midpoint circle drawing

Hi,

i am having trouble getting my circle centered. When i run my program it draws the circle waaay in the upper left hand corner of my window so i can't even see a circle.

How can i get it to draw around a specified origin? I have this so far.

i have a feeling the circle is being draw outside my field of view. But how can i get it so the center of the circle is somewhere on the form where i can see the whole circle?

I am using the midpoint circle algorithm.

Code:

---

Option Explicit
Dim radius As Integer
Dim midpoint As Integer
Dim x, y, d As Integer

Private Sub cmdDrawCircle_Click()
    radius = InputBox("Please enter the radius of the circle")
    Call MidPointcircle
   
End Sub

Private Sub CirclePoints()
    PSet (x, y)
    PSet (y, x)
    PSet (y, -x)
    PSet (x, -y)
    PSet (-x, -y)
    PSet (-y, -x)
    PSet (-y, x)
    PSet (-x, y)
End Sub

Private Sub MidPointcircle()
   
   
    x = 0
    y = radius
    d = 1 - radius
    Call CirclePoints
    Do While y > x
        If d < 0 Then
            d = d + x * 2 + 3
            x = x + 1
        Else
            d = d + (x - y) * 2 + 5
            x = x + 1
            y = y - 1
           
        End If
    Call CirclePoints
    Loop
   
   
End Sub

Private Sub Form_Load()
    DrawWidth = 1
End Sub

---

thanks!

Hi,
Usually you must provide some sort of offset for the center of the circle to be drawn. The fact that it is in the top-left corner (probably showing only 1/4 of a circle).

Do something like this.

Code:

---

'these will represent the X and Y offsets
DIM mnScreenOffsetX AS LONG
DIM mnScreenOffsetY AS LONG

'assuming you are drawing to form1
mnScreenOffsetX = form1.width / 2
mnScreenOffsetY = form1.height / 2

'now, the above points should represent the center of your form
'To draw a simple circle in the middle, you could do something like
'this.
form1.circle (mnScreenOffsetX, mnScreenOffsetY), fRadius, nColor

---

In your example, let's take one PSET...

PSet (x, y)

Modify it to read PSet (mnScreenOffsetX + x, mnScreenOffsetY + y)

Hope this helps.
Regards,
ChuckB

Ah,

a drawing problem. I had this. But it is because u need to do one more line of code.

Me.Show


That is probably all u needed to do. Just use things like this for it to be easier;

Private Sub DrawCircle_Click()
Dim radius As Integer
radius = InputBox("Please Enter the radius of the circle")
Me.Show
Me.CurrentX = 1300 'The horizontal coordinate of the form
Me.CurrentY = 1300 'The vertical coordinate of the form
Me.Circle (Me.CurrentX, Me.CurrentY), radius
End Sub

Hope this helped

Scale(-100, 100) - (-100, 100)