Window Management in MacProlog

• Create a new window :

   
  wcreate/[6,7]
  wcreate(Name, Visible, Top, Left, Depth, Width, Go_away)

  Note : Display windows created by MacProlog environment do not have Go_away boxes, to distinguish them from edit (program) windows

  wpcreate/8
  wpcreate(Name, Visible, Syntax, Mode, Top, 
  		Left, Depth, Width)

  Will create a new program edit window. The syntax specifies how the code in the window is to be compiled (e.g. EDINBURGH, KSL, PROLOG++), the Mode corresponds to whether the window is Interpreted or Optimised
• Window types :

  windows/2
  windows(Type, Window_list)

  where Type refers to prog, disp, ctrl or grap, the list is returned in the variable Window_list

  wtype/2
  wtype(Window, Type)

  where Window is the name of a window and its type is returned in Type
• Displaying a window and removing it :

  wkill/1  
  wkill(Window)
  whide/1
  whide(Window)
  wshow/1
  wshow(Window)
  wvis/1
  wvis(Window)
  wfront/1
  wfront(Window)

  where Window is the name of a window. When a window is hidden, its contents are preserved in a buffer - and one can still read or write to it. When a window is killed, anything that it may contain is now lost.

mywin :-
 wcreate(win1, 1, 50, 60, 100, 200, 1),
 wpen(win1,yellow),
 wpaper(win1,magenta).

  
Figure 2: A window with a Go-Away button

• The look :

  wsize/5
  wsize(Window, Top, Left, Depth, Width)
  wlen/2
  wlen(Window, Length)
  wpen/2
  wpen(Window, Colour)
  wpaper/2
  wpaper(Window, Colour)

  where Window is the name of a window. In the wsize definition, other than the window name, all other arguments may be variables - in which case they will be instantiated to the current values for the named window. The Length variable refers to the length of text in the window. wpen is the foreground (text) and wpaper the background colour of the window. Colour can be white, black, red, blue, yellow, green, cyan, magenta

Another very useful and important command for windows management is the actdeact call :

actdeact(Window, Prog)

• where Window is the name of a window, and Prog refers to a program name called when the window is activated (i.e. when the window becomes the front window) or deactivated (i.e. when the window is closed or ceases to be the front window).
• The Prog must contain three different scenarios :

  Prog(activate, Window) :-
  	code for activation ...
  
  Prog(deactivate, Window) :-
   	code for deactivation ...
  
  Prog(close, Window) :-
  	code for closing ...

• Especially useful for manipulating the Menu Bar - so that when certain windows are at the front, relevant menus can be made available
• No calls should be included in an actdeact program that might cause further window activations or deactivation - could lead to endless loops!!
• Windows should not be killed in their activate or deactivate modes.