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LScreenCapture::CaptureHotKeyCallBack

Summary

Signals that the user has pressed the capture HotKey.

Syntax

#include "ltwrappr.h"

virtual L_INT LScreenCapture::CaptureHotKeyCallBack(nHotKey, uHotKeyModifiers)

Parameters

L_INT nHotKey

Key code for activation key.

L_UINT uHotKeyModifiers

Modifier keys used with nHotKey. Possible values are listed below and may be combined using the bitwise OR ( | ) operator.

Value	Meaning
MOD_ALT	Alt Key pressed.
MOD_CONTROL	Control key pressed.
MOD_SHIFT	Shift key pressed.
0	No modifier key was pressed.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

You can override this function to do initialization processing before the capture operation starts.

Required DLLs and Libraries

LTDIS
LTSCR
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64.

Example

// ScreenCapture Callbacks 
class LUserScreenCapture : public LScreenCapture 
{ 
   HWND m_hWnd; 
public: 
   LUserScreenCapture(HWND hWnd){m_hWnd = hWnd;} 
   virtual ~LUserScreenCapture(){}; 
   virtual L_INT  CaptureHotKeyCallBack(L_INT nHotKey,L_UINT uHotKeyModifiers); 
   virtual L_INT  ScreenCaptureCallBack(); 
}; 
 
// This callback will be called once the hotkey is pressed 
 
L_INT LUserScreenCapture::CaptureHotKeyCallBack(L_INT nHotKey,L_UINT uHotKeyModifiers) 
{ 
   UNREFERENCED_PARAMETER(nHotKey); 
 
   UNREFERENCED_PARAMETER(uHotKeyModifiers); 
 
   MessageBox(m_hWnd, TEXT("HotKey pressed."), TEXT("CaptureHotKeyCallBack"), MB_OK); 
   return SUCCESS; 
} 
 
// This callback will be called once an image is captured 
L_INT  LUserScreenCapture::ScreenCaptureCallBack() 
{ 
   RECT rcClientRect; 
   HDC hDC; 
 
   hDC = GetDC(m_hWnd); 
 
   // get the client rect of the window 
   GetClientRect(m_hWnd, &rcClientRect); 
 
   // paint the captured image 
   m_pBitmap->Paint()->SetDC(hDC); 
 
   m_pBitmap->SetDstRect(&rcClientRect); 
 
   m_pBitmap->Paint()->PaintDC(); 
 
   ReleaseDC(m_hWnd, hDC); 
 
   return SUCCESS; 
} 
 
L_INT LScreenCapture__CaptureHotKeyCallBackExample(HWND hWnd) 
 
{ 
   L_INT nRet; 
   LBitmapBase LeadBitmap; 
   LUserScreenCapture screenCapture(hWnd); 
   LEADCAPTUREOPTION CaptureOptions; 
 
   screenCapture.SetBitmap(&LeadBitmap); 
 
   // get original capture options 
 
   nRet = screenCapture.GetCaptureOptions(&CaptureOptions); 
 
   if(nRet == SUCCESS) 
 
   { 
 
      // Set capture count to 2 
 
      CaptureOptions.uCount = 2; 
 
      nRet = screenCapture.SetCaptureOptions(&CaptureOptions); 
      if(nRet != SUCCESS) 
         return nRet; 
 
   } 
   else 
      return nRet; 
 
   // EnableCallBack should be called in order for the callbacks to be activated 
 
   screenCapture.EnableCallBack(TRUE); 
 
   // CaptureActiveWindow - HotKey = F11 
 
   // After calling this function above callbacks will be called 
 
   nRet = screenCapture.CaptureActiveWindow(); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
 
}