OpenEuphoria

Re: color difference equations

• Posted by Greg Haberek <ghaberek at gmail.com> Sep 30, 2004
• 493 views

How weird.... GMail displays Google Ads pertaining to the message
you're reading. One of the 'Related Pages' links that popped up was
this: www.easyrgb.com/math which I'm sure you'll find quite useful.

~Greg


On Thu, 30 Sep 2004 00:41:35 +0200, mic _ <stabmaster_ at hotmail.com> wrote:
> 
> Where did you get that code from? It looks very similar to something I wrote
> a long time ago, but I can't remember for what program.
> Anyway, you could view the two colors as 3D vectors and calculate the
> difference in length of the vectors, the angle between the vectors or some
> other measure.  Or you could calculate the luma of each color and take the
> difference between those (where luma = 0.299*R + 0.587*G + 0.114*B). I bet
> there are lots of other formulaes.
> 
> 
> >I don't know which formula this function uses, but it doesn't work good:
> >}}}
<eucode>
> >--// Returns difference of two colors.
> >--// atom between 0 and 1.
> >--// 0 = smallest difference
> >--// 1 = biggest difference
> >global function weighted_color_distance (COLOR color1, COLOR color2)
> >   integer rmean
> >   integer dr,dg,db
> >
> >   rmean = floor((GetRValue (color1) + GetRValue (color2)) / 2)
> >   dr = (GetRValue (color1) - GetRValue (color2))
> >   dr *= dr
> >   dr = floor((dr * (512 + rmean)) / 256)
> >
> >   dg = (GetGValue (color1) - GetGValue (color2))
> >   dg = (dg * dg)  * 4
> >
> >   db = (GetBValue (color1) - GetBValue (color2))
> >   db *= db
> >   db = floor((db * (767 - rmean)) / 256)
> >
> >   return (dr + dg + db) / 584970
> >end function
> ></eucode>
{{{

> >
> >
> 
> 
>