Question

Using Java 2D I’ve patched several Bezier curves (CubicCurve2D) together to create a “blob”. The problem I now face is how to:

1. Efficiently fill the blob with a given colour.
2. Efficiently determine whether a given point lies inside the blob.

I noticed thst CubicCurve2D implements Shape which provides numerous contains methods for determining “insideness” and that Graphics2D is able to fill a Shape via the fill(Shape) (which I believe uses Shape‘s getPathIterator methods to do this).

Given this I was hoping I could create a composite Shape, whereby my getPathIterator(AffineTransform) method would simply link the underlying PathIterators together. However, this is producing a NoSuchElementException once my shape contains more than one CubicCurve2D. Even if I do manage to achieve this I’m not convinced it will work as expected because a CubicCurve2D is always filled on the convex side, and my “blob” is composed of concave and convex curves. The “contains” problem is even harder as a point can legitimately lie within the blob but not within any of the individual curves.

• Am I approaching this problem in the correct way (trying to implement Shape?) or is there an idiomatic way to do this that I’m unaware of? I would have thought that the problem of compositing geometric shapes would be fairly common.
• Does anyone have any suggestions regarding how to solve this problem?

Thanks in advance.

Answer 1

I’m not sure I understand your question but composite shapes can be created with the class java/awt/geom/Area.