MATLAB: How can I divide x-axis background into different colored zones

differenet colored regionsplot backgroundx-axis background

I want to divide x-axis background into different colored\grid zones
to have a shape like this:
I use:
 plot(A,B,'k');
hold on;
 area(A(1:13),B(1:13),'basevalue',0,'FaceColor','g');
 area(A(13:end),B(13:end),'basevalue',0,'FaceColor','r');
but it produced this shape:
I am only want to have three separate zones.
HOW CAN I DO THIS ?

Best Answer

I will leave it to you to define the colours, but otherwise this code should work for you without modification in your code, except for the plot(x,y) statements:
x = linspace(0, 3E+5);
y = cumsum(rand(size(x)));
figure(1)
plot(x, y)
hold on
patch([0 1E+5 1E+5 0], [max(ylim) max(ylim) 0 0], 'r')
patch([1E+5 2E+5 2E+5 1E+5], [max(ylim) max(ylim) 0 0], 'g')
patch([2E+5 3E+5 3E+5 2E+5], [max(ylim) max(ylim) 0 0], 'b')
plot(x, y, 'k', 'LineWidth',1.5)
hold off
NOTE — You have to re-plot the original line after plotting the patches, because the patches overplot the data line. The first plot call is necessary to define the axes and the figure.
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