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From: d88-jwa@nada.kth.se (Jon W{tte)
Newsgroups: comp.sys.mac.programmer
Subject: Re: transfer mode that doesn't clobber black bits?
Message-ID: <1990Dec26.153039.3805@nada.kth.se>
Date: 26 Dec 90 15:30:39 GMT
References: <3666@orbit.cts.com> <1990Dec26.111555.3333@usenet@scion.CS.ORST.EDU>
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 27

In article <1990Dec26.111555.3333@usenet@scion.CS.ORST.EDU> kempkec@mist.CS.ORST.EDU (Christopher Kempke) writes:
>In article <3666@orbit.cts.com> pj@pnet51.orb.mn.org (Paul Jacoby) writes:
>>Problem: I draw the arrows (based on an array of endpoints) using
>>PenMode(patXor), and then go in an add the heads.  If I leave the PenMode as
>>patXor, I end up knocking a few pixels out of the arrowshaft, at the points

>      srcOr will do what you want, not dropping the pixels.  "Erase" is
>      generally a srcBic (Bit Clear) operation.  Page I-157 of Inside

>      This assumes that your "heads" don't occlude anything but the shaft.
>      If this isn't the case, then no, there's no solution (no pattern mode

I see several solutions:

1) Draw the arrow (both shaft and head) as a region, which you then
   fill using patXor. This might be slow.

2) _CopyBits the bounding box of the arrow BEFORE the arrow is drawn.
   then erase it by CopyBitsing back what was there before, and make
   a new copy of what is at the new place. This might flicker.

Happy hacking,

							h+@nada.kth.se
-- 

Jon W{tte, Stockholm, Sweden, h+@nada.kth.se