How to draw 3 overlapping circles with different colors?

Question

Is there a free software to draw following in ubuntu? How to color the overlap zone? I am not able to figure this out in GIMP.

enter image description here

2014/06/02

Indeed this is possible in gimp pretty easily.

Create three circles with colors #ff0000, #00ff00 and #0000ff each to own layer with transparent background
Add black background layer
Position those circles as in your image
Use Additive Blending mode for all of them
Just remove black background if necessary

2014/06/02

Karl Ove Hufthammer · Accepted Answer · 6/1/2014 9:27:00 PM

You can use Inkscape. Basically, youâ€™ll have to break the circles into several parts, one for each possible intersection of circles:

Select two circles you want to create the intersection for.
Use Object â†’ Intersection (Ctrl + *) to create the intersection.
Copy the intersection to the clipboard (Ctrl + C).
Undo the intersection operation (Ctrl + Z), which deletes the intersection object and restores the original circles.
Paste the intersection object in place (Ctrl + Alt + V, not Ctrl + V).
Colour the intersection.
Repeat steps 1â€“6 for the remaining pairs of circles, and again on the three two-circle intersections (to create the middle intersection).

You might also want to use the difference operator (Ctrl + -) on the outer circles to cut out the shape of the inner parts.