winform GDI基础（二）画带圆角的矩形框

private void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.SmoothingMode = SmoothingMode.HighQuality;//去掉锯齿
g.CompositingQuality = CompositingQuality.HighQuality;//合成图像的质量
g.TextRenderingHint = TextRenderingHint.SingleBitPerPixelGridFit;//去掉文字的锯齿
System.Drawing.Pen p = new System.Drawing.Pen(Color.FromArgb(255, 146, 126, 102), 2); drawRoundedRect(g, p, 20, 20, 200, 200, 20);
} /// <summary>
/// 带圆角矩形
/// </summary>
/// <param name="radius">圆角半径</param>
private void drawRoundedRect(Graphics g, System.Drawing.Pen pen, int x, int y, int width, int height, int radius)
{
//去掉圆角的锯齿
g.SmoothingMode = SmoothingMode.HighQuality; //上
g.DrawLine(pen, new PointF(x + radius, y), new PointF(x + width - radius, y));
//下
g.DrawLine(pen, new PointF(x + radius, y + height), new PointF(x + width - radius, y + height));
//左
g.DrawLine(pen, new PointF(x, y + radius), new PointF(x, y + height - radius));
//右
g.DrawLine(pen, new PointF(x + width, y + radius), new PointF(x + width, y + height - radius)); //左上角
g.DrawArc(pen, new Rectangle(x, y, radius * 2, radius * 2), 180, 90);
//右上角
g.DrawArc(pen, new Rectangle(x + width - radius * 2, y, radius * 2, radius * 2), 270, 90);
//左下角
g.DrawArc(pen, new Rectangle(x, y + height - radius * 2, radius * 2, radius * 2), 90, 90);
//右下角
g.DrawArc(pen, new Rectangle(x + width - radius * 2, y + height - radius * 2, radius * 2, radius * 2), 0, 90);
}