.NET : 如何利用GDI+绘制折线图

来源：互联网发布：em算法python实现编辑：程序博客网时间：2024/05/16 08:29

这是今天课堂上讲的一个范例小程序。 其实很多图表控件大多也是这样画出来的。

            //如何从零开始构造一个图片            Bitmap b = new Bitmap(600, 400);            Graphics bg = Graphics.FromImage(b);            //背景颜色先清除掉            bg.Clear(Color.LightGray);            //先画横轴            bg.DrawLine(                new Pen(Color.Black),                new Point(10, 380),                new Point(580, 380));            bg.DrawLine(                new Pen(Color.Black),                new Point(570, 370),                new Point(580, 380));            bg.DrawLine(                new Pen(Color.Black),                new Point(570, 390),                new Point(580, 380));            //再画纵轴            bg.DrawLine(                new Pen(Color.Black),                new Point(20, 390),                new Point(20, 20));            bg.DrawLine(                new Pen(Color.Black),                new Point(10, 30),                new Point(20, 20));            bg.DrawLine(                new Pen(Color.Black),                new Point(30, 30),                new Point(20, 20));            //画我们那条趋势线            List points = new List()            {                new Point(20,380),                new Point(40,365),                new Point(55,350),                new Point(100,300),                new Point(200,120),                new Point(570,30)};            bg.DrawLines(                new Pen(Color.Red),                points.ToArray());            foreach (var item in points)            {                item.Offset(-10, -10);                bg.FillEllipse(                    new SolidBrush(Color.Yellow),                    new Rectangle(item,new Size(20,20)));                item.Offset(5, 5);                bg.DrawString(                    item.Y.ToString(),                    new Font("Arial", 6),                    new SolidBrush(Color.Blue),                    item);            }            bg.Dispose();            b.Save("demo.bmp");

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