As a very crude way to demostrate alpha channel in jgtk, open the
file ~addons/graphics/gl2/gl2.ijs , find the verb irgba2cairo
irgba2cairo=: 3 : 0
'r g b a'=. 255%~ 4{.y,0
a=. 1-a
(r,g,b), a
)
change the the 'a=. 1-a' to
a=. 0.5 [ 1-a
then open the config base.cfg, change the noun GL2ExtGlcmd to 0.
restart J and try some gkt plot.
Вск, 13 Май 2012, bill lam писал(а):
> plot depends gl2 and gl2 does not yet support alpha channel. The main
> difficulty is to decide alpha to mean opacity or translucence. One
> of them is incompatible with the old gl2 while the other is incompatible
> with cairo, iirc.
>
> Вск, 13 Май 2012, June Kim (김창준) писал(а):
> > Hello
> >
> > Is there any way to use the alpha channel in plot(in J7 or J602)?
> > http://en.wikipedia.org/wiki/RGBA_color_space
> >
> > The thing is I will draw a lot of overlapped line plots and if the lines
> > are a bit transparent it would look much easier to see the patterns.
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