Subject: Enhancements to LiteWindow

From: [email-masked] (J|rgen Lindskov Knudsen)
Date: Sat, 3 Oct 87 18:18:52 EST

I would like to share with you two exercises in utilizing the object oriented
part of NeWS to extend existing applications.  The first exercise was to
implement a zap-control in the upper right corner of the frame.  The second
exercise was to make it possible to specify the windows should be fixed-sized
even when they were created hidden, like as a consequence of forkunix (psterm,
clocks, etc.).  Following the "--- cut here ---" line is the NeWS-code, with
examples of its usage.

Happy NeWS'ing.

	Jorgen Lindskov Knudsen
	Computer Science Department
	Aarhus University, Denmark
	(e-mail: [email-masked]  -or-  [email-masked])
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/EnhancedWindow LiteWindow []

% This window class implements fixed-sized windows, even when the window
% is created from forkunix.
% Furthermore, a zap-box is added to the frame controls.
%
% Copyright:  Jorgen Lindskov Knudsen, Comp. Sci. Dept., Aarhus Univ., Denmark
% All non-profit utilizations of this code is allowed.

classbegin

% Class Variables

% dictionary to contain fixed-window constraints, if any.
	/FixedWindow nulldict def

% Methods

% The following methods illustrates the addition of a Zap-box in the upper
% right corner of the window.  The ease of adding the zap-box to the existing
% window-system, illustrates the strengths of Object oriented design.

    /CreateFrameControls { % - => - (Create zap control canvas/item, too)
   	 /CreateFrameControls super send
  	  gsave
		FrameCanvas setcanvas
		/ZapControl FrameCanvas newcanvas dup begin
		    /Mapped true def
		    /EventsConsumed /AllEvents def
		end def
		0 0 BorderTop BorderRight rectpath ZapControl reshapecanvas
  	  grestore
    } def % CreateFrameControls

    /CreateFrameInterests { % - => - (Create zap control interest, too)
   	 /CreateFrameInterests super send
		FrameInterests begin
		    /FrameZapEvent
			PointButton /destroy
			DownTransition ZapControl eventmgrinterest def
		end
    } def % CreateFrameInterests

    /MoveFrameControls { % - => - ([Re]set zap control shape, too)
   	 /MoveFrameControls super send
  	  gsave
		ZapControl setcanvas
		FrameWidth BorderRight sub
		    FrameHeight BorderTop sub movecanvas
   	 grestore
    } def % MoveFrameControls

    /PaintFrameControls { % - => - (Paint zap control area, too)
   	 /PaintFrameControls super send
   	 gsave
		ZapControl setcanvas 2 4 moveto /panel_check_off showicon
   	 grestore
    } def % PaintFrameControls

% The following two methods implements fixed-sized windows, irrespectively
% of whether the window is created through forkunix or other means.

    /reshapefromuser {	% - => -
			% create a fixed-sized window if /FixedWindow
			% is not the nulldict.
			% Otherwise, let the user outline the window.
			% If fixed-sized, the x y w h of the window is
			% defined in the dict /FixedWindow, named
			% /FixedX, /FixedY, /FixedW, and FixedH.
	FixedWindow nulldict ne
	  {FixedWindow begin FixedX FixedY FixedW FixedH end /reshape self send
	   /FixedWindow nulldict store % remove fixed-sized window constraint
	  }{/reshapefromuser super send } ifelse
    } def % reshapefromuser

   /fixedwindowsize { % X Y W H proc => -
		      % Initializes FixedWindow with the extent given by
		      % X Y W H, and then executes proc.
		      % If another fixed-sized constraint is currently
		      % active, this process will wait for the previous
		      % to be utilized.
	{ {FixedWindow nulldict ne {pause}{exit} ifelse} loop % waiting loop
	  /FixedWindow dictbegin
		/FixedX 7 -1 roll def /FixedY 6 -1 roll def
		/FixedW 5 -1 roll def /FixedH 4 -1 roll def
	  dictend store
	  end%defines the entries to signal fixed-sized windows and their size.
	  exec%execute proc-parameter that may instantiate fixed-sized windows.
	} fork % spin-off instantiating process.
    } def % fixedwindowsize
classend def % EnhancedWindow

%
%	install EnhancedWindow as the default windows:
%

/DefaultWindow EnhancedWindow store

% Fixed-sized windows are then created in the following way:
%	1092 840 56 56
%        	{(/usr/lib/NeWS/demo/roundclock) forkunix}
%	/fixedwindowsize DefaultWindow send
%
%	0 610 528 290
%	        {(psterm -t sun -C) forkunix}
%	/fixedwindowsize DefaultWindow send