Re: MCL and color XOR-ing

[bill@cambridge.apple.com (Bill St. Clair)]

>Hello all you happy people,
> 
>I would like to know how to draw in color and in xor mode. Right now, if I
>set xor mode on, all subsequent drawing is done only in black and white.
>I assume there's something else I should do. I do have color windows; I
>set the :color-p keyword to initialize instance of a window to t.

I took a minute to read Inside Macintosh.

IM V-58 states that "The Xor mode complements the bits in the destination
corresponding to the bits equal to 1 in the source. When used on a colored 
destination, the color of the inverted destination isn't defined.

IM V-59 says, "subOver  This mode assignes to the destination pixel the 
color closest to the difference of the source and destination RGB values... 
If the destination bitmap is one bit deep, subOver reverts to Xor."

Have you tried using subOver instead of Xor?