绘制椭圆时平滑曲线

Question

我正在尝试将图片框画成圆形，这是我的代码：

Private WithEvents pParent As ThumbControl
    Sub New(ByVal pnParent As ThumbControl, ByVal Path As String, Optional ByVal DataString As String = "")
        pParent = pnParent
        strPath = Path
        strData = DataString
        Me.SizeMode = Windows.Forms.PictureBoxSizeMode.StretchImage
        Me.Size = New Size(100, 100)

        Dim gp As New System.Drawing.Drawing2D.GraphicsPath()
        gp.AddEllipse(0, 0, Me.Width - 3, Me.Height - 3)
        Dim rg As New Region(gp)

        Me.Region = rg
End Sub

绘画方法：

Protected Overrides Sub OnPaint(ByVal pe As System.Windows.Forms.PaintEventArgs)
    MyBase.OnPaint(pe)
    If Not bSelected Then
        If pParent.HighLightMode = iHighliteMode.GlassAndForeGround Then
            If bOver Then
                Dim rc As New Rectangle(0, 0, 100, 100)
                Dim rc1 As New Rectangle(0, 0, 100, 50)
                pe.Graphics.FillEllipse(New SolidBrush(Color.FromArgb(100, pParent.Highlight.R, pParent.Highlight.G, pParent.Highlight.B)), rc)
                Dim br As New System.Drawing.Drawing2D.LinearGradientBrush(rc1, Color.FromArgb(180, 255, 255, 255), Color.FromArgb(80, 255, 255, 255), Drawing2D.SmoothingMode.AntiAlias)
                pe.Graphics.FillEllipse(br, rc1)
            End If

        ElseIf pParent.HighLightMode = iHighliteMode.BackGroundOnly Then
            If bOver Then
                Dim rc1 As New Rectangle(-2, -2, 100, 100)
                Dim br As New System.Drawing.Drawing2D.LinearGradientBrush(rc1, Color.FromArgb(180, 255, 255, 255), Color.FromArgb(80, 255, 255, 255), Drawing2D.SmoothingMode.AntiAlias)
                pe.Graphics.FillEllipse(br, rc1)
            End If
        ElseIf pParent.HighLightMode = iHighliteMode.GlassOnly Then
            If bOver Then
                Dim rc1 As New Rectangle(0, 0, 100, 100)
                Dim br As New System.Drawing.Drawing2D.LinearGradientBrush(rc1, Color.FromArgb(180, 255, 255, 255), Color.FromArgb(80, 255, 255, 255), Drawing2D.SmoothingMode.AntiAlias)
                pe.Graphics.FillEllipse(br, rc1)
            End If
        ElseIf pParent.HighLightMode = iHighliteMode.GlassAndBackGround Then
            If bOver Then
                Dim rc1 As New Rectangle(0, 0, 100, 100)
                Dim br As New System.Drawing.Drawing2D.LinearGradientBrush(rc1, Color.FromArgb(180, 255, 255, 255), Color.FromArgb(80, 255, 255, 255), Drawing2D.SmoothingMode.AntiAlias)
                pe.Graphics.FillEllipse(br, rc1)
            End If
        End If
        'Dim irc1 As New Rectangle(0, 0, 90, 100)
        'pe.Graphics.DrawEllipse(New Pen(pParent.SelectedColor, 1), irc1)
    End If

    'If bSelected Then
    '    Dim irc As New Rectangle(0, 0, 90, 90)
    '    pe.Graphics.DrawEllipse(New Pen(pParent.SelectedColor, 2), irc)
    'End If
End Sub

Protected Overrides Sub OnPaintBackground(ByVal pevent As System.Windows.Forms.PaintEventArgs)
    MyBase.OnPaintBackground(pevent)
    If Not bSelected Then
        If pParent.HighLightMode = iHighliteMode.GlassAndBackGround Then
            If bOver Then
                'Dim rc As New Rectangle(0, 0, 180, 150)
                'Dim rc1 As New Rectangle(0, 0, 100, 80)
                'pevent.Graphics.FillEllipse(New SolidBrush(Color.FromArgb(100, pParent.Highlight.R, pParent.Highlight.G, pParent.Highlight.B)), rc)
                'Dim br As New System.Drawing.Drawing2D.LinearGradientBrush(rc1, Color.FromArgb(180, 255, 255, 255), Color.FromArgb(80, 255, 255, 255), Drawing2D.LinearGradientMode.Vertical)
                'pevent.Graphics.FillRectangle(br, rc1)
            End If
        ElseIf pParent.HighLightMode = iHighliteMode.BackGroundOnly Then
            If bOver Then
                Dim rc As New Rectangle(0, 0, 90, 100)
                Dim rc1 As New Rectangle(0, 0, 100, 80)
                pevent.Graphics.FillEllipse(New SolidBrush(Color.FromArgb(100, pParent.Highlight.R, pParent.Highlight.G, pParent.Highlight.B)), rc)
                Dim br As New System.Drawing.Drawing2D.LinearGradientBrush(rc1, Color.FromArgb(180, 255, 255, 255), Color.FromArgb(80, 255, 255, 255), Drawing2D.SmoothingMode.AntiAlias)

            End If
        End If
    End If
End Sub

我得到一条非平滑曲线，如下所示：

如何获得平滑的圆角曲线

Answer 1

在绘制椭圆之前，设置SmoothingMode，例如

Dim grp As Graphics = PictureBox1.CreateGraphics
grp.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
grp.FillEllipse(Brushes.Blue, New Rectangle(0, 0, 100, 100))