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From: siegel@booga.Eng.Sun.COM (Josh Siegel)
Newsgroups: comp.windows.news
Subject: TNT 2.0: Fade between two images
Message-ID: <12526@exodus.Eng.Sun.COM>
Date: 30 Apr 91 17:06:59 GMT
Sender: news@exodus.Eng.Sun.COM
Lines: 106


This programs fades between two images.  It is very CPU intensive
while generating the images when you first look at them.

==

% Written by Josh Siegel (siegel@sun.com)
%
% This is "slow" in some parts but compaired to what
% is really slowing us down...
%

/bf (OPENWINHOME) getenv (/demo/images/bf.im8) append readcanvas def
/lady (OPENWINHOME) getenv (/demo/images/mandrill.im8) append readcanvas def

/MyCanvas ClassCanvas 
dictbegin
    /tempcan null def
    /cans 11 array def
    /prev_value 0 def
dictend
classbegin
    /magiccan 256 256 1 [ 1.0 0 0 1.0 0 0 ] null buildimage def

    /minsize {256 256} def

    /Paint {
	prev_value /prev_value null def
	/Painter self send
    } def

    /Update_view {
	pop cvi /Painter self send
    } def

    /Painter { % val => -
	dup prev_value ne {
	    dup /prev_value exch def
	    gsave dup getcans not {
		% Set the filter
		magiccan setcanvas 
		10 div setgray
		clippath fill
		
		% Paint the first image on
		tempcan setcanvas initmatrix clippath pathbbox scale pop pop 
		lady imagecanvas
		
		initmatrix true magiccan imagepath currentpath
		clippath pathbbox scale pop pop setpath clip bf imagecanvas 
	    } if
	    can setcanvas
	    tempcan imagecanvas
	    grestore
	} {
	    pop
	} ifelse
    } def
    
    /getcans { % num => bool
	dup cans exch get dup null ne {
	    exch pop /tempcan exch store true
	} {
	    pop
	    gsave
	    framebuffer setcanvas initmatrix
	    
	    /tempcan framebuffer newcanvas store
	    tempcan /Retained true put
	    
	    [1 0 0 1 0 0 ] setmatrix
	    0 0 256 256 rectpath tempcan reshapecanvas
	    tempcan setcanvas
	    cans exch tempcan put false
	    grestore
	} ifelse
    } def
classend def

/can framebuffer /new MyCanvas send def

/win can framebuffer /new ClassBaseWindow send def
/place win send
/new ClassEventMgr send /activate win send
/map win send

/pan2 /Calculated framebuffer /new ClassPanel send def
/win2 pan2 framebuffer /new ClassBaseWindow send def
/slider2 framebuffer /new ClassHSlider send def

can /settarget slider2 send
/Update_view /setpreviewer slider2 send
/Update_view /setnotifier slider2 send

0 10 /setrange slider2 send
/minsize { 128 30 } /promote slider2 send
/preferredsize { 128 30 } /promote slider2 send
true /setendboxes slider2 send
1 /settickmarks slider2 send
{cvi} /setnormalizer slider2 send

/slider2 slider2 [/Center { /Center PARENT POSITION} ] /addclient pan2 send
/place win2 send
win2 /addsubwindow win send

/map win2 send