Re: mixing color.... result of multiple translucent color fill?



yep, it's not too difficult to code as you said ;-).
In fact I had it solve a while ago, I just forget to mention it!

Thanks for anwering anyway ;-)

"Phil N" <PhilN@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:858E1C84-D3DA-402A-B125-5C183CEC64E2@xxxxxxxxxxxxxxxx
> What you need is essentially to do the alpha blend mathematically in your
> code. Let's say your rectangle is sitting there with a base color C1 =
> {R1,
> G1, B1} with aplha A1 = 1.0. You want to do paint over it with some C2 =
> {R2, G2, B2} with alpha A2 < 1.0.
>
> For each color component c1 e {R1, G1, B1} and c2 e {R2, G2, B2} of colors
> C1 and C2, the corresponding component of the blended color C3 will be c3
> =
> c1 * ( 1 - A2 ) + c2 * ( A2 ), and its alpha will be 1.0.
>
> I'm sorry I could only give you the math here, but it shouldn't be too
> difficult to code. Additionally, note that I assumed a 0..1.0 scale for
> alpha; I don't have a framework reference handy, so I can't remember how
> alpha is scaled.
>
> "Lloyd Dupont" wrote:
>
>> I have some painting where I fill the same rect a few times with various
>> translucent color.
>> I would like to paint it only once with an opaque color which would be
>> the
>> mix of all my transparent colors.
>>
>> how do I determine the resulting color of multiple (tanslucent) color
>> fill?
>>
>>
>>


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