How can I fill the area under a curve with different colors?

Hi. I want to inquire about filling the area under a curve with distinct hues. Your assistance with this matter would be greatly appreciated. Thank you.

Answer 1

[Voss]

Here's one way:

x = 1:100;
y = log(x);

xb = [1 15 55.5 100];
yb = interp1(x,y,xb);

plot(x,y)

hold on
colors = 'gyr';
for ii = 1:numel(xb)-1
    idx = (x >= xb(ii)) & (x < xb(ii+1));
    x_fill = [xb(ii), xb(ii), x(idx), xb(ii+1), xb(ii+1)];
    y_fill = [0,      yb(ii), y(idx), yb(ii+1), 0       ];
    fill(x_fill,y_fill,colors(ii));
end

Answer 2

[John D'Errico]

Simple.

Just use fill (or patch) to fill THREE patches, each with the desired color. How can it be any simpler?

Or, you could build 3 polyshapes, then plot then with the desired color. Again, quite easy.

Answer 3

[Matt J]

One way:

x=0:0.01:4;
y=1-exp(-x);

color={'g','y','r'};
edges=0:4;

for i=1:3
    r=(edges(i)<=x)&(x<=edges(i+1));
    area(x(r), y(r), FaceColor=color{i}); hold on
end; hold off