[Scilab-users] gcf().anti_aliasing : Confirmation of (un)effect?

[Samuel Gougeon]

Le 07/05/2018 à 14:36, Samuel Gougeon a écrit :
>
> Hello,
>
> The gcf().anti_aliasing figure property was implemented many years ago 
> (in the early Scilab 5.x versions).
>
> It aims to reduce the "staircase effect" for lines drawn very close to 
> vertical or horizontal directions.
>
> Yet, has anyone ever seen an actual effect on graphic rendering, as 
> expected and described in the related SEP#16 
> <http://gitweb.scilab.org/?p=scilab.git;a=blob;f=SEP/SEP_016_anti_aliasing.odt;h=e267088c7ed7e5a4cd0ae29b744616332423224e;hb=HEAD> 
> ?
> I never did, whatever were the computer and its graphic card i used.
> Still now with Scilab 6.0, i don't see any effect.
>
> The staircase effect can easily be seen with the following code:
>
> x = [0 1];
> y = (0:0.02:1)';
> y = [y y+0.02]';
> clf
> plot2d(x,y)
> f = gcf();
> f.anti_aliasing  // should display "off" (by default)
>
> f = scf();
> f.anti_aliasing = "8x";
> plot2d(x,y)
> Then compare both figures.
> I get the following, whatever is the .anti_aliasing value.
>
>
> Does anyone get anything else, closer to the expected "dithered" 
> rendering?
> Either it will be possible to better document the effect of this property,
> as requested in the bug report 6777 
> <http://bugzilla.scilab.org/show_bug.cgi?id=6777>, or to reopen the 
> bug 11311 <http://bugzilla.scilab.org/show_bug.cgi?id=11311> reporting
> that it is out of work.

Thanks Rafael & Antoine.
I have finally got it. It works

  * only with usecanvas(%t). The bug 11311
    <http://bugzilla.scilab.org/show_bug.cgi?id=11311> claimed that it
    was killed in usecanvas(%t) mode. Maybe fixing it has killed it in
    usecanvas(%f) mode...

  * only up to Scilab 5.4.1 included. Scilab 5.5.0 has killed any
    graphic rendering in usecanvas(%t) mode (and has changed the
    usecanvas() type of output from boolean to integer).

With 5.4.1, usecanvas(%t) displays:


which is the expected rendering.

I am going to see what's on bugzilla about usecanvas()...

Samuel



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