git diff image files on the command line, with color

README.md

This is a simple way to spot check that the modified image in your git index is the image you actually want without having to leave the command line.

Example: http://i.imgur.com/RUenUcM.png

Instructions

1. Install git, ImageMagick, and jp2a via your favorite package manager.
2. Put img-ascii-diff somewhere (e.g. ~/bin/img-ascii-diff).
3. Put attributes in ~/.config/git/attributes.
4. Modify ~/.gitconfig and add the lines below, pointing to wherever you put img-ascii-diff.
5. ???
6. Profit!

@rroblak and @tylercal

attributes

*.jpg diff=asciidiff
*.jpeg diff=asciidiff
*.png diff=asciidiff
*.gif diff=asciidiff

gitconfig

[diff "asciidiff"]
  textconv = ~/bin/img-ascii-diff

img-ascii-diff

#!/bin/bash

# We have to convert to jpeg before we identify, otherwise
# identify returns 0x0 for the committed version of the file
# (no idea why this is the case). Also, we wrap the identify
# command in an echo to append a newline.
convert -quiet $1 jpg:- | echo $(identify -format '%[fx:w]x%[fx:h]' -)

convert -quiet $1 jpg:- | jp2a --colors --width=60 -