Matlab: Fitting two x axis and a title in figure - matlab

Question

I am having trouble getting my title to show when I have a figure with two x-axis.
The plot looks good and the axis scales are as I would like them to be but the second axis label and the title end up outside my figure.
How do I get the plot and axis to have the same size and change the size of the figure to include labels and title?
Here is a minimal example:
x1 = linspace(0, 5);
y11 = sin(x1);
y12 = cos(x1);
x2 = linspace(4, 12);
figure(1)
plot(x1, y11, 'r');
hold on
grid on
plot(x1, y12, 'k');
axis([0 5 -1 1.8]);
legend('sin(x)', 'cos(x)');
xlabel('x')
ylabel('y-label');
ax1 = gca;
ax1_pos = ax1.Position;
ax2 = axes('Position', ax1_pos,...
'XAxisLocation', 'top',...
'YAxisLocation', 'right',...
'Color', 'none');
ax2.YColor = 'w';
title('2:nd Harmonics');
line(x2,0,'Parent',ax2,'Color','k')
xlabel('n');

Answer 1

As a workaround you could pre-define the Position property (i.e. size) of the 1st axes before generating the plot so that the title appears correctly even if you add a 2nd axes. For example, right after the call to figure(1) add something like this:
ax1 = axes('Position',[0.11 0.11 0.75 0.75]);
Also, if you wish to print exponent values in the title you can use Latex formatting as follows:
title('2^{nd} Harmonics');
Here is the whole code with output:
clear
clc
close all
x1 = linspace(0, 5);
y11 = sin(x1);
y12 = cos(x1);
x2 = linspace(4, 12);
figure(1)
%// Set axes position manually
ax1 = axes('Position',[0.11 0.11 0.75 0.75]);
plot(x1, y11, 'r');
hold on
grid on
plot(x1, y12, 'k');
axis([0 5 -1 1.8]);
legend('sin(x)', 'cos(x)');
xlabel('x')
ylabel('y-label');
%ax1 = gca;
ax1_pos = get(ax1,'Position');
ax2 = axes('Position', ax1_pos,...
'XAxisLocation', 'top',...
'YAxisLocation', 'right',...
'Color', 'none');
set(ax2,'YColor','w');
%// Notice the Latex formatting to print the exponent
title('2^{nd} Harmonics');
line(x2,0,'Parent',ax2,'Color','k')
xlabel('n');
Then you can resize as you wish; the title stays visible.