Split all landscape images in a directory in half

README.md

split_landscape.sh

Find all landscape images in a directory (sub directories included) and split them in half from right to left. For the opposite direction, remove the magick -reverse option on line 32.

Requires imagemagick (brew install imagemagick on macOS).

$ cd [directory]
$ ./split_landscape.sh

or

$ ./split_landscape.sh [directory]

split_landscape.sh

#!/usr/bin/env sh

if [[ -z "$1" ]]; then
  DIRECTORY="."
else
  DIRECTORY="$1"
fi

echo "🔄 Looking for image files in \"$DIRECTORY\""

# Loop recursively through image files in a directory
### Alternative method to find image files (requires GNU grep: brew install grep)
### find "$DIRECTORY" -name '*' -exec file {} \; | ggrep -o -P '^.+: \w+ image'
find "$DIRECTORY" -type f -print0 | xargs -0 file --mime-type | grep -F 'image/' | cut -d ':' -f 1 | while read FILE_PATH; do
  r=$(magick identify -format '%[fx:(w>h)]' "$FILE_PATH") # Check whether the file is portrait or landscape
  if [[ r -eq 1 ]] # 0 -> landscape and 1 -> portrait
  then
      # FILE_PATH = ``../directory/image.jpg`
      FILE_NAME="${FILE_PATH%.*}" # FILE_NAME = `../directory/image`
      FILE_EXTENSION="${FILE_PATH##*.}" # FILE_EXTENSION = `jpg`
      OUTPUT=""$FILE_NAME"_%d.$FILE_EXTENSION" # OUTOUT = `../directory/image_%d.jpg`

      magick identify -format "%[input] %[magick] %[width]x%[height] %[bit-depth]-bit %[colorspace]\n" "$FILE_PATH"

      ## Debugging
      # echo "FILE_PATH = $FILE_PATH"
      # echo "FILE_NAME = $FILE_NAME"
      # echo "FILE_EXTENSION = $FILE_EXTENSION"
      # echo "OUTPUT = $OUTPUT"
      # echo "----------"

      magick "$FILE_PATH" -crop 2x1@ -reverse +repage "$OUTPUT" # Split image file in half with output file names reversed for right-to-left
      rm "$FILE_PATH" # Delete landscape file
  fi
done

echo "✅ Done!"

Thank you for this, this was exactly what I was looking for!

I did run into some issues when running this

identify: GetHslInt failure 0 0,0 @ error/fx.c/ExecuteRPN/3159.
identify: ExecuteRPN failed   @ error/fx.c/FxEvaluateChannelExpression/4022.
identify: GetHslInt failure 0 0,0 @ error/fx.c/ExecuteRPN/3159.
identify: ExecuteRPN failed   @ error/fx.c/FxEvaluateChannelExpression/4022.
...

Here's an updated version that does work!

#!/usr/bin/env sh

if [ -z "$1" ]; then
  DIRECTORY="."
else
  DIRECTORY="$1"
fi

echo "🔄 Looking for image files in \"$DIRECTORY\""

find "$DIRECTORY" -type f -print0 | xargs -0 file --mime-type | grep -F 'image/' | cut -d ':' -f 1 | while read -r FILE_PATH; do
  dimensions=$(magick identify -format '%wx%h' "$FILE_PATH" 2>/dev/null)
  if [ $? -ne 0 ]; then
    echo "⚠️  Error identifying $FILE_PATH"
    continue
  fi

  width=$(echo "$dimensions" | cut -d'x' -f1)
  height=$(echo "$dimensions" | cut -d'x' -f2)

  if [ "$width" -gt "$height" ]; then # landscape
      FILE_NAME="${FILE_PATH%.*}"
      FILE_EXTENSION="${FILE_PATH##*.}"
      OUTPUT="${FILE_NAME}_%d.${FILE_EXTENSION}"

      magick identify -format "%[input] %[magick] %[width]x%[height] %[bit-depth]-bit %[colorspace]\n" "$FILE_PATH" 2>/dev/null

      if [ $? -ne 0 ]; then
        echo "⚠️  Error identifying $FILE_PATH"
        continue
      fi

      magick "$FILE_PATH" -crop 2x1@ -reverse +repage "$OUTPUT"
      if [ $? -eq 0 ]; then
        rm "$FILE_PATH"
      else
        echo "⚠️  Error processing $FILE_PATH"
      fi
  fi
done

echo "✅ Done!"