LZ-Adv: programming help

Subject: LZ-Adv: programming help
From: Will Stokes <wstokes@vertex.ucls.uchicago.edu>
Date: Mon, 18 Nov 1996 10:41:51 -0600 (CST)
In-Reply-To: <>
OK, I'm the kid that posted the q's about using the line routine and I
have gotten it to work, sortuv. I built a test prog. were I draw a line
from a fixed point to a slidable point which could be slid to the right or
left with the arrow keys and the prog. worked beuatifully. Next I tried to
impliment what I was really after. See diagram below. However, when I
tried to do this the program drew weird lines that did not make any since
and jumped all over the screen in weird ways when the sliding point was
moved. Why is  this? I have a feeling it has to do with my mathmatic
manupulations that are screwing it up for some reason. I'll post the code
when I get home.


              P


        A           B




  C                      D


P is sliding point which can be slid to right and left along horizen.
A and B the midpoins of CP and DP respectively. C is (40,0) and D is
(86,0) so depending on P the values of A and B are calculated. 
	To do this I load the x-coordinated P, subtract the x-coordinate
of C or D, divide by two, and add it to C/D respectively. I'll check to
see if I did that right. anyway that should get the x-coordinates fo A and
B right? THe Y-coordinates are always 27. I try to work this out somemore
but I think I have gotten it correctly so far. Any ideas as to what I'm
doing wrong? I use sub b to subtract b from a such that a=a-b and add to
add b to a.


			Will Stokes
 
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