Subject: Re: [stella] tia hue luminance From: Adam Wozniak <adam@xxxxxxxxxxxxxxxx> Date: Tue, 9 Dec 2003 20:17:30 -0800 (PST) |
On Tue, 9 Dec 2003, Eric Ball wrote: > Y' = ( COLU AND 15 ) * 0.045 > hue = 180 degrees - ( COLU / 16 - 1 ) * 24 degrees > saturation = 0 if ( COLU / 16 == 0 ), otherwise saturation = 20 / 92.5 > U' = saturation * cos ( hue ) > V' = saturation * sin ( hue ) > > R' = 1.140V' + Y' > G' = Y' - 0.3947U' - 0.5808V' > B' = 2.033U' + Y' > > Clip the values of R'G'B' to the range 0.0 - 1.0. > > I'm not sure why my colors are off. I thought it might have been that I > reversed something somewhere, but I just double checked my spreadsheet and > don't see any problems. Maybe Adam will have better luck with his program. http://cuddlepuddle.org/~adam/z.html My calculated value agreed with your web page, +/-1, for the few colors I spot checked. I still think it's a little dark, and col=F is a little off. Can I extrapolate a little? If I wanted to add "brightness/saturation/hue" adjustments... would "brightness" affect the 0.045 multiplier for Y'? would "saturation" affect the 20/92.5 value? would "hue" phase shift the hue value? -- adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam/pgp.html Will code for food. http://cuddlepuddle.org/~adam/resume.html "The dinosaurs are not around today because they did not have a space program." -- Arthur C. Clarke ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [stella] tia hue luminance, Eric Ball | Thread | Re: [stella] tia hue luminance, Adam Wozniak |
Re: [stella] tia hue luminance, Eric Ball | Date | Re: [stella] tia hue luminance, Adam Wozniak |
Month |