用.net GDI+制作时钟

GDI+ 是 Windows XP 操作系统中提供二维矢量图形、图像处理和版式的部分。GDI+ 在 GDI（较早版本的 Windows 中提供的 Graphics Device Interface）的基础上进行了改进，添加了新功能并优化了现有功能。

利用GDI+可以很方面的画图绘图，并且也能很方便地操作图形数据。下面本人以一个简单的例子来展示如果用C#和GDI+来制作一个时钟。

运行结果如下：

程序代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Text;
using System.Threading;
using System.Windows.Forms;

namespace Clock
{
    public partial class MainForm : Form
    {
        private PointF center;
        private float r;
        private Pen hourPen;
        private Pen minutePen;
        private Pen secondPen;
        private Thread timeThread;

        public MainForm()
        {
            InitializeComponent();
            ShowInTaskbar = false;//不在任务栏中显示
            SetStyle(ControlStyles.DoubleBuffer, true);
            SetStyle(ControlStyles.UserPaint,true);
            SetStyle(ControlStyles.AllPaintingInWmPaint,true);

            center = new PointF(ClientSize.Width/ 2.0f, ClientSize.Height/ 2.0f);
            r = Math.Min(ClientSize.Width / 2.0f, ClientSize.Height / 2.0f);
            hourPen = new Pen(Color.Black, 2.5f);
            minutePen = new Pen(Color.Black, 1.5f);
            secondPen = new Pen(Color.Black, 0.5f);
            timeThread=new Thread(new ThreadStart(DrawTime));
            timeThread.Start();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.Clear(BackColor);
            //g.SmoothingMode = SmoothingMode.AntiAlias;
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.DrawArc(secondPen, new RectangleF(center.X - r, center.Y - r, 2 * r-3, 2 * r-3), 0, 360);

            GraphicsPath round = new GraphicsPath();
            round.AddArc(new RectangleF(center.X - r, center.Y - r, 2 * r - 3, 2 * r - 3), 0, 360);
            Region = new Region(round);

            Pen pen=new Pen(Color.Blue,3.0f);
            for (int i = 0; i < 59; i++)
            {
                g.ResetTransform();
                g.TranslateTransform(center.X, center.Y);
                g.RotateTransform(i * 6);
                if ((i == 0) || (i % 5 == 4))
                {
                    g.DrawLine(hourPen, r - 12, 0, r - 5, 0);
                }
                else
                {
                    g.DrawLine(secondPen, r - 6, 0, r - 5, 0);
                }
            }
            
            
            float hour,minute,second;
            hour=DateTime.Now.Hour;
            minute=DateTime.Now.Minute;
            second=DateTime.Now.Second;
            hour=hour+minute/60f+second/3600f;
            minute=minute+second/60f;
            //画时针
            g.ResetTransform();
            g.TranslateTransform(center.X, center.Y);
            g.RotateTransform(hour * 30+270-6);
            g.DrawLine(hourPen, 0, 0, r * 0.5f, 0f);
            //画分针
            g.ResetTransform();
            g.TranslateTransform(center.X, center.Y);
            g.RotateTransform(minute * 6+270-6);
            g.DrawLine(minutePen, 0, 0, r * 0.6f, 0f);
            //画秒针
            g.ResetTransform();
            g.TranslateTransform(center.X, center.Y);
            g.RotateTransform(second * 6+270-6);
            g.DrawLine(secondPen, 0, 0, r * 0.7f, 0f);
            base.OnPaint(e);
        }

        private void DrawTime()
        {
            while (true)
            {
                Invalidate();
                Thread.Sleep(900);//为避免某些延时影响，900ms画一次时钟指针
            }
        }

        protected void Dispose(object sender,EventArgs e)
        {
            Dispose();
            base.Dispose(Disposing);
            Application.Exit();
        }

        private void tsmExit_Click(object sender, EventArgs e)
        {
            Close();
            Dispose();
            base.Dispose(Disposing);
            Application.Exit();
        }
    }
}

程序代码比较简单，而且也做了注释，估计大家都看得懂，我就不罗唆了。以后有时间再做难度稍大一点的例子。