Re: [GD-DEVEL] trasparent image width antialiasing

On 2/1/07, yagyog <[email protected]> wrote:
> ----- Original Message -----
> From: "Pierre" <[email protected]>
> To: "yagyog" <[email protected]>
> Cc: <[email protected]>
> Sent: Thursday, February 01, 2007 1:17 PM
> Subject: Re: [GD-DEVEL] trasparent image width antialiasing
>
>
> > On 2/1/07, yagyog <[email protected]> wrote:
> >> ----- Original Message -----
> >> From: "Pierre" <[email protected]>
> >> To: "yagyog" <[email protected]>
> >> Cc: <[email protected]>
> >> Sent: Thursday, February 01, 2007 12:35 PM
> >> Subject: Re: [GD-DEVEL] trasparent image width antialiasing
> >>
> >>
> >> > Hi,
> >> >
> >> > On 1/30/07, yagyog <[email protected]> wrote:
> >> >> ----- Original Message -----
> >> >> From: "Pierre" <[email protected]>
> >> >> To: "yagyog" <[email protected]>
> >> >> Cc: <[email protected]>
> >> >> Sent: Tuesday, January 30, 2007 3:48 PM
> >> >> Subject: Re: [GD-DEVEL] trasparent image width antialiasing
> >> >>
> >> >>
> >> >> > On 1/30/07, yagyog <[email protected]> wrote:
> >> >> >> I have a problem, Excused but I do not speak English
> >> >> >>
> >> >> >>
> >> >> >> I have in input one image png with antialising
> >> >> >> with uniform solid background
> >> >> >>
> >> >> >> I would want
> >> >> >>
> >> >> >> 1) to eliminate the background
> >> >> >> 2) recreate the channel alpha in order not to lose the antialising
> >> >> >> on
> >> >> >> the
> >> >> >> text
> >> >> >>
> >> >> >> It is possible?
> >> >> >> you can give me of the information ?
> >> >> >>
> >> >> >> I try this code but not work:
> >> >> >>
> >> >> >> //
> >> >> >> //load a, load b  and create test
> >> >> >> //
> >> >> >> a = myLoadPng("a.png");
> >> >> >> b = myLoadPng("b.png");
> >> >> >
> >> >> > Can you give us a link to the images a.png and b.png please?
> >> >> >
> >> >> > --Pierre
> >> >> >
> >> >> Yes
> >> >> the color is changed but ,
> >> >> it does not change nothing
> >> >>
> >> >> http://www.yag.altervista.org/varius/a.png
> >> >> http://www.yag.altervista.org/varius/b.png
> >> >> my result
> >> >> http://www.yag.altervista.org/varius/test.png
> >> >
> >> > You have to use the alpha component in your image. So the blending
> >> > will be done when you copy a or b over test
> >>
> >> >. But if the original  images do not contain any alpha components
> >> Exact! :(
> >>
> >> , the anti aliasing being
> >> > done against a given color (green and yellow in your case), you will
> >> > have a visible aliasing.
> >> >
> >> Excuse I have not understood well
> >> you could makes to understand me better. even with of the code
> >
> > There is no way to achieve what you want without using the alpha
> > component in your images.
> >
> > Here is an example image:
> > http://blog.thepimp.net/misc/test_text_aa_alpha.png
> >
> > Load it in gimp/gqview, you will see the alpha values in the edges.
> >
> therefore
>
> I cannot realize what I said with one image without channel alpha? solution
> does not exist one practically
>
> And if I have one image with the channel alpha?

Please load http://blog.thepimp.net/misc/test_text_aa_alpha.png in
your image editor and read the alpha values of the text borders. You
will see what I mean.

--Pierre