git image diff

git-img-diff

#!/bin/bash

diff=0
if [ "$1" = "-d" ]
then
    diff=1
    shift
fi

if [ $# -eq 0 ]
then
    prevc=HEAD
    images=$(git diff --stat | grep -E '(\.jpg|\.png|\.svg)' | awk '{print $1}')
else
    prevc=$1^
    images=$(git diff --stat $1..$prevc | grep -E '(\.jpg|\.png|\.svg)' | awk '{print $1}')
fi

function get_git_dir () {
    ls .git &> /dev/null || (cd .. && get_git_dir)
    echo $PWD
}

for i in $images
do
    img=$(basename $i)
    img1=/tmp/imgdiff.$img
    img2=/tmp/imgdiff2.$img

    gitdir=$(get_git_dir)
    cd $gitdir

    if [ -z $1 ]
    then
        cat $i > $img1
    else
        git show $1:$i > $img1
    fi

    git show $prevc:$i > $img2
    output=/tmp/$img.diff.png
    if [ $diff -eq 1 ]
    then
        composite $img2 $img1 -compose difference $output
    else
        convert -bordercolor "#ff0000" -border 5 $img2 $img2
        convert -bordercolor "#00ff00" -border 5 $img1 $img1
        montage -tile 2x1 -background "#000000" -geometry +4+4 $img2 $img1 $output
    fi

    size=$(identify $output | cut -d" " -f3)
    width=$(echo $size|cut -d"x" -f1)
    if [ $width -gt 1000 ]
    then
        convert -scale 1000 $output $output
    fi
    display $output
done

The license of this code is wtfpl http://www.wtfpl.net/about/