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";
