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);
}
}