截图小工具开发笔记

一、开发环境及工具

Windows 7 系统，开发软件为Microsoft Visual Studio Ultimate 2012

二、实现的功能

屏幕截屏，保存到图片或者保存到剪切板。截屏范围可以随意移动或者改变大小，自由度很高。先预览一下效果：

三、实现原理

共2个窗体，1个是主窗体，主要功能进行热键设置，抓取屏幕到图片传给另一个窗体，另一个窗体对传过来的图片继续截取等操作。

四、开发手记

1.新建winform项目

2.主界面设计如图:

窗体主要属性设置如下：

//窗口样式
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
//窗口图标
  this.Icon = ((System.Drawing.Icon)(resources.GetObject("$this.Icon")));
//禁止最大化            
this.MaximizeBox = false;
//窗口名称
 this.Name = "PicCut";
//窗口初始位置为屏幕中心
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
//窗口标题为“截图设置”
this.Text = "截图设置";
//窗口浮在所有窗口上面
 this.TopMost = true;

此窗口内主要包括2个label控件，1个ComboBox和1个PictureBox，摆放位置如上图。label用于显示文字说明；ComboBox用于显示热键0—9个数字供选择；PictureBox用于显示二维码图片。

3.主界面的主要功能是对热键进行设置，同时我们程序运行，该界面自动最小化到托盘，双击进行截图，有机显示上述主界面进行设置，设置完毕可以最小化自动到托盘，点击关闭程序会自动退出。

 

（1）自动到托盘

主界面拖入“notifyIcon”，主要属性设置如下图，其中Text是鼠标滑动到拖盘区域图标上的提示；Icon是托盘图标；Visible设置为false，默认不显示托盘区域图标。

 

 

主要程序代码。窗体载入时，最小化窗体，同时设置ComboBox空间的默认值。

private void PicCut_Load(object sender, EventArgs e)
{
     this.WindowState = FormWindowState.Minimized;       
     NumberCbox.SelectedIndex = CutPicSet.Default.KeyNumber;            
}

窗口大小发生变化时，如果窗口最小化，隐藏当前窗体，托盘区域显示图标。

private void PicCut_SizeChanged(object sender, EventArgs e)
 {
           if (this.WindowState == FormWindowState.Minimized)
            {
                 this.Hide();
                MinNot.Visible = true;   
            }
 }

上述两段代码实现了，程序开始运行时候，窗口最小化隐藏，同时托盘区域显示图标。

（2）托盘图标左键双击进行截图操作

private void MinNot_MouseDoubleClick(object sender, MouseEventArgs e)
{
      if (e.Button==MouseButtons.Left)
     {
       //显示截图窗体
        ShowCutPic();
      }
}

ShowCutPic函数：

protected void ShowCutPic()
        {
            // 创建的空白图片和屏幕大小一样大的图片
            Bitmap CatchBmp = new Bitmap(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height);            
            // 我们可以通过Graphics这个类在这个空白图片上画图
            Graphics g = Graphics.FromImage(CatchBmp);
            // 把屏幕图片拷贝到我们创建的空白图片 CatchBmp中
            g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height));
            //这个我们截图的窗体创建截图窗体
            cutter = new CutPic();
             // 截图窗体的图片属性设置我们刚才新建的图片;
            cutter.Image = CatchBmp;
           //显示窗体
            cutter.ShowDialog();
        }

 

（3）托盘图标右键单击显示界面设置

 private void MinNot_MouseClick(object sender, MouseEventArgs e)
        {
            if (e.Button== MouseButtons.Right)
            {
//显示主窗体
                this.Show();
//隐藏托盘图标
                MinNot.Visible = false;
//当前窗口普通设置
                this.WindowState = FormWindowState.Normal;               
            }
                   
        }

（4）热键设置

/// <summary>
        /// 如果函数执行成功，返回值不为0。
        /// 如果函数执行失败，返回值为0。要得到扩展错误信息，调用GetLastError。
        /// </summary>
        /// <param name="hWnd">要定义热键的窗口的句柄</param>
        /// <param name="id">定义热键ID（不能与其它ID重复）</param>
        /// <param name="fsModifiers">标识热键是否在按Alt、Ctrl、Shift、Windows等键时才会生效</param>
        /// <param name="vk">定义热键的内容</param>
        /// <returns></returns>
        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool RegisterHotKey(IntPtr hWnd, int id, KeyModifiers fsModifiers, Keys vk);

        /// <summary>
        /// 注销热键
        /// </summary>
        /// <param name="hWnd">要取消热键的窗口的句柄</param>
        /// <param name="id">要取消热键的ID</param>
        /// <returns></returns>
        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool UnregisterHotKey(IntPtr hWnd, int id);

        /// <summary>
        /// 辅助键名称。
        /// Alt, Ctrl, Shift, WindowsKey
        /// </summary>
        [Flags()]
        public enum KeyModifiers { None = 0, Alt = 1, Ctrl = 2, Shift = 4, WindowsKey = 8 }

        /// <summary>
        /// 注册热键
        /// </summary>
        /// <param name="hwnd">窗口句柄</param>
        /// <param name="hotKey_id">热键ID</param>
        /// <param name="keyModifiers">组合键</param>
        /// <param name="key">热键</param>
        public static void RegHotKey(IntPtr hwnd, int hotKeyId, KeyModifiers keyModifiers, Keys key)
        {
            if (!RegisterHotKey(hwnd, hotKeyId, keyModifiers, key))
            {
                int errorCode = Marshal.GetLastWin32Error();
                if (errorCode == 1409)
                {
                    MessageBox.Show("热键被占用 ！");
                }
                else
                {
                    MessageBox.Show("注册热键失败！错误代码：" + errorCode);
                }
            }
        }

        /// <summary>
        /// 注销热键
        /// </summary>
        /// <param name="hwnd">窗口句柄</param>
        /// <param name="hotKey_id">热键ID</param>
        public static void UnRegHotKey(IntPtr hwnd, int hotKeyId)
        {
            //注销指定的热键
            UnregisterHotKey(hwnd, hotKeyId);
        }

private const int WM_HOTKEY = 0x312; //窗口消息-热键
        private const int WM_CREATE = 0x1; //窗口消息-创建
        private const int WM_DESTROY = 0x2; //窗口消息-销毁
        private const int Space = 0x3572; //热键ID
        protected override void WndProc(ref Message m)
        {
            base.WndProc(ref m);
            switch (m.Msg)
            {
                case WM_HOTKEY: //窗口消息-热键ID
                    switch (m.WParam.ToInt32())
                    {
                        case Space: //热键ID
//按下热键显示截图窗体
                            ShowCutPic();
                            break;
                        default:
                            break;
                    }
                    break;
                case WM_CREATE: //窗口消息-创建
                    SetHotKey(CutPicSet.Default.KeyNumber);
                    break;
                case WM_DESTROY: //窗口消息-销毁
                    UnRegHotKey(Handle, Space); //销毁热键
                    break;
                default:
                    break;
            }
        }

        public void SetHotKey(int keynumber)
        {
            if (keynumber == 0)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D0);
            }
            else if (keynumber == 1)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D1);
            }
            else if (keynumber == 2)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D2);
            }
            else if (keynumber == 3)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D3);
            }
            else if (keynumber == 4)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D4);
            }
            else if (keynumber == 5)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D5);
            }
            else if (keynumber == 6)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D6);
            }
            else if (keynumber == 7)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D7);
            }
            else if (keynumber == 8)
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D8);
            }
            else
            {
                RegHotKey(Handle, Space, KeyModifiers.Ctrl, Keys.D9);
            }
        }

 （5）图形热键设置

 private void NumberCbox_SelectedIndexChanged(object sender, EventArgs e)
        {
//把配置文件设置NumberCbox的选择值
            CutPicSet.Default.KeyNumber = NumberCbox.SelectedIndex;
            CutPicSet.Default.Save();
//先卸载原来注册的热键
            UnRegHotKey(Handle, Space);
//从新设置选择的热键
            SetHotKey(NumberCbox.SelectedIndex);
        }

4、截图界面设计

新建窗体CutPic，名称与之前的名称相对应，主要属性设置如下：

Name：CutPic

WindowState:Maximized

TopMost:true

FormBorderStyle:None

5、截图功能实现

主要代码如下：

 private Point m_ptStart;        //起始点位置
        private Point m_ptCurrent;      //当前鼠标位置
        private Point m_ptTempForMove;  //移动选框的时候临时用
        private Rectangle m_rectClip;   //限定鼠标活动的区域
        private Rectangle[] m_rectDots = new Rectangle[8];  //八个控制点
        protected bool m_bMoving;
        protected bool m_bChangeWidth;
        protected bool m_bChangeHeight;
        protected bool m_bMouseHover;
        private bool _IsDrawed; /// 获取当前是否已经选择区域
        private Image _Image;
        ///
        /// 要裁剪的图像
        ///
        [Description("要裁剪的图像"), Category("Customs")]
        public Image Image
        {
            get { return _Image; }
            set
            {
                if (value == this._Image) return;
                _Image = value;
             //   this.Clear();
            }
        }
        private Color _MaskColor = Color.FromArgb(125, 0, 0, 0);
        ///
        /// 遮罩颜色
        ///
        [Description("遮罩颜色"), Category("Customs")]
        public Color MaskColor
        {
            get { return _MaskColor; }
            set
            {
                if (_MaskColor == value) return;
                _MaskColor = value;
                if (this._Image != null) this.Invalidate();
            }
        }
        private Rectangle _SelectedRectangle;/// 获取或设置悬着区域
       
        public CutPic()
        {
            SetStyle(ControlStyles.UserPaint, true);  
            SetStyle(ControlStyles.AllPaintingInWmPaint, true); // 禁止擦除背景.  
            SetStyle(ControlStyles.DoubleBuffer, true); // 双缓冲  

            InitializeComponent();
        }

        private void CutPic_MouseDown(object sender, MouseEventArgs e)
        {
            if (this._Image == null)
            {
                return;//Image属性null或者已经锁定选择 直接返回
            }
            m_ptStart = e.Location;
            m_bChangeHeight = true;
            m_bChangeWidth = true;

            //判断若不在限定范围内操作 返回
            m_rectClip = this.DisplayRectangle;
                Size sz = this.Size;
                sz = this.Size;                
                m_rectClip.Intersect(new Rectangle(Point.Empty, sz));
                m_rectClip.Width++; m_rectClip.Height++;
                Cursor.Clip = RectangleToScreen(m_rectClip);
            

            if (ToolsPanel.Visible==true)
            {
                ToolsPanel.Visible = false;
            }
            //如果 已经选择区域 若鼠标点下 判断是否在控制顶点上
            if (this._IsDrawed)
            {
                this._IsDrawed = false; //默认表示 要更改选取设置 清楚IsDrawed属性
                if (m_rectDots[0].Contains(e.Location))
                {
                    m_ptStart.X = this._SelectedRectangle.Right;
                    m_ptStart.Y = this._SelectedRectangle.Bottom;
                }
                else if (m_rectDots[1].Contains(e.Location))
                {
                    m_ptStart.Y = this._SelectedRectangle.Bottom;
                    m_bChangeWidth = false;
                }
                else if (m_rectDots[2].Contains(e.Location))
                {
                    m_ptStart.X = this._SelectedRectangle.X;
                    m_ptStart.Y = this._SelectedRectangle.Bottom;
                }
                else if (m_rectDots[3].Contains(e.Location))
                {
                    m_ptStart.X = this._SelectedRectangle.Right;
                    m_bChangeHeight = false;
                }
                else if (m_rectDots[4].Contains(e.Location))
                {
                    m_ptStart.X = this._SelectedRectangle.X;
                    m_bChangeHeight = false;
                }
                else if (m_rectDots[5].Contains(e.Location))
                {
                    m_ptStart.X = this._SelectedRectangle.Right;
                    m_ptStart.Y = this._SelectedRectangle.Y;
                }
                else if (m_rectDots[6].Contains(e.Location))
                {
                    m_ptStart.Y = this._SelectedRectangle.Y;
                    m_bChangeWidth = false;
                }
                else if (m_rectDots[7].Contains(e.Location))
                {
                    m_ptStart = this._SelectedRectangle.Location;
                }
                else if (this._SelectedRectangle.Contains(e.Location))
                {
                    m_bMoving = true;
                    m_bChangeWidth = false;
                    m_bChangeHeight = false;
                }
                else { this._IsDrawed = true; }   //若以上条件不成立 表示不需要更改设置
            }
        }

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

        private void CutPic_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            if (_Image!=null)
            {
                  g.DrawImage(this._Image,0,0,this._Image.Width,this._Image.Height);//原图
                  using (SolidBrush sb = new SolidBrush(this._MaskColor))
                  {
                      g.FillRectangle(sb, this.ClientRectangle);//遮罩
                  }
                  if (!this._SelectedRectangle.IsEmpty)
                      this.DrawSelectedRectangle(g);//选框
            }
            SetPanleLocation();
        }

        private void CutPic_Load(object sender, EventArgs e)
        {
            for (int i = 0; i < 8; i++)
            {
                m_rectDots[i].Size = new Size(5, 5);
            }        
                          
            m_ptTempForMove = this.DisplayRectangle.Location;
          
        }

        private void CutPic_MouseMove(object sender, MouseEventArgs e)
        {
            m_ptCurrent = e.Location;
            if (this._Image == null)
            {
                return;
            }
            if (this._IsDrawed)
            {//如果已经绘制 移动过程中判断是否需要设置鼠标样式
                this.SetCursorStyle(e.Location);
            }
            else if (e.Button == MouseButtons.Left)
            {//否则可能表示在选择区域或重置大小
                if (m_bChangeWidth)
                {//是否允许选区宽度改变 如重置大小时候 拉动上边和下边中点时候
                    this._SelectedRectangle.X = e.Location.X > m_ptStart.X ? m_ptStart.X : e.Location.X;
                    this._SelectedRectangle.Width = Math.Abs(e.Location.X - m_ptStart.X);
                }
                if (m_bChangeHeight)
                {
                    this._SelectedRectangle.Y = e.Location.Y > m_ptStart.Y ? m_ptStart.Y : e.Location.Y;
                    this._SelectedRectangle.Height = Math.Abs(e.Location.Y - m_ptStart.Y);
                }
                if (m_bMoving)
                {//如果是移动选区 判断选区移动范围
                    int tempX = m_ptTempForMove.X + e.X - m_ptStart.X;
                    int tempY = m_ptTempForMove.Y + e.Y - m_ptStart.Y;
                    
                    if (tempX < 0) tempX = 0;
                        if (tempY < 0) tempY = 0;
                        if (this._SelectedRectangle.Width + tempX >= m_rectClip.Width) tempX = m_rectClip.Width - this._SelectedRectangle.Width - 1;
                        if (this._SelectedRectangle.Height + tempY >= m_rectClip.Height) tempY = m_rectClip.Height - this._SelectedRectangle.Height - 1;
                   
                    this._SelectedRectangle.X = tempX;
                    this._SelectedRectangle.Y = tempY;
                }
                this.Invalidate();
            }
            else if (!this._IsDrawed)
            {
                this.Invalidate();//否则 在需要绘制放大镜并且还没有选好区域同时 都重绘
            }
        }
        ///
        /// 判断鼠标当前位置显示样式
        ///
        /// 鼠标坐标
        protected virtual void SetCursorStyle(Point pt)
        {
            if (m_rectDots[0].Contains(pt) || m_rectDots[7].Contains(pt))
                this.Cursor = Cursors.SizeNWSE;
            else if (m_rectDots[1].Contains(pt) || m_rectDots[6].Contains(pt))
                this.Cursor = Cursors.SizeNS;
            else if (m_rectDots[2].Contains(pt) || m_rectDots[5].Contains(pt))
                this.Cursor = Cursors.SizeNESW;
            else if (m_rectDots[3].Contains(pt) || m_rectDots[4].Contains(pt))
                this.Cursor = Cursors.SizeWE;
            else if (this._SelectedRectangle.Contains(pt))
                this.Cursor = Cursors.SizeAll;
            else
                this.Cursor = Cursors.Default;
        }

        private void CutPic_MouseUp(object sender, MouseEventArgs e)
        {
            this._IsDrawed = !this._SelectedRectangle.IsEmpty;
            m_ptTempForMove = this._SelectedRectangle.Location;
            m_bMoving = false;
            m_bChangeWidth = false;
            m_bChangeHeight = false;
            Cursor.Clip = Rectangle.Empty;
            ToolsPanel.Visible = true;
            this.Invalidate();

            
           
        }

        public void SetPanleLocation()
        {
            ToolsPanel.Left = this._SelectedRectangle.Left + this._SelectedRectangle.Width - ToolsPanel.Width;
            ToolsPanel.Top =  this._SelectedRectangle.Top+this._SelectedRectangle.Height+5;
        }


        ///
        /// 绘制选框
        ///
        /// 绘图表面
        protected virtual void DrawSelectedRectangle(Graphics g)
        {
            m_rectDots[0].Y = m_rectDots[1].Y = m_rectDots[2].Y = this._SelectedRectangle.Y - 2;
            m_rectDots[5].Y = m_rectDots[6].Y = m_rectDots[7].Y = this._SelectedRectangle.Bottom - 2;
            m_rectDots[0].X = m_rectDots[3].X = m_rectDots[5].X = this._SelectedRectangle.X - 2;
            m_rectDots[2].X = m_rectDots[4].X = m_rectDots[7].X = this._SelectedRectangle.Right - 2;
            m_rectDots[3].Y = m_rectDots[4].Y = this._SelectedRectangle.Y + this._SelectedRectangle.Height / 2 - 2;
            m_rectDots[1].X = m_rectDots[6].X = this._SelectedRectangle.X + this._SelectedRectangle.Width / 2 - 2;

            g.DrawImage(this._Image, this._SelectedRectangle, this._SelectedRectangle, GraphicsUnit.Pixel);
            g.DrawRectangle(Pens.Cyan, this._SelectedRectangle.Left, this._SelectedRectangle.Top, this._SelectedRectangle.Width - 1, this._SelectedRectangle.Height - 1);
            foreach (Rectangle rect in m_rectDots)
                g.FillRectangle(Brushes.Yellow, rect);
            string str = string.Format("X:{0} Y:{1} W:{2} H:{3}",
                this._SelectedRectangle.Left, this._SelectedRectangle.Top, this._SelectedRectangle.Width, this._SelectedRectangle.Height);
            Size szStr = g.MeasureString(str, this.Font).ToSize();
            Point ptStr = new Point(this._SelectedRectangle.Left, this._SelectedRectangle.Top - szStr.Height - 5);
            if (ptStr.Y < 0) ptStr.Y = this._SelectedRectangle.Top + 5;
            if (ptStr.X + szStr.Width > this.Width) ptStr.X = this.Width - szStr.Width;
            using (SolidBrush sb = new SolidBrush(Color.FromArgb(125, 0, 0, 0)))
            {
                g.FillRectangle(sb, new Rectangle(ptStr, szStr));
                g.DrawString(str, this.Font, Brushes.White, ptStr);
            }
        }

        private void SaveBT_Click(object sender, EventArgs e)
        {
            SaveFileDialog saveFileDialog = new SaveFileDialog();
            saveFileDialog.FileName = DateTime.Now.ToString("yyyyMMddhhmmss");
            saveFileDialog.Filter = "png|*.png|bmp|*.bmp|jpg|*.jpg|gif|*.gif";
            if (saveFileDialog.ShowDialog() != DialogResult.Cancel)
            {
                System.Drawing.Rectangle cropArea = new System.Drawing.Rectangle(_SelectedRectangle.X, _SelectedRectangle.Y, _SelectedRectangle.Width, _SelectedRectangle.Height);
                Bitmap bmpImage = new Bitmap(this._Image);
                Bitmap bmpCrop = bmpImage.Clone(cropArea, bmpImage.PixelFormat);
                bmpCrop.Save(saveFileDialog.FileName);
                this.DialogResult = DialogResult.OK;
                this.Close();
            }
            else
            {
                this.Focus();
            }
        }
       

        private void CutPic_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            if (this._SelectedRectangle.Contains(e.Location))
            {
                //复制图片到剪切板
                System.Drawing.Rectangle cropArea = new System.Drawing.Rectangle(_SelectedRectangle.X, _SelectedRectangle.Y, _SelectedRectangle.Width, _SelectedRectangle.Height);
                Bitmap bmpImage = new Bitmap(this._Image);
                Bitmap bmpCrop = bmpImage.Clone(cropArea, bmpImage.PixelFormat);
                Clipboard.SetImage(bmpCrop);
                this.DialogResult = DialogResult.OK;
                this.Close();
            }
        }
//如果按下ESC键退出截图功能
        private void CutPic_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyValue==27)
            {
                this.DialogResult = DialogResult.OK;
                this.Close();
            }
        }

这样截图功能就已经实现了。源代码下载，请点击