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

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

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 ?
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, or to reopen the bug 11311 reporting
that it is out of work.

Thanks
Samuel


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amonmayr amonmayr
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Re: gcf().anti_aliasing : Confirmation of (un)effect?

Hello Samuel,

With your example, I don't see any difference on the various computers I have.
I think I used anti_aliasing in the past but I cannot find back a script where I used it.
I think I used it on 3D plots (surf?), maybe for the export to graphic files but I am not sure.
If I can find something I'll let you know.

Antoine


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 ?
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, or to reopen the bug 11311 reporting
that it is out of work.

Thanks
Samuel



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Rafael Guerra Rafael Guerra
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Re: gcf().anti_aliasing : Confirmation of (un)effect?

In reply to this post by Samuel GOUGEON
Hi Samuel,

Could not see any anti-aliasing being performed, either in Scilab 5 or
Scilab 6.
A quick trial on customizing the anti-aliasing settings in NVIDIA Quadro
K4100M for the Scilab program did not help either:
<http://mailinglists.scilab.org/file/t495698/NVIDIA_antialiasing.gif>

It may need more tweaking.

Regards,
Rafael




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Samuel GOUGEON Samuel GOUGEON
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Re: gcf().anti_aliasing : Confirmation of (un)effect?

In reply to this post by 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 ?
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, or to reopen the bug 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 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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