C# 实现屏幕截图

 

//创建用户控件

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace CutDrawing
{
    public partial class Catch : Form
    {
        public Catch()
        {
            InitializeComponent();
        }
        #region 用户变量
        //记录鼠标按下坐标，确定绘图起点
        private Point DownPoint = Point.Empty;
        //截图完成
        private bool CatchFinished = false;
        //截图开始
        private bool CatchStart = false;
        //保存原始图像
        private Bitmap originBmp;
        //保存截图的矩形
        private Rectangle CatchRect;
        #endregion

        private void Catch_Load(object sender, EventArgs e)
        {
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint, true);
            this.UpdateStyles();
            //BackgroundImage为全屏图片，我们另用变量来保存全屏图片
            originBmp = new Bitmap(this.BackgroundImage);
        }

        private void Catch_MouseClick(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right)
            {
                this.DialogResult = DialogResult.OK;
                this.Close();
            }
        }

        private void Catch_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                //如果捕捉没有开始
                if (!CatchStart)
                {
                    CatchStart = true;
                    //保存鼠标按下坐标
                    DownPoint = new Point(e.X, e.Y);
                }
            }
        }

        private void Catch_MouseMove(object sender, MouseEventArgs e)
        {
            //如果捕捉开始
            if (CatchStart)
            {
                //新建一个图片对象，并让它与原始图片相同
                Bitmap destBmp = (Bitmap)originBmp.Clone();
                //获取鼠标的坐标
                Point newPoint = new Point(DownPoint.X, DownPoint.Y);
                //在刚才新建的图片上新建一个画板
                Graphics g = Graphics.FromImage(destBmp);
                //获取画笔对象
                Pen pen = new Pen(Color.Blue, 1);
                //获取矩形的长和宽
                int width = Math.Abs(e.X - DownPoint.X);
                int height = Math.Abs(e.Y - DownPoint.Y);
                //判断矩形的起始坐标
                if (e.X < DownPoint.X)
                    newPoint.X = e.X;
                if (e.Y < DownPoint.Y)
                    newPoint.Y = e.Y;
                //保存矩形
                CatchRect = new Rectangle(newPoint, new Size(width, height));
                //将矩形花在这个画板上
                g.DrawRectangle(pen, CatchRect);
                //释放这个画板
                g.Dispose();
                //重新创建一个Graphics类
                Graphics g1 = this.CreateGraphics();
                //如果之前那个画板不释放，而直接g=this.CreateGraphics()这样的话无法释放掉第一次创建的g,因为只是把地址转到新的g了，如同string一样。
                //将刚才所画的图片画到这个窗体上
                g1.DrawImage(destBmp, new Point(0, 0));
                //这个也可以属于二次缓冲技术，如果直接将矩形画在窗体上，会造成图片抖动并且会有无数个矩形
                //释放这个画板
                g1.Dispose();
                //释放掉Bmp对象。
                destBmp.Dispose();
                //要及时释放不会再次使用的对象，不然内存将会被大量消耗
            }
        }

        private void Catch_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                //如果已经开始绘制
                if (CatchStart)
                {
                    //将开始绘制设为false
                    CatchStart = false;
                    //完成绘制设为true
                    CatchFinished = true;
                }
            }
        }

        private void Catch_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left && CatchFinished)
            {
                if (CatchRect.Contains(new Point(e.X, e.Y)))
                {
                    //新建一个与矩形等大的空白图片
                    Bitmap catchedBmp = new Bitmap(CatchRect.Width, CatchRect.Height);
                    //在空白图片上新建一个画板
                    Graphics g = Graphics.FromImage(catchedBmp);
                    //将origin中的指定部分按照指定大小画在画板上
                    g.DrawImage(originBmp, new Rectangle(0, 0, CatchRect.Width, CatchRect.Height), CatchRect, GraphicsUnit.Pixel);
                    //将图片保存到剪贴板上
                    Clipboard.SetImage(catchedBmp);
                    //释放Graphics对象
                    g.Dispose();
                    //完成一次操作
                    CatchFinished = false;
                    //将背景图片设置为originBmp中的图片
                    this.BackgroundImage = originBmp;
                    //释放新图片对象
                    catchedBmp.Dispose();
                    this.DialogResult = DialogResult.OK;
                    this.Close();
                }
            }
        }
    }
}

//主窗体截图按钮方法

private void btnCatch_Click(object sender, EventArgs e)
{
//隐藏当前窗体
this.Hide();
//让线程睡眠一段时间，窗体消失需要一点时间
Thread.Sleep(50);
Catch catchForm = new Catch();
//新建一个和屏幕大小相同的图片
Bitmap CatchBmp = new Bitmap(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height);
//在新图片上创建一个画布
Graphics g = Graphics.FromImage(CatchBmp);
//保存全屏图片
g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height));
//将Catch窗体的背景设为全屏时的图片
catchForm.BackgroundImage = CatchBmp;

if (catchForm.ShowDialog() == DialogResult.OK)
{
//如果Catch窗体结束，就将剪贴板中的图片放到信息发送框中
IDataObject iData = Clipboard.GetDataObject();
DataFormats.Format myFormat = DataFormats.GetFormat(DataFormats.Bitmap);
if (iData.GetDataPresent(DataFormats.Bitmap))
{
rtxtMessage.Paste(myFormat);
//清楚剪切板中的对象
Clipboard.Clear();
}
//再次显示此窗体
this.Show();
}
}