L_CaptureActiveWindow

#include "l_bitmap.h"

L_LTSCR_API L_INT L_CaptureActiveWindow(pBitmap, uBitmapStructSize, pCaptureInfo, uInfoStructSize, pfnCaptureCallback, pUserData)

pBITMAPHANDLE pBitmap;	pointer to the bitmap handle
L_UINT uBitmapStructSize;	size in bytes, of the structure pointed to by pBitmap
pLEADCAPTUREINFO pCaptureInfo;	pointer to info structure
L_UINT uInfoStructSize;	size in bytes, of the structure pointed to by pCaptureInfo
CAPTURECALLBACK pfnCaptureCallback;	optional callback function
L_VOID * pUserData;	pointer to more parameters for the callback

Captures an image of the currently active window.

Parameter	Description
pBitmap	Pointer to a bitmap handle that references the captured data.
uBitmapStructSize	Size in bytes, of the structure pointed to by pBitmap, for versioning. Use sizeof(BITMAPHANDLE).
pCaptureInfo	Address of the LEADCAPTUREINFO structure to be filled with information regarding the captured image's source. Pass NULL if you are not interested in extra information about the capture.
uInfoStructSize	Size in bytes, of the structure pointed to by pCaptureInfo, for versioning. Use sizeof(LEADCAPTURE).
pfnCaptureCallback	Optional callback function for additional processing.
	If you do not provide a callback function, use NULL as the value of this parameter.
	If you do provide a callback function, use the function pointer as the value of this parameter.
	The callback function must adhere to the function prototype described in CAPTURECALLBACK Function.
pUserData	Void pointer that you can use to pass one or more additional parameters that the callback function needs.
	To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID ;*. The callback function, which receives the address in its own pUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure.
	If the additional parameters are not needed, you can pass NULL in this parameter.

Returns

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

Comments

This function performs a screen capture of the currently active window. The callback can be used to do multiple captures, depending on the options set using L_SetCaptureOption.

Required DLLs and Libraries

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.

Example

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
static L_INT EXT_CALLBACK pfnCaptureCallback(pBITMAPHANDLE    pBitmap, 
pLEADCAPTUREINFO pCaptureInfo, 
L_VOID         * pUserData) 
{ 
   UNREFERENCED_PARAMETER(pCaptureInfo); 
   UNREFERENCED_PARAMETER(pUserData); 
   /* save the captured image */ 
   return(L_SaveBitmap (MAKE_IMAGE_PATH(TEXT("ActiveWindow.bmp")), pBitmap, FILE_BMP, 0, 0, NULL)); 
} 
L_INT CaptureActiveWindowExample(L_VOID) 
{ 
   BITMAPHANDLE    Bitmap; 
   LEADCAPTUREINFO CaptureInfo; 
   memset(&CaptureInfo, 0, sizeof(LEADCAPTUREINFO)); 
   /*To call the L_CaptureActiveWindow*/ 
   L_INT nRet = L_CaptureActiveWindow (&Bitmap, sizeof(BITMAPHANDLE), 
   &CaptureInfo, sizeof(LEADCAPTUREINFO), 
   pfnCaptureCallback, 
   NULL); 
   if (Bitmap.Flags.Allocated) 
      L_FreeBitmap (&Bitmap); 
   return nRet; 
}

Help Version 19.0.2017.10.27

LEADTOOLS Screen Capture C API Help

Introduction

Version History

Getting Started with Screen Capture

Redistributables/Files To Be Included With Your Application

Quick Reference

Function References

Functions:	L_SetCaptureOption, L_SetCaptureOptionDlg, CAPTURECALLBACK, L_StopCapture, L_CaptureWindow
Topics:	Screen Capture C API Function Groups: Capture Functions
	Implementing Screen Capture