Painters doesn't render line styles properly

Hey there! I'm trying to export a figure as a pdf, and as such I set painters as the renderer for my figure. However, I don't seem to be getting the correct linestyles that I specify. Here's a mwe of what is happening:

x=linspace(0,1,100);
[X,Y]=meshgrid(x);
Z=peaks(100);
set(gcf,'Renderer','painters');
hold all
surf(X,Y,Z)
shading interp
contour3(X,Y,Z+1,[1,1],'LineStyle','--','LineWidth',1,'LineColor','w')
contour3(X,Y,Z+1,[2,2],'LineStyle','-.','LineWidth',1,'LineColor','w')
view(2)

As you can see the plot shows solid lines. By increasing the linewidth I see that the lines are actually dashed and dotted, but as they are they are pretty unusable. Anyone knows how to fix this issue?

[Jaime Abad Arredondo]

As a comment: I've seen this post from 2011 refering to the R14 release:

https://es.mathworks.com/matlabcentral/answers/94703-why-am-i-unable-to-specify-a-dashed-line-style-for-contour-plots-of-large-matrices-in-matlab-7-0-r1,

There it says that you can get the linestyles to show by making the size of the matrix you are plotting smaller. I have checked and it works, but in practive it seems to require a matrix smaller than 50x50, which is just not enough for what I want to plot.

[Rik]

Perhaps using plot to create the lines might work better?

[Jaime Abad Arredondo]

It seems like the behavior of plot3 and contour3 is the same... See the result below. I have also added the same figure generated with smaller matrices and you can see that the lines appear properly. I might have to resample the contour lines with less data points... A bit of a bummer considering that with openGL it works straight away.

figure(1)
clf
set(gcf,'Renderer','painters');
tiledlayout(1,2)

N0v=[20,100];

for j=1:length(N0v)
    nexttile()
    x=linspace(0,1,N0v(j));
    [X,Y]=meshgrid(x);
    Z=peaks(N0v(j));
    hold all
    surf(X,Y,Z)
    shading interp
    levels=[0,1];
    cs={'w','r'};
    lst={'-.','--'};

    for i=1:length(levels)
        M=contour3(X,Y,Z,levels(i)*[1,1],'LineColor','none','Visible','off');
        c=1;
        aux=true;
        while aux
            height_contour=M(1,c);
            NP_cont=M(2,c);
            x=M(1,c+(1:NP_cont));
            y=M(2,c+(1:NP_cont));
            z=ones(size(x))*(height_contour+1);
            plot3(x,y,z,...
                'LineStyle',lst{i},'LineWidth',1,...
                'Color',cs{i})
            c=c+NP_cont+1;
            if c>size(M,2)
                aux=false;
            end
        end

    end
    view(2)
end

Answer 1

[Shivam]

Hi,

From the information you have provided, I understand that you are facing an issue getting the correct linestyles while setting the renderer for the figure as “painters.” Also, setting the renderer as “painters” works for you in the case of small matrices.

Since you have tried “OpenGL,” you can also use “zbuffer” to get the correct linestyles. Here is the sample code:

set(gcf, 'Renderer', 'zbuffer'); 

You can refer to the following documentation to know more about set and Renderer:

1. https://www.mathworks.com/help/releases/R2023a/matlab/ref/set.html
2. https://www.mathworks.com/help/releases/R2023a/matlab/ref/matlab.ui.figure-properties.html#prop_Renderer

I hope it helps.

[Rik]

Wouldn't a doc page about the renderers make more sense as a reference?

[Jaime Abad Arredondo]

Thanks for the suggestion!

As I see from the internet, z-buffer is not supported by matlab from release 2014b. In fact, when looking at the renderers page from mathworks, the term 'z-buffer' doesn't appear on the page. Setting it as a render engine still works though (see below). However this doesn't solve the issue at hand, since z-buffer generates the images by rasterizing, and therefore can't be properly exported as a vector file.

x=linspace(0,1,1000);
[X,Y]=meshgrid(x);
Z=peaks(1000);
set(gcf,'Renderer','zbuffer');
hold all
surf(X,Y,Z)
shading interp
contour3(X,Y,Z+1,[1,1],'LineStyle','--','LineWidth',1,'LineColor','w')
contour3(X,Y,Z+1,[2,2],'LineStyle','-.','LineWidth',1,'LineColor','r')
view(2)