Realbasic Sine/Cosine Test

'// Drawing a circle using a point on a x,y coordinate plane.
'// Assume Slider1.Value is your radii in degrees, and Slider1.Maximum is 360 in degrees.
'// Also assume the Width/Height to be variable; in my tests, they were w=400 and h=200, giving it an oval effect.

Sub Paint(g As Graphics)

  Dim p As New Picture(g.Width, g.Height, 24)
  Dim gl As Graphics
  If p = Nil Then gl = g Else gl = p.Graphics

  gl.ForeColor = RGB(255, 255, 255)
  gl.FillRect(0, 0, gl.Width, gl.Height)

  Dim x, y As Double
  Dim pi As Double = 3.1415926535897932384626433832795

  '// note that pi is not a constant, but is rather a variable... RealBasic does
  '// have some limitations, and this helps with using the pi value below:

  x = Cos(Slider1.Value / Slider1.Maximum * 2 * pi) * gl.Width / 2 + gl.Width / 2
  y = Sin(Slider1.Value / Slider1.Maximum * 2 * pi) * gl.Height / 2 + gl.Height / 2

  x = Round(x)
  y = Round(y)

  gl.ForeColor = RGB(0, 0, 0)
  gl.FillOval(x - 2, y - 2, 5, 5) '// draws the point on our x,y plane for this radius

  '// Chr(176) as used below is the degree sign on the Unicode character map
  gl.DrawString("r=" + Str(Slider1.Value / Slider1.Maximum * 2 * pi) + EndOfLine _
  + "r=" + Str(Slider1.Value / Slider1.Maximum * 360) + Chr(176), gl.Width / 2, gl.Height / 2)

  If p <> Nil Then g.DrawPicture(p, 0, 0)

End Sub