Create circle icon with green frame

make-icon-badge.sh

#!/bin/sh

# usage: make-icon-badge.sh [diameter_in_cm] src_file dst_file
#   make-icon-badge.sh 3.6 nom-with-cray.jpg  nom-with-cray.png

# Crop or mask an image into a circle - Stack Overflow
# https://stackoverflow.com/questions/999251/crop-or-mask-an-image-into-a-circle
#
# I want to change DPI with ImageMagick without changing the actual byte-size of the image data
# https://superuser.com/questions/479197/i-want-to-change-dpi-with-imagemagick-without-changing-the-actual-byte-size-of-t
#

function min() {
  if [[ "$1" -lt "$2" ]]; then
    echo "$1"
  else
    echo "$2"
  fi
}

function calc() {
  awk "BEGIN {print $1}"
}

diameter_in_cm="$1"
src_file="$2"
dst_file="$3"

src_w=$(identify -format "%w" "$src_file")
src_h=$(identify -format "%h" "$src_file")

diameter_in_pixel=$(min $src_w $src_h)
pixels_per_cm=$(calc "$diameter_in_pixel / $diameter_in_cm")
mm_in_pixels=$(calc "int($pixels_per_cm / 10 + 0.5)")

# Geometory for inner circle mask
mask_radius=$(calc "int($diameter_in_pixel / 2)")
mask_size=${diameter_in_pixel}x${diameter_in_pixel}
xoff=$(calc "($src_w - $diameter_in_pixel) / 2")
yoff=$(calc "($src_h - $diameter_in_pixel) / 2")

crop_geom=$mask_size+$xoff+$yoff

# Geometory for green circle frame
frame_radius=$(calc "$mask_radius + $mm_in_pixels")
frame_diameter=$(calc "$frame_radius * 2")
frame_size=${frame_diameter}x${frame_diameter}

convert \
  -units PixelsPerCentimeter -density $pixels_per_cm \
  -size $frame_size canvas:none -fill green -draw "circle $frame_radius,$frame_radius $frame_radius,0" \
  \(\
      "$src_file" -crop $crop_geom \
      \( -size $mask_size canvas:none -fill white -draw "circle $mask_radius,$mask_radius $mask_radius,0" \) \
      -compose CopyOpacity -composite \
  \)\
  -compose Over -gravity center -composite "$dst_file"