Re: xlib:create-glyph-cursor -- a spec issue

[Mike McMahon <MMcM@STONY-BROOK.SCRC.Symbolics.COM>]

    Date: Wed, 26 Jul 89  15:17:12 EDT
    From: Kerry Kimbrough <Kimbrough@dsg.csc.ti.com>

       >     What is
       >     supposed to happen when mask-font is specified but mask-char is omitted?  The
       >     code just wires mask-char=0, which doesn't seem particularly useful. Several
       >     alternatives are possible.
       > 
       >     1. Signal error
       > 	
       >     2. Default to source-char
       > 
       >     3. Default to 0
       > 
       >     4. Default to (font-default-char mask-font)
       > 
       >     5. If (eq source-font mask-font), default to (1+ source-char), else signal
       >        error.
       > 
       >     I suggest #5.  Since the source/mask-char's have to be tightly coupled, it's not
       >     reasonable that any single value could serve as a default mask-char, so #2 is
       >     plausible but #1 is more correct.  But #5 also allows a short-hand for a common
       >     idiom based on a special font structure (like that of the "cursor" font).
       > 
       > 5 sounds reasonable, especially if mask-font defaults to source-font.


    But it doesn't. Omitting mask-font means "no mask", i.e. "mask is all 1's".

Right, as I noted in my follow-on message.  It's still reasonable.