Line Control

[n_tarr]

I know the line control can be used for many things but this I have not seen how to do.

How would you rotate/spin a line control at a constant radius? When it would go round, it should also be able to draw a perfect round circle (well not perfect). A wanted to use this as a radar screen for a game I am thinking about. Does anyone know how I would do this?

Nathan

[Mushroom Realm]

Why not just use the .circle property for the circle part. You should probably whip up a function for the spinning of a line control. Im working on it.

[Mushroom Realm]

Making the circle is up to u. But heres the function for moving the line:

Function SpinLine(Line As Line, Spinpoint As Long, SpintoX As Long, SpintoY As Long)
With Line
.X1 = Spinpoint
.Y1 = Spinpoint
.X2 = SpintoX
.Y2 = SpintoY
End With
End Function

Just Copy and Paste that into ur code.

Line is the line control that u want to spin.

Spinpoint is line control's x1,y1 locations (the center of the circle)

SpintoX and SpintoY move the x2,y2 coordinates to wherever u want.this will allow it to spin.

Use that if u want, or u can improve it, like by setting it up so that u just have to give it a degree (0 - 360) and it spins to that point.

[Sastraxi]

Unfortunately that'll get you nowhere, you need to know how to spin it. Use this, and I'll explain it:

Function Radar(mLine As Line, CentreX As Long, CentreY As Long, Degree As Long, Radius As Double)
Dim Rad As Double
 
    Rad = Degree * (3.1415926 / 180)
 
    With mLine
        .X2 = CentreX + Cos(Rad) * Radius
        .Y2 = CentreY + Sin(Rad) * Radius
        .X1 = CentreX
        .Y1 = CentreY
    End With
 
End Function

If you haven't done maths before, here we go. The first line converts the degrees (0 - 359) to Radians. Then, it takes the centre of the circle, and adds the cosine of the radius to it (the horizontal bit). It then multiplies this by the radius to get either a positive or negative value that tells you where the X point is. Same with the Y.

[n_tarr]

I don't know everything about maths but Im getting there. Thanks for your help everyone.

[n_tarr]

Ive got it working! I have put the timer() function into the code to time twice how long the line will do one revolution and then another, at a specific timer interval (set speed of the rotation). When set to an interval of 100 (1/100 of a second), it runs fine on most computers, spinning the circle at the same rate. But when set to an interval of 1 (1 milisecond), many computers either spin the line faster or slower. Why is this? Is there any way the circle can be run at the this rate on any computer?

[n_tarr]

Here is the soucre code. Hope it helps.

Private Sub Form_Load()

pi = 4 * Atn(1) ' Calculate the value of pi.

'Call function to prepare line control in position
Call DrawCircle(linsec, linsec.X1, linsec.Y1, 0, 1000)

End Sub

Function DrawCircle(mLine As Line, CentreX As Long, CentreY As Long, Degree As Long, Radius As Double)

Dim Rad As Double 'Declare radians

Degree = Degree + 1 'Increment Degrees

Rad = Degree * (pi / 180) 'set value for Rad

'Set co-ordinates for each property position
With mLine
.X2 = CentreX + Cos(Rad) * Radius 'X end of line
.Y2 = CentreY + Sin(Rad) * Radius 'Y end of line
.X1 = CentreX 'X start of line
.Y1 = CentreY 'Y "" "" ""
End With

End Function

Private Sub Timer1_Timer()

'rotate circle
Call DrawCircle(linsec, linsec.X1, linsec.Y1, Degree, 1000)

Finish = Timer
TimeElaps = Finish - Start
Label1.Caption = TimeElaps 'get time

'test for 359 degreee and set value to 0 degree
If Degree >= 359 Then

If Label2.Caption = 0 Then
Label2.Caption = TimeElaps: Degree = 0: SecondTime = Label2.Caption

ElseIf Label2.Caption <> 0 And Label3.Caption = 0 Then

Label3.Caption = TimeElaps - SecondTime
Label11.Caption = Label3.Caption / 360

Call DrawCircle(linsec, linsec.X1, linsec.Y1, 0, 1000)

Command1.Enabled = True
Timer1.Enabled = False
End If

End If

Label4 = Degree

End Sub