I want to draw a path line that can be any shape (square, round, outline etc), and along this path line I want even dots to appear.
I also want to be able to resize the shape (as in the example attached)
This is very easy to do using “DrawPath” and defining points for the path and using a pen defined as dots.
The problem I have is I want the dots to be evenly placed along the path, on any shape or size I draw.
In the example I have created, I create a square with 4 points and draw a dotted path.
There are 2 buttons that allows me to resize the square (larger or smaller) this helps show the problem more clearly.
The path starts at the top left corner and finishes back at the top left corner, the dots are evenly placed along the path, except the final dots at the end of the path. (Sometimes the dots are even and other times they are not even).
The shapes I want to draw can be any size and any shape, but I have used a square in this example to show the problem I have.
Can anyone please help point me in the direction I need to go that allows me to draw the dots and give the impression that they are even all along the path, for all shapes and sizes.
In the pictures below if you change the size of the shape, one will have even looking dots, the other will not.
Good:
The picture shows a path line that has dots that look even.
Bad:
The picture shows a path line that has dots that clash at the start and end of the path line – NOT GOOD
Any help much appreciated
Thanks
Setting up the project:
Create a new project and add a form, add a panel to the form that fills the bottom part of the form, add at the top of the form a label and 2 buttons.
Add the code below to the form:
Full project also available for download:
Dotted Line Code
Imports System.Drawing.Drawing2D Imports System.Math Public Class Form1 Public pathLinesStart As GraphicsPath = New GraphicsPath Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim TPoint(5) As PointF Dim Npoint As PointF = Nothing 'For x1 As Integer = 0 To 4 'Npoint = New PointF(30, 30) 'TPoint(0) = Npoint 'Npoint = New PointF(300, 30) 'TPoint(1) = Npoint 'Npoint = New PointF(300, 300) 'TPoint(2) = Npoint 'Npoint = New PointF(30, 300) 'TPoint(3) = Npoint 'Npoint = New PointF(30, 30) 'TPoint(4) = Npoint 'Npoint = New PointF(30, 30) 'TPoint(5) = Npoint Npoint = New PointF(126, 126) TPoint(0) = Npoint Npoint = New PointF(205, 126) TPoint(1) = Npoint Npoint = New PointF(205, 205) TPoint(2) = Npoint Npoint = New PointF(126, 205) TPoint(3) = Npoint Npoint = New PointF(126, 126) TPoint(4) = Npoint Npoint = New PointF(126, 126) TPoint(5) = Npoint 'Next pathLinesStart.AddLines(TPoint) CalculateNewPoints(True, 0) Me.Refresh() End Sub Private Sub Panel1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Panel1.Paint Dim p As Pen = New Pen(Color.Black, 5) p.LineJoin = LineJoin.Round p.EndCap = LineCap.Round p.StartCap = LineCap.Round Dim g As Graphics = e.Graphics p.DashStyle = DashStyle.Dot p.DashCap = DashCap.Round g.InterpolationMode = InterpolationMode.HighQualityBicubic g.SmoothingMode = SmoothingMode.HighQuality p.Color = Color.Red g.DrawPath(p, pathLinesStart) End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click ' Increase change point size CalculateNewPoints(True, 10) Me.Refresh() End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click ' Decrease change point size CalculateNewPoints(False, 10) Me.Refresh() End Sub Public Sub CalculateNewPoints(ByRef Increase As Boolean, ByVal PercentageChange As Double) Dim RotatePerc As Single = 0 Dim pathLines As GraphicsPath = pathLinesStart Dim xmin As Single = 0 Dim xmax As Single = 0 Dim ymin As Single = 0 Dim ymax As Single = 0 Dim xmin2 As Single = 0 Dim xmax2 As Single = 0 Dim ymin2 As Single = 0 Dim ymax2 As Single = 0 Dim CPoint As PointF = New Point(0, 0) Dim CPoint2 As PointF = New Point(0, 0) Dim OldPoint As PointF = New Point(0, 0) xmin = pathLines.PathPoints(0).X xmax = pathLines.PathPoints(0).X ymin = pathLines.PathPoints(0).Y ymax = pathLines.PathPoints(0).Y For x1 As Integer = 0 To UBound(pathLines.PathPoints) If pathLines.PathPoints(x1).X < xmin Then xmin = pathLines.PathPoints(x1).X End If If pathLines.PathPoints(x1).X > xmax Then xmax = pathLines.PathPoints(x1).X End If If pathLines.PathPoints(x1).Y < ymin Then ymin = pathLines.PathPoints(x1).Y End If If pathLines.PathPoints(x1).Y > ymax Then ymax = pathLines.PathPoints(x1).Y End If Next Dim xwidth As Single = ((xmax  xmin)) Dim ywidth As Single = ((ymax  ymin)) ' Find the centre point of the annotation CPoint = New PointF(((xwidth / 2)) + xmin, ((ywidth / 2)) + ymin) Dim aAngle As Single = 0 Dim nChngY As Single = 0 Dim nChngX As Single = 0 Dim nChng As Single = 0 Dim nPercChng As Double = (PercentageChange / 100) Dim xPoint As Single = 0 Dim yPoint As Single = 0 Dim TPoint(UBound(pathLines.PathPoints)) As PointF Dim Npoint As PointF = Nothing Label1.Text = "" For x1 As Integer = 0 To UBound(pathLines.PathPoints) OldPoint = New PointF((pathLines.PathPoints(x1).X), (pathLines.PathPoints(x1).Y)) aAngle = CSng(Math.Atan2((OldPoint.Y  CPoint.Y), (OldPoint.X  CPoint.X))) ' get length of Hypotenuse nChngX = CSng(Math.Pow((CPoint.X  OldPoint.X), 2)) nChngY = CSng(Math.Pow((CPoint.Y  OldPoint.Y), 2)) nChng = CSng((Math.Sqrt((nChngX + nChngY)))) ' get percentage changed based on length of Hypotenuse Dim nChngPc As Double = nChng * nPercChng xPoint = CSng((Math.Cos(aAngle) * nChngPc)) yPoint = CSng(CSng((Math.Sin(aAngle) * nChngPc))) If OldPoint.X > (CPoint.X) Then ' add xPoint = Math.Abs(xPoint) Else ' sub xPoint = Math.Abs(xPoint) xPoint = 0  xPoint End If If OldPoint.Y > (CPoint.Y) Then ' add yPoint = Math.Abs(yPoint) Else ' sub yPoint = Math.Abs(yPoint) yPoint = 0  yPoint End If Dim X1a As Single, Y1a As Single, X2a As Single, Y2a As Single If Increase = True Then 'larger X1a = ((OldPoint.X + (xPoint))) Y1a = (OldPoint.Y + (yPoint)) Else 'smaller X1a = ((OldPoint.X  (xPoint))) Y1a = (OldPoint.Y  (yPoint)) End If Dim r As Double = Math.Atan(Y1a / X1a) ' get length of Hypotenuse nChngX = CSng(Math.Pow((CPoint.X  X1a), 2)) nChngY = CSng(Math.Pow((CPoint.Y  Y1a), 2)) nChng = CSng((Math.Sqrt((nChngX + nChngY)))) r = ((Math.PI / 180) * (nChng)) Dim ROT As Single = CSng(((Math.PI / 180) * RotatePerc)) r = nChng X2a = CSng((r * Cos(ROT) * Cos(aAngle))  (r * Sin(ROT) * Sin(aAngle))) Y2a = CSng((r * Sin(ROT) * Cos(aAngle)) + (r * Cos(ROT) * Sin(aAngle))) X2a = X2a + CPoint.X Y2a = Y2a + CPoint.Y Npoint = New PointF(CInt((X2a)), CInt((Y2a))) TPoint(x1) = Npoint Label1.Text = Label1.Text + "(" + Npoint.X.ToString + "," + Npoint.Y.ToString + ")  " Next pathLinesStart = New GraphicsPath pathLinesStart.AddLines(TPoint) End Sub End Class
Attached File(s)

DottedLine.zip (72.31K)
Number of downloads: 75
This post has been edited by AdamSpeight2008: 12 April 2012  02:50 PM
Reason for edit:: Please use the CODE TAGS for for code, next time