Oxyplot Mouse Events (03) MouseDown

MouseDown

Imports Oxyplot.Axes
Imports Oxyplot.Series
Public Class Form
    Private WithEvents Model As PlotModel
    Private WithEvents Line As LineSeries
    Private indexOfPointToMove As Integer
    Private Sub Form_Load(sender As Object, e As EventArgs) Handles Me.Load
        Model = New PlotModel With {
            .Subtitle = "Left click to edit or add points.",
            .Title = "MouseDown",
            .LegendSymbolLength = 40,
            .Background = OxyColors.White
        }
        Dim linearAxisX = New LinearAxis With {
            .Position = AxisPosition.Bottom
        }
        Model.Axes.Add(linearAxisX)
        Dim linearAxisY = New LinearAxis()
        Model.Axes.Add(linearAxisY)
        Line = New LineSeries With {
            .Color = OxyColors.SkyBlue,
            .MarkerFill = OxyColors.SkyBlue,
            .MarkerSize = 6,
            .MarkerStroke = OxyColors.White,
            .MarkerStrokeThickness = 1.5,
            .MarkerType = MarkerType.Circle,
            .Title = "LineSeries1"
        }
        Line.Points.Add(New DataPoint(0, 10))
        Line.Points.Add(New DataPoint(10, 40))
        Line.Points.Add(New DataPoint(40, 20))
        Line.Points.Add(New DataPoint(60, 30))
        Model.Series.Add(Line)
        PlotView.Model = Model
        indexOfPointToMove = -1
    End Sub
    Private Sub Line_MouseDown(sender As Object, e As OxyMouseDownEventArgs) Handles Line.MouseDown
        If e.ChangedButton = OxyMouseButton.Left Then
            Dim indexOfNearestPoint As Integer = CInt(Math.Round(e.HitTestResult.Index))
            Dim nearestPoint As ScreenPoint = Line.Transform(Line.Points(indexOfNearestPoint))
            If (nearestPoint - e.Position).Length < 10 Then
                indexOfPointToMove = indexOfNearestPoint
            Else
                Dim i As Integer = CInt(e.HitTestResult.Index + 1)
                Line.Points.Insert(i, Line.InverseTransform(e.Position))
                indexOfPointToMove = i
            End If
            Line.LineStyle = LineStyle.DashDot
            Model.InvalidatePlot(False)
            e.Handled = True
        End If
    End Sub
    Private Sub Line_MouseMove(sender As Object, e As OxyMouseEventArgs) Handles Line.MouseMove
        If indexOfPointToMove >= 0 Then
            Line.Points(indexOfPointToMove) = Line.InverseTransform(e.Position)
            Model.InvalidatePlot(False)
            e.Handled = True
        End If
    End Sub
    Private Sub Line_MouseUp(sender As Object, e As OxyMouseEventArgs) Handles Line.MouseUp
        indexOfPointToMove = -1
        Line.LineStyle = LineStyle.Solid
        Model.InvalidatePlot(False)
        e.Handled = True
    End Sub
    Private Sub Model_MouseDown(sender As Object, e As OxyMouseDownEventArgs) Handles Model.MouseDown
        If e.ChangedButton = OxyMouseButton.Left Then
            Line.Points.Add(Line.InverseTransform(e.Position))
            indexOfPointToMove = Line.Points.Count - 1
            Model.InvalidatePlot(False)
            e.Handled = True
        End If
    End Sub
End Class

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