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How to Merge Color using "Area" Command?

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Benjamin on 8 Apr 2021 at 16:12
Answered: Star Strider on 8 Apr 2021 at 21:00
Dear experts,
I need to find a way around the fact that by using the area command in MATLAB, the new plotted color on top of the previous color. Is there any way that the colors merge?
Take a look at the figures below, please.
area([1 2 3],'FaceColor','red');hold on
area([.5 .6 .7],'FaceColor','blue');hold on
But I want the colors red and blue merge and turn into what ever color it will, for example purple in this case.
P.S. I already know that I can simply use the purple color in the example above, but because my actual MATLAB program are couple of curves, and I need to also see the color beneath the upper colors, that's why I tried to put an easy example here.
I appreciate your help in advance.
  1 Comment
Benjamin on 8 Apr 2021 at 16:24
I also tried the patch and fill command, but they also result in covering the previous color!

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Accepted Answer

Star Strider
Star Strider on 8 Apr 2021 at 21:00
With respect to patch, set 'FaceAlpha'; of both to 0.5 (or anything less than 1) to see the two patches overlap, with appropriate colour mixing.
Example —
x = linspace(0, 3);
y1 = 1 + x/2;
y2 = 0.5 + x/5;
patch([x, fliplr(x)], [y1, zeros(size(y1))], 'b', 'FaceAlpha', 0.8)
hold on
patch([x, fliplr(x)], [y2, zeros(size(y2))], 'r', 'FaceAlpha', 0.3)
hold off
Esperiment to get the result you want.

More Answers (1)

Adam Danz
Adam Danz on 8 Apr 2021 at 20:43
You can use a patch object with interpolated face color.
This example in the documentation shows how to do this. Once you get it started, if you have any trouble, share what you've got, describe the new problem, and I can nudge you along in the right direction.

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