Vb.net图像蒙版沿边缘平滑

Question

大家好，我正在尝试通过使用蒙版来使我的图像看起来漂亮和平滑（抗锯齿），以便制作如下所示的圆形图像：

原图如下：

上图的蒙版是这样的（红色是要取出的蒙版颜色）：

它有效，但它给了我那些不太好的锯齿状边缘。掩码是 .png，图像本身也是 .png。

我用来制作面具的代码是这样的：

picNextTopic1.Image = Image.FromStream(wc.OpenRead(anAPI.wallOrgPostImage(keying).Replace("{width}", "50").Replace("{height}", "50"))) 'Download the image from the website.                  
picNextTopic1.Image = ApplyMask(New Bitmap(picNextTopic1.Image), New Bitmap(My.Resources.mask), Color.Red) 'Apply mask to the downloaded image above.

ApplyMask 函数是这样的：

Public Function ApplyMask(ByVal bImg As Bitmap, ByVal bMask As Bitmap, ByVal maskColor As Color) As Image
    Dim wImg As Integer = bImg.Width
    Dim hImg As Integer = bImg.Height
    Dim wMask As Integer = bMask.Width
    Dim hMask As Integer = bMask.Height
    Dim intMask As Integer = maskColor.ToArgb
    Dim intTransparent As Integer = Color.Transparent.ToArgb

    Using fpImg As New FastPix(bImg)
        Using fpMask As New FastPix(bMask)
            Dim pixelsImg = fpImg.PixelArray
            Dim pixelsMask = fpMask.PixelArray

            For y As Integer = 0 To Math.Min(hImg, hMask) - 1
                For x As Integer = 0 To Math.Min(wImg, wMask) - 1
                    Dim iImg As Integer = (y * wImg) + x
                    Dim iMask As Integer = (y * wMask) + x

                    If pixelsMask(iMask) = intMask Then
                        pixelsImg(iImg) = intTransparent
                    End If
                Next
            Next
        End Using
    End Using

    Return bImg
End Function

使用 FastPix 发现 here。

任何帮助解决这个问题都会很棒！谢谢！

更新 我拥有的透明表单代码：

Public Sub InitializeMyForm()
    BackColor = Color.Plum
    TransparencyKey = BackColor
End Sub

Answer 1

玩弄这个，我确实设法使用 TextureBrush 以这种方式制作了一个平滑的图像：

Dim profile As Image = Image.FromFile("c:\...\profile.png")

Protected Overrides Sub OnPaint(e As PaintEventArgs)
  e.Graphics.Clear(Color.SteelBlue)
  e.Graphics.SmoothingMode = SmoothingMode.AntiAlias
  Using tb As New TextureBrush(profile)
    tb.TranslateTransform(120, 64)
    Using p As New GraphicsPath
      p.AddEllipse(120, 64, profile.Width, profile.Width)
      e.Graphics.FillPath(tb, p)
    End Using
  End Using
  MyBase.OnPaint(e)
End Sub

TranslateTransform 和 AddEllipse 位置使用相同的点信息来适当地“居中”纹理画笔。

结果：