Picturebox with round corners without serration?

Question

What I need to do is a PictureBox that has rounded corners, but the problem is that I can’t make them round without serrations.

One of the ways I found it was by using the property Region:

 Private Function GetRoundedRect(ByVal retangulo As RectangleF, ByVal raio As Single) As GraphicsPath
    ' Se o raio do arco for maior ou igual à metada da largura ou altura do retângulo
    ' retorna um objeto no formato de capsula.
    If raio >= (Math.Min(retangulo.Width, retangulo.Height) / 2.0) Then
        Return GetCapsule(retangulo)
    End If

    Dim diametro As Single = raio + raio
    Dim arcRect As New RectangleF(retangulo.Location, New SizeF(diametro, diametro))
    Dim gp As New GraphicsPath()

    ' Arco superior esquerdo.
    gp.AddArc(arcRect, 180, 90)

    ' Arco superior direito.
    arcRect.X = retangulo.Right - diametro
    gp.AddArc(arcRect, 270, 90)

    ' Arco inferior direito.
    arcRect.Y = retangulo.Bottom - diametro
    gp.AddArc(arcRect, 0, 90)

    ' Arco inferior esquerdo
    arcRect.X = retangulo.Left
    gp.AddArc(arcRect, 90, 90)

    gp.CloseFigure()
    Return gp
End Function

Private Function GetCapsule(ByVal retangulo As RectangleF) As GraphicsPath
    Dim diametro As Single
    Dim arcRect As RectangleF
    Dim gp As New GraphicsPath()
    Try

        If retangulo.Width > retangulo.Height Then
            ' Capsula horizontal
            diametro = retangulo.Height
            arcRect = New RectangleF(retangulo.Location, New SizeF(diametro, diametro))
            gp.AddArc(arcRect, 90, 180)
            arcRect.X = retangulo.Right - diametro
            gp.AddArc(arcRect, 270, 180)
        ElseIf retangulo.Height > retangulo.Width Then
            ' Capsula horizontal
            diametro = retangulo.Width
            arcRect = New RectangleF(retangulo.Location, New SizeF(diametro, diametro))
            gp.AddArc(arcRect, 180, 180)
            arcRect.Y = retangulo.Bottom - diametro
            gp.AddArc(arcRect, 0, 180)
        Else
            ' Circulo
            gp.AddEllipse(retangulo)
        End If
    Catch e As Exception
        gp.AddEllipse(retangulo)
    Finally
        gp.CloseFigure()
    End Try

    Return gp
End Function

How I used:

 Protected Overrides Sub OnPaint(e As PaintEventArgs)

    Me.Region = New System.Drawing.Region(GetRoundedRect(New RectangleF(0, 0, Width, Height), 20))

    MyBase.OnPaint(e)
End Sub

This works, but generates serrated corners:

So I thought I’d do the same thing using the Graphics. What I tried to do was delimit the area where the image would appear leaving the rest with the color of Background of the control where the Picturebox was.

Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
    ' Qualidade
    e.Graphics.CompositingQuality = CompositingQuality.HighQuality
    e.Graphics.SmoothingMode = SmoothingMode.HighQuality
    e.Graphics.CompositingMode = CompositingMode.SourceOver
    e.Graphics.InterpolationMode = InterpolationMode.HighQualityBilinear


    Dim Fonte As Bitmap = ImaList(0)

    Dim f As GraphicsPath = GetRoundedRect(New RectangleF(0, 0, PictureBox1.Width, PictureBox1.Height), 20)
    Dim borderPen As New Pen(PictureBox1.Parent.BackColor, 1) With {
        .Alignment = PenAlignment.Outset
    }

    ' Cria limite para área do desenho
    e.Graphics.Clip = New Region(f)

    ' Desenha a imagem
    e.Graphics.DrawImage(Fonte, 0, 0, PictureBox1.Width, PictureBox1.Height)

    'Aplica uma bordar para nao ficar serrilhado
    e.Graphics.DrawPath(borderPen, f)

End Sub

The result is good, it no longer gets the serrated, but when trying to put a label same as the previous image it looks the same as the bottom of the image.

So what I wanted to know is how can I leave the rounded edges without serration, taking into account the controls that are inside it? Just remembering that the label has an animation of going up and down, so I need events to work normally.

Answer 1

Lucas Pedro, try using the "Antialias". It would be something like this:

 // Set the SmoothingMode property to smooth the line.
    e.Graphics.SmoothingMode = 
        System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

See also:

Graphics.Smoothingmode Property

Antialiasing for Drawing2d.Graphicspath

How to make Smooth round Ellipse form?