create empty pie chart (or not generate the graph)

Hi! I would like to create empty pie chart (I know it is not very useful).

Using 'pie' does not allow this. so I had thought of generating a circle and placing the legend on the side. Is this possible?

matrix_new = [];

labels = matrix_new(:,1);
percentages = matrix_new(:,2);
            
figure
p = pie(percentages);
    
theta = linspace(0,2*pi,500);
line(cos(theta),sin(theta),'Color','k','LineWidth',0.6);

label_str = load("label_str.mat");
lgd.Title.String = "title";

If it's not possibile, how can I make it so that when 'matrix_new' is empty it doesn't generate the graph for me (so don't do anything)?

Answer 1

[Voss]

Maybe something like this:

matrix_new = [];

figure

if isempty(matrix_new)
    % matrix_new is empty: create the circle
    theta = linspace(0,2*pi,500);
    line(cos(theta),sin(theta),'Color','k','LineWidth',1);
    % mimic pie() axes appearance:
    axis off
    axis equal
else
    % matrix new is not empty: create the pie() chart
    labels = matrix_new(:,1);
    percentages = matrix_new(:,2);
    p = pie(percentages);
end

% I'm not sure where this mat file comes from, but it should contain enough
% labels for the data in matrix_new:
label_str = load("label_str.mat");

% create the legend:
lgd = legend(label_str.label_str,'Location','EastOutside');
lgd.Title.String = "title";

[Alberto Acri]

yes, that's good. Can I ask if the legend can be moved a little to the left, for example?

[Voss]

Not sure about that.