gif-anim-cap-frame

#!/bin/bash
SCRIPT=$(readlink -f "$0")
SCRIPTPATH=$(dirname "$SCRIPT")
SETTINGS="$SCRIPTPATH/gif-anim-settings"
. "$SETTINGS" || {
	echo "Error running '$SETTINGS' to get settings" >&2;
	exit 1;
}

full_frame_path () {
	local idx="$1"
	printf "$ga_dir_frames/%03d.$ga_frame_ext" "$idx"
}

lock_obtain() {
	while [ -e "$ga_framecap_lock_fn" ]; do
		# If the lockfile exists, print warning
		echo "Lockfile $ga_framecap_lock_fn exists" >&2
		# Read the PID
		lock_pid=$(cat "$ga_framecap_lock_fn")
		# Check if the PID in the lockfile is still running
		if ps -p $lock_pid > /dev/null; then
			echo "Waiting for lock to be released by PID $lock_pid..." >&2
			# Count number of HALF SECONDS that have passed
			half_seconds_passed=0
			# Wait for the lock to be released, checking every 0.5 seconds
			while [ -e "$ga_framecap_lock_fn" ] && ps -p $lock_pid > /dev/null; do
				sleep 0.5
				((half_seconds_passed++))
				# If the lock is not released within $ga_waitlock_secs, kill the PID
				if [ $half_seconds_passed -ge $((2*$ga_waitlock_secs)) ]; then
					echo "Lock not released, killing PID $lock_pid" >&2
					kill $lock_pid || true
					break
				fi
			done
		else
			echo "Process $lock_pid not running, removing lock" >&2
			rm -f "$ga_framecap_lock_fn"
		fi
	done

	# Once the lockfile is gone or removed, create a new one with the current PID and set a trap to remove it when the script exits.
	echo $$ > "$ga_framecap_lock_fn"
	trap "rm -f $ga_framecap_lock_fn" EXIT
}

# Make dir again since user might have removed frames dir
# (Like, they selected a position with gif-anim-select-area,
#  which creates the dir and stores the coordinates, but
#  then maybe the user removes the frames/ folder
#  and begins capturing frames.  So we have to ensure the
#  frames/ folder exists.)
mkdir -p "$ga_dir_frames"

# Get prior frame (get filename; strip extension)
idx=$(cd "$ga_dir_frames" && ls *.$ga_frame_ext | tail -1 | sed -e 's/\..*$//' 2>/dev/null)
echo "IDX: $idx"
if [[ -n "$idx" ]]; then
	idx=${idx%.*}
	while true; do
		idx=$((idx+1))
		tmppath=$(full_frame_path "$idx")
		if [[ ! -f $tmppath ]]; then # Testing if somehow the last file from ls | tail exists
			break
		fi
	done
else
	idx=0
fi
# New frame filename:
fn_frame=$(full_frame_path "$idx")
echo " Frame file: $fn_frame"

coords=$(<$ga_fn_coords)
echo "Coordinates: $coords"
if [ -z "$WAYLAND_DISPLAY" ]; then
	# Coords are x11 WxH+x+y
	# scrot wants x,y,w,h
	w=${coords%x*}
	h=${coords#*x}; h=${h%%+*}
	x=${coords#*+}; x=${x%+*}
	y=${coords##*+}
	echo "scrot coords (x,y,w,h): $x,$y,$w,$h"
	scrot_co="$x,$y,$w,$h"

	echo "Sending off our child to go capture some pixels to bring back home"
	echo " to the family..."
	echo " Running: scrot -k -a '$scrot_co' '$fn_frame'"
	scrot -k -a "$scrot_co" "$fn_frame"
else
	echo "Sending off our child to go capture some pixels to bring back home"
	echo " to the family..."
	echo "Running: grim -g '$coords' '$fn_frame'"
	grim -g "$coords" "$fn_frame"
fi

if [[ ! -f "$fn_frame" ]]; then
	echo "We tried to create frame but somehow couldn't: $fn_frame" >&2
else
	echo "Frame captured: $fn_frame"
fi