AW: what RGB is blue?

Tiemo Hollmann TB toolbook at kestner.de
Fri Jul 1 07:58:15 EDT 2011


Mark, you made my day!
With this approach I even don't need to take the mousecolor anymore. I can
just go with my blue and the threshold.
Thanks, Tiemo

> -----Ursprüngliche Nachricht-----
> Von: use-livecode-bounces at lists.runrev.com [mailto:use-livecode-
> bounces at lists.runrev.com] Im Auftrag von Tiemo Hollmann TB
> Gesendet: Freitag, 1. Juli 2011 12:41
> An: 'How to use LiveCode'
> Betreff: AW: what RGB is blue?
> 
> Thank you Mark, for your profound advice.
> It sounds just as what I was looking for. I will give it a try
> Thanks
> Tiemo
> 
> > -----Ursprüngliche Nachricht-----
> > Von: use-livecode-bounces at lists.runrev.com [mailto:use-livecode-
> > bounces at lists.runrev.com] Im Auftrag von Mark Schonewille
> > Gesendet: Freitag, 1. Juli 2011 11:53
> > An: How to use LiveCode
> > Betreff: Re: what RGB is blue?
> >
> > Tiemo,
> >
> > The distance between any colour (1) and a colour chosen by you (2; e.g.
> r=0,
> > g=0, b=255) can be calculated as
> >
> > sqrt((r1-r2)^2+(g1-g2)^2+(b1-b2)^2) <= T
> >
> > where T is a threshold between 0 and 442 set by you. Change the colour
of
> the
> > background pixel whenever the distance between the colour of that pixel
> and
> > your selected colour is less than the threshold.
> >
> > I use this technique in Color Converter http://www.color-converter.com
> >
> > --
> > Best regards,
> >
> > Mark Schonewille
> >
> > Economy-x-Talk Consulting and Software Engineering
> > Homepage: http://economy-x-talk.com
> > Twitter: http://twitter.com/xtalkprogrammer
> > KvK: 50277553
> >
> > New: Download the Installer Maker Plugin 1.6 for LiveCode here
> > http://qery.us/ce
> >
> > On 1 jul 2011, at 11:39, Tiemo Hollmann TB wrote:
> >
> > > Hello,
> > >
> > > I am taking the mousecolor at different points from an image by script
> (not
> > > by clicking). I would like to analyse if the color I've taken is a
"kind
> of
> > > blue", or another color. I want to change the backgroundcolor of an
> image.
> > > The background is always blue, but different blues and changing over
the
> > > background. So what I want to do is to verify, what is background and
> what
> > > is foreground of my image.
> > >
> > > 100% pure blue would be 0,0,255. But for a human being 25,75,130
> (greyblue)
> > > is also still blue, but 240,20,180 is pink, though the third RGB value
> is
> > > higher as in my greyblue.
> > >
> > > So I can't just check only the third RGB value, neither the sum or
cross
> > > total. Has anybody ever heard, if you can define at all by math "what
is
> > > blue"?
> > >
> > > Any color specialist around here?
> > >
> > > Tiemo
> > >
> >
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> 
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