Option Strict On

Imports System.Drawing.Drawing2D
Public Class PhotoSlider
    Inherits Control

    '########## Credits #########
    '# GDI PhotoSlider          #
    '# Created by: Blink        #
    '# Released on: 27 dec 2012 #
    '############################
    'You can contact me at:
    'http://www.hackforums.net/member.php?action=profile&uid=551863

#Region "Properties"
    Public Property Images As ImageList

    Private _intArrowSize As Integer = 10
    Public Property ArrowSize As Integer
        Get
            Return _intArrowSize
        End Get
        Set(ByVal value As Integer)
            _intArrowSize = value
            Invalidate()
        End Set
    End Property

    Private _intHoverOutset As Integer = 10
    Public Property HoverOutset As Integer
        Get
            Return _intHoverOutset
        End Get
        Set(ByVal value As Integer)
            _intHoverOutset = value
            Invalidate()
        End Set
    End Property

    Private _intOverlap As Integer = 5
    Public Property Overlap As Integer
        Get
            Return _intOverlap
        End Get
        Set(ByVal value As Integer)
            _intOverlap = value
            Invalidate()
        End Set
    End Property

    Private _intFocused As Integer = 0
    Public Property FocusedIndex As Integer
        Get
            Return _intFocused
        End Get
        Set(ByVal value As Integer)
            _intFocused = value
            Invalidate()
        End Set
    End Property

    Private _blnDrawOutline As Boolean = True
    Public Property DrawOutline As Boolean
        Get
            Return _blnDrawOutline
        End Get
        Set(ByVal value As Boolean)
            _blnDrawOutline = value
            Invalidate()
        End Set
    End Property
#End Region

    Sub New()
        Size = New Size(600, 150)
        DoubleBuffered = True
    End Sub

    Public Sub MoveForward()
        If FocusedIndex + 1 > Images.Images.Count - 1 Then
            FocusedIndex = 0
        Else
            FocusedIndex += 1
        End If
    End Sub

    Public Sub MoveBackward()
        If FocusedIndex - 1 < 0 Then
            FocusedIndex = Images.Images.Count - 1
        Else
            FocusedIndex -= 1
        End If
    End Sub

    'Gets index relative to the focused index
    Private Function GetIndex(ByVal intOff As Integer) As Integer
        If FocusedIndex + intOff = Images.Images.Count Then
            Return 0
        ElseIf FocusedIndex + intOff = Images.Images.Count + 1 Then
            Return 1
        ElseIf FocusedIndex + intOff = -1 Then
            Return Images.Images.Count - 1
        ElseIf FocusedIndex + intOff = -2 Then
            Return Images.Images.Count - 2
        Else
            Return FocusedIndex + intOff
        End If
    End Function

    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        Dim G As Graphics = e.Graphics

        'Order is important for Overlap
        For i As Integer = -2 To 0
            If i <> HoveredIndex Then
                DrawPicture(G, i)
            End If
            If i <> Math.Abs(i) And Math.Abs(i) <> HoveredIndex Then
                DrawPicture(G, Math.Abs(i))
            End If
        Next

        'Draw hovered last for Overlap
        If HoveredIndex <> -3 Then
            DrawPicture(G, HoveredIndex)
        End If

        DrawArrow(G, 0) 'Left
        DrawArrow(G, 1) 'Right

        MyBase.OnPaint(e)
    End Sub

    Sub DrawArrow(ByVal G As Graphics, ByVal intArrowIndex As Integer)
        Dim rctBounds As Rectangle = GetArrowBounds(intArrowIndex)
        Dim intHalf As Integer = CInt(ArrowSize / 2)
        Dim intAlfa As Integer
        If intArrowIndex = HoveredArrow And blnMouseIsDown Then
            intAlfa = 255
        ElseIf intArrowIndex = HoveredArrow Then
            intAlfa = 200
        Else
            intAlfa = 150
        End If
        G.SmoothingMode = SmoothingMode.AntiAlias
        Select Case intArrowIndex
            Case 0 'Left
                Dim gpLeftArrow As New GraphicsPath
                gpLeftArrow.AddLine(rctBounds.X + intHalf, rctBounds.Y + 0, rctBounds.X + ArrowSize, rctBounds.Y + 0)
                gpLeftArrow.AddLine(rctBounds.X + ArrowSize, rctBounds.Y + 0, rctBounds.X + intHalf, rctBounds.Y + intHalf)
                gpLeftArrow.AddLine(rctBounds.X + intHalf, rctBounds.Y + intHalf, rctBounds.X + ArrowSize, rctBounds.Y + ArrowSize)
                gpLeftArrow.AddLine(rctBounds.X + ArrowSize, rctBounds.Y + ArrowSize, rctBounds.X + intHalf, rctBounds.Y + ArrowSize)
                gpLeftArrow.AddLine(rctBounds.X + intHalf, rctBounds.Y + ArrowSize, rctBounds.X + 0, rctBounds.Y + intHalf)
                gpLeftArrow.AddLine(rctBounds.X + 0, rctBounds.Y + intHalf, rctBounds.X + intHalf, rctBounds.Y + 0)

                G.FillPath(New SolidBrush(Color.FromArgb(intAlfa, 75, 75, 75)), gpLeftArrow)
            Case 1 'Right
                Dim gpRightArrow As New GraphicsPath
                gpRightArrow.AddLine(rctBounds.X + 0, rctBounds.Y + 0, rctBounds.X + intHalf, rctBounds.Y + 0)
                gpRightArrow.AddLine(rctBounds.X + intHalf, rctBounds.Y + 0, rctBounds.X + ArrowSize, rctBounds.Y + intHalf)
                gpRightArrow.AddLine(rctBounds.X + ArrowSize, rctBounds.Y + intHalf, rctBounds.X + intHalf, rctBounds.Y + ArrowSize)
                gpRightArrow.AddLine(rctBounds.X + intHalf, rctBounds.Y + ArrowSize, rctBounds.X + 0, rctBounds.Y + ArrowSize)
                gpRightArrow.AddLine(rctBounds.X + 0, rctBounds.Y + ArrowSize, rctBounds.X + intHalf, rctBounds.Y + intHalf)
                gpRightArrow.AddLine(rctBounds.X + intHalf, rctBounds.Y + intHalf, rctBounds.X + 0, rctBounds.Y + 0)

                G.FillPath(New SolidBrush(Color.FromArgb(intAlfa, 75, 75, 75)), gpRightArrow)
        End Select
    End Sub

    Sub DrawPicture(ByVal G As Graphics, ByVal index As Integer)
        G.FillRectangle(Brushes.White, GetPictureBounds(index))
        Try
            G.DrawImage(Images.Images(GetIndex(index)), GetPictureBounds(index))
        Catch ex As Exception
            G.FillRectangle(Brushes.CornflowerBlue, GetPictureBounds(index))
        End Try
        If DrawOutline Then G.DrawRectangle(Pens.Black, GetPictureBounds(index))
    End Sub

    'Returns the bounds of the requested index, inclusive the hover
    Private Function GetPictureBounds(ByVal Index As Integer) As Rectangle
        If Not Index = HoveredIndex Then
            Return GetNormalPictureBounds(Index)
        Else
            Dim rctNormal As Rectangle = GetNormalPictureBounds(Index)
            Return New Rectangle(rctNormal.X - HoverOutset, rctNormal.Y - HoverOutset, rctNormal.Width + 2 * HoverOutset, rctNormal.Height + 2 * HoverOutset)
        End If
    End Function

    'Returns the bounds of the requested index, exclusive the hover
    Private Function GetNormalPictureBounds(ByVal Index As Integer) As Rectangle
        Select Case Index
            Case -2
                Dim rctNext As Rectangle = GetNormalPictureBounds(Index + 1)
                Return New Rectangle(rctNext.X + (Overlap * 3) - rctNext.Width, rctNext.Y + Overlap, rctNext.Width - Overlap * 2, rctNext.Height - 2 * Overlap)
            Case -1
                Dim rctNext As Rectangle = GetNormalPictureBounds(Index + 1)
                Return New Rectangle(rctNext.X + (Overlap * 3) - rctNext.Width, rctNext.Y + Overlap, rctNext.Width - Overlap * 2, rctNext.Height - 2 * Overlap)
            Case 0
                Return New Rectangle(CInt(Width / 2) - CInt((Height - ArrowSize) / 2 - HoverOutset), HoverOutset, (Height - ArrowSize) - HoverOutset * 2, (Height - ArrowSize) - HoverOutset * 2 - 1)
            Case 1
                Dim rctPrevious As Rectangle = GetNormalPictureBounds(Index - 1)
                Return New Rectangle(rctPrevious.X + rctPrevious.Width - Overlap, rctPrevious.Y + Overlap, rctPrevious.Width - Overlap * 2, rctPrevious.Height - Overlap * 2)
            Case 2
                Dim rctPrevious As Rectangle = GetNormalPictureBounds(Index - 1)
                Return New Rectangle(rctPrevious.X + rctPrevious.Width - Overlap, rctPrevious.Y + Overlap, rctPrevious.Width - Overlap * 2, rctPrevious.Height - Overlap * 2)
        End Select
    End Function

    Private HoveredIndex As Integer = -3
    Private HoveredArrow As Integer = -1
    Protected Overrides Sub OnMouseMove(ByVal e As System.Windows.Forms.MouseEventArgs)
        Dim intNewHovered As Integer = GetHoveredIndex(e.Location)
        If intNewHovered <> HoveredIndex Then
            HoveredIndex = intNewHovered
            Invalidate()
        End If
        Dim intNewHoveredArrow As Integer = GetHoveredArrowIndex(e.Location)
        If intNewHoveredArrow <> HoveredArrow Then
            HoveredArrow = intNewHoveredArrow
            Invalidate()
        End If
        MyBase.OnMouseMove(e)
    End Sub

    Protected Overrides Sub OnMouseLeave(ByVal e As System.EventArgs)
        HoveredIndex = -3
        Invalidate()
        MyBase.OnMouseLeave(e)
    End Sub

    Private blnMouseIsDown As Boolean = False
    Protected Overrides Sub OnMouseDown(ByVal e As System.Windows.Forms.MouseEventArgs)
        blnMouseIsDown = True
        Invalidate()
        MyBase.OnMouseDown(e)
    End Sub

    Protected Overrides Sub OnMouseUp(ByVal e As System.Windows.Forms.MouseEventArgs)
        blnMouseIsDown = False
        Dim intIndex As Integer = GetHoveredIndex(e.Location)
        If intIndex <> -3 Then
            FocusedIndex = GetIndex(intIndex)
        End If
        Dim intArrow As Integer = GetHoveredArrowIndex(e.Location)
        If intArrow = 0 Then
            MoveBackward()
        ElseIf intArrow = 1 Then
            MoveForward()
        End If
        MyBase.OnMouseUp(e)
    End Sub

    Private Function GetHoveredIndex(ByVal pntLoc As Point) As Integer
        For i As Integer = 0 To -2 Step -1
            If GetPictureBounds(i).Contains(pntLoc) Then
                Return i
            ElseIf GetPictureBounds(Math.Abs(i)).Contains(pntLoc) Then
                Return Math.Abs(i)
            End If
        Next
        Return -3
    End Function

    Private Function GetArrowBounds(ByVal intIndex As Integer) As Rectangle
        Select Case intIndex
            Case 0 'Left
                Return New Rectangle(CInt(Width / 2) - ArrowSize - 1, Height - 1 - ArrowSize, ArrowSize, ArrowSize)
            Case 1 'Right
                Return New Rectangle(CInt(Width / 2) + 1, Height - 1 - ArrowSize, ArrowSize, ArrowSize)
        End Select
    End Function

    Private Function GetHoveredArrowIndex(ByVal pntLoc As Point) As Integer
        For i As Integer = 0 To 1
            If GetArrowBounds(i).Contains(pntLoc) Then
                Return i
            End If
        Next
        Return -1
    End Function
End Class