C# 实现截图软件功能实例代码

public Bitmap GetScreen()
 {
  //获取整个屏幕图像,不包括任务栏
  Rectangle ScreenArea = Screen.GetWorkingArea(this);
  Bitmap bmp = new Bitmap(ScreenArea.Width,ScreenArea.Height);
  using (Graphics g = Graphics.FromImage(bmp))
  {
  g.CopyFromScreen(0,new Size(ScreenArea.Width,ScreenArea.Height));
  }
  return bmp;
 }

#region 绘制功能
 protected override void OnPaint(PaintEventArgs pe)
 {
  base.OnPaint(pe);
  Graphics g = pe.Graphics;
  DrawHistory(g);
  //绘制当前线
  if (startDraw && this.curLine.PointList != null && this.curLine.PointList.Count > 0)
  {
  DrawLine(g,this.curLine);
  }
  if (startDraw && this.curRect.Start != null && this.curRect.End != null && this.curRect.Start != this.curRect.End) {
  DrawRectangle(g,this.curRect);
  }
 }
 public void DrawHistory(Graphics g) {
  //绘制线历史记录
  if (LineHistory != null)
  {
  foreach (HLine lh in LineHistory)
  {
   if (lh.PointList.Count > 10)
   {
   DrawLine(g,lh);
   }
  }
  }
  //绘制矩形历史记录
  if (RectHistory != null)
  {
  foreach (HRectangle lh in RectHistory)
  {
   if (lh.Start!=null&& lh.End!=null && lh.Start!=lh.End)
   {
   DrawRectangle(g,lh);
   }
  }
  }
 }
 /// <summary>
 /// 绘制线
 /// </summary>
 /// <param name="g"></param>
 /// <param name="line"></param>
 private void DrawLine(Graphics g,HLine line) {
  g.SmoothingMode = SmoothingMode.AntiAlias;
  using (Pen p = new Pen(line.LineColor,line.LineWidth))
  {
  //设置起止点线帽 
  p.StartCap = LineCap.Round;
  p.EndCap = LineCap.Round;

  //设置连续两段的联接样式 
  p.LineJoin = LineJoin.Round;
  g.DrawCurve(p,line.PointList.ToArray()); //画平滑曲线 
  }
 }
 /// <summary>
 /// 绘制矩形
 /// </summary>
 /// <param name="g"></param>
 /// <param name="rect"></param>
 private void DrawRectangle(Graphics g,HRectangle rect)
 {
  g.SmoothingMode = SmoothingMode.AntiAlias;
  using (Pen p = new Pen(rect.LineColor,rect.LineWidth))
  {
  //设置起止点线帽 
  p.StartCap = LineCap.Round;
  p.EndCap = LineCap.Round;

  //设置连续两段的联接样式 
  p.LineJoin = LineJoin.Round;
  g.DrawRectangle(p,rect.Start.X,rect.Start.Y,rect.End.X - rect.Start.X,rect.End.Y - rect.Start.Y); //画平滑曲线 
  }
 }
 public void Earser(Point p0)
 {
  for (int i = lineHistory.Count - 1; i >= 0; i--)
  {
  HLine line = lineHistory[i];
  bool flag = false;
  foreach (Point p1 in line.PointList)
  {
   double distance = GetDistance(p0,p1);
   if (Math.Abs(distance) < 6)
   {
   //需要删除
   flag = true;
   break;
   }

  }
  if (flag)
  {
   lineHistory.RemoveAt(i);
  }
  }
  //擦除矩形
  for (int i = rectHistory.Count - 1; i >= 0; i--)
  {
  HRectangle rect = rectHistory[i];
  
  if (p0.X>rect.Start.X && p0.X<rect.End.X && p0.Y > rect.Start.Y && p0.Y < rect.End.Y) {
   
   rectHistory.RemoveAt(i);
  }
  }
 }
 /// <summary>
 /// 获取两点之间的距离
 /// </summary>
 /// <param name="p0"></param>
 /// <param name="p1"></param>
 /// <returns></returns>
 private double GetDistance(Point p0,Point p1) {
  return Math.Sqrt(Math.Pow((p0.X - p1.X),2) + Math.Pow((p0.Y - p1.Y),2));
 }
 #endregion