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Useful magick for images.

WHERNTO: techniq 

image of Imagemagick

Since we are going text/prg based for most things, we may consider imagemagick as a fairly regular replacement for gimp. This effort will also lead to understanding graphic software terminology.

Imagemagick website and Examples of ImageMagick Usage

Waiting items below will be elaborated on and some eliminated.

Quick Fixes

stitching gifs together

as explained here, the idea is to separate frames, join them, put it all back together: convert 1.gif -coalesce a-%04d.gif convert 2.gif -coalesce b-%04d.gif

for f in a-*.gif; do convert $f ${f/a/b} +append $f; done # append frames

convert -loop 0 -delay 20 a-*.gif result.gif # rejoin frames


in a dir with jpg,png this is the sort of thing that can be done: magick montage -geometry 99x55>+2+2 -tile 4x1 *.{jpg,png} 00.jpg


open or import image mark crop with one of the tools (rect,ellipse …) make tool transparent select additionally (hold shift) the entire image object > set clip

make png transparent

convert test.png -transparent white trans.png

Features and Capabilities

Command-line processing: utilize ImageMagick from the command-line.

ImageMagick command-line consists of

  • one or more required input filenames:

    • filename globbing magick *.jpg images.gif
    • explicit image format magick -size 640x480 -depth 8 rgb:image image.png
    • using built-in images and patterns magick -size 640x480 pattern:checkerboard checkerboard.png
    • STDIN, STDOUT, and file descriptors not sure what is going on??
    • selecting certain frames from an image magick 'images.gif[0]' image.png magick 'images.gif[0-3]' images.mng
    • selecting a region of an image magick -size 6000x4000 -depth 8 'rgb:image[600x400+1900+2900]' image.jpg
    • forcing an inline image resize magick '*.jpg' -resize 120x120 thumbnail%03d.png but better magick '*.jpg[120x120]' thumbnail%03d.png
    • forcing an inline image crop magick '*.jpg' -crop 120x120+10+5 thumbnail%03d.png
    • filename references magick @myimages.txt mymovie.gif magick image-%d.jpg[1-5]
  • zero, one, or more image settings.
  • zero, one, or more image operators.
  • zero, one, or more image sequence operators.
  • zero, one, or more image stacks.
  • zero or one output image filenames


Animation: create a GIF animation sequence from a group of images.

Bilateral blur: non-linear, edge-preserving, and noise-reducing smoothing filter.

Color management: accurate color management with color profiles or in lieu of– built-in gamma compression or expansion as demanded by the colorspace.

Color thresholding: force all pixels in the color range to white otherwise black.

Complex text layout: bidirectional text support and shaping.

Composite: overlap one image over another.

Connected component labeling: uniquely label connected regions in an image.

Convex hull: smallest area convex polygon containing the image foreground objects. In addition, the minimum bounding box and unrotate angle are also generated.

Decorate: add a border or frame to an image.

Delineate image features: Canny edge detection, Hough lines.

Discrete Fourier transform: implements the forward and inverse DFT.

Distributed pixel cache: offload intermediate pixel storage to one or more remote servers.

Draw: add shapes or text to an image.

Encipher or decipher an image: convert ordinary images into unintelligible gibberish and back again.

Format conversion: convert an image from one format to another (e.g. PNG to JPEG).

Generalized pixel distortion: correct for, or induce image distortions including perspective.

Heterogeneous distributed processing: certain algorithms are OpenCL-enabled to take advantage of speed-ups offered by executing in concert across heterogeneous platforms consisting of CPUs, GPUs, and other processors.

High dynamic-range images: accurately represent the wide range of intensity levels found in real scenes ranging from the brightest direct sunlight to the deepest darkest shadows.

Histogram equalization: use adaptive histogram equalization to improve contrast in images.

Image cache: secure methods and tools to cache images, image sequences, video, audio or metadata in a local folder..

Image calculator: apply a mathematical expression to an image, image sequence, or image channels.

Image gradients: create a gradual blend of two colors whose shape is horizontal, vertical, circular, or elliptical.

Image identification: describe the format and attributes of an image.

ImageMagick on the iPhone: convert, edit, or compose images on your iOS device such as the iPhone or iPad.

Large image support: read, process, or write mega-, giga-, or tera-pixel image sizes.

Montage: juxtapose image thumbnails on an image canvas.

Morphology of shapes: extract features, describe shapes, and recognize patterns in images.

Motion picture support: read and write the common image formats used in digital film work.

Multispectral imagery: support multispectral imagery up to 64 bands.

Noise and color reduction: Kuwahara Filter, mean-shift.

Perceptual hash: map visually identical images to the same or similar hash– useful in image retrieval, authentication, indexing, or copy detection as well as digital watermarking.

Special effects: blur, sharpen, threshold, or tint an image.

Text & comments: insert descriptive or artistic text in an image.

Threads of execution support: ImageMagick is thread safe and most internal algorithms execute in parallel to take advantage of speed-ups offered by multicore processor chips.

Transform: resize, rotate, deskew, crop, flip or trim an image.

Transparency: render portions of an image invisible.

Virtual pixel support: convenient access to pixels outside the image boundaries.