简单绘图出来的图片很粗糙毛点多

[yrlxm]

   Dim objBitmap As New Bitmap(me_width, me_height)
        Dim objGraphic As Graphics = Graphics.FromImage(objBitmap)

        Dim redBrush As New SolidBrush(Color.Red)
        Dim blueBrush As New SolidBrush(Color.Blue)
        Dim greenBrush As New SolidBrush(Color.Green)
        Dim whiteBrush As New SolidBrush(Color.White)
        Dim bgBrush As New SolidBrush(System.Drawing.ColorTranslator.FromHtml("#E5F1F4"))

        Dim blackPen As New Pen(Color.Black, 2)
        Dim rect As New Rectangle(0, 0, me_width, me_height)
        '  Dim b3 As New LinearGradientBrush(rect, Color.Yellow, Color.Black, LinearGradientMode.Horizontal)

        objGraphic.FillRectangle(bgBrush, 0, 0, me_width, me_height)

[yrlxm]

[exception92]

WPF么？？？

[yrlxm]

再次求教。。。。