Thanks, Troy! I don't need to draw the curve, actually -- I'm just using it to scale incoming data. Specifically, I'm taking an incoming float number between 0. and 1.0 that is a linear scaling of pitch and reshaping it.
If you're curious, yes, this is related to my previous post about pitch-tracking. Specifically, I'm doing the pitch-tracking in Max/MSP with the fiddle~ object and sending the resulting pitch and amplitude, scaled, to a QC comp that uses the pitch to control the hue of a gradient. Even more specifically, it's something I put together for Wiley Wiggins, who is doing visuals with The Octopus Project in Hexadecagon, which is a free show this evening in Austin, TX. "Music for eight-channel sound and eight-channel video performed live in the round. Awesome!" http://www.theoctopusproject.com/hxdx.html Wish I could be there but, alas, I'm in NYC. cheers, dan On Mar 19, 2010, at 4:27 PM, Troy Koelling wrote: > If those circles are control points, I'd probably guess this is a cubic > spline. CoreGraphics has the ability to draw that if you need to. > > This is a pretty good rundown: > http://cocoawithlove.com/2008/07/coregraphics-curves-and-lines-sample.html > > On Mar 19, 2010, at 1:15 PM, Chris Wood wrote: > >> See also gaussian curve/bell curve/s-curve... Although of course that was a >> straight spline curve in the first pic. Splines will give you what you want, >> but maybe not in the most simple way. >> >> Chris >> >> >> On 19 Mar 2010, at 19:52, Dan Winckler wrote: >> >>> Thanks, Tom and Jon! I remembered Grapher earlier today and it was a big >>> help, even though polynomial curves are not among its examples (sure beats >>> my old TI-82). Now to tweak the numbers until they give me the shape I >>> need. Additional help still welcome if offered. :) >>> >>> best, >>> dan >>> >>> >>> >>> <Screen shot 2010-03-19 at 3.49.57 PM.png> >>> >>> >>> On Mar 19, 2010, at 3:40 PM, Jon Pugh wrote: >>> >>>> At 3:14 PM -0400 3/19/10, Dan Winckler wrote: >>>>> What do you call a curve like the one in the attached image? Rather, >>>>> what's the mathematical term for the equation that produces such a double >>>>> curve. I am trying to scale an incoming float number (0.0 1.0) so that >>>>> it changes more quickly in the middle of the range (~0.2 - 0.8) than at >>>>> the top and bottom (~ 0.0 - 0.2, 0.8 - 1.0). Right now I've got >>>>> exponential scaling, which works for the bottom of the range but not the >>>>> top. >>>> >>>> This is a curve produced by a polynomial equation. I recommend opening >>>> the application Grapher, which came with your Mac, and entering this >>>> equation: x = y^3+y^2+y >>>> >>>> This will give you a curve approximating the one you've drawn. Then you >>>> can play with adding numbers before the various terms (i.e. 3y^3, etc) to >>>> change the shape of the curve. >>>> >>>> Good luck. >>>> >>>> Jon >>>> _______________________________________________ >>>> Do not post admin requests to the list. They will be ignored. >>>> Quartzcomposer-dev mailing list ([email protected]) >>>> Help/Unsubscribe/Update your Subscription: >>>> http://lists.apple.com/mailman/options/quartzcomposer-dev/dan%40danwinckler.com >>>> >>>> This email sent to [email protected] >>> >>> _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Quartzcomposer-dev mailing list ([email protected]) >>> Help/Unsubscribe/Update your Subscription: >>> http://lists.apple.com/mailman/options/quartzcomposer-dev/psonice%40gmail.com >>> >>> This email sent to [email protected] >> >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Quartzcomposer-dev mailing list ([email protected]) >> Help/Unsubscribe/Update your Subscription: >> http://lists.apple.com/mailman/options/quartzcomposer-dev/tkoelling%40apple.com >> >> This email sent to [email protected] > _______________________________________________ Do not post admin requests to the list. They will be ignored. Quartzcomposer-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/quartzcomposer-dev/archive%40mail-archive.com This email sent to [email protected]
