extract-x11-icon.sh

#!/bin/sh

xprop -notype 32c _NET_WM_ICON |
  perl -0777 -pe '@_=/\d+/g;
    printf "P7\nWIDTH %d\nHEIGHT %d\nDEPTH 4\nMAXVAL 255\nTUPLTYPE RGB_ALPHA\nENDHDR\n", splice@_,0,2;
    $_=pack "N*", @_;
    s/(.)(...)/$2$1/gs' > /tmp/icon.pam

convert /tmp/icon.pam /tmp/icon.png
wezterm imgcat /tmp/icon.png