HistogramChartHelper.vb

Imports System.Windows.Forms.DataVisualization.Charting


Namespace Branzfire.System.Windows.Forms.DataVisualization.Charting.Utilities
    ''' <summary>
    ''' Helper class that creates a histogram chart. Histogram is a data
    ''' distribution chart which shows how many values, from the data series,
    ''' are inside each segment interval.  
    ''' 
    ''' You can define how many intervals you want to have using the SegmentIntervalNumber
    ''' field or the exact length of the interval using the SegmentIntervalWidth
    ''' field. Actual segment interval number can be slightly different due
    ''' to the automatic interval rounding.
    ''' </summary>
    Public Class HistogramChartHelper
#Region "Fields"

        ''' <summary>
        ''' Number of class intervals the data range is devided in.
        ''' This property only has affect when "SegmentIntervalWidth" is 
        ''' set to double.NaN.
        ''' </summary>
        Public SegmentIntervalNumber As Integer = 20

        ''' <summary>
        ''' Histogram class interval width. Setting this value to "double.NaN"
        ''' will result in automatic width calculation based on the data range
        ''' and number of required interval specified in "SegmentIntervalNumber".
        ''' </summary>
        Public SegmentIntervalWidth As Double = Double.NaN

        ''' <summary>
        ''' Indicates that percent frequency should be shown on the right axis
        ''' </summary>
        Public ShowPercentOnSecondaryYAxis As Boolean = True

#End Region   ' Fields

#Region "Methods"

        ''' <summary>
        ''' Creates a histogram chart.
        ''' </summary>
        ''' <param name="chartControl">Chart control reference.</param>
        ''' <param name="dataSeriesName">Name of the series which stores the original data.</param>
        ''' <param name="histogramSeriesName">Name of the histogram series.</param>
        Public Sub CreateHistogram(ByVal chartControl As Chart, ByVal dataSeriesName As String, ByVal histogramSeriesName As String)
            ' Validate input

            If chartControl Is Nothing Then
                Throw (New ArgumentNullException("chartControl"))
            End If
            If chartControl.Series.IndexOf(dataSeriesName) < 0 Then
                'If chartControl.Series.GetIndex(dataSeriesName) < 0 Then
                Throw (New ArgumentException("Series with name'" & dataSeriesName & "' was not found.", "dataSeriesName"))
            End If

            Try
                ' Make data series invisible
                chartControl.Series(dataSeriesName).Enabled = False

                ' Check if histogram series exists
                Dim histogramSeries As Series = Nothing
                If chartControl.Series.IndexOf(histogramSeriesName) < 0 Then
                    'If chartControl.Series.GetIndex(histogramSeriesName) < 0 Then
                    ' Add new series
                    histogramSeries = chartControl.Series.Add(histogramSeriesName)

                    ' Set new series chart type and other attributes
                    histogramSeries.ChartType = SeriesChartType.Column
                    histogramSeries.BorderColor = Color.Black
                    histogramSeries.BorderWidth = 1
                    histogramSeries.BorderDashStyle = ChartDashStyle.Solid

                    'histogramSeries.IsValueShownAsLabel = True
                Else
                    histogramSeries = chartControl.Series(histogramSeriesName)
                    histogramSeries.Points.Clear()
                End If

                ' Get data series minimum and maximum values
                Dim minValue As Double = Double.MaxValue
                Dim maxValue As Double = Double.MinValue
                Dim pointCount As Integer = 0
                Dim dataPoint As DataPoint
                For Each dataPoint In chartControl.Series(dataSeriesName).Points
                    ' Process only non-empty data points
                    If (Not dataPoint.IsEmpty) Then
                        'If (Not dataPoint.Empty) Then
                        If dataPoint.YValues(0) > maxValue Then
                            maxValue = dataPoint.YValues(0)
                        End If
                        If dataPoint.YValues(0) < minValue Then
                            minValue = dataPoint.YValues(0)
                        End If
                        pointCount += 1
                    End If
                Next dataPoint

                ' Calculate interval width if it's not set
                If Double.IsNaN(Me.SegmentIntervalWidth) Then
                    Me.SegmentIntervalWidth = (maxValue - minValue) / SegmentIntervalNumber
                    Me.SegmentIntervalWidth = RoundInterval(Me.SegmentIntervalWidth)
                End If

                ' Round minimum and maximum values
                minValue = Math.Floor(minValue / Me.SegmentIntervalWidth) * Me.SegmentIntervalWidth
                maxValue = Math.Ceiling(maxValue / Me.SegmentIntervalWidth) * Me.SegmentIntervalWidth

                ' Create histogram series points
                Dim currentPosition As Double = minValue
                currentPosition = minValue
                Do While currentPosition <= maxValue
                    ' Count all points from data series that are in current interval
                    Dim count As Integer = 0
                    Dim datPoint As DataPoint
                    For Each datPoint In chartControl.Series(dataSeriesName).Points
                        If (Not datPoint.IsEmpty) Then
                            Dim endPosition As Double = currentPosition + Me.SegmentIntervalWidth
                            If datPoint.YValues(0) >= currentPosition AndAlso datPoint.YValues(0) < endPosition Then
                                count += 1

                                ' Last segment includes point values on both segment boundaries
                            ElseIf endPosition >= maxValue Then
                                If datPoint.YValues(0) >= currentPosition AndAlso datPoint.YValues(0) <= endPosition Then
                                    'count += 1
                                End If
                            End If
                        End If
                    Next datPoint


                    ' Add data point into the histogram series
                    histogramSeries.Points.AddXY(currentPosition + Me.SegmentIntervalWidth / 2.0, count)

                    currentPosition += Me.SegmentIntervalWidth
                Loop

                ' Adjust series attributes
                histogramSeries("PointWidth") = "1"
                'histogramSeries("PointWidth") = "0.8"

                ' Adjust chart area
                Dim chartArea As ChartArea = chartControl.ChartAreas(histogramSeries.ChartArea)
                chartArea.AxisY.Title = "Frequency"
                chartArea.AxisX.Minimum = minValue
                chartArea.AxisX.Maximum = maxValue

                ' Set axis interval based on the histogram class interval
                ' and do not allow more than 10 labels on the axis.
                Dim axisInterval As Double = Me.SegmentIntervalWidth
                Do While (maxValue - minValue) / axisInterval > 10.0
                    axisInterval *= 2.0
                Loop
                chartArea.AxisX.Interval = axisInterval

                ' Set chart area secondary Y axis
                chartArea.AxisY2.Enabled = AxisEnabled.Auto
                If Me.ShowPercentOnSecondaryYAxis Then
                    chartArea.RecalculateAxesScale()

                    chartArea.AxisY2.Enabled = AxisEnabled.True
                    chartArea.AxisY2.LabelStyle.Format = "P0"
                    chartArea.AxisY2.MajorGrid.Enabled = False
                    chartArea.AxisY2.Title = "Percent of Total"

                    chartArea.AxisY2.Minimum = 0
                    chartArea.AxisY2.Maximum = chartArea.AxisY.Maximum / (pointCount / 100.0)
                    Dim minStep As Double = CDbl(IIf((chartArea.AxisY2.Maximum > 20.0), 5.0, 1.0))
                    chartArea.AxisY2.Interval = Math.Ceiling((chartArea.AxisY2.Maximum / 5.0 / minStep)) * minStep

                End If

                'Dim SearchWithinThis As String = chartArea.AxisX.Title
                'Dim SearchForThis As String = " No. Sprinklers Operated"
                'Dim FirstCharacter As Integer = SearchWithinThis.IndexOf(SearchForThis)

                'If FirstCharacter <> -1 Then 'substring found
                '    chartArea.AxisX.Minimum = 0
                '    chartArea.AxisX.Maximum = NumSprinklers + 1
                'End If

            Catch ex As Exception
                MsgBox(Err.Description, MsgBoxStyle.OkOnly, "Exception in Sub CreateHistogram")
            End Try
        End Sub

        Public Sub CreateHistogram_SPR(ByVal chartControl As Chart, ByVal dataSeriesName As String, ByVal histogramSeriesName As String)
            'version of histogram for no. of sprinklers operated
            ' Validate input

            If chartControl Is Nothing Then
                Throw (New ArgumentNullException("chartControl"))
            End If
            If chartControl.Series.IndexOf(dataSeriesName) < 0 Then
                'If chartControl.Series.GetIndex(dataSeriesName) < 0 Then
                Throw (New ArgumentException("Series with name'" & dataSeriesName & "' was not found.", "dataSeriesName"))
            End If

            Try
                ' Make data series invisible
                chartControl.Series(dataSeriesName).Enabled = False

                ' Check if histogram series exsists
                Dim histogramSeries As Series = Nothing
                If chartControl.Series.IndexOf(histogramSeriesName) < 0 Then
                    'If chartControl.Series.GetIndex(histogramSeriesName) < 0 Then
                    ' Add new series
                    histogramSeries = chartControl.Series.Add(histogramSeriesName)

                    ' Set new series chart type and other attributes
                    histogramSeries.ChartType = SeriesChartType.Column
                    histogramSeries.BorderColor = Color.Black
                    histogramSeries.BorderWidth = 1
                    histogramSeries.BorderDashStyle = ChartDashStyle.Solid

                    'histogramSeries.IsValueShownAsLabel = True

                Else
                    histogramSeries = chartControl.Series(histogramSeriesName)
                    histogramSeries.Points.Clear()
                End If

                ' Get data series minimum and maximum values
                Dim minValue As Double = Double.MaxValue
                Dim maxValue As Double = Double.MinValue
                Dim pointCount As Integer = 0
                Dim dataPoint As DataPoint
                For Each dataPoint In chartControl.Series(dataSeriesName).Points
                    ' Process only non-empty data points
                    If (Not dataPoint.IsEmpty) Then
                        'If (Not dataPoint.Empty) Then
                        If dataPoint.YValues(0) > maxValue Then
                            maxValue = dataPoint.YValues(0)
                        End If
                        If dataPoint.YValues(0) < minValue Then
                            minValue = dataPoint.YValues(0)
                        End If
                        pointCount += 1
                    End If
                Next dataPoint

                ' Calculate interval width if it's not set
                If Double.IsNaN(Me.SegmentIntervalWidth) Then
                    Me.SegmentIntervalWidth = (maxValue - minValue) / SegmentIntervalNumber
                    Me.SegmentIntervalWidth = RoundInterval(Me.SegmentIntervalWidth)
                End If

                ' Round minimum and maximum values
                minValue = Math.Floor(minValue / Me.SegmentIntervalWidth) * Me.SegmentIntervalWidth
                maxValue = Math.Ceiling(maxValue / Me.SegmentIntervalWidth) * Me.SegmentIntervalWidth

                ' Create histogram series points
                Dim currentPosition As Double = minValue
                currentPosition = minValue
                Do While currentPosition <= maxValue
                    ' Count all points from data series that are in current interval
                    Dim count As Integer = 0
                    Dim datPoint As DataPoint
                    For Each datPoint In chartControl.Series(dataSeriesName).Points
                        If (Not datPoint.IsEmpty) Then
                            Dim endPosition As Double = currentPosition + Me.SegmentIntervalWidth
                            If datPoint.YValues(0) >= currentPosition AndAlso datPoint.YValues(0) < endPosition Then
                                count += 1

                                ' Last segment includes point values on both segment boundaries
                            ElseIf endPosition >= maxValue Then
                                If datPoint.YValues(0) >= currentPosition AndAlso datPoint.YValues(0) <= endPosition Then
                                    count += 1
                                End If
                            End If
                        End If
                    Next datPoint


                    ' Add data point into the histogram series
                    histogramSeries.Points.AddXY(currentPosition + Me.SegmentIntervalWidth / 2.0, count)
                    currentPosition += Me.SegmentIntervalWidth
                Loop

                ' Adjust series attributes
                histogramSeries("PointWidth") = "1"
                'histogramSeries("PointWidth") = "0.8"


                ' Adjust chart area
                Dim chartArea As ChartArea = chartControl.ChartAreas(histogramSeries.ChartArea)
                chartArea.AxisY.Title = "Frequency"
                chartArea.AxisX.Minimum = minValue
                chartArea.AxisX.Maximum = maxValue

                ' Set axis interval based on the histogram class interval
                ' and do not allow more than 10 labels on the axis.
                Dim axisInterval As Double = Me.SegmentIntervalWidth
                Do While (maxValue - minValue) / axisInterval > 10.0
                    axisInterval *= 2.0
                Loop
                chartArea.AxisX.Interval = axisInterval

                ' Set chart area secondary Y axis
                chartArea.AxisY2.Enabled = AxisEnabled.Auto
                If Me.ShowPercentOnSecondaryYAxis Then
                    chartArea.RecalculateAxesScale()

                    chartArea.AxisY2.Enabled = AxisEnabled.True
                    chartArea.AxisY2.LabelStyle.Format = "P0"
                    chartArea.AxisY2.MajorGrid.Enabled = False
                    chartArea.AxisY2.Title = "Percent of Total"

                    chartArea.AxisY2.Minimum = 0
                    chartArea.AxisY2.Maximum = chartArea.AxisY.Maximum / (pointCount / 100.0)
                    Dim minStep As Double = CDbl(IIf((chartArea.AxisY2.Maximum > 20.0), 5.0, 1.0))
                    chartArea.AxisY2.Interval = Math.Ceiling((chartArea.AxisY2.Maximum / 5.0 / minStep)) * minStep

                End If

                If chartArea.AxisX.Title = " No. Sprinklers Operated" Then
                    chartArea.AxisX.Minimum = 0
                    chartArea.AxisX.Maximum = NumSprinklers + 1
                End If

            Catch ex As Exception
                MsgBox(Err.Description, MsgBoxStyle.OkOnly, "Exception in Sub CreateHistogram")
            End Try
        End Sub

        ''' <summary>
        ''' Helper method which rounds specified axsi interval.
        ''' </summary>
        ''' <param name="interval">Calculated axis interval.</param>
        ''' <returns>Rounded axis interval.</returns>
        Friend Function RoundInterval(ByVal interval As Double) As Double
            Try

                ' If the interval is zero return error
                If interval = 0.0 Then
                    'Throw (New ArgumentOutOfRangeException("interval", "Interval can not be zero."))
                    Exit Function
                End If

                ' If the real interval is > 1.0
                Dim step_Renamed As Double = -1
                Dim tempValue As Double = interval
                Do While tempValue > 1.0
                    step_Renamed += 1
                    tempValue = tempValue / 10.0
                    If step_Renamed > 1000 Then
                        Throw (New InvalidOperationException("Auto interval error due to invalid point values or axis minimum/maximum."))
                    End If
                Loop

                ' If the real interval is < 1.0
                tempValue = interval
                If tempValue < 1.0 Then
                    step_Renamed = 0
                End If

                Do While tempValue < 1.0
                    step_Renamed -= 1
                    tempValue = tempValue * 10.0
                    If step_Renamed < -1000 Then
                        Throw (New InvalidOperationException("Auto interval error due to invalid point values or axis minimum/maximum."))
                        Exit Function
                    End If
                Loop

                Dim tempDiff As Double = interval / Math.Pow(10.0, step_Renamed)
                If tempDiff < 3.0 Then
                    tempDiff = 2.0
                ElseIf tempDiff < 7.0 Then
                    tempDiff = 5.0
                Else
                    tempDiff = 10.0
                End If


                ' Make a correction of the real interval
                Return tempDiff * Math.Pow(10.0, step_Renamed)

            Catch ex As Exception
                MsgBox(Err.Description, MsgBoxStyle.OkOnly, "Exception in Function RoundInterval")

            End Try
        End Function

#End Region   ' Methods

    End Class
End Namespace