Need a Algorithm for Getting the border of a shape

Question

I have a problem...I want a pseudocode..for the following problem
Aim:
I need the lines to be ordered first and then also it should be in anticlockwise directions (if the points are also not ordered for these
ordered lines ..order them too... in anti clockwise direction)
Specification:
I have a vector of lines and arcs to form a shape....
...the lines are not ordered (say for example line 1 followed by 2 ,3 and so
on... but the vector contains lines in random order say 1 3 5 2 4 so
on...please note the vector contains points for the line only and no
identification for the order.)
The lines will combine to form any shape (eg rectangle ..rhombus or any
polygon or shape.) the shape can also contain lines along diagonal too.. or
some lines intersecting the polygon at any of the sides...but within the
boundary
for example..
new java.awt.Point(10, 20));
new java.awt.Point(10, 50)); //line 4
new java.awt.Point(40, 50));
new java.awt.Point(10, 50)); //line 3
new java.awt.Point(40, 50));
new java.awt.Point(40, 20)); //line 1
new java.awt.Point(10, 20));
new java.awt.Point(40, 20)); //line 2
new java.awt.Point(10, 25));
new java.awt.Point(40, 35)); //line 5
new java.awt.Point(40, 25));
new java.awt.Point(10, 45)); //line 6
kindly if any one knows the solution for this or any site which has a
solution for this...please send it or find the solution at the earliest.
Thanking u in advance.
Oliver

Answer 1

My problem is I have a shape which can be formed from either arcs or lines or maybe both.This shape can contain lines in the inside ,touching the borders .Basically any combinations of lines or arcs a user can imagine.
A simple example.
__a___
|\ / |
b| f\/ e | d
|__\___|
c
Now say this is the shape and the lines for forming the shape are a,b,c,d,e,f these lines are contained in the vector, but say in random order ex. b,e,f,a,d,c
Now from these vectos I need the lines to be ordered in a sequence like a,b,c,d,e,f but I need the border first, NOTE the lines contain no identification like a,b but the startpoint and endpoints in the vector.
AIM: I need the lines ordered in anticlockwise direction.
Now taking the above diagram the corners could contain arcs instead of the lines intersecting.