2 Java GeneralPath之间的带状线

Question

Can anyone give me a hint or help me with my following ( hopefully also interesting :-) ) problem.

I have 2 GeneralPath in my JavaProgramm and I would like to findout the stripline between them.

Following situation:

I have 2 GeneralPath A & B

A is a yellow triangle with 3 points ( moveto, lineto, lineto , close )

B (red) was a triangle and is a result of a substraction BA:

B = new Area(gp_B); // General path B area object
A = new Area(gp_A); // General path A area object
B.subtract(A);

B has 4 points after the substraction. So there is no intersection between A & B and GeneralPath anymore and A doesn't have any points that matches any points of GeneralPath B.

How can I findout the stripline between them ?

My example is simplified for better explaining. My GeneralPath A & B could also contain Beziercurves with Cubeto:

Regards Andreas

Answer 1

i doubt that you would get an desired answer, so i first give you some tipps to limit the complexity of your task:

i would reduce your task to so called simple polygons. That are non self intersecting polygons. once that works you may try to extend to bezier paths.
To do your task for a generall path, this is very demaning (is this a master thesis where you have 6 months time for your job, or a CAD system with a customer willing to pay?)

If you still want to do that:
start hand drawing the most complex scenarios: fully overlapping (like a wooden cross).

Then who does the subtraction? is that ready working? which limitations the subtraction has (simple polygons vs non simple)

One possibility :

get the source code of the subtraction, try to understand, and extend that part that does the cutting, such that it returns an additional stripe path.

The other solution:

A1: compare old objects with the points after cutting. Determine the new introduced points. follow one point on the path until an old point is reached. do that in the other direction, too. concat both directions.

do that for all new points, and finally you get a list of stripes, probably you have to clean up by removinh duplicate lines.