本实例全部文章目录
（一）功能概览
（二）创建项目、注册热键、显示截图主窗口
（三）托盘图标及菜单的实现
（四）基本截图功能实现
（五）针对拖拽时闪烁卡顿现象的优化
（六）添加配置管理功能
（七）添加放大镜的功能
（八）添加键盘操作截图的功能
（九）使用自定义光标，QQ截图时的光标
（十）在截图中包含鼠标指针形状
实现原理
基本截图的功能主要靠响应主窗体的鼠标按下、鼠标移动、鼠标抬起几个事件的功能来实现的。截取的图片区域使用“Label”组件来显示，需要重新实现“Label”组件的“Paint”方法。
左键单击开始截图，右键单击取消截图，双击鼠标左键完成截图，将截取的图片保存到Windows剪贴板中。
添加“Label”组件
工具箱》公共组件》双击“Label”组件，修改组件属性：
Name=lbl_CutImage，
AutoSize=False，
BackColor=Transparent，
Text = “”
“Form1_Load”事件添加代码：
this.lbl_CutImage.Hide();
定义截图功能依赖的基本变量
#region 截图基本变量 /// <summary> /// 用于判断是否已经开始截图，控制信息框是否显示。 /// </summary> private bool isCuting; /// <summary> /// 鼠标按下的点 /// </summary> private Point beginPoint; /// <summary> /// 最终确定的绘图基点 /// </summary> private Point endPoint; /// <summary> /// 用于记录截图显示区域的大小（包括调整块的区域，调整区域边框宽度2px） /// </summary> private Rectangle cutImageRect = new Rectangle(0, 0, 5, 5); #endregion
定义枚举类型：更新UI的模式
/// <summary> /// 更新UI的模式，用于标记哪些需要显示，哪些需要隐藏； /// </summary> [FlagsAttribute] public enum UpdateUIMode : uint { //值得注意的是，如果要使用组合值，那么就不能用连接的数字表示，必须是几何级增长！ None = 0, ShowTextPro = 1, ShowPenStyle = 2, ShowToolBox = 4, ShowInfoBox = 8, ShowZoomBox = 16, ShowCutImage = 32, HideTextPro = 64, HidePenStyle = 128, HideToolBox = 256, HideInfoBox = 512 }
添加方法：计算并保存截图的区域框的大小
/// <summary> /// 计算并保存截图的区域框的大小 /// </summary> private void SaveCutImageSize(Point beginPoint, Point endPoint) { // 保存最终的绘图基点，用于截取选中的区域 this.endPoint = beginPoint; // 计算截取图片的大小 int imgWidth = Math.Abs(endPoint.X - beginPoint.X) + 1; int imgHeight = Math.Abs(endPoint.Y - beginPoint.Y) + 1; int lblWidth = imgWidth + 4; int lblHeight = imgHeight + 4; // 设置截图区域的位置和大小 this.cutImageRect = new Rectangle(beginPoint.X - 2, beginPoint.Y - 2, lblWidth, lblHeight); }
添加方法：执行截图,将选定区域的图片保存到剪贴板
/// <summary> /// 执行截图,将选定区域的图片保存到剪贴板 /// </summary> /// <param name="saveToDisk"> /// 是否将图片保存到磁盘 /// </param> private void ExecCutImage(bool saveToDisk, bool uploadImage) //bool saveToDisk = false, bool uploadImage = false { // 如果图片获取区域不可见,则退出保存图片过程 if (!this.lbl_CutImage.Visible) { return; } Rectangle srcRect = new Rectangle(); srcRect.X = this.lbl_CutImage.Location.X + 2; srcRect.Y = this.lbl_CutImage.Location.Y + 2; srcRect.Width = this.lbl_CutImage.Width - 4; srcRect.Height = this.lbl_CutImage.Height - 4; Rectangle destRect = new Rectangle(0, 0, srcRect.Width, srcRect.Height); Bitmap bmp = new Bitmap(srcRect.Width, srcRect.Height); Graphics g = Graphics.FromImage(bmp); g.DrawImage(this.screenImage, destRect, srcRect, GraphicsUnit.Pixel); Clipboard.SetImage(bmp); ExitCutImage(true); }
添加方法：退出截图过程
/// <summary> /// 退出截图过程 /// </summary> private void ExitCutImage(bool hideWindow) // = true { this.lbl_CutImage.Visible = false; this.isCuting = false; if (hideWindow) { this.screenImage.Dispose(); this.Hide(); } }
主窗口鼠标按下事件处理程序
/// <summary> /// 截图窗口鼠标按下事件处理程序 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Form1_MouseDown(object sender, MouseEventArgs e) { // 左键单击事件 if (e.Button == MouseButtons.Left && e.Clicks == 1) { if (!this.lbl_CutImage.Visible) { this.isCuting = true; this.beginPoint = e.Location; this.endPoint = e.Location; SaveCutImageSize(e.Location, e.Location); UpdateCutInfoLabel(UpdateUIMode.ShowCutImage | UpdateUIMode.ShowInfoBox); } } // 左键双击事件 if (e.Button == MouseButtons.Left && e.Clicks == 2) { if (this.lbl_CutImage.Visible) { ExecCutImage(false, false); } } // 右键单击事件 if (e.Button == MouseButtons.Right) { ExitCutImage(!this.lbl_CutImage.Visible); } }
主窗口鼠标移动事件处理程序
/// <summary> /// 截图窗口鼠标移动事件处理程序 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Form1_MouseMove(object sender, MouseEventArgs e) { // 如果截取区域不可见,则退出处理过程 if (!this.lbl_CutImage.Visible) { UpdateCutInfoLabel(UpdateUIMode.None); return; } Point pntBgn = this.beginPoint; Point pntEnd = e.Location; // 如果是反向拖动，重新设置起始点 if (e.Location.X < this.beginPoint.X && e.Location.Y < this.beginPoint.Y) { pntBgn = e.Location; pntEnd = this.beginPoint; } else { if (e.Location.X < this.beginPoint.X) { pntBgn = new Point(e.Location.X, this.beginPoint.Y); pntEnd = new Point(this.beginPoint.X, e.Location.Y); } else { if (e.Location.Y < this.beginPoint.Y) { pntBgn = new Point(this.beginPoint.X, e.Location.Y); pntEnd = new Point(e.Location.X, this.beginPoint.Y); } } } if (this.isCuting) { SaveCutImageSize(pntBgn, pntEnd); } UpdateCutInfoLabel(UpdateUIMode.None); }
主窗口鼠标抬起事件处理程序
/// <summary> /// 截图窗口鼠标抬起事件处理程序 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Form1_MouseUp(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { if (this.isCuting) { this.isCuting = false; UpdateCutInfoLabel(UpdateUIMode.None); } } }
截取区域图片绘制
/// <summary> /// 截取区域图片的绘制事件处理程序 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void lbl_CutImage_Paint(object sender, PaintEventArgs e) { int imgWidth = this.lbl_CutImage.Width - 4; int imgHeight = this.lbl_CutImage.Height - 4; if (imgWidth < 1) { imgWidth = 1; } if (imgHeight < 1) { imgHeight = 1; } // 创建缓存图像，先将要绘制的内容全部绘制到缓存中，最后再一次性绘制到 Label 上， // 这样可以提高性能，并且可以防止屏幕闪烁的问题 Bitmap bmp_lbl = new Bitmap(this.lbl_CutImage.Width, this.lbl_CutImage.Height); Graphics g = Graphics.FromImage(bmp_lbl); // 将要截取的部分绘制到缓存 Rectangle destRect = new Rectangle(2, 2, imgWidth, imgHeight); Point srcPoint = this.lbl_CutImage.Location; srcPoint.Offset(2, 2); Rectangle srcRect = new Rectangle(srcPoint, new System.Drawing.Size(imgWidth, imgHeight)); g.DrawImage(this.screenImage, destRect, srcRect, GraphicsUnit.Pixel); SolidBrush brush = new SolidBrush(Color.FromArgb(10, 124, 202)); Pen pen = new Pen(brush, 1.0F); //以下部分（边框和调整块）的绘制放在（编辑内容）的后面，是解决绘制编辑内容会覆盖（边框和调整块）的问题 // 绘制边框外的区域，解决会被编辑内容覆盖的问题 // 上边 destRect = new Rectangle(0, 0, this.lbl_CutImage.Width, 2); srcPoint = this.lbl_CutImage.Location; //srcPoint.Offset(2, 2); srcRect = new Rectangle(srcPoint, new System.Drawing.Size(this.lbl_CutImage.Width, 2)); g.DrawImage(this.BackgroundImage, destRect, srcRect, GraphicsUnit.Pixel); // 下边 destRect = new Rectangle(0, this.lbl_CutImage.Height - 2, this.lbl_CutImage.Width, 2); srcPoint = this.lbl_CutImage.Location; srcPoint.Offset(0, this.lbl_CutImage.Height - 2); srcRect = new Rectangle(srcPoint, new System.Drawing.Size(this.lbl_CutImage.Width, 2)); g.DrawImage(this.BackgroundImage, destRect, srcRect, GraphicsUnit.Pixel); // 左边 destRect = new Rectangle(0, 2, 2, this.lbl_CutImage.Height - 4); srcPoint = this.lbl_CutImage.Location; srcPoint.Offset(0, 2); srcRect = new Rectangle(srcPoint, new System.Drawing.Size(2, this.lbl_CutImage.Height - 4)); g.DrawImage(this.BackgroundImage, destRect, srcRect, GraphicsUnit.Pixel); // 右边 destRect = new Rectangle(this.lbl_CutImage.Width - 2, 2, 2, this.lbl_CutImage.Height - 4); srcPoint = this.lbl_CutImage.Location; srcPoint.Offset(this.lbl_CutImage.Width - 2, 2); srcRect = new Rectangle(srcPoint, new System.Drawing.Size(2, this.lbl_CutImage.Height - 4)); g.DrawImage(this.BackgroundImage, destRect, srcRect, GraphicsUnit.Pixel); // 绘制边框 g.DrawLine(pen, 2, 2, this.lbl_CutImage.Width - 3, 2); g.DrawLine(pen, 2, 2, 2, this.lbl_CutImage.Height - 3); g.DrawLine(pen, this.lbl_CutImage.Width - 3, 2, this.lbl_CutImage.Width - 3, this.lbl_CutImage.Height - 3); g.DrawLine(pen, 2, this.lbl_CutImage.Height - 3, this.lbl_CutImage.Width - 3, this.lbl_CutImage.Height - 3); // 绘制四个角的调整块 g.FillRectangle(brush, 0, 0, 4, 5); g.FillRectangle(brush, this.lbl_CutImage.Width - 4, 0, 4, 5); g.FillRectangle(brush, 0, this.lbl_CutImage.Height - 5, 4, 5); g.FillRectangle(brush, this.lbl_CutImage.Width - 4, this.lbl_CutImage.Height - 5, 4, 5); // 绘制中间的四个调整块 int blockX = this.lbl_CutImage.Width / 2 - 2; int blockY = this.lbl_CutImage.Height / 2 - 2; g.FillRectangle(brush, blockX, 0, 4, 5); g.FillRectangle(brush, 0, blockY, 4, 5); g.FillRectangle(brush, blockX, this.lbl_CutImage.Height - 5, 4, 5); g.FillRectangle(brush, this.lbl_CutImage.Width - 4, blockY, 4, 5); // 绘制到 Label 上 e.Graphics.DrawImage(bmp_lbl, 0, 0); bmp_lbl.Dispose(); }
双击鼠标左键完成截图功能
/// <summary> /// 截取区域图片的鼠标按下事件处理程序 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void lbl_CutImage_MouseDown(object sender, MouseEventArgs e) { // 左键双击事件 if (e.Button == MouseButtons.Left && e.Clicks == 2) { if (this.lbl_CutImage.Visible) { ExecCutImage(false, false); } } }
注意：代码都贴完了，别忘了为窗体或组件绑定事件处理程序；
例如：截取区域图片的鼠标按下事件处理程序“lbl_CutImage_MouseDown”，就是“lbl_CutImage”组件的“MouseDown”事件的处理程序，绑定方法参考下图：
到此，基本截图的功能实现已经实现，赶快去截取一张图片，粘贴到QQ的聊天窗口看看吧。
源码下载：http://download.csdn.net/detail/testcs_dn/7261365