Moze mi ktoś wyjaśnić jak ten kod rysuje okrąg bo nie mogę normalnie tego objąć umysłem

"
Sub Lcd_circle(byval X As Word , Byval Y As Word , Byval Radius As Integer , Byval Color As Word)
Local X0 As Word , Y0 As Word , Error As Integer
Local Xp As Word , Yp As Word , Xe As Word , Ye As Word

Error = -radius
Xp = Radius
Yp = 0

While Xp >= Yp
 X0 = X + Xp : Y0 = Y + Yp
 Call Lcd_set_pixel(x0 , Y0 , Color)
 X0 = X - Xp : Y0 = Y + Yp
 Call Lcd_set_pixel(x0 , Y0 , Color)
 X0 = X + Xp : Y0 = Y - Yp
 Call Lcd_set_pixel(x0 , Y0 , Color)
 X0 = X - Xp : Y0 = Y - Yp
 Call Lcd_set_pixel(x0 , Y0 , Color)

X0 = X + Yp : Y0 = Y + Xp
 Call Lcd_set_pixel(x0 , Y0 , Color)
 X0 = X - Yp : Y0 = Y + Xp
 Call Lcd_set_pixel(x0 , Y0 , Color)
 X0 = X + Yp : Y0 = Y - Xp
 Call Lcd_set_pixel(x0 , Y0 , Color)
 X0 = X - Yp : Y0 = Y - Xp
 Call Lcd_set_pixel(x0 , Y0 , Color)
  Error = Error + Yp
   Incr Yp
   Error = Error + Yp

If Error >= 0 Then
     Decr Xp
     Error = Error - Xp
     Error = Error - Xp
   End If
Wend

End Sub"

#matematyka #programowanie