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  1. Newsgroups: comp.graphics
  2. Path: sparky!uunet!munnari.oz.au!uniwa!watson
  3. From: watson@maths.uwa.oz.au (David Watson)
  4. Subject: Re: Angle between two coordinate locations
  5. Message-ID: <1992Jul22.234146.5571@uniwa.uwa.edu.au>
  6. Sender: news@uniwa.uwa.edu.au (USENET News System)
  7. Nntp-Posting-Host: madvax.maths.uwa.oz.au
  8. Organization: University of Western Australia
  9. References: <l6faduINN8f0@girtab.usc.edu> <stare.18.0@edstar.rl.af.mil>
  10. Date: Wed, 22 Jul 1992 23:41:46 GMT
  11. Lines: 34
  12.  
  13.  
  14. >>I have a problem where I need to obtain the angle between two points
  15. >>on the screen.  For instance:
  16.  
  17. >>        +------------------------------------------+
  18. >>        |   * <-point 1                            |
  19. >>        |                                          |
  20. >>        |                                          |
  21. >>        |                                          |
  22. >>        |                                          |
  23. >>        |                                          |
  24. >>        |                                          |
  25. >>        |                   * <-point 2            |
  26. >>        |                                          |
  27. >>        +------------------------------------------+
  28.  
  29. >>I would expect the function to return the angle as being 135 degrees
  30. >>( or should if my picture was accurate )  Any help would be greatly
  31. >>appreciated.  Thanks
  32.  
  33. >I'm a little confused, How do you define an angle between two points without
  34. >first defining the location of the vertex.  Is the vertex just assumed to be
  35. >the origin (0,0)?
  36. >Edward M.Starczewski       email: stare@lonex.rl.af.mil
  37.  
  38. I wondered about that too, but if it were (0,0) the angle returned
  39. would be less than 135 degrees.
  40. Give us a clue, Randi
  41.  
  42. --
  43. Dave Watson                           Internet: watson@maths.uwa.oz.au
  44. Department of Mathematics            
  45. The University of Western Australia               Tel: (61 9) 380 3359
  46. Nedlands, WA 6009  Australia.                     FAX: (61 9) 380 1028
  47.