ImageMagickがマジック

プログラムで画像処理をする時に便利なのが「ImageMagick」です。

ImageMagick - Convert, Edit, or Compose Bitmap Images

ImageMagick® creates, edits, composes, and converts bitmap images. Resize an image, crop it, change its shades and colors, add captions, and more.

https://imagemagick.org/index.php

「ImageMagick」の「convert」コマンドをプログラムから実行するようにすれば、たいていの画像処理はプログラムすることができます。例えば、COBOLで作成したプログラムでjpeg画像を作成したり画像の加工できたりします。面白いですよね。

convertコマンドには目がくらむようなオプションがあるんです。

Version: ImageMagick 7.0.8-62 Q16 x86 2019-08-24 http://www.imagemagick.org

Copyright: Copyright (C) 1999-2018 ImageMagick Studio LLC

License: http://www.imagemagick.org/script/license.php

Visual C++: 180040629

Features: Cipher DPC Modules OpenCL OpenMP(2.0)

Delegates (built-in): bzlib cairo flif freetype gslib heic jng jp2 jpeg lcms lqr lzma openexr pangocairo png ps raw rsvg tiff webp xml zlib

Usage: convert [options ...] file [ [options ...] file ...] [options ...] file

Image Settings:

 -adjoin             join images into a single multi-image file

 -affine matrix      affine transform matrix

 -alpha option       activate, deactivate, reset, or set the alpha channel

 -antialias          remove pixel-aliasing

 -authenticate password

                      decipher image with this password

 -attenuate value    lessen (or intensify) when adding noise to an image

 -background color   background color

 -bias value         add bias when convolving an image

 -black-point-compensation

                      use black point compensation

 -blue-primary point chromaticity blue primary point

 -bordercolor color  border color

 -caption string     assign a caption to an image

 -clip               clip along the first path from the 8BIM profile

 -clip-mask filename associate a clip mask with the image

 -clip-path id       clip along a named path from the 8BIM profile

 -colors value       preferred number of colors in the image

 -colorspace type    alternate image colorspace

 -comment string     annotate image with comment

 -compose operator   set image composite operator

 -compress type      type of pixel compression when writing the image

 -define format:option

                      define one or more image format options

 -delay value        display the next image after pausing

 -density geometry   horizontal and vertical density of the image

 -depth value        image depth

 -direction type     render text right-to-left or left-to-right

 -display server     get image or font from this X server

 -dispose method     layer disposal method

 -dither method      apply error diffusion to image

 -encoding type      text encoding type

 -endian type        endianness (MSB or LSB) of the image

 -family name        render text with this font family

 -features distance  analyze image features (e.g. contrast, correlation)

 -fill color         color to use when filling a graphic primitive

 -filter type        use this filter when resizing an image

 -font name          render text with this font

 -format "string"    output formatted image characteristics

 -fuzz distance      colors within this distance are considered equal

 -gravity type       horizontal and vertical text placement

 -green-primary point chromaticity green primary point

 -intensity method   method to generate an intensity value from a pixel

 -intent type        type of rendering intent when managing the image color

 -interlace type     type of image interlacing scheme

 -interline-spacing value

                      set the space between two text lines

 -interpolate method pixel color interpolation method

 -interword-spacing value

                      set the space between two words

 -kerning value      set the space between two letters

 -label string       assign a label to an image

 -limit type value   pixel cache resource limit

 -loop iterations    add Netscape loop extension to your GIF animation

 -matte              store matte channel if the image has one

 -mattecolor color   frame color

 -moments            report image moments

 -monitor            monitor progress

 -orient type        image orientation

 -page geometry      size and location of an image canvas (setting)

 -ping               efficiently determine image attributes

 -pointsize value    font point size

 -precision value    maximum number of significant digits to print

 -preview type       image preview type

 -quality value      JPEG/MIFF/PNG compression level

 -quiet              suppress all warning messages

 -read-mask filename associate a read mask with the image

 -red-primary point  chromaticity red primary point

 -regard-warnings    pay attention to warning messages

 -remap filename     transform image colors to match this set of colors

 -repage geometry    size and location of an image canvas

 -respect-parentheses settings remain in effect until parenthesis boundary

 -sampling-factor geometry

                      horizontal and vertical sampling factor

 -scene value        image scene number

 -seed value         seed a new sequence of pseudo-random numbers

 -size geometry      width and height of image

 -stretch type       render text with this font stretch

 -stroke color       graphic primitive stroke color

 -strokewidth value  graphic primitive stroke width

 -style type         render text with this font style

 -support factor     resize support: > 1.0 is blurry, < 1.0 is sharp

 -synchronize        synchronize image to storage device

 -taint              declare the image as modified

 -texture filename   name of texture to tile onto the image background

 -tile-offset geometry

                      tile offset

 -treedepth value    color tree depth

 -transparent-color color

                      transparent color

 -undercolor color   annotation bounding box color

 -units type         the units of image resolution

 -verbose            print detailed information about the image

 -view               FlashPix viewing transforms

 -virtual-pixel method

                      virtual pixel access method

 -weight type        render text with this font weight

 -white-point point  chromaticity white point

 -write-mask filename associate a write mask with the image

Image Operators:

 -adaptive-blur geometry

                      adaptively blur pixels; decrease effect near edges

 -adaptive-resize geometry

                      adaptively resize image using 'mesh' interpolation

 -adaptive-sharpen geometry

                      adaptively sharpen pixels; increase effect near edges

 -alpha option       on, activate, off, deactivate, set, opaque, copy

                      transparent, extract, background, or shape

 -annotate geometry text

                      annotate the image with text

 -auto-gamma         automagically adjust gamma level of image

 -auto-level         automagically adjust color levels of image

 -auto-orient        automagically orient (rotate) image

 -auto-threshold method

                      automatically perform image thresholding

 -bench iterations   measure performance

 -black-threshold value

                      force all pixels below the threshold into black

 -blue-shift factor  simulate a scene at nighttime in the moonlight

 -blur geometry      reduce image noise and reduce detail levels

 -border geometry    surround image with a border of color

 -bordercolor color  border color

 -brightness-contrast geometry

                      improve brightness / contrast of the image

 -canny geometry     detect edges in the image

 -cdl filename       color correct with a color decision list

 -channel mask       set the image channel mask

 -charcoal radius    simulate a charcoal drawing

 -chop geometry      remove pixels from the image interior

 -clahe geometry     contrast limited adaptive histogram equalization

 -clamp              keep pixel values in range (0-QuantumRange)

 -colorize value     colorize the image with the fill color

 -color-matrix matrix apply color correction to the image

 -connected-components connectivity

                      connected-components uniquely labeled

 -contrast           enhance or reduce the image contrast

 -contrast-stretch geometry

                      improve contrast by 'stretching' the intensity range

 -convolve coefficients

                      apply a convolution kernel to the image

 -cycle amount       cycle the image colormap

 -decipher filename  convert cipher pixels to plain pixels

 -deskew threshold   straighten an image

 -despeckle          reduce the speckles within an image

 -distort method args

                      distort images according to given method ad args

 -draw string        annotate the image with a graphic primitive

 -edge radius        apply a filter to detect edges in the image

 -encipher filename  convert plain pixels to cipher pixels

 -emboss radius      emboss an image

 -enhance            apply a digital filter to enhance a noisy image

 -equalize           perform histogram equalization to an image

 -evaluate operator value

                      evaluate an arithmetic, relational, or logical expression

 -extent geometry    set the image size

 -extract geometry   extract area from image

 -fft                implements the discrete Fourier transform (DFT)

 -flip               flip image vertically

 -floodfill geometry color

                      floodfill the image with color

 -flop               flop image horizontally

 -frame geometry     surround image with an ornamental border

 -function name parameters

                      apply function over image values

 -gamma value        level of gamma correction

 -gaussian-blur geometry

                      reduce image noise and reduce detail levels

 -geometry geometry  preferred size or location of the image

 -grayscale method   convert image to grayscale

 -hough-lines geometry

                      identify lines in the image

 -identify           identify the format and characteristics of the image

 -ift                implements the inverse discrete Fourier transform (DFT)

 -implode amount     implode image pixels about the center

 -kuwahara geometry  edge preserving noise reduction filter

 -lat geometry       local adaptive thresholding

 -level value        adjust the level of image contrast

 -level-colors color,color

                      level image with the given colors

 -linear-stretch geometry

                      improve contrast by 'stretching with saturation'

 -liquid-rescale geometry

                      rescale image with seam-carving

 -local-contrast geometry

                      enhance local contrast

 -mean-shift geometry delineate arbitrarily shaped clusters in the image

 -median geometry    apply a median filter to the image

 -mode geometry      make each pixel the 'predominant color' of the

                      neighborhood

 -modulate value     vary the brightness, saturation, and hue

 -monochrome         transform image to black and white

 -morphology method kernel

                      apply a morphology method to the image

 -motion-blur geometry

                      simulate motion blur

 -negate             replace every pixel with its complementary color

 -noise geometry     add or reduce noise in an image

 -normalize          transform image to span the full range of colors

 -opaque color       change this color to the fill color

 -ordered-dither NxN

                      add a noise pattern to the image with specific

                      amplitudes

 -paint radius       simulate an oil painting

 -perceptible epsilon

                      pixel value less than |epsilon| become epsilon or

                      -epsilon

 -polaroid angle     simulate a Polaroid picture

 -posterize levels   reduce the image to a limited number of color levels

 -profile filename   add, delete, or apply an image profile

 -quantize colorspace reduce colors in this colorspace

 -raise value        lighten/darken image edges to create a 3-D effect

 -random-threshold low,high

                      random threshold the image

 -range-threshold values

                      perform either hard or soft thresholding within some range of values in an image

 -region geometry    apply options to a portion of the image

 -render             render vector graphics

 -resample geometry  change the resolution of an image

 -resize geometry    resize the image

 -roll geometry      roll an image vertically or horizontally

 -rotate degrees     apply Paeth rotation to the image

 -rotational-blur angle

                      rotational blur the image

 -sample geometry    scale image with pixel sampling

 -scale geometry     scale the image

 -segment values     segment an image

 -selective-blur geometry

                      selectively blur pixels within a contrast threshold

 -sepia-tone threshold

                      simulate a sepia-toned photo

 -set property value set an image property

 -shade degrees      shade the image using a distant light source

 -shadow geometry    simulate an image shadow

 -sharpen geometry   sharpen the image

 -shave geometry     shave pixels from the image edges

 -shear geometry     slide one edge of the image along the X or Y axis

 -sigmoidal-contrast geometry

                      increase the contrast without saturating highlights or

                      shadows

 -sketch geometry    simulate a pencil sketch

 -solarize threshold negate all pixels above the threshold level

 -sparse-color method args

                      fill in a image based on a few color points

 -splice geometry    splice the background color into the image

 -spread radius      displace image pixels by a random amount

 -statistic type geometry

                      replace each pixel with corresponding statistic from the

                      neighborhood

 -strip              strip image of all profiles and comments

 -swirl degrees      swirl image pixels about the center

 -threshold value    threshold the image

 -thumbnail geometry create a thumbnail of the image

 -tile filename      tile image when filling a graphic primitive

 -tint value         tint the image with the fill color

 -transform          affine transform image

 -transparent color  make this color transparent within the image

 -transpose          flip image vertically and rotate 90 degrees

 -transverse         flop image horizontally and rotate 270 degrees

 -trim               trim image edges

 -type type          image type

 -unique-colors      discard all but one of any pixel color

 -unsharp geometry   sharpen the image

 -vignette geometry  soften the edges of the image in vignette style

 -wave geometry      alter an image along a sine wave

 -wavelet-denoise threshold

                      removes noise from the image using a wavelet transform

 -white-threshold value

                      force all pixels above the threshold into white

Image Channel Operators:

 -channel-fx expression

                      exchange, extract, or transfer one or more image channels

 -separate           separate an image channel into a grayscale image

Image Sequence Operators:

 -append             append an image sequence

 -clut               apply a color lookup table to the image

 -coalesce           merge a sequence of images

 -combine            combine a sequence of images

 -compare            mathematically and visually annotate the difference between an image and its reconstruction

 -complex operator   perform complex mathematics on an image sequence

 -composite          composite image

 -copy geometry offset

                      copy pixels from one area of an image to another

 -crop geometry      cut out a rectangular region of the image

 -deconstruct        break down an image sequence into constituent parts

 -evaluate-sequence operator

                      evaluate an arithmetic, relational, or logical expression

 -flatten            flatten a sequence of images

 -fx expression      apply mathematical expression to an image channel(s)

 -hald-clut          apply a Hald color lookup table to the image

 -layers method      optimize, merge, or compare image layers

 -morph value        morph an image sequence

 -mosaic             create a mosaic from an image sequence

 -poly terms         build a polynomial from the image sequence and the corresponding

                      terms (coefficients and degree pairs).

 -print string       interpret string and print to console

 -process arguments  process the image with a custom image filter

 -smush geometry     smush an image sequence together

 -write filename     write images to this file

Image Stack Operators:

 -clone indexes      clone an image

 -delete indexes     delete the image from the image sequence

 -duplicate count,indexes

                      duplicate an image one or more times

 -insert index       insert last image into the image sequence

 -reverse            reverse image sequence

 -swap indexes       swap two images in the image sequence

Miscellaneous Options:

 -debug events       display copious debugging information

 -distribute-cache port

                      distributed pixel cache spanning one or more servers

 -help               print program options

 -list type          print a list of supported option arguments

 -log format         format of debugging information

 -version            print version information

By default, the image format of 'file' is determined by its magic

number. To specify a particular image format, precede the filename

with an image format name and a colon (i.e. ps:image) or specify the

image type as the filename suffix (i.e. image.ps). Specify 'file' as

'-' for standard input or output.

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