I would like to draw an arc/sector on a given ellipse between to given points. For that I need the degree numbers but I met some unexpected difficulties during creation.
I naively assumed that the degree would be the degree between the straight lines from the sector created, which is true for circles and if the points are in 90° steps but not for anything else. E.g. in the picture each sector is 30° you can see (and measure) that the sectors are not actually in 30° so my question is how are the degrees calculated?
It is obvious, even to the naked eye, that the value of degrees for each sector is not 30 degrees. This would possibly be true if you had a circle, but here you have an ellipse. If you are drawing the ellipse and the lines on a canvas then you will know the endpoint x/y values for each line and the values required to draw the ellipse (an arc with a sweep of 360 degrees). Thus you should be able to draw an arc for any part of the ellipse.
drawArcsOnEllipse.aia (3.9 KB)
Thank you, however this does not help me with my program. How do I calculate the degrees between two points on the ellipse? (An answer as a mathematical term is enough, I don't need the code)
Hmmm...