Help needed Calculating New points along a straight line:
I need some help working out the point positions along a straight line:
I will try to explain what I am doing:
I have two points (x1, y1) and (x2,y2) and have a straight line between the 2 points, from this I can work out the distance between the 2 points lets say it is 50.
What I want to do is increase or decrease the length of the line by a predefined amount lets say 10.
So If I increase the line length by 10 (from 50 to 60), What I want to work out is what point(x3,y3) would be at the end of the increased line.
Hope this makes sense.
I have tried to work out the new point using the angle but it does not work correctly, it does not seems to produce a perfectly straight line and the angle from point (x1,y1) to the new (x3,y3) is not the same as the angle from point (x1,y1 to x2,y2).
This is what I have tried:
:I work out the angle
aAngle =Math.Atan((Y2 – Y1) / (X2 – X2))
:get the length of the line and increase by 10
nChngX = Math.Pow((X1 –X2), 2))
nChngY = Math.Pow((Y1 – Y2), 2))
nChng = Math.Sqrt(nChngX + nChngY) + 10
:work out the new points (x3,y3)
X3 = CSng((Math.Cos(aAngle) * nChng))
Y3 = CSng(CSng((Math.Sin(aAngle) * nChng)))
If someone could post some sample code, in either c# or vb.net that would be much appreciated.