I'm doing a program in Java to draw a PieChart based on given value as link below.
Given that the diameter, radius, angle degree, center point (150,150) and First Point A (150,0) for each value of (x, y) respectively for piechart as below:
piechart diameter, radius and angle degree
The problem is that I cannot complete my program, because I do not understand how to calculate the next Point B (x,y), Point C (x,y), Point D (x,y) and Point E (x,y).
Is it possible to get the value of those point? I'm not a math student and doing simple java programming consisting math calculation is simply my interest. I'm much appreciated to anyone who can help me on this problem.
It would be much easier if we let the circle’s radius = r and center = O(0, 0).
To a data point P(x, y) on the circumference with its central angle α known, means that point is given in polar co-ordinate in the form [r, α].
The inter-relationship between (x, y) and [r, α] is {x = r* cos α, and y = r * sin α}.
Note that all angles are measured counter-clockwise-ly from the first point (the positive x-axis).
If Q(m, n) is the next point whose included central angle is β, then Q, in polar co-ordinates, is [r, δ]; where δ = β + α.