by Zeev Rotshtein (1 Submission)
Category: Graphics
Compatability: Visual Basic 5.0
Difficulty: Unknown Difficulty
Originally Published: Thu 11th August 2005
Date Added: Mon 8th February 2021
Rating: 
(1 Votes)
Draws a curve from a random array of 3-9 coordinates. (Press numbers 3-9 for the size of the array and Enter to draw).
API Declarations
Option Explicit
Const STEP = 100
Public Enum SplineSegment
SplineMiddleSegment = &H0
SplineFirstSegment = &H1
SplineLastSegment = &H2
SplineSingleSegment = &H3
End Enum
Public Type Coordinate
X As Double
Y As Double
End Type
Public Sub HalfSpline(Board As Form, Point1 As Coordinate, Point2 As Coordinate, Point3 As Coordinate, Optional Flag As SplineSegment = SplineMiddleSegment)
Dim p1 As Coordinate
Dim p3 As Coordinate
If (Flag And SplineFirstSegment) Then
p1.X = Point1.X
p1.Y = Point1.Y
Else
p1.X = (Point1.X + Point2.X) / 2
p1.Y = (Point1.Y + Point2.Y) / 2
End If
If (Flag And SplineLastSegment) Then
p3.X = Point3.X
p3.Y = Point3.Y
Else
p3.X = (Point3.X + Point2.X) / 2
p3.Y = (Point3.Y + Point2.Y) / 2
End If
SingleSpline Board, p1, Point2, p3
End Sub
Public Sub SingleSpline(Board As Form, Point1 As Coordinate, Point2 As Coordinate, Point3 As Coordinate)
Dim i As Integer
Dim CurrX1 As Double
Dim CurrY1 As Double
Dim CurrX2 As Double
Dim CurrY2 As Double
Dim StepX1 As Double
Dim StepY1 As Double
Dim StepX2 As Double
Dim StepY2 As Double
Dim DX As Double
Dim DY As Double
Dim LastDX As Double
Dim LastDy As Double
CurrX1 = Point1.X
CurrY1 = Point1.Y
CurrX2 = Point2.X
CurrY2 = Point2.Y
StepX1 = (Point2.X - Point1.X) / STEP
StepY1 = (Point2.Y - Point1.Y) / STEP
StepX2 = (Point3.X - CurrX2) / STEP
StepY2 = (Point3.Y - CurrY2) / STEP
LastDX = CurrX1
LastDy = CurrY1
For i = 0 To STEP
DX = ((CurrX2 - CurrX1) * (i / STEP)) + CurrX1
DY = ((CurrY2 - CurrY1) * (i / STEP)) + CurrY1
Board.Line (DX, DY)-(LastDX, LastDy)
LastDX = DX
LastDy = DY
CurrX1 = CurrX1 + StepX1
CurrY1 = CurrY1 + StepY1
CurrX2 = CurrX2 + StepX2
CurrY2 = CurrY2 + StepY2
Next i
End Sub
VBcoders
Option Explicit
Option Base 1
Dim Points As Integer
Const FRAME_WIDTH = 300
Const FRAME_HEIGHT = 500
Const WELCOME_STR = "Welcome. Hit the ENTER!"
Const TITLE_STR = "Spline Maker"
Const DEF_POINTS = 5
Dim P() As Coordinate
Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
If KeyCode = 13 Then Form_Paint
End Sub
Private Sub Form_KeyPress(KeyAscii As Integer)
Dim Num As Integer
Num = KeyAscii - Asc("0")
If (Num > 2 And Num < 10) Then
Points = Num
WriteOnForm Points & " points"
End If
End Sub
Private Sub Form_Load()
Points = DEF_POINTS
WriteOnForm WELCOME_STR & vbTab & "[" & Points & " points]"
End Sub
Private Sub Form_Paint()
Dim i As Integer
Randomize
Cls
ReDim P(Points)
For i = 1 To Points
P(i).X = ScaleLeft + Rnd * (ScaleWidth - FRAME_WIDTH)
P(i).Y = ScaleTop + Rnd * (ScaleHeight - FRAME_HEIGHT)
ForeColor = vbBlack
Line (P(i).X - 50, P(i).Y - 50)-(P(i).X + 50, P(i).Y + 50)
Line (P(i).X - 50, P(i).Y + 50)-(P(i).X + 50, P(i).Y - 50)
CurrentX = P(i).X + 50
CurrentY = P(i).Y + 50
Print Str(i) 'Chr((Asc("A") - 1) + i)
If i > 1 Then
Line (P(i).X, P(i).Y)-(P(i - 1).X, P(i - 1).Y), vbGreen
End If
Next i
ForeColor = vbRed
DrawSpline
End Sub
Sub DrawSpline()
Dim i As Integer
For i = 2 To Points - 1
HalfSpline Me, P(i - 1), P(i), P(i + 1), (-(i = 2)) + (-2 * (i = Points - 1))
Next i
End Sub
Sub WriteOnForm(Text As String)
Cls
CurrentX = (ScaleLeft + ScaleWidth - TextWidth(Text)) / 2
CurrentY = (ScaleTop + ScaleHeight - TextHeight(Text)) / 2
Print Text
End Sub
No comments have been posted about Draws a curve from a random array of 3-9 coordinates. (Press numbers 3-9 for the size of the array . Why not be the first to post a comment about Draws a curve from a random array of 3-9 coordinates. (Press numbers 3-9 for the size of the array .
