c/c++语言开发共享C++实现功能齐全的屏幕截图示例(附demo)

目录

• 1、概述
• 2、屏幕截图的主要功能点
• 3、屏幕截图的主体实现思路
• 3.1、截图主窗口全屏置顶
• 3.2、桌面灰化
• 3.3、窗口自动套索
• 3.4、区域放大
• 3.5、截取区域的选择
• 3.5、截图工具条
• 3.6、矩形等图元的绘制
• 4、桌面灰化的实现细节
• 5、窗口自动套索实现
• 6、区域放大实现
• 7、截取区域的选择
• 8、矩形等图元的绘制
• 9、截图窗口的绘制机制
• 10、截图退出类型的详细设计
• 11、创建位图时将createcompatiblebitmap替换成createdibsection
• 12、最后

  // 拷贝桌面，lprect 代表选定区域，bsave 标记是否将图片内容保存到剪切板中  hbitmap cscreencatchdlg::copyscreentobitmap( lprect lprect )   {                                 // 确保选定区域不为空矩形      if ( isrectempty( lprect ) )      {          return null;      }            cstring strlog;         // 为屏幕创建设备描述表      hdc hscrdc = ::createdc( _t("display"), null, null, null );       if ( hscrdc == null )      {          strlog.format( _t("[ccatchscreendlg::copyscreentobitmap] 创建display失败, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );             return null;      }         // 为屏幕设备描述表创建兼容的内存设备描述表      hdc hmemdc = ::createcompatibledc( hscrdc );       if ( hmemdc == null )      {          strlog.format( _t("[ccatchscreendlg::copyscreentobitmap]创建与hscrdc兼容的hmemdc失败, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );             ::deletedc( hscrdc );          return null;      }         int nx = 0;      int ny = 0;      int nx2 = 0;      int ny2 = 0;         int nwidth = 0;       int nheight = 0;         // 保证left小于right，top小于bottom      long ltemp = 0;      if ( lprect->left > lprect->right )      {          ltemp = lprect->left;          lprect->left = lprect->right;          lprect->right = ltemp;      }      if ( lprect->top > lprect->bottom )      {          ltemp = lprect->top;          lprect->top = lprect->bottom;          lprect->bottom = ltemp;      }            // 获得选定区域坐标      nx = lprect->left;      ny = lprect->top;      nx2 = lprect->right;      ny2 = lprect->bottom;            // 确保选定区域是可见的      if ( nx < 0 )      {          nx = 0;      }         if ( ny < 0 )      {          ny = 0;      }         if ( nx2 > m_xscreen )      {          nx2 = m_xscreen;      }         if ( ny2 > m_yscreen )      {          ny2 = m_yscreen;      }         nwidth = nx2 - nx;      nheight = ny2 - ny;      // 创建一个与屏幕设备描述表兼容的位图      hbitmap hbitmap = ::createcompatiblebitmap( hscrdc, nwidth, nheight );       if ( hbitmap == null )      {          strlog.format( _t("[ccatchscreendlg::copyscreentobitmap]创建与hscrdc兼容的bitmap失败, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );             ::deletedc( hscrdc );          ::deletedc( hmemdc );          return null;      }      // 把新位图选到内存设备描述表中      ::selectobject( hmemdc, hbitmap );                 bool bret = ::bitblt( hmemdc, 0, 0, nwidth, nheight, hscrdc, nx, ny, srccopy | captureblt );  // captureblt - 该参数保证能够截到透明窗口      if ( !bret )      {          strlog.format( _t("[ccatchscreendlg::copyscreentobitmap]将hscrdc拷贝到hmemdc失败, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );             ::deletedc( hscrdc );          ::deletedc( hmemdc );          ::deleteobject( hbitmap );          return null;      }            if ( hscrdc != null )      {          ::deletedc( hscrdc );      }         if ( hmemdc != null )      {          ::deletedc( hmemdc );      }         return hbitmap; // hbitmap资源不能释放，因为函数外部要使用  }

  void cscreencatchdlg::graylightbmp()  {      cstring strlog;         cdc *pdc = getdc();      assert( pdc );      if ( pdc == null )      {          strlog.format( _t("[ccatchscreendlg::dograylightbmp] getdc失败, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );          return;      }         cbitmap cbmp;       cbmp.attach( m_hgreybitmap ); // 此处使用临时保存亮色位图的m_hdarkbitmap      bitmap bmp;       cbmp.getbitmap( &bmp );       cbmp.detach(); // 需要将对象和句柄分离，m_hdarkbitmap位图资源需要保存在内存中，如不分离，则当对象消亡时，m_hdarkbitmap位图资源会自动被释放掉      uint *pdata = new uint[bmp.bmwidth * bmp.bmheight];       if ( pdata == null )      {          int nsize = bmp.bmwidth * bmp.bmheight;          strlog.format( _t("[ccatchscreendlg::dograylightbmp]pdata通过new申请%s字节的内存失败，直接return"), nsize );          writescreencatchlog( strlog );             releasedc( pdc );          return;      }         bitmapinfo bmpinfo;       bmpinfo.bmiheader.bisize = sizeof(bitmapinfoheader);       bmpinfo.bmiheader.biwidth = bmp.bmwidth;       bmpinfo.bmiheader.biheight = -bmp.bmheight;       bmpinfo.bmiheader.biplanes = 1;       bmpinfo.bmiheader.bicompression = bi_rgb;       bmpinfo.bmiheader.bibitcount = 32;             int nret = getdibits( pdc->m_hdc, m_hgreybitmap, 0, bmp.bmheight, pdata, &bmpinfo, dib_rgb_colors );      if ( 0 == nret )      {          strlog.format( _t("[ccatchscreendlg::dograylightbmp]getdibits失败 nret == 0, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );      }         // 将图像中的所有像素点的rgb值都乘以0.4，即实现了图像的灰化      uint color, r, g, b;       for ( int i = 0; i < bmp.bmwidth * bmp.bmheight; i++ )       {           color = pdata[i];           b = ( color << 8 >> 24 ) * 0.4;           g = ( color << 16 >> 24 ) * 0.4;           r = ( color << 24 >> 24 ) * 0.4;           pdata[i] = rgb(r, g, b);       }          // 如果函数成功，那么返回值就是复制的扫描线数；如果函数失败，那么返回值是0。      nret = setdibits( pdc->m_hdc, m_hgreybitmap, 0, bmp.bmheight, pdata, &bmpinfo, dib_rgb_colors );       if ( 0 == nret )      {          strlog.format( _t("[ccatchscreendlg::dograylightbmp]setdibits失败 nret == 0, getlasterror: %d"),               getlasterror() );          writescreencatchlog( strlog );      }         delete []pdata;      pdata = null;      releasedc( pdc );  }

  	// 使用enumwindows来枚举当前系统打开的所有大窗口  	::enumwindows( enumwindowsproc, null );        bool cenumwindows::enumwindowsproc( hwnd hwnd, lparam lparam )  {  	tchar achwndname[max_path+1] = {0};     	if ( ::iswindow(hwnd) && ::iswindowvisible(hwnd) && !::isiconic(hwnd) )  	{  		// 保存所有有效窗口  		enumedwindowinfo twndinfo;  		twndinfo.m_hwnd = hwnd;     		::getwindowtext( hwnd, achwndname, sizeof(achwndname)/sizeof(tchar) );  		twndinfo.m_strwndname = achwndname;     		 将桌面区域过滤掉  		//if ( !_tcscmp( twndinfo.m_strwndname, _t("program manager") ) )  		//{  		//	return true;  		//}     		::getwindowrect( hwnd, &(twndinfo.m_rcwnd) );  		m_listwindows.push_back( twndinfo );  	}     	return true;  }

  // 在内存pmemdc中绘制自动套索窗口  void cscreencatchdlg::drawautolassowndarea( cdc* pmemdc, cdc* plightdc )  {  	if ( pmemdc == null || plightdc == null )  	{  		return;  	}     	if ( m_rctargetwnd.isrectempty() )  	{  		return;  	}     	// 先从亮色图片将目标窗口抠出  	crect rcarea = m_rctargetwnd;  	bool bret = pmemdc->bitblt( rcarea.left, rcarea.top, rcarea.width(), rcarea.height(),  		plightdc, rcarea.left, rcarea.top, srccopy );  	if ( !bret )  	{  		writescreencatchlog( _t("[ccatchscreendlg::drawautolassowndpic]pmemdc->bitblt(rcarea.left,rcarea.top…失败") );  	}     	rcarea.left = (rcarea.left-4<0) ? 4 : rcarea.left;  	rcarea.top = (rcarea.top-4<0) ? 4 : rcarea.top;  	rcarea.right = (rcarea.right+4>m_xscreen) ? (m_xscreen-4) : rcarea.right;  	rcarea.bottom = (rcarea.bottom+4>m_yscreen) ? (m_yscreen-4) : rcarea.bottom;     	// 再在目标窗口周边画上自动套索边界线      cpen pen( ps_solid, 1, rgb( 0, 174, 255 ) );  	cpen* poldpen = pmemdc->selectobject( &pen );  	cbrush* poldbrush = ( cbrush* )pmemdc->selectstockobject( null_brush ); // 使用null_brush调用selectstockobject可以实现透明画刷的效果  	rcarea.inflaterect( 1, 1 );  	pmemdc->rectangle( &rcarea );  	rcarea.inflaterect( 1, 1 );  	pmemdc->rectangle( &rcarea );  	rcarea.inflaterect( 1, 1 );  	pmemdc->rectangle( &rcarea );  	rcarea.inflaterect( 1, 1 );  	pmemdc->rectangle( &rcarea );  	//rcarea.deflaterect( 1, 1 );  	//rcarea.deflaterect( 1, 1 );  	//pmemdc->rectangle( &rcarea );  	//rcarea.deflaterect( 1, 1 );  	//pmemdc->rectangle( &rcarea );  	//rcarea.deflaterect( 1, 1 );  	//pmemdc->rectangle( &rcarea );     	pmemdc->selectobject( poldbrush );  	pmemdc->selectobject( poldpen );  }

  /  // ccatchtracker - simple rectangular tracking rectangle w/resize handles        // ccatchtracker类从mfc源文件copy过来，根据自身的需要做了修改，对消息机制  // 做了点改动，增加了部分接口        #ifndef catch_screen_tracker_h  #define catch_screen_tracker_h     #define cx_border   1  #define cy_border   1     #define wm_update_toolbar_pos ( wm_user+700 ) // 更新截图工具条位置消息，当截取区域发生变化时要向界面发送该消息     #define crit_recttracker    5  void afxapi afxlockglobals(int nlocktype);  void afxapi afxunlockglobals(int nlocktype);  void afxapi afxdeleteobject(hgdiobj* pobject);     enum trackerhit  {  	hitnothing = -1,  	hittopleft = 0, hittopright = 1, hitbottomright = 2, hitbottomleft = 3,  	hittop = 4, hitright = 5, hitbottom = 6, hitleft = 7, hitmiddle = 8  };     class ccatchtracker  {  public:  // constructors  	ccatchtracker();  	ccatchtracker(lpcrect lpsrcrect, uint nstyle);     // style flags  	enum styleflags  	{  		solidline = 1, dottedline = 2, hatchedborder = 4,  		resizeinside = 8, resizeoutside = 16, hatchinside = 32,  		resizemiddle =80 //设置中间  	};     // hit-test codes  	//enum trackerhit  	//{  	//	hitnothing = -1,  	//	hittopleft = 0, hittopright = 1, hitbottomright = 2, hitbottomleft = 3,  	//	hittop = 4, hitright = 5, hitbottom = 6, hitleft = 7, hitmiddle = 8  	//};     // operations  	void draw(cdc* pdc) const;  	void gettruerect(lprect lptruerect) const;  	bool setcursor(cwnd* pwnd, uint nhittest) const;  	bool track(cwnd* pwnd, cpoint point, bool ballowinvert =true,  		cwnd* pwndclipto = null);  	bool trackrubberband(cwnd* pwnd, cpoint point, bool ballowinvert = true);  	int hittest(cpoint point) const;  	int normalizehit(int nhandle) const;     // overridables  	virtual void drawtrackerrect(lpcrect lprect, cwnd* pwndclipto,  		cdc* pdc, cwnd* pwnd);  	virtual void adjustrect(int nhandle, lprect lprect);  	virtual void onchangedrect(const crect& rectold);  	virtual uint gethandlemask() const;     // implementation  public:  	virtual ~ccatchtracker();     public:  	// 设置调整光标  	void setresizecursor(uint nid_n_s,uint nid_w_e,uint nid_nw_se, uint nid_ne_sw,uint nidmiddle);  	// 创建画刷,内部调用  	void createpen();  	// 设置矩形颜色  	void setrectcolor(colorref rectcolor);  	// 设置该矩形tracker是否可以移动，当点击截图工具条中的按钮后即不可移动  	void setmovable( bool bmoveable );  	bool getmovable(){ return m_bmovable; };     	// implementation helpers  	int hittesthandles(cpoint point) const;  	void gethandlerect(int nhandle, crect* phandlerect) const;  	void getmodifypointers(int nhandle, int**ppx, int**ppy, int* px, int*py);  	virtual int gethandlesize(lpcrect lprect = null) const;  	bool trackhandle(int nhandle, cwnd* pwnd, cpoint point, cwnd* pwndclipto);  	void construct();      void setmsghwnd(hwnd hwnd);     public:  	// attributes  	uint m_nstyle;          // current state  	crect m_rect;           // current position (always in pixels)  	csize m_sizemin;        // minimum x and y size during track operation  	int m_nhandlesize;      // size of resize handles (default from win.ini)  	bool m_ballowinvert;    // flag passed to track or trackrubberband  	crect m_rectlast;  	csize m_sizelast;  	bool m_berase;          // true if drawtrackerrect is called for erasing  	bool m_bfinalerase;     // true if dragtrackerrect called for final erase     	colorref m_rectcolor;   // 当前矩形颜色      hwnd m_hmsgwnd;         // 向界面发送消息的窗口句柄      bool m_bmovable;        // 标记该矩形tracker是否可以移动，当点击截图工具条中的按钮后即不可移动  };     #endif

  		switch (msg.message)  		{  		// handle movement/accept messages  		case wm_lbuttonup:  		case wm_mousemove:  			rectold = m_rect;  			// handle resize cases (and part of move)  			if (px != null)  				*px = (int)(short)loword(msg.lparam) - xdiff;  			if (py != null)  				*py = (int)(short)hiword(msg.lparam) - ydiff;     			// handle move case  			if (nhandle == hitmiddle)  			{  				m_rect.right = m_rect.left + nwidth;  				m_rect.bottom = m_rect.top + nheight;  			}     			// 发送矩形区域的左上角和右下角的坐标给界面，一方面在移动矩形时要用到，  			// 一方面在更新界面中的截图工具条的位置时要用到  			if ( iswindow( m_hmsgwnd ) ) // 检验是否是有效的窗口句柄  			{  				bool blbtnup = false;  				if ( msg.message == wm_lbuttonup )  				{  					blbtnup = true;  				}  				::sendmessage(m_hmsgwnd, wm_update_toolbar_pos, (wparam)&m_rect, (lparam)blbtnup );  			}

  // 形状基类  class cshape  {  public:  	cshape();  	virtual ~cshape();     	virtual void draw( cdc* pdc ) = 0;     protected:  	cpoint m_startpt;  // 起点  	cpoint m_endpt;    // 终点      colorref m_color;  // 当前使用颜色  };

  // 矩形  class crectangle : public cshape  {  public:  	crectangle( cpoint startpt, cpoint endpt );  	~crectangle();     	void draw( cdc* pdc );  };

  crectangle::crectangle( cpoint startpt, cpoint endpt )  {  	m_startpt = startpt;  	m_endpt = endpt;  }     crectangle::~crectangle()  {     }     void crectangle::draw( cdc* pdc )  {  	if ( pdc == null )  	{  		return;  	}     	pen pen( color(255, 0, 0), 2.0 );  	pen.setlinecap(linecapround, linecapround, dashcapround);  	graphics graphics( pdc->getsafehdc() );  	//graphics.setsmoothingmode( smoothingmodeantialias );  	//graphics.drawrectangle( &pen, m_startpt.x, m_startpt.y, m_endpt.x-m_startpt.x, m_endpt.y-m_startpt.y );     	crect rctemp(  m_startpt.x, m_startpt.y, m_endpt.x, m_endpt.y );  	rctemp.normalizerect();  	status stret = graphics.drawrectangle( &pen, rctemp.left, rctemp.top,   		rctemp.width(), rctemp.height() );  }

  	case embtnellipse: // 画椭圆  		{  			// 为了抗锯齿，均使用gdi+来绘制图元（gdi绘制直线和曲线时有明显的锯齿）  			pen pen( color(255, 0, 0), width_draw_pen );  			graphics graphics( m_tmpdrawdc.getsafehdc() );  			graphics.setsmoothingmode( smoothingmodeantialias );  			graphics.drawellipse( &pen, m_drawstartpt.x/*-m_recttracker.m_rect.left*/, m_drawstartpt.y/*-m_recttracker.m_rect.top*/,   				point.x-m_drawstartpt.x/*+m_recttracker.m_rect.left*/,   				point.y-m_drawstartpt.y/*+m_recttracker.m_rect.top*/ );  		}  		break;

  bool cscreencatchdlg::onerasebkgnd( cdc* pdc )   {  	return true;  }

  cpaintdc::cpaintdc(cwnd* pwnd)  {  	assert_valid(pwnd);  	assert(::iswindow(pwnd->m_hwnd));     	if (!attach(::beginpaint(m_hwnd = pwnd->m_hwnd, &m_ps)))  		afxthrowresourceexception();  }     cpaintdc::~cpaintdc()  {  	assert(m_hdc != null);  	assert(::iswindow(m_hwnd));     	::endpaint(m_hwnd, &m_ps);  	detach();  }

  enum emquittype  {  	emquitinvalid = -1,     // 无效退出类型  	emescquit   = 0,        // 按esc键退出  	emrclickquit,           // 右键单击退出  	emldclickquit,          // 左键双击退出  	emsendtoblogquit,       // 发送到微博退出  	emsavequit,             // 保存截图后退出  	emcancelquit,           // 取消截图退出  	emcompletequit,         // 完成截图退出  	emmemorylackquit,       // 内存不足引起的gdi操作失败退出  	emcutrectemptyquit      // 截取区域为空退出         };

  // 创建设备无关位图，解决调用createcompatiblebitmap api函数因内存不足创建位图  // 失败的问题  hbitmap createdibbitmap( const int nwidth, const int nheight )  {  	bitmapinfo bmi;  	::zeromemory( &bmi, sizeof(bmi) );  	bmi.bmiheader.bisize = sizeof(bmi.bmiheader);  	bmi.bmiheader.biwidth = nwidth;  	bmi.bmiheader.biheight = nheight;  	bmi.bmiheader.biplanes = 1;  	bmi.bmiheader.bibitcount = 32;  	bmi.bmiheader.bicompression = bi_rgb;  	bmi.bmiheader.bisizeimage = nwidth * nheight * 4;//4=bmi.bmiheader.bibitcount/8     	void* pvbits = null;  	return ::createdibsection( null, &bmi, dib_rgb_colors, &pvbits, null, 0 );  }

  void ctestscreencatchdlg::onbnclickedbtnstartcapture()  {  	cstring strpath = getmodulefullpath();     	// 该接口中会弹出截图的模态框，截图对话框关闭后该接口才会返回  	// 接口弹出模块框，不会堵塞整个线程，模态框内部会接管消息循环，会分发消息  	doscreencatch( (lpctstr)strpath );     	emquittype emquittype = getquittype();  	if ( emquittype == emldclickquit || emquittype == emcompletequit )  	{  		if ( ispicfilesaved() )  		{  			tchar achpcipath[max_path] = { 0 };  			getpicfilesavedpath( achpcipath, sizeof(achpcipath)/sizeof(tchar) );     			cstring strtip;  			strtip.format( _t("截图保存到路径：%s"), achpcipath );  			afxmessagebox( strtip );  		}  	}  	else if ( emquittype == emmemorylackquit )  	{  		afxmessagebox( _t("截图失败，可能是内存不足引起的，退出部分程序后再试！") );  	}  }