GDI画图时的锯齿效果弱化



GDI画图时的锯齿效果弱化
当在画图时，图形有时会出现锯齿，可以使用SmoothingMode.AntiAlias来消除
代码如下：

g.SmoothingMode = SmoothingMode.AntiAlias;

使图像的边缘圆滑清晰锐化的可以试试FillPath
代码如下

g.FillPath((Brushes.Black), path);

或者是

针对于文本锯齿的话，可以采用TextRenderingHint
代码如下
          

 SolidBrush brush = new SolidBrush(Color.Green);
            e.Graphics.DrawString("ABCDEFGHIJKL", new Font("宋体", 15f), brush, 0, 20);
            //消除锯齿
            e.Graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
            e.Graphics.DrawString("ABCDEFGHIJKL", new Font("宋体", 15f), brush, 0, 50);
有时候使用Graphics.Clear()方法，会在图像上出现颗粒型的点，尽量不要采用Graphics.Clear()来填充区域，一般使用Graphics.FillPath();
有兴趣的可以尝试下下面的代码：
        public Form11()
        {
            InitializeComponent();
            this.BackColor = Color.Black;
            Method();
            this.Paint += Draw;
        }
        Bitmap bitmap1;
        private void Draw(object sender, PaintEventArgs e)
        {
            e.Graphics.DrawImage(bitmap1, 0, 0);
            e.Graphics.DrawString("ABCDEFGHIJKL", new Font("宋体", 15f), new SolidBrush(Color.Green), 0, 50); 
        }
        private void Method()
        {
            bitmap1 = new Bitmap(500, 500);
            Graphics g = Graphics.FromImage(bitmap1);
            GraphicsPath path = new GraphicsPath();
            //g.SmoothingMode = SmoothingMode.AntiAlias;  //使绘图质量最高，即消除锯齿
            //g.CompositingMode = CompositingMode.SourceCopy;
            //g.TextRenderingHint = TextRenderingHint.AntiAlias;

            
            int alpha = 1;
            for (int i = 20; i > 2; i--)
            {

                path.Reset();
                path.AddEllipse(20, 20, 50, 50);
                path.Widen(new Pen(Color.Black, i));
                g.SetClip(path);
                //g.Clear(Color.Black); // wrong
                g.ResetClip();
                //g.FillPath((Brushes.Black), path); // right
                g.FillPath(new SolidBrush(Color.FromArgb(alpha += 10, 255, 255, 255)), path);
            }
        }