A Little Challenge: Spin the Circle

[bplus]

Yours is nice I think you can cut it in half by eliminating the 2nd loop, seems like you might be able to change aspect like I change xr below.

here is a different approach:

Code: (Select All)

_Title "Spinning Circle" ' b+ 2024-09-10  highlight front edge

Screen _NewImage(620, 620, 32)

_ScreenMove 300, 60

cx = 308: cy = 308: xr = 0: dxr = 1: dyr = 1: yr = 300: c1~& = &HFFFF0000

Do

    Cls

    FEllipse cx, cy, xr, 300, &HFFFFFFFF

    FEllipse 310, 310, xr, 300, c1~&

    xr = xr + dxr

    If xr > 300 Then dxr = -dxr: xr = 299: cx = 312: cy = 312: _Delay .1

    If xr < 0 Then

        dxr = -dxr: xr = 1: cx = 308: cy = 308

        If c1~& = &HFFFF0000 Then c1~& = &HFF008800 Else c1~& = &HFFFF0000

    End If

    _Display

    _Limit 120

Loop Until _KeyDown(27)



Sub FEllipse (CX As Long, CY As Long, xr As Long, yr As Long, C As _Unsigned Long)

    If xr = 0 Or yr = 0 Then Exit Sub

    Dim h2 As _Integer64, w2 As _Integer64, h2w2 As _Integer64

    Dim x As Long, y As Long

    w2 = xr * xr: h2 = yr * yr: h2w2 = h2 * w2

    Line (CX - xr, CY)-(CX + xr, CY), C, BF

    Do While y < yr

        y = y + 1

        x = Sqr((h2w2 - y * y * w2) \ h2)

        Line (CX - x, CY + y)-(CX + x, CY + y), C, BF

        Line (CX - x, CY - y)-(CX + x, CY - y), C, BF

    Loop

End Sub

Edit Correction: I was flipping colors too often sorry, should be OK now!