add render script for reproducible screenshots

scripts/render.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# usage: render.sh width height [extra kitty args...]
+#   useful for reproducible screenshots of terminal/vim setups 
+
+set -euo pipefail
+w=${1:?width}; h=${2:?height}
+out="kitty-$(date +%Y%m%d-%H%M%S).png"
+shift 2 || true
+
+# spawn a kitty window w/ a mark
+title="kitty-$(date +%s%N)"
+kitty --title "$title" "$@" &
+
+# create a targeted rule for the marked window and resize
+sleep 2
+swaymsg "for_window [title=\"$title\"] mark --add $title, floating enable, resize set width ${w} px height ${h} px, move position center" >/dev/null
+
+# get the spawned window geometry
+sleep 2
+geom=$(swaymsg -t get_tree | jq -r --arg t "$title" '.. | select(.name? == $t) | .rect | "\(.x),\(.y) \(.width)x\(.height)"')
+wgeom=$(swaymsg -t get_tree | jq -r --arg t "$title" '.. | select(.name? == $t) | .window_rect | "\(.x),\(.y) \(.width)x\(.height)"')
+
+read gx gy _ < <(awk -F'[ ,x]' '{print $1,$2}' <<<"$geom")
+read wx wy ww wh < <(awk -F'[ ,x]' '{print $1,$2,$3,$4}' <<<"$wgeom")
+inner_geom="$((gx+wx)),$((gy+wy)) ${ww}x${wh}"
+
+echo title=$title
+echo geom=$geom
+echo out=$out
+
+# take a screenshot
+mkdir -p "$(dirname "$out")"
+grim -g "$inner_geom" "$out"
+echo "saved: $out"
+