ericmcg@pnet91.cts.com (Eric Mcgillicuddy) (06/06/91)
Mega question: What are Bsplines and how can they be drawn using Quickdraw II? I have seen this term is a number of places and am very curious about it. I would appreciate any code fragments that can demonstrate them on a GS as well (language independence, but no Assembly :) (Unlless WELL documented :) 10q. UUCP: bkj386!pnet91!ericmcg INET: ericmcg@pnet91.cts.com
toddpw@nntp-server.caltech.edu (Todd P. Whitesel) (06/06/91)
ericmcg@pnet91.cts.com (Eric Mcgillicuddy) writes: >What are Bsplines and how can they be drawn using Quickdraw II? Bsplines are curves that are formed by parametric interpolation of a list of "control points" -- if you have a list of points, and connect them in order, you'll get a jaggy 'curve' with sharp corners and so on; draw the set of Bspline segments specified by that same list of points and you'll get a smooth curve shaped roughly like the jaggy one, as if the jaggy curve had all its corners severely smoothed out. No existing implementation of Quickdraw is capable of drawing Bsplines as objects. The TrueType font engine might be able to do it, they are using curves that should be a superset of cubic Bsplines (which is what most people simply refer to as Bsplines). I do have code examples but they would take a while to explain (they use matrix operations to represent and evaluate the curve points), and I'm not sure if I have a stable executable with the curve code in it that you can run on a stock GS. Todd Whitesel toddpw @ tybalt.caltech.edu P.S. do it quick, I leave in a little over a week.
meekins@anaconda.cis.ohio-state.edu (Tim Meekins) (06/06/91)
In article <819@generic.UUCP> ericmcg@pnet91.cts.com (Eric Mcgillicuddy) writes: >Mega question: > >What are Bsplines and how can they be drawn using Quickdraw II? B-splines are a special interpolating function which allows drawing smooth curves. They can be drawn by QD II to extent that anything can be drawn by QD II by using _MoveTo and _LineTo. Basically, input to the spline function is a set of control points. As the line is drawn, the line tends to head towards these pointes, but not necessarily pass through them. > >I have seen this term is a number of places and am very curious about it. >I would appreciate any code fragments that can demonstrate them on a GS as >well (language independence, but no Assembly :) (Unlless WELL documented :) > Maybe I can throw something together over the weekend. Don't get over excited though, it is not going to be very speedy. It will be sort of like 3-D graphics on the GS. There are ways of doing it quickly, but not easily. -- ++------------S-U-P-P-O-R-T---S-H-A-R-E-W-A-R-E---O-R---D-I-E-!-----------++ || Tim Meekins || Snail Mail: || Apple II || || meekins@cis.ohio-state.edu || 8372 Morris Rd. || Forever! || \\___timm@pro-tcc.cts.com________/\____Hilliard, OH 43026__/\_____________//
benson@vuse.vanderbilt.edu (Paul Benson) (06/07/91)
In article <819@generic.UUCP> ericmcg@pnet91.cts.com (Eric Mcgillicuddy) writes: >Mega question: > >What are Bsplines and how can they be drawn using Quickdraw II? Get THE necessary book, _Numerical Recipes in C: The Art of Scientific Computing_ by William H. Press, Brian P. Flattery, et al. Cambridge Press. Also available for FORTRAN and Pascal. Their C implementations are somewhat backward, but the code works along with a good description of what you are doing and why. Paul Benson Vanderbilt University GEnie: p.benson1
scottg@gnh-starport.cts.com (Scott Gentry) (06/11/91)
For a good example of BSplines and other graphics code in Pascal, you can check out a book titled "Computer Graphics Software Construction" by Rankin from Prentice Hall; ISBN 0-13-162793. The code in this text is easy to understand and best of all requires minimal effort to port to a GS (drawing code primarily). A long time ago when I was playing with splines and Bezier curves, I sent the code to some people. I may still have it on my GS at home but it's really quite trivial to port the code from the book mentioned above. Granted, it's not going to set speed records, but it can show everyone what needs to be done. _______________________________________________________________________________ | Scott Gentry * ALPE AFL Scott * I never said that!| | 2051 Mercator Drive * GEnie W.GENTRY * But you never | | Reston, VA 22091 * UUCP: uunet!ingr!ne1300! * know! | | (703) 264-5652 * brnded!scott * Do You? | |_____________________________________________________________________________|
stephens@latcs1.lat.oz.au (Philip J Stephens) (06/12/91)
Scott Gentry writes: >For a good example of BSplines and other graphics code in Pascal, you can >check out a book titled "Computer Graphics Software Construction" by Rankin >from Prentice Hall; ISBN 0-13-162793. Ha! John Rankin just so happens to be the supervisor for my honours thesis in computer animation! I'm sure he'll get a kick out of hearing about this one. <grin> <\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/><\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\> < Philip J. Stephens >< "Many views yield the truth." > < Hons. student, Computer Science >< "Therefore, be not alone." > < La Trobe University, Melbourne >< - Prime Song of the viggies, from > < AUSTRALIA >< THE ENGIMA SCORE by Sheri S Tepper > </\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\></\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/>
samkho@athena.mit.edu (Samuel P Kho) (06/12/91)
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