Using a Window Manager

A window manager is a component that automates distribution of message such as mouse clicks and key presses to one of several event handlers.


The initial windows

First our usual setup:

include "gui/__init__";
open FlxGui;

println$ "Basic Window Controller Test";

var font_name = dflt_sans_serif_font();
var font : font_t = get_font(font_name, 12);
var lineskip = get_lineskip font;

Now, we make two similar windows, at different locations but different titles.

var w1 = create_resizable_window("Felix:gui_05_window_controller_01",100,100,400,400);
w1.add$ mk_drawable FlxGui::clear lightgrey;
w1.add$ mk_drawable FlxGui::write (100,100,font,black,"Basic Window Controller Test#1");;

var w2 = create_resizable_window("WINDOW 2",400,100,400,400);
w2.add$ mk_drawable FlxGui::clear blue;
w2.add$ mk_drawable FlxGui::write (100,100,font,black,"Basic Window Controller Test#2");;

The Event handler

The same as before!

// make an event handler for our window
chip ehandler
  (var w:window_t)
connector pins
  pin input : %<event_t
   // get a first event from the window manager
  var e: event_t = read pins.input;
  // while the event isn't a quit event ..
  while e.window.event.SDL_WindowEventID != SDL_WINDOWEVENT_CLOSE  do
    // print a diagnostic
    var s =
      match e with
      | WINDOWEVENT we =>
        we.type.SDL_EventType.str + ": " + we.event.SDL_WindowEventID.str + " wid=" + we.windowID.str
      | _ =>
    var linepos = 100 + 4 * lineskip;
    if s != "" do
      println$ s;
      var r = rect_t (100,linepos - 2*lineskip,300,4*lineskip);
      w.add$ mk_drawable fill (r, green);
      w.add$ mk_drawable FlxGui::write (100,linepos,font,black,"EVENT: "+ s);
    // get another event
    e= read pins.input;

  // we must have got a quit ..
  println$ "++++++CLOSE EVENT";

The Window manager

Noe for the fun bit. First, our mainline creates a window manager object:

  //create a window manager
  var wm = window_manager();

Now, we create two window controllers. There will be clients of the window manager.

// create a window controller for our window
var eh1 = ehandler w1;
var wc1 = window_controller (w1, eh1);
var eh2 = ehandler w2;
var wc2 = window_controller (w2, eh2);

Note that in this case the same event handler is bound to two distinct windows, and then a window controller is bound to them, as well as the window (again!)

Next, we simply add the window controller clients to the window manager.

// attach controller to window manager
var wno1 = wm.add_window wc1;
println$ "Window number " + wno1.str;

var wno2 = wm.add_window wc2;
println$ "Window number " + wno2.str;

When we do this, we get back a window number, assigned by the window manager, so we can refer to the windows in a way the window manager understands (although we’re not doing that here).


  wm.run_with_timeout 10.0;
  println$ "gui05 quitting";

we just run the window manager, in this case with a timeout because its a demo.