vb.net - 圆角矩形不准确

我找到的每个使用GDI +绘制圆角矩形的示例代码都是这样的(从BobPowell.net提起并稍作修改):

  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

这将生成一个圆角矩形，其中只有左上角是准确的。

必须关闭AntiAliasing，因为它正在通过远程桌面连接，而我不能依靠它的可用性。此外，我正在寻找一个清晰的圆角矩形。

我尝试调整其他角的大小并更改笔的对齐方式，但是似乎没有任何方法可以生成简单，准确的圆角矩形。

在良好的旧winform中，是否有办法绘制比此更好的圆角矩形？

最佳答案

1)将源图像的大小调整为原始大小的二进制倍数。通常，我将重新采样宽度和高度到原始宽度的4倍(或8或16)。

2)执行我的所有GDI +绘图操作(当然，请考虑将我的坐标乘以4的系数)。无需使用任何花哨的抗锯齿功能。

3)将图像重新采样回原始尺寸。缩小图像可获得良好的平滑效果，并最大程度地减少了线条，曲线等中的舍入误差。

private Bitmap GenerateButton(int overSampling) {

    int overSampling = 8;
    int width=(48 + 10 + 10 + 6) * overSampling;
    int height=(24 + 10 + 10 + 6) * overSampling;

    // Draw the button with the rounded corners, but do
    // so at 8 times the normal size.
    Bitmap bitmap=new Bitmap(width,height);
    using (Graphics g = Graphics.FromImage(bitmap)) {
        g.Clear(Color.White);
        g.SmoothingMode = SmoothingMode.None;
        DrawRoundRect(overSampling, g, new Pen(Color.Red, overSampling), 10, 10, 48, 24, 6);
    }

    // Shrink the image down to its intended size
    Bitmap shrunkVersion=new Bitmap(bitmap.Width / overSampling, bitmap.Height / overSampling);
    using (Graphics g = Graphics.FromImage(shrunkVersion)) {
        // Use hi-quality resampling for a nice, smooth image.
        g.InterpolationMode = InterpolationMode.HighQualityBicubic;
        g.DrawImage(bitmap, 0, 0, shrunkVersion.Width, shrunkVersion.Height);
    }

    return shrunkVersion;
}

private void DrawRoundRect(int overSampling, Graphics g, Pen p, float x, float y, float width, float height, float radius)
{
    using (GraphicsPath gp = new GraphicsPath())
    {
        gp.StartFigure();
        gp.AddArc((x + width - radius) * overSampling, y * overSampling, (radius * 2) * overSampling, (radius * 2) * overSampling, 270, 90);
        gp.AddArc((x + width - radius) * overSampling, (y + height - radius) * overSampling, (radius * 2) * overSampling, (radius * 2) * overSampling, 0, 90);
        gp.AddArc(x * overSampling, (y + height - radius) * overSampling, radius * 2 * overSampling, radius * 2 * overSampling, 90, 90);
        gp.AddArc(x * overSampling, y * overSampling, radius * 2 * overSampling, radius * 2 * overSampling, 180, 90);
        gp.CloseFigure();
        g.DrawPath(p, gp);
    }
}

没有过度采样:

进行8次过采样:

关于vb.net - 圆角矩形不准确，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/6060525/