#!/bin/bash

if ! command -v slop >/dev/null; then
    echo "capture: slop not found" >&2
    exit 1
fi

out=${1:-$(date +%Y%m%d-%H%M%S).png}

coords=$(slop -f "%x %y %w %h" 2>/dev/null) || exit 1
read x y w h <<<"$coords"

ffmpeg -f x11grab -loglevel error -s ${w}x${h} \
    -i ${DISPLAY}+${x},${y} -frames:v 1 -y "$out"

echo "$out"