MyPagePainter.vb

Imports DevExpress.XtraRichEdit
Imports DevExpress.XtraRichEdit.API.Layout
Imports DevExpress.XtraRichEdit.API.Native
Imports System.Drawing

Namespace LineNumberingExample

#Region "#MyPagePainter"
    Public Class MyPagePainter
        Inherits PagePainter

        Private richEditControl As RichEditControl

        Private previousColumnIndex As Integer = -1

        Private lineNumberFont As Font

        Public Sub New(ByVal richEdit As RichEditControl)
            MyBase.New()
            richEditControl = richEdit
        End Sub

        Public Sub New(ByVal richEdit As RichEditControl, ByVal backColor As Color, ByVal style As CharacterStyle)
            MyBase.New()
            richEditControl = richEdit
            NumberingHighlightColor = backColor
            NumberingFontName = style.FontName
            NumberingFontSize = If(style.FontSize, 10F)
            NumberingFontColor = If(style.ForeColor, Color.Black)
        End Sub

        Public Property NumberingFontName As String

        Public Property NumberingFontSize As Single

        Public Property NumberingFontColor As Color

        Public Property NumberingHighlightColor As Color

        Public Property LineNumberPadding As Integer

        Public Overrides Sub DrawPage(ByVal page As LayoutPage)
            lineNumberFont = New Font(NumberingFontName, NumberingFontSize, FontStyle.Regular)
            MyBase.DrawPage(page)
            lineNumberFont.Dispose()
        End Sub

        Public Overrides Sub DrawPageArea(ByVal pageArea As LayoutPageArea)
            Dim lineNumberBounds As Rectangle = New Rectangle(New Point(-LineNumberPadding, 0), New Size(LineNumberPadding, pageArea.Bounds.Height))
            Canvas.FillRectangle(New RichEditBrush(NumberingHighlightColor), lineNumberBounds)
            MyBase.DrawPageArea(pageArea)
            previousColumnIndex = -1
        End Sub

        Public Overrides Sub DrawColumn(ByVal column As LayoutColumn)
            Dim pageArea As LayoutPageArea = column.GetParentByType(Of LayoutPageArea)()
            If pageArea IsNot Nothing Then
                Dim leftBoundary As Integer = 0
                If previousColumnIndex >= 0 Then
                    leftBoundary = pageArea.Columns(previousColumnIndex).Bounds.Right
                End If

                If column.LineNumbers.Count > 0 Then
                    HighlightLineNumberingArea(column, leftBoundary)
                End If

                previousColumnIndex += 1
            End If

            MyBase.DrawColumn(column)
        End Sub

        Public Overrides Sub DrawLineNumberBox(ByVal lineNumberBox As LineNumberBox)
            Canvas.DrawString(lineNumberBox.Text, lineNumberFont, New RichEditBrush(NumberingFontColor), lineNumberBox.Bounds, richEditControl.LayoutUnit)
        End Sub

        Private Sub HighlightLineNumberingArea(ByVal column As LayoutColumn, ByVal leftBoundary As Integer)
            Dim page As LayoutPage = column.GetParentByType(Of LayoutPage)()
            Dim marginBounds As Rectangle = New Rectangle(New Point(leftBoundary, 0), New Size(column.Bounds.X - leftBoundary, page.Bounds.Height))
            Canvas.FillRectangle(New RichEditBrush(NumberingHighlightColor), marginBounds)
        End Sub
    End Class
#End Region  ' #MyPagePainter
End Namespace