Add script for trimming transparent pixels off all images in a directory - for issues like #90 #75

scripts/trim_dir.sh

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+
+PROJECT="pokesprite/trim_dir"
+DESCRIPTION="Trims off transparent pixels from all images in a directory."
+SELF="trim_dir.sh"
+VERSION="1.0.0"
+
+function check_prerequisites {
+  arr=('magick')
+  for tool in "${arr[@]}"; do
+    if ! command -v $tool >/dev/null 2>&1; then
+      echo "$SELF: error: the '$tool' command is not available"
+      exit
+    fi
+  done
+}
+
+function trim {
+  # Note: adds a 1px transparent border before trimming to ensure that only transparent pixels are removed.
+  # Add e.g. "-border 2x2" right before the output (before PNG32:..) to add transparent padding.
+  magick convert "$1" -bordercolor none -border 1x1 -trim +repage PNG32:"$1"
+}
+
+function trim_dir {
+  for d in "$@"; do
+    find "$d" -name '*.png' -print0 |
+    while IFS= read -r -d '' f; do
+      trim "$f"
+    done
+  done
+}
+
+function argparse {
+  if [[ ( -z "$1" ) || ( "$1" == "-h" ) ]]; then
+    echo "usage: $SELF [-v] [-h] path[, path[, ...]]"
+    if [ "$1" == "-h" ]; then
+      echo "$DESCRIPTION"
+      exit 0
+    fi
+    exit 1
+  fi
+  if [ "$1" == "-v" ]; then
+    echo "$PROJECT-$VERSION"
+    exit
+  fi
+
+  check_prerequisites
+  trim_dir "$@"
+}
+
+if [[ "${BASH_SOURCE[0]}" = "${0}" ]]; then
+  argparse $@
+fi