Gnome | Aseprite thumbnail generator

aseprite-thumbnailer

#!/usr/bin/sh

if [ $# -ge 2 -a $# -lt 4 ]; then
  mkdir -p /tmp/Aseprite
  filename="$(mktemp -d -p /tmp/Aseprite/).png"

  if [ $# -eq 2 ]; then
    aseprite -b --frame-range "0,0" $1 --trim --sheet $filename
  elif [ $# -eq 3 ]; then
    aseprite -b --frame-range "0,0" $1 --shrink-to "$3,$3" --trim --sheet $filename
  fi
  test="/home/metaphore/Desktop/tmp-icon/output.png"
  mkdir -p $(dirname "$2"); mv $filename $2;
  convert -colorspace sRGB $2 -background transparent -flatten -filter Point -thumbnail $3x$3 -gravity center -extent $3x$3 png32:$2
else
  echo "Parameters for aseprite thumbnailer are: inputfile outputfile [size]"
fi

aseprite.thumbnailer

[Thumbnailer Entry]
TryExec=aseprite-thumbnailer
Exec=aseprite-thumbnailer %i %o %s
MimeType=image/x-aseprite

aseprite.xml

<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
  <mime-type type="image/x-aseprite">
         <comment xml:lang="en">Aseprite Pixel Art</comment>
         <magic priority="50">
                <match type="little16" value="0xA5E0" offset="4"/>
         </magic>
         <glob pattern="*.ase"/>
         <glob pattern="*.aseprite"/>
        <icon name="aseprite"/>
  </mime-type>
</mime-info>

Pre-requirements:

1. Aseprite must be installed and aseprite executable should be available from the PATH.
2. Imagemagic must be installed and convert should be available from the PATH.

Installation:

1. Register a new mime type: update-mime-database aseprite.xml.
2. Place aseprite-thumbnailer to /usr/bin/aseprite-thumbnailer (don't forget to make it executable).
3. Place aseprite.thumbnailer to ~/.local/share/thumbnailers/aseprite.thumbnailer
4. Delete all failed thumbs: rm -r ~/.cache/thumbnails/failed

P.S. Tested with Pop!_OS Gnome 42