Semantics of flipping inks

• To: clim@BBN.COM
• Subject: Semantics of flipping inks
• From: Lawrence.G.Mayka@att.com
• Date: Sat, 23 Apr 94 15:13:56 CDT
• Original-From: lgm@ieain.ih.att.com

CLIM 2.0 on Allegro CL 4.2
CLIM 2.0-beta on LispWorks 3.2

I'm having some difficulty with the semantics of flipping inks.  The
documentation is clear, for example, as to what CLIM:+FLIPPING-INK+
does to output whose color happens to exactly match either
CLIM:+FOREGROUND-INK+ or CLIM:+BACKGROUND-INK+.  But what does it do
to any other color?  Are the consequences entirely unspecified?  I
tried repeated evaluations of the following expression in a CLIM
Listener, on two different CLIM 2.0 implementations:

(clim:with-room-for-graphics ()
  (clim:draw-circle* *standard-output* 100 100 100 :ink <color>)
  (clim:draw-rectangle* *standard-output* 50 50 150 150 :ink clim:+flipping-ink+))

For <color> I used, in turn, CLIM:+RED+, CLIM:+GREEN+, CLIM:+BLUE+,
CLIM:+YELLOW+, CLIM:+MAGENTA+, and CLIM:+CYAN+.  The resulting
rectangles were of the following colors:

Circle		Rectangle
------		 ---------
red		gray
green		black
blue		black
yellow		gray
magenta		red
cyan		light green

Is there any simple mental model I can use to predict the behavior of
flipping inks?


        Lawrence G. Mayka
        AT&T Bell Laboratories
        lgm@ieain.att.com

Standard disclaimer.

• Semantics of flipping inks
• From: Scott McKay <swm@harlequin.com>
• Re: Semantics of flipping inks
• From: "William M. York" <york@parc.xerox.com>

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