VERSION 5.00
Begin VB.Form Form1 
   AutoRedraw      =   -1  'True
   Caption         =   "No Frills Fractals"
   ClientHeight    =   6105
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   5250
   LinkTopic       =   "Form1"
   ScaleHeight     =   6105
   ScaleWidth      =   5250
   StartUpPosition =   3  'Windows Default
   Begin VB.Frame Frame1 
      Caption         =   "Julia Parameters"
      Height          =   1215
      Left            =   2280
      TabIndex        =   14
      Top             =   3360
      Width           =   2175
      Begin VB.TextBox Text7 
         Height          =   285
         Left            =   960
         TabIndex        =   18
         Text            =   "0.6"
         Top             =   720
         Width           =   855
      End
      Begin VB.TextBox Text6 
         Height          =   285
         Left            =   960
         TabIndex        =   16
         Text            =   "0.3"
         Top             =   360
         Width           =   855
      End
      Begin VB.Label Label7 
         Caption         =   "Imaginary"
         Height          =   255
         Left            =   120
         TabIndex        =   17
         Top             =   720
         Width           =   735
      End
      Begin VB.Label Label6 
         Caption         =   "Real"
         Height          =   255
         Left            =   120
         TabIndex        =   15
         Top             =   360
         Width           =   615
      End
   End
   Begin VB.OptionButton Option2 
      Caption         =   "Julia"
      Height          =   255
      Left            =   2280
      TabIndex        =   13
      Top             =   5040
      Width           =   855
   End
   Begin VB.OptionButton Option1 
      Caption         =   "Mandelbrot"
      Height          =   255
      Left            =   2280
      TabIndex        =   12
      Top             =   4680
      Value           =   -1  'True
      Width           =   1215
   End
   Begin VB.TextBox Text5 
      Height          =   285
      Left            =   1200
      TabIndex        =   11
      Text            =   "100"
      Top             =   4920
      Width           =   735
   End
   Begin VB.TextBox Text4 
      Height          =   285
      Left            =   1200
      TabIndex        =   9
      Text            =   "1.5"
      Top             =   4560
      Width           =   735
   End
   Begin VB.TextBox Text3 
      Height          =   285
      Left            =   1200
      TabIndex        =   8
      Text            =   "-1.5"
      Top             =   4200
      Width           =   735
   End
   Begin VB.TextBox Text2 
      Height          =   285
      Left            =   1200
      TabIndex        =   7
      Text            =   "1.5"
      Top             =   3840
      Width           =   735
   End
   Begin VB.TextBox Text1 
      Height          =   285
      Left            =   1200
      TabIndex        =   6
      Text            =   "-2.5"
      Top             =   3480
      Width           =   735
   End
   Begin VB.CommandButton Command1 
      Caption         =   "Draw"
      Height          =   495
      Left            =   1560
      TabIndex        =   1
      Top             =   5400
      Width           =   1575
   End
   Begin VB.PictureBox Picture1 
      Height          =   3060
      Left            =   120
      ScaleHeight     =   200
      ScaleMode       =   3  'Pixel
      ScaleWidth      =   320
      TabIndex        =   0
      Top             =   120
      Width           =   4860
   End
   Begin VB.Label Label5 
      Caption         =   "Iterations"
      Height          =   255
      Left            =   120
      TabIndex        =   10
      Top             =   4920
      Width           =   735
   End
   Begin VB.Label Label4 
      Caption         =   "Y Max"
      Height          =   255
      Left            =   120
      TabIndex        =   5
      Top             =   4560
      Width           =   855
   End
   Begin VB.Label Label3 
      Caption         =   "Y Min"
      Height          =   255
      Left            =   120
      TabIndex        =   4
      Top             =   4200
      Width           =   855
   End
   Begin VB.Label Label2 
      Caption         =   "X Max"
      Height          =   255
      Left            =   120
      TabIndex        =   3
      Top             =   3840
      Width           =   855
   End
   Begin VB.Label Label1 
      Caption         =   "X Min"
      Height          =   255
      Left            =   120
      TabIndex        =   2
      Top             =   3480
      Width           =   855
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
' This program draws no frills fractals
' It's designed to show how to draw fractals rather than to be a fast
' or useful program

Option Explicit

Private Sub Command1_Click()
Dim Xmin As Single
Dim Xmax As Single
Dim Ymin As Single
Dim Ymax As Single
Dim MaxIter As Integer
Dim P As Single
Dim Q As Single
Dim initx As Single
Dim inity As Single
Dim xs As Single
Dim ys As Single
Dim x As Integer
Dim y As Integer
Dim i As Integer

' Read the paramters fro m the text boxes
Xmin = Val(Text1.Text)
Xmax = Val(Text2.Text)
Ymin = Val(Text3.Text)
Ymax = Val(Text4.Text)
MaxIter = Val(Text5.Text)
P = Val(Text6.Text)
Q = Val(Text7.Text)

' This works out the scaling factor for each pixel
xs = (Xmax - Xmin) / Picture1.ScaleWidth
ys = (Ymax - Ymin) / Picture1.ScaleHeight

' now draw the fractal

If Option1.Value = True Then
    ' Mandelbrot set
    For y = 0 To Picture1.ScaleHeight - 1
        For x = 0 To Picture1.ScaleWidth - 1
            ' work out the coordinate of the pixel
            initx = Xmin + xs * x
            inity = Ymin + ys * y
            ' iterate with these parameters
            i = IterateM(initx, inity, MaxIter)
            ' plot the pixel
            Picture1.PSet (x, y), QBColor((i Mod 15) + 1)
        Next
    Next
    
    Else
    
    ' Julia set
    For y = 0 To Picture1.ScaleHeight - 1
        For x = 0 To Picture1.ScaleWidth - 1
            ' work out the coordinate of the pixel
            initx = Xmin + xs * x
            inity = Ymin + ys * y
            ' iterate with these parameters
            i = IterateJ(initx, inity, MaxIter, P, Q)
            ' plot the pixel
            Picture1.PSet (x, y), QBColor((i Mod 15) + 1)
        Next
    Next
End If
End Sub


Public Function IterateM(initx As Single, inity As Single, MaxIter As Integer) As Integer
' this function works out how many iterations are needed for a given point on the
' mandelbrot set

' x->x*x-y*y+x0
' y->2*x*y+y0


Dim x As Single
Dim y As Single
Dim xsq As Single
Dim ysq As Single
Dim i As Integer
    
' precalculate the first iteration
x = initx + initx * initx - inity * inity
y = inity + initx * inity + initx * inity
ysq = y * y
xsq = x * x

For i = 2 To MaxIter
    ' new imaginary value
    y = inity + x * y + x * y
    ' new real value
    x = initx - ysq + xsq
    ' work out the squared values
    ysq = y * y
    xsq = x * x
    ' check the bailout condition
    If (xsq + ysq) > 4 Then Exit For
Next i
IterateM = i
End Function

Public Function IterateJ(initx As Single, inity As Single, MaxIter As Integer, P As Single, Q As Single) As Integer
' this function works out how many iterations are needed for a given point on the
' julia set

' x->x*x-y*y+P
' y->2*x*y+Q

Dim x As Single
Dim y As Single
Dim xsq As Single
Dim ysq As Single
Dim i As Integer
    
' get the initial values of x and y ready
x = initx
y = inity
xsq = x * x
ysq = y * y

For i = 1 To MaxIter
    'new imaginary value
    y = Q + x * y + x * y
    ' new real value
    x = P - ysq + xsq
    ' work out the squared values
    ysq = y * y
    xsq = x * x
    ' check the bailout condition
    If (xsq + ysq) > 4 Then Exit For
Next i

IterateJ = i

End Function

Private Sub Option1_Click()
'if mandelbrot set is clicked, then put in some
' sensible starting coordinates
Text1.Text = -2.5
Text2.Text = 1.5
Text3.Text = -1.5
Text4.Text = 1.5

End Sub

Private Sub Option2_Click()
'if julia set is clicked, then put in some
' sensible starting coordinates

Text1.Text = -1.5
Text2.Text = 1.5
Text3.Text = -1.5
Text4.Text = 1.5

End Sub