%!
%
% Date: Tue, 26 Jul 88 21:28:05 EDT
% To: NeWS-makers@brillig.umd.edu
% Subject: NeWS magnifying glass
% From: eagle!icdoc!Ist!jh@ucbvax.Berkeley.EDU  (Jeremy Huxtable)

% NeWS magnifying glass
%
% Jeremy Huxtable
%
% Mon Jul 25 17:36:06 BST 1988

% Class "Magnifier" implements a NeWS magnifying glass. It consists of a
% window, which displays the area around the cursor as you move it. Pressing
% the left mouse button stops the magnifier, while selecting "Restart" from
% the window menu starts it off again. "Zoom in/out" from the menu do what you
% might expect.
%
% This file is just under 100 lines long (including comments). The SunView
% glass program is an object file over 3/4 Mb in size, so there are no apologies
% for lacking features.
%
% No doubt hundreds of wonderful features may be added, but here is a start...

/Magnifier DefaultWindow [
    /EventMgr
    /Factor
]
classbegin
    /FrameLabel (Magnifying Glass) def

    /new {
	/new super send begin
	    /Factor 1 def
	    currentdict
	end
    } def

    /map {
	/map super send
	magnify
    } def

    /PaintClient { magnify_it } def

    /zoom { % increment => -
	/Factor Factor 3 2 roll add store
	Factor 0 eq { /Factor 1 store } if
    } def

    /magnify_it {
	framebuffer newcanvas       % create source canvas
	framebuffer setcanvas       % shape it to the same size as ClientCanvas
	currentcursorlocation
	exch ClientWidth 2 div sub
	exch ClientHeight 2 div sub
	ClientWidth Factor div ClientHeight Factor div rectpath
	dup reshapecanvas
	dup /Transparent true put   % make it transparent
	dup /Mapped true put        % and map it

	ClientCanvas setcanvas
	ClientWidth ClientHeight scale
	dup imagecanvas

	/Mapped false put           % unmap the source canvas
    } def

    /magnify {
	EventMgr null eq {
	    /EventMgr [
		/MouseDragged { magnify_it redistributeevent }
		null null eventmgrinterest
		PointButton { pop stop_it }
		null null eventmgrinterest
	    ] forkeventmgr def
	} if
    } def

    /stop_it {
	EventMgr null ne { EventMgr killprocess /EventMgr null def } if
    } def

    /DestroyClient {
	stop_it
	/DestroyClient super send
    } def

classend def


/window framebuffer /new Magnifier send def
{
    /ClientMenu [
	(Zoom in)   { 1 /zoom ThisWindow send }
	(Zoom out)  { -1 /zoom ThisWindow send }
	(Restart)   { /magnify ThisWindow send }
	(Quit)      { currentprocess killprocessgroup }
    ] /new DefaultMenu send def
} window send

/reshapefromuser window send
/map window send