8-dump.

       --compress method
           Use the specified compression method for writing images, e.g.  G3,
           G4, Zip, ... The default depends on the output format.

       --decompress method
           Use the specified decompression method for reading images.

       --quality n
           Use the specified quality used for writing compressed images. Valid
           values are integers from 0 to 100. The default is 75.

       --resolution xdpi [ydpi]
           Set metadata resolution.

       --size width height
           Set image dimensions for raw images.

       --split file...
           Split the image in Y-direction into multiple images.

   Scaling, cropping, transformations
       --bicubic-scale x
           Scale image data with bi-cubic filter. Use scale factor x.

       --bilinear-scale x
           Scale image data with bi-linear filter. Use scale factor x.

       --box-scale x
           (Down)scale image data with box filter. Use scale factor x.

       --ddt-scale x
           Scale image data with data dependent triangulation. Use scale
           factor x.

       --nearest-scale x
           Scale image data to nearest neighbour. Use scale factor x.

       --scale x
           Scale image data using a method suitable for specified factor x.

       --thumbnail x
           Quick and dirty down-scale for a thumbnail. Use scale factor x.

       --crop x y w h
           Crop the specified area out of the image.

           Fast auto crop.

           Flip the image vertically.

           Flip the image horizontally.

       --rotate n
           Rotate the image n degrees.

       --brightness x
           Change the image brightness.

       --contrast x
           Change the image contrast.

       --saturation x
           Change the image saturation.

       --lightness x
           Change the image lightness.

       --hue x
           Change the image hue.

           Negate the image.

       --gamma x
           Change the image gamma.

           Transform the image to span the full color range.

       --colorspace colorspace
           Convert image colorspace. Valid values are: BW, BILEVEL, GRAY,
           GRAY1, GRAY2, GRAY4, RGB, YUV and CYMK.

       --floyd-steinberg n
           Perform Floyd-Steinberg dithering using n shades.

       --riemersma n
           Perform Riemersma dithering using n shades.

       --blur stdev
           Perform gaussian blur with standard deviation stdev.

           Shuffle every 2nd line.

           Detect edges.

       --convolve x11 x12 ... x1n ... xn1 xn2 ... xnn
           Convolve the image using the specified convolution matrix.

       --foreground color
           Set foreground color.

       --background color
           Set background color.

       --font font
           Use the specified font for drawing text.

       --text-rotation n
           Use the specified text rotation.

       --text x1 y1 height text
           Draw text.

       --stroke-width n
           Set stroke width for vector primitives.

       --line x1 y1 x2 y2
           Draw a line.

       -h, --help
           Display help text and exit.


       Image data must be read using -i or --input, processing routines are
       selected by their name with two leading dashes (e.g.  --rotate) and at
       any point the data might be written into a file with -o or --output,
       for example:

           econvert -i lenea.tiff --box-scale 0.5 -o medium.png --box-scale 0.5 -o little.png

   Lossless transformations of JPEG files
       The library delays image decoding as much as possible and provides
       lossless algorithms to work on compressed data (such as JPEGs)

           econvert -i AV220-Scan.JPG --resolution 300x300 -o 1.jpg --rotate 90 -o 2.jpg --rotate 180 -o 3.jpg --rotate -90 -o 4.jpg --flip -o 5.jpg --flop -o 6.jpg --scale 0.25 -o thumb.jpg

       In this example 1.jpg will be created from the original JPEG DCT
       coefficients, those coefficients will be rearranged and 2.jpg, 3.jpg,
       4.jpg, 5.jpg and 6.jpg will be written without any additional loss in
       quality. Only at the end, for image thumb.jpg, the DCT will actually be
       decoded — but due to the accelerated JPEG scaling only partially.

   Thumbnails of bi-level images
       When 1 bit, black and white, images are scaled down, the output often
       looks bad, as the library algorithms always operate in the color-space
       the image data is stored in. To work around this problem, the
       colorspace must be changed (e.g. to 8 bit gray) before applying the box
       scaler. At the end the result might be converted back to just a few
       shades of gray such as 2 or 4 bit:

           econvert -i avision-bw-scan.pbm --colorspace gray8 --box-scale 0.125 --colorspace gray2 -o thumb.png

   Faster JPEG down-scaling
       If you don't care about quality, only about throughput, you can force
       nearest neighbor scaling by just specifying a scale factor the JPEG
       decoder can accelerate (½, ¼, or 1/8) and apply the remaining scaling
       manually. To achieve faster scaling with the effective factor 1/3:

           econvert -i big.jpg --scale .5 --nearest-scale 0.66 -o thumb.jpg

   Working with digital camera RAW data
       Wide range of digital camera RAW formats is supported. Usually decoding
       of RAW data should be transparent and automatic, however some formats
       also are also valid TIFF files and the embedded thumbnail might be
       picked by in favour of the actual RAW content. This this cases the
       dcraw decoder can explicitly be requested with the decoder prefix of
       the input parameter:

           econvert -i dcraw:img_0123.cr2 ...

       To quickly extract the embedded thumbnail preview, specify thumb as
       decompression method before the image is loaded:

           econvert --decompress thumb -i dcraw:img_0123.cr2 ...

   Loading arbitrary raw data
       It is possible to load arbitrary raw data via the raw: codec
       specification; color-depth (colorspace) and size for the raw data have
       to be explicitly specified:

           econvert --size 1696x32 --colorspace rgb8 -i raw:data-file ...




       Jakub Wilk <>
           Wrote this manual page for the Debian system.
           This manual page incorporates texts found on the ExactImage


       This manual page was written for the Debian system (and may be used by

       Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU General Public License, Version 2 or (at
       your option) any later version published by the Free Software

       On Debian systems, the complete text of the GNU General Public License
       can be found in /usr/share/common-licenses/GPL-2.