%!

% deadwin.ps
%
% by: Jeremy Huxtable jh@uk.co.ist
%

% This program will remove all those irritating 'dead' windows and canvases
% from your screen. When run, it will let you choose a point on the screen
% and will then walk the canvas tree, zapping all (mapped) canvases which enclose that
% point. The canvases will be unmapped, made non-retained, and all their
% interests revoked. This will at least hide them from your gaze, and may
% even make them go away altogether, though I wouldn't count on it. What is
% really needed is to trawl through the whole NeWS data structures trying to
% find the reference which is keeping the canvases there.

% Before running:
%       Make sure that your windows are out of the way as there is no unzapping
% a window.

% The canvas tree walking routine is useful for all sorts of things such as
% popping up an object browser on a window and for investigating all those
% unmapped canvases which lurk behind your screen.

/zapcanvas { % x y canvas =>
    dup /Mapped get {
	dup getcanvaslocation
	2 index setcanvas
	clippath pathbbox 4 2 roll pop pop
	framebuffer setcanvas
	% If the point is in this canvas, and the canvas is a) not the
	% framebuffer, and b) mapped, zap it.  The most we can do is
	% to unmap the canvas, stop it being retained, and remove its
	% interests.
	rectpath 3 copy pop pointinpath {
	    dup framebuffer ne 1 index /Mapped get and {
		dup /Mapped false put
		dup /Retained false put
		dup /Interests get {
		    revokeinterest
		} forall
	    } if
	} if
	/TopChild get                           % get first child
	{
		dup null eq { exit } if         % exit loop if no more
		3 copy zapcanvas                % recurse for this child
		/CanvasBelow get                % get next child
	} loop
    } if
    pop pop pop
} def

fboverlay setcanvas
getclick
framebuffer setcanvas
framebuffer zapcanvas