get circles to orbit

[Navarone]

I have been learning how to draw circles. Now I want to learn how to make a circle orbit another. I imagine there are many ways to do this? Given my code below, what would be the simplest method to have the smaller circle orbit the larger one?

Private Sub Form_Activate()
    Dim eX, eY, eR, eRGB1, mX, mY, mR, mRGB1 'declare variables
    ScaleMode = 5 'set scale to inches
    'FillColor = RGB(255, 255, 255) 'set color to fill circle
    'FillStyle = 0 'set transparent or solid
    'DrawWidth = 3 'set line weight of cirle
    DrawStyle = 0 'set solid =1, dashed=2 or dotted=3
    eX = ScaleWidth / 2 'centers circle on form
    eY = ScaleHeight / 2 'centers circle on form
    mX = eX + 1.5 'centers circle on form
    mY = eY + 0 'centers circle on form
    eR = 1
    mR = 0.25
    eRGB1 = RGB(255, 255, 255) 'set line color of circle
    mRGB1 = RGB(255, 255, 255) 'set line color of circle
    'draw the circles
    Circle (eX, eY), eR, eRGB1
    Circle (mX, mY), mR, mRGB1
End Sub

[Maldrid]

Here you go. All you need to do is copy this code and paste over your old code. Then add a timer to the form and set the interval to 90.

Private Type tCircle
    X As Double
    Y As Double
    R As Single
    Color As Long
End Type
Private xMove As Double
Private yMove As Double
Private BigCircle As tCircle
Private SmallCircle As tCircle
Private Const PI = 3.14159265
Private Radius As Single
Private dDegree As Single
Const SPEED = 90
Private Function Cosine(ByVal degrees As Single) As Double
    Cosine = Cos(degrees * PI / 180)
End Function
Private Function Sine(ByVal degrees As Single) As Double
    Sine = Sin(degrees * PI / 180)
End Function
Private Sub Form_Activate()
    
    ScaleMode = 5 'set scale to inches
    'FillColor = RGB(255, 255, 255) 'set color to fill circle
    'FillStyle = 0 'set transparent or solid
    'DrawWidth = 3 'set line weight of cirle
    DrawStyle = 0 'set solid =1, dashed=2 or dotted=3
    
    BigCircle.X = ScaleWidth / 2 'centers circle on form
    BigCircle.Y = ScaleHeight / 2 'centers circle on form
    BigCircle.R = 1
    
    SmallCircle.X = BigCircle.X + BigCircle.R + 0.5
    SmallCircle.Y = BigCircle.Y
    SmallCircle.R = 0.25
    
    Radius = BigCircle.R + 0.5
    dDegree = 0
    
    BigCircle.Color = RGB(255, 255, 255) 'set line color of circle
    SmallCircle.Color = RGB(255, 255, 255) 'set line color of circle
  
    
    'draw the circles
    Circle (BigCircle.X, BigCircle.Y), BigCircle.R, BigCircle.Color
    Circle (SmallCircle.X, SmallCircle.Y), SmallCircle.R, SmallCircle.Color
End Sub
Private Sub Timer1_Timer()
    Dim xDif As Single
    
    'erase the old circle
    SmallCircle.Color = Me.BackColor
    Circle (SmallCircle.X, SmallCircle.Y), SmallCircle.R, SmallCircle.Color
    
    'move the circle
    If dDegree > 360 Then
        dDegree = 1
    End If
    
    yMove = Sine(dDegree) * Radius
    xMove = Cosine(dDegree) * Radius
    
    SmallCircle.Y = BigCircle.Y + yMove
    SmallCircle.X = BigCircle.X + xMove
    
    dDegree = dDegree + .5
    
    'draw the circle
    SmallCircle.Color = RGB(255, 255, 255) 'set line color of circle
    Circle (SmallCircle.X, SmallCircle.Y), SmallCircle.R, SmallCircle.Color
    
    Timer1.Interval = SPEED
End Sub

[Maldrid]

You can change the SPEED constant to whatever you like, but I left it at 90, but you lower it make it move faster.

[Navarone]

Hey thanks

I'll give this a try.