rubywm.rb - a minimalist WM using pure-x11 and based on TinyWM

rubywm.rb

# Based on TinyWM by Nick Welch

require 'X11'

dpy = X11::Display.new
root = dpy.screens.first.root

# OK, so pure-x11 *really* badly needs built in keysym lookup,
# but I don't want to add that without doing it properly, so this
# is a temporary hack.

reply = dpy.get_keyboard_mapping
$kmap = reply.keysyms.map { |c| X11::KeySyms[c] }.each_slice(reply.keysyms_per_keycode).to_a
$key_to_sym = {}
$kmap.each_with_index{|sym, key| $key_to_sym[sym.first] = key+dpy.display_info.min_keycode }

 f1,f2,f3,f4 = *[:f1,:f2,:f3,:f4].map {|sym| $key_to_sym[sym] }
[f1,f2,f3,f4].each {|key| dpy.grab_key(true, root, X11::Form::Mod1, key , :async, :async) }
mask = X11::Form::ButtonPressMask|X11::Form::ButtonReleaseMask|X11::Form::PointerMotionMask
dpy.grab_button(true, root, mask, :async, :async, 0, 0, 1, X11::Form::Mod1)
dpy.grab_button(true, root, mask, :async, :async, 0, 0, 3, X11::Form::Mod1)

# FIXME: This is *NOT* the right way to find the maximum window size
# as it does not take into account panels etc., but as a crude start it's fine.
rootgeom = dpy.get_geometry(root)

old_geom = {}

start = nil
attr = nil
loop do
  ev = dpy.next_packet
  p ev
  case ev
  when X11::Form::KeyPress
    if ev.child
      case ev.detail
      when f1 # Alt + F1: Send to top
        dpy.configure_window(ev.child, stack_mode: :above)
      when f2 # Alt + F2: Maximize or revert
        geom = dpy.get_geometry(ev.child)

        # If maximized, and we know the old size, we revert the size.
        if (og = old_geom[ev.child]) &&
           geom.x == 0 && geom.y == 0 &&
           geom.width  == rootgeom.width &&
           geom.height == rootgeom.height
          dpy.configure_window(ev.child, x: og.x, y: og.y, width: og.width, height: og.height)
        else
          # Otherwise we maximize
          old_geom[ev.child] = geom
          dpy.configure_window(ev.child, x: 0, y: 0, width: rootgeom.width, height: rootgeom.height, stack_mode: :above)
        end
      when f3 # Alt + F3: Send to bottom
        dpy.configure_window(ev.child, stack_mode: :below)
      when f4 # Alt + F4: Close
        dpy.destroy_window(ev.child)
      end
    end
  when X11::Form::ButtonPress
    if ev.child  # Whichever button, we want to know more about this window
      attr = dpy.get_geometry(ev.child)
      start = ev
    end
  when X11::Form::MotionNotify # if start.button == 1 we move; if 3 we resize, all with the same request:
    if start&.child
      xdiff = ev.root_x - start.root_x;
      ydiff = ev.root_y - start.root_y;
      dpy.configure_window(start.child, 
        x: attr.x + (start.detail==1 ? xdiff : 0),
        y: attr.y + (start.detail==1 ? ydiff : 0),
        width:  [1, attr.width  + (start.detail==3 ? xdiff : 0)].max,
        height: [1, attr.height + (start.detail==3 ? ydiff : 0)].max
      )
    end
  when X11::Form::ButtonRelease
    # Make sure we don't accidentally operate on another window.
    start.child = nil if start
  end
end