problem in fitting graph in accurate Cartesian

[duaaayyad]

Hi
thank you very much for your help
I have some problems in drawing graphs in vb6
first : how can I fit the graph to start from a certain point x+1 is the same as x it seems the same start even x+1 must shift up one step

second can the drawn graph be in centimeter instead of pixel >>> so that the step can be shwon clearly

third : how we can use coordinates fit on gapgh or we can just use a picture shws it

his is my school small project in vb6 its for drawing graphs for functions in math

give me feed back and help please

Const pi = 3.14159265358979

Private Sub Combo1_Click()
Picture1.ScaleTop = 500
 

Picture1.ScaleLeft = -50
 

Picture1.ScaleWidth = 100
 

Picture1.ScaleHeight = -1000
 
Picture1.DrawWidth = 2

If Combo1.ListIndex = 0 Then

 b = InputBox("enter x factor")
 c = InputBox("enter the free value of x")
  Picture1.Line (-60, 10 * -c)-(60, 10 * -c)
 Picture1.Line (0, 500)-(0, -500)

 For X = -30 To 30 Step 0.01
  Y = b * X + c
 Picture1.PSet (X, Y), vbBlue
 Next X
End If
If Combo1.ListIndex = 1 Then
Picture1.Cls
 a = InputBox("enter x2 factor")

 b = InputBox("enter x factor")
 c = InputBox("enter the free value of x")
'   Picture1.Line (-40, 10 * -c)-(40, 10 * -c)
' Picture1.Line (0, 400)-(0, -400)
  Picture1.Line (-60, 10 * -c)-(60, 10 * -c)
 Picture1.Line (0, 500)-(0, -500)

 For X = -20 To 20 Step 0.01
  Y = a * X ^ 2 + b * X + c
 Picture1.PSet (X, Y), vbBlue
 Next X
End If
If Combo1.ListIndex = 2 Then

 a = InputBox("enter x3 factor")
 b = InputBox("enter x2 factor")
 c = InputBox("enter x factor")
 
 d = InputBox("enter the free value of x")
   
   Picture1.Line (-40, 10 * -d)-(40, 10 * -d)
 Picture1.Line (0, 400)-(0, -400)

 For X = -20 To 20 Step 0.01
  Y = a * X ^ 3 + b * X ^ 2 + c * X + d
 Picture1.PSet (X, Y), vbBlue
 Next X
End If


End Sub


Private Sub Combo2_Click()
 Dim CenterX As Long, CenterY As Long
 Dim X As Double, Y As Double
 Dim Ax As Double, Ay As Double
 'Adjust these values to fit your need.
 If Combo2.ListIndex = 0 Then
 
Picture1.Cls

 Ax = 10
 Ay = 50
 With Picture1
 .ScaleMode = vbPixels
 CenterX = .ScaleWidth / 2
 CenterY = .ScaleHeight / 2
 Picture1.Line (CenterX, .ScaleTop)-(CenterX, .ScaleHeight), vbBlack
 Picture1.Line (.ScaleLeft, CenterY)-(.ScaleWidth, CenterY), vbBlack
 b = InputBox("in (a+sin bx) enter cos factor b")
 c = InputBox("enter the other free factor a")

 For X = 0 To 2 * CenterX Step 0.2
 Y = -Ay * b * Sin(c * ((X - CenterX) / Ax)) + CenterY
 Picture1.PSet (X, Y), vbBlue
 Next
 End With
 End If
 
  If Combo2.ListIndex = 1 Then
Picture1.Cls

 Ax = 10
 Ay = 50
 With Picture1
 .ScaleMode = vbPixels
 CenterX = .ScaleWidth / 2
 CenterY = .ScaleHeight / 2
 Picture1.Line (CenterX, .ScaleTop)-(CenterX, .ScaleHeight), vbBlack
 Picture1.Line (.ScaleLeft, CenterY)-(.ScaleWidth, CenterY), vbBlack
   b = InputBox("in (a+cos bx) enter cos factor b")
 c = InputBox("enter the other free factor a")

 For X = 0 To 2 * CenterX Step 0.2
 Y = -Ay * b * Cos(c * ((X - CenterX) / Ax)) + CenterY
 Picture1.PSet (X, Y), vbBlue
 Next
 End With
 End If
  If Combo2.ListIndex = 2 Then
Picture1.Cls

 Ax = 10
 Ay = 50
 With Picture1
 .ScaleMode = vbPixels
 CenterX = .ScaleWidth / 2
 CenterY = .ScaleHeight / 2
 Picture1.Line (CenterX, .ScaleTop)-(CenterX, .ScaleHeight), vbBlack
 Picture1.Line (.ScaleLeft, CenterY)-(.ScaleWidth, CenterY), vbBlack
 For X = 0 To 2 * CenterX Step 0.2
 Y = -Ay * Tan((X - CenterX) / Ax) + CenterY
 Picture1.PSet (X, Y), vbBlue
 Next
 End With
 End If

  If Combo2.ListIndex = 3 Then
Picture1.Cls

 Ax = 10
 Ay = 50
 With Picture1
 .ScaleMode = vbPixels
 CenterX = .ScaleWidth / 2
 CenterY = .ScaleHeight / 2
 Picture1.Line (CenterX, .ScaleTop)-(CenterX, .ScaleHeight), vbBlack
 Picture1.Line (.ScaleLeft, CenterY)-(.ScaleWidth, CenterY), vbBlack
 For X = 0 To 2 * CenterX Step 0.2
 Y = -Ay * Sin((X - CenterX) / Ax) ^ 2 + CenterY
 Picture1.PSet (X, Y), vbBlue
 Next
 End With
 End If

  If Combo2.ListIndex = 4 Then
Picture1.Cls

 Ax = 10
 Ay = 50
 With Picture1
 .ScaleMode = vbPixels
 CenterX = .ScaleWidth / 2
 CenterY = .ScaleHeight / 2
 Picture1.Line (CenterX, .ScaleTop)-(CenterX, .ScaleHeight), vbBlack
 Picture1.Line (.ScaleLeft, CenterY)-(.ScaleWidth, CenterY), vbBlack
 For X = 0 To 2 * CenterX Step 0.2
 Y = -Ay * Cos((X - CenterX) / Ax) ^ 2 + CenterY
 Picture1.PSet (X, Y), vbBlue
 Next
 End With
 End If

 End Sub

Private Sub Command1_Click()
Picture1.Cls
Picture1.ScaleTop = 500
 

Picture1.ScaleLeft = -50
 

Picture1.ScaleWidth = 100
 

Picture1.ScaleHeight = -1000
 
Picture1.DrawWidth = 2
 Picture1.Line (-40, 0)-(40, 0)
 Picture1.Line (0, 400)-(0, -400)



End Sub

Private Sub Form_Load()
Picture1.ScaleTop = 500
 

Picture1.ScaleLeft = -50
 

Picture1.ScaleWidth = 100
 

Picture1.ScaleHeight = -1000
 
Picture1.DrawWidth = 2
 Picture1.Line (-40, 0)-(40, 0)
 Picture1.Line (0, 400)-(0, -400)


Combo1.AddItem "linear "
Combo1.AddItem " sqaure"
Combo1.AddItem "Cubicaم"

Combo2.AddItem "sin "
Combo2.AddItem " cos"
Combo2.AddItem "tan"
Combo2.AddItem "sin2"

Combo2.AddItem "cos2"


End Sub


Private Sub Label3_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Label3.Caption = " ÚÒíÒí ÇáØÇáÈ " & Chr(10) & " Ýí ÇÞÊÑÇä ßËíÑ ÇáÍÏæÏ " & Chr(10) & "ÃÓ3 + È Ó2 + Ì Ó + Ï" & Chr(10) & " à åí ãÚÇãá Ó3 æ È åí ãÚÇãá Ó2 æ Ì åí ãÚÇãá Ó æ Ï åí ÇáÍÏ ÇáãØáÞ"
End Sub


Private Sub Label4_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Label4.Caption = " ÚÒíÒí ÇáØÇáÈ " & Chr(10) & " Ýí ÇÞÊÑÇäÇÊ ÇáãËáËíÉ " & Chr(10) & "à ÌÇÈ Ó Ãæ ÃÌÊÇ È Ó" & Chr(10) & " à åí ãÚÇãá ÇáÌíÈ Çæ ÇáÌÊÇ æ È åí ãÚÇãá ÇáÒÇæíÉ"

End Sub