圆角矩形不准确

Question

我发现使用GDI +绘制圆角矩形的每个示例代码都是这样的(从BobPowell.net中解除并略微修改):

  Private Sub Panel1_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) Handles Panel1.Paint
    e.Graphics.Clear(SystemColors.Window)
    e.Graphics.SmoothingMode = SmoothingMode.None

    Call DrawRoundRect(e.Graphics, Pens.Red, 10, 10, 48, 24, 6)
  End Sub

  Public Sub DrawRoundRect(ByVal g As Graphics, ByVal p As Pen, ByVal x As Single, ByVal y As Single, ByVal width As Single, ByVal height As Single, ByVal radius As Single)
    Using gp As New GraphicsPath()
      gp.StartFigure()
      gp.AddArc(x + width - radius, y, radius * 2, radius * 2, 270, 90)
      gp.AddArc(x + width - radius, y + height - radius, radius * 2, radius * 2, 0, 90)
      gp.AddArc(x, y + height - radius, radius * 2, radius * 2, 90, 90)
      gp.AddArc(x, y, radius * 2, radius * 2, 180, 90)
      gp.CloseFigure()
      g.DrawPath(p, gp)
    End Using
  End Sub

这会产生一个圆角矩形,只有左上角是准确的.

AntiAliasing必须关闭,因为它通过远程桌面连接,我不能依赖它可用.此外,我正在寻找一个清晰的圆角矩形.

我已经尝试调整其他角落的大小并更改笔对齐,但似乎没有任何东西可以产生简单,准确的圆角矩形.

有没有办法在旧的winforms中绘制比这更好的圆角矩形？

Answer 1

我发现最好的解决方案就是老式的 Windows API：

Private Sub DrawRoundRect(ByVal g As Graphics, ByVal r As Rectangle)
  Dim hDC As IntPtr = g.GetHdc
  Dim hPen As IntPtr = CreatePen(PS_SOLID, 0, ColorTranslator.ToWin32(Color.Red))
  Dim hOldPen As IntPtr = SelectObject(hDC, hPen)
  SelectObject(hDC, GetStockObject(NULL_BRUSH))
  RoundRect(hDC, r.Left, r.Top, r.Right - 1, r.Bottom - 1, 12, 12)
  SelectObject(hDC, hOldPen)
  DeleteObject(hPen)
  g.ReleaseHdc(hDC)
End Sub

这会产生我一直在寻找的对称圆角矩形：