graphicsmagick / linux
gm identify Monterey.jpg
Monterey.jpg JPEG 1920x1080+0+0 DirectClass 8-bit 535.4Ki 0.000u 0m:0.000001s
display
animate=show animation eg gif
composite=blend/merge image togather
conjure = interprets MSL
convert
import=read image from window
mogrify= image scaling, image rotation, color reduction etc overwrites original
montage =tiled image
options
-adjoin = join images into a single multi-image file
image%02d.miff
-affine <matrix>
This option provides a transform matrix {sx,rx,ry,sy,tx,ty} for use by subsequent -draw or -transform options.
-antialias
remove pixel aliasing
-append
creates a single image where the images in the original set are stacked top-to-bottom.
-asc-cdl <spec>
-authenticate <string>
password for pdf
-auto-orient
-average
average a set of images
-backdrop
-colorspace <value>
the type of colorspace
Choices are: CineonLog, CMYK, GRAY, HSL, HWB, OHTA, RGB,
Rec601Luma, Rec709Luma, Rec601YCbCr, Rec709YCbCr, Transparent,
XYZ, YCbCr, YIQ, YPbPr, or YUV.
-comment "%m:%f %wx%h"
-compress <type>
the type of image compression
Choices are: None, BZip, Fax, Group3, Group4, JPEG, Lossless,
LZW, RLE, Zip, LZMA, JPEG2000, JPEG2000, JBIG, JBIG2, WebP, or
ZSTD.
Use the -quality option to set the compression level to be used
by the JPEG, JPEG-2000, PNG, MIFF, MPEG, and TIFF encoders. Use
the -sampling-factor option to set the sampling factor to be
used by the DPX, JPEG, MPEG, and YUV encoders for downsampling
the chroma channels.
-density <width>x<height>
horizontal and vertical resolution in pixels of the image This
option specifies the image resolution to store while encoding a
raster image or the canvas resolution while rendering (reading)
vector formats such as Postscript, PDF, WMF, and SVG into a
raster image. Image resolution provides the unit of measure to
apply when rendering to an output device or raster image. The
default unit of measure is in dots per inch (DPI). The -units
option may be used to select dots per centimeter instead.
The default resolution is 72 dots per inch, which is equivalent
to one point per pixel (Macintosh and Postscript standard).
Computer screens are normally 72 or 96 dots per inch while
printers typically support 150, 300, 600, or 1200 dots per inch.
To determine the resolution of your display, use a ruler to
measure the width of your screen in inches, and divide by the
number of horizontal pixels (1024 on a 1024x768 display). If
the file format supports it, this option may be used to update
the stored image resolution. Note that Photoshop stores and
obtains image resolution from a proprietary embedded profile. If
this profile is not stripped from the image, then Photoshop will
continue to treat the image using its former resolution,
ignoring the image resolution specified in the standard file
header. The density option is an attribute and does not alter
the underlying raster image. It may be used to adjust the
rendered size for desktop publishing purposes by adjusting the
scale applied to the pixels. To resize the image so that it is
the same size at a different resolution, use the -resample
option.
-depth <value>
depth of the image
This is the number of bits of color to preserve in the image.
Any value between 1 and QuantumDepth (build option) may be
specified, although 8 or 16 are the most common values. Use this
option to specify the depth of raw images whose depth is unknown
such as GRAY, RGB, or CMYK, or to change the depth of any image
after it has been read. The depth option is applied to the
pixels immediately so it may be used as a form of simple
compression by discarding the least significant bits. Reducing
the depth in advance may speed up color quantization, and help
create smaller file sizes when using a compression algorithm
like LZW or ZIP.
-format <string>
output formatted image characteristics
When used with the identify utility, or the convert utility with
output written to the 'info:-' file specification, use this
option to print information about the image in a format of your
choosing. You can include the image filename, type, width,
height, Exif data, or other image attributes by embedding
special format characters:
%b file size
%c comment
%d directory
%e filename extension
%f filename
%g page dimensions and offsets
%h height
%i input filename
%k number of unique colors
%l label
%m magick
%n number of scenes
%o output filename
%p page number
%q image bit depth
%r image type description
%s scene number
%t top of filename
%u unique temporary filename
%w width
%x horizontal resolution
%y vertical resolution
%A transparency supported
%C compression type
%D GIF disposal method
%G Original width and height
%H page height
%M original filename specification
%O page offset (x,y)
%P page dimensions (width,height)
%Q compression quality
%T time delay (in centi-seconds)
%U resolution units
%W page width
%X page horizontal offset (x)
%Y page vertical offset (y)
%@ trim bounding box
%# signature
\n newlin
\r carriage return
%% %
-format "%m:%f %wx%h"
Where "<tag>" may be one of the following:
* (print all Exif tags, in keyword=data format)
! (print all Exif tags, in tag_number format)
#hhhh (print data for Exif tag #hhhh)
ImageWidth
ImageLength
BitsPerSample
Compression
PhotometricInterpretation
FillOrder
DocumentName
ImageDescription
Make
Model
StripOffsets
Orientation
SamplesPerPixel
RowsPerStrip
StripByteCounts
XResolution
YResolution
PlanarConfiguration
ResolutionUnit
TransferFunction
Software
DateTime
Artist
WhitePoint
PrimaryChromaticities
TransferRange
JPEGProc
JPEGInterchangeFormat
JPEGInterchangeFormatLength
YCbCrCoefficients
YCbCrSubSampling
YCbCrPositioning
ReferenceBlackWhite
CFARepeatPatternDim
CFAPattern
BatteryLevel
Copyright
ExposureTime
FNumber1
IPTC/NAA
ExifOffset
InterColorProfile
ExposureProgram
SpectralSensitivity
GPSInfo
ISOSpeedRatings
OECF
ExifVersion
DateTimeOriginal
DateTimeDigitized
ComponentsConfiguration
CompressedBitsPerPixel
ShutterSpeedValue
ApertureValue
BrightnessValue
ExposureBiasValue
MaxApertureValue
SubjectDistance
MeteringMode
LightSource
Flash
FocalLength
MakerNote
UserComment
SubSecTime
SubSecTimeOriginal
SubSecTimeDigitized
FlashPixVersion
ColorSpace
ExifImageWidth
ExifImageLength
InteroperabilityOffset
FlashEnergy
SpatialFrequencyResponse
FocalPlaneXResolution
FocalPlaneYResolution
FocalPlaneResolutionUnit
SubjectLocation
ExposureIndex
SensingMethod
FileSource
SceneType
JPEG specific information (from reading a JPEG file) may be
obtained like this:
%[JPEG-<tag>]
Where "<tag>" may be one of the following:
* (all JPEG-related tags, in
keyword=data format)
Quality IJG JPEG "quality" estimate
Colorspace JPEG colorspace numeric ID
Colorspace-Name JPEG colorspace name
Sampling-factors JPEG sampling factors
-geometry <width>x<height>{+-}<x>{+-}<y>{%}{@}{!}{^}{<}{>}
Specify dimension, offset, and resize options.
example
gm convert -resize 300 image.png resize-300-image.png
gm convert -resize 300*300
gm convert -flop = mirror image
gm convert -flip = flip verticaly
gm convert -monochrome
gm convert input.jpg -resize 300x output.jpg = preserve aspect ratio
gm convert input.jpg -resize x200 output.jpg = same
gm convert input.jpg -thumbnail 300x200^ -gravity center -extent 300x200 output.jpg
convert -list format
sudo apt install libsixel-bin
img2sixel
-7, -8: Selects the SIXEL graphics norm. -7 selects the VT level 3 norm (default), and -8 selects the VT level 4 norm.
-e: Enables relative color specification.
-I: Ignores delays in GIF animations.
-i: Inverts the color output.
-u: Uses built-in dithering instead of an external one.
-g: Enables gamma correction.
-v: Prints the version number and exits.
-S, -P, -D, -O, -V, -H: Various options for handling GIF animations.
-p colors: Specifies the number of colors to use.
-m file: Specifies a source file for color quantization.
-d diffusiontype: Specifies the type of error diffusion.
-f findtype: Specifies the method for finding the nearest color.
-s selecttype: Specifies the method for selecting representative colors.
-c geometory: Specifies the output device’s screen geometry.
-w width, -h height: Specifies the width and height of the output image.
-r resamplingtype: Specifies the method for resampling.
-q quality: Specifies the output quality.
-l loopmode: Specifies the loop mode for GIF animations.
-t palettetype: Specifies the type of palette to use.
-n macronumber: Specifies the macro number for DEC SIXEL.
-C score: Specifies the score for color matching.
-b palette: Specifies the palette file.
-E encodepolicy: Specifies the policy for encoding.
-B bgcolor: Specifies the background color.
-o outfile: Specifies the output file. If not specified, the output is written to standard output.
filename ...: Specifies the input file(s). If not specified, the input is read from standard input.
stty size
43 158
cat catimg
width=$(tput cols)
height=$(tput lines)
width=$((width * 16))
height=$((height * 16))
img2sixel -w $width -h $height $1
resampling -r
nearest -> Nearest-Neighbor method
gaussian -> Gaussian filter
hanning -> Hanning filter
hamming -> Hamming filter
bilinear -> Bilinear filter (default)
welsh -> Welsh filter
bicubic -> Bicubic filter
lanczos2 -> Lanczos-2 filter
lanczos3 -> Lanczos-3 filter
lanczos4 -> Lanczos-4 filter
lossless compression tools
https://imageoptim.com/versions.html
https://imageoptim.com/online
sudo apt-get install trimage
using optipng, pngcrush, advpng and jpegopti
MozJPEG, pngquant, Pngcrush, 7zip, SVGO and Google Zopfli
https://github.com/google/guetzli
A perceptual JPEG encoder, aiming for excellent compression density at high visual quality
sudo apt install guetzli
https://www.kokkonen.net/tjko/projects.html#jpegoptim
JPEG optimization utility providing lossless and lossy compression.
sudo apt install jpegoptim
https://optipng.sourceforge.net
optiPNG is a PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections.
sudo apt install optipng
https://github.com/shssoichiro/oxipng
Multithreaded PNG optimizer written in Rust
cargo install oxipng
https://pmt.sourceforge.io/pngcrush/
sudo apt install pngcrush
other
https://converseen.fasterland.net
sudo apt install converseen
uses imagemagick
https://cairosvg.org/
pip3 install cairosvg
https://dechifro.org/dcraw/
https://www.gmic.eu/
sudo apt install gmic
https://www.imagemagick.org/script/index.php
https://github.com/nagadomi/waifu2x
https://waifu2x.udp.jp/
https://pngquant.org/
Lossy compression of PNG images.
sudo apt install pngquant
https://github.com/google/zopfli
Zopfli Compression Algorithm is a compression library programmed in C to
perform very good, but slow, deflate or zlib compression.
Highly efficient PNG optimisation tool using Google's zopfli library
sudo apt install zopfli
https://github.com/Huluti/Curtail