Useful ImageMagick commands

usefulimagemagickcommands.sh

#!/bin/bash

# Note, if using Cygwin, ImageMagick is *not* installed by default and will need to
# be manually selected during the install.

# Using these turns out to be much less effort than firing up GIMP and, moreover,
# all of these operations are of course scriptable for batch processing of images.

# RESIZING AN IMAGE
# Note that if file extensions don't match, the image will be converted
# to the format implied by the output file extension.

convert source.png|jpg|etc -resize WIDTH_IN_PIXELSxHEIGHT_IN_PIXELS output.png|jpg|etc

# RESIZING EXAMPLE

convert close_all_positions_256.png -resize 128x128 close_all_positions_128.png

# SWAPPING COLOUR CHANNELS
# Turns out to be super-useful. Here's an example that swaps the red and
# green channels:

convert close_all_positions_256.png \( +clone -channel G -fx R \) +swap -channel R -fx v.G close_all_profitable_positions_256.png

# OVERLAYING IMAGES
# The following example overlays one image on another. The second image
# is also resized and placed over the bottom right corner of the first:

magick convert close_all_profitable_positions_256.png play_256.png -gravity Center -geometry 128x128+64+64 -composite -resize 256x256 close_all_profitable_positions_and_reinstate_as_orders.png