wrong colors thin lines

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wrong colors thin lines

chloros
Dear Octave users,

i've attached the image of a meshplot and some line diagrams as they
appear on my laptop (intel graphics). If the line width is set to 2 or
greater, everything is fine. For the standard line width and line width
1, the colors are somehow twisted.

It happens with 4.2.2 (comes pre-installed with Fedora Core 27) and the
behavior is the same with a build made from the last mercurial
development branch.

I really do not know what else I could do. If anyone has an idea, please let me know.

figure;
plot([0 1],[0.5 0.5],'color',[0 0 1])
hold on
plot([0 1],[1 1],'color',[0 0 1],'LineWidth',1)
plot([0 1],[2 2],'color',[0 0 1],'LineWidth',2)
plot([0 1],[3 3],'color',[0 0 1],'LineWidth',3)
ylim([0 4]);

figure;
[X,Y,Z]=sombrero;
mesh(X,Y,Z,Z);

Best regards
Chloros


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Re: wrong colors thin lines

apjanke-floss
I cannot reproduce on macOS 10.13 with Octave 4.4.0. The colors look fine
there: blue for everything, or a blue-green gradient for the sombrero plot.

This looks like maybe a weird subpixel aliasing issue. Do you have any
graphics settings that could control subpixel aliasing?



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Re: wrong colors thin lines

chloros
In reply to this post by chloros

> This looks like maybe a weird subpixel aliasing issue. Do you have
> any
> graphics settings that could control subpixel aliasing?

What I found out is that subpixel rendering is done only for fonts. The
problem with the thin line color occurs only in octave. in Scilab,
Gnuplot etc. everything is fine.

I've also forced xwindow into software mode (instead of hardware
acceleration). No change. graphics_toolkit ("gnuplot") is fine, but
"fltk" and "qt" are causing trouble. very strange.

best regards