public partial class Form4 : Form
{
public Form4()
{
InitializeComponent();
}
#region 用戶變量
private Point DownPoint = Point.Empty;//記錄鼠標按下座標，用來確定繪圖起點
private bool CatchFinished = false;//用來表示是否截圖完成
private bool CatchStart = false;//表示截圖開始
private Bitmap originBmp;//用來保存原始圖像
private Rectangle CatchRect;//用來保存截圖的矩形
#endregion
private void Form4_Load(object sender, EventArgs e)
{
this.SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint, true);
this.UpdateStyles();
//以上兩句是爲了設置控件樣式爲雙緩衝，這可以有效減少圖片閃爍的問題，關於這個大家可以自己去搜索下
originBmp = new Bitmap(this.BackgroundImage);//BackgroundImage爲全屏圖片，我們另用變量來保存全屏圖片
}
private void Form4_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (!CatchStart)
{//如果捕捉沒有開始
CatchStart = true;
DownPoint = new Point(e.X, e.Y);//保存鼠標按下座標
}
}
}
private void Form4_MouseClick(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right)
{
this.DialogResult = DialogResult.OK;
this.Close();
}
}
private void Form4_MouseMove(object sender, MouseEventArgs e)
{
if (CatchStart)
{//如果捕捉開始
Bitmap destBmp = (Bitmap)originBmp.Clone();//新建一個圖片對象，並讓它與原始圖片相同
Point newPoint = new Point(DownPoint.X, DownPoint.Y);//獲取鼠標的座標
Graphics g = Graphics.FromImage(destBmp);//在剛纔新建的圖片上新建一個畫板
Pen p = new Pen(Color.Blue, 1);
int width = Math.Abs(e.X - DownPoint.X), height = Math.Abs(e.Y - DownPoint.Y);//獲取矩形的長和寬
if (e.X < DownPoint.X)
{
newPoint.X = e.X;
}
if (e.Y < DownPoint.Y)
{
newPoint.Y = e.Y;
}
CatchRect = new Rectangle(newPoint, new Size(width, height));//保存矩形
g.DrawRectangle(p, CatchRect);//將矩形畫在這個畫板上
g.Dispose();//釋放目前的這個畫板
p.Dispose();
Graphics g1 = this.CreateGraphics();//重新新建一個Graphics類
//如果之前那個畫板不釋放，而直接g=this.CreateGraphics()這樣的話無法釋放掉第一次創建的g,因爲只是把地址轉到新的g了．如同string一樣
g1 = this.CreateGraphics();//在整個全屏窗體上新建畫板
g1.DrawImage(destBmp, new Point(0, 0));//將剛纔所畫的圖片畫到這個窗體上
//這個也可以屬於二次緩衝技術，如果直接將矩形畫在窗體上，會造成圖片抖動並且會有無數個矩形．
g1.Dispose();
destBmp.Dispose();//要及時釋放，不然內存將會被大量消耗
}
}
private void Form4_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (CatchStart)
{
CatchStart = false;
CatchFinished = true;
}
}
}
private void Form4_MouseDoubleClick(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left && CatchFinished)
{
if (CatchRect.Contains(new Point(e.X, e.Y)))
{
Bitmap CatchedBmp = new Bitmap(CatchRect.Width, CatchRect.Height);//新建一個於矩形等大的空白圖片
Graphics g = Graphics.FromImage(CatchedBmp);
g.DrawImage(originBmp, new Rectangle(0, 0, CatchRect.Width, CatchRect.Height), CatchRect, GraphicsUnit.Pixel);
//把orginBmp中的指定部分按照指定大小畫在畫板上
Clipboard.SetImage(CatchedBmp);//將圖片保存到剪貼板
g.Dispose();
CatchFinished = false;
this.BackgroundImage = originBmp;
CatchedBmp.Dispose();
this.DialogResult = DialogResult.OK;
this.Close();
}
}
}
}
//以下是聊天窗體的點擊事件
private void button2_Click(object sender, EventArgs e)
{
this.Hide();//隱藏當前窗體
Thread.Sleep(50);//讓線程睡眠一段時間，窗體消失需要一點時間
Form4 CatchForm = new Form4();
Bitmap CatchBmp = new Bitmap(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height);//新建一個和屏幕大小相同的圖片
Graphics g = Graphics.FromImage(CatchBmp);
g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height));//保存全屏圖片
CatchForm.BackgroundImage = CatchBmp;//將Catch窗體的背景設爲全屏時的圖片
if (CatchForm.ShowDialog() == DialogResult.OK)
{//如果Catch窗體結束,就將剪貼板中的圖片放到信息發送框中
IDataObject iData = Clipboard.GetDataObject();
DataFormats.Format myFormat = DataFormats.GetFormat(DataFormats.Bitmap);
if (iData.GetDataPresent(DataFormats.Bitmap))
{
richTextBox1.Paste(myFormat);
//richtextbox1.Paste(myFormat);
Clipboard.Clear();//清除剪貼板中的對象
}
this.Show();//重新顯示窗體
}
}