Combining Images with Regions

1. Add the following lines in one of your source code files (for example: IMPORTS.CPP).

   // Please note to change the path to the LEADTOOLS toolkit location on your system. 
   Under (WIN64)  add the following line: 
   #pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\x64\\Ltimgefx_x.lib") 
   #pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\x64\\Ltdis_x.lib") 
   #pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\x64\\Ltfil_x.lib") 
   Under (WIN32) add the following line: 
   #pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\Win32\\Ltimgefx_u.lib") 
   #pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\Win32\\Ltdis_u.lib") 
   #pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\Win32\\Ltfil_u.lib") 

2. Include the following header file:
   (Please note to change the path to the LEADTOOLS toolkit location on your system.)

   #include "../../../L_Bitmap.h" 

3. Define the following global variables:

   HWND hWndClient; /* Handle of the current child window */   
   RGNXFORM XForm; /* Structure for transforming display coordinates */   
   RECT rClientArea; /* Client area of the current window */   
   RECT rRgnRect; /* Rectangle that defines the region */   
   BITMAPHANDLE BitmapDst; /* Destination bitmap */   
   BITMAPHANDLE BitmapSrc; /* Source bitmap */   
   L_INT XDst; /* Column offset of the destination */   
   L_INT YDst; /* Row offset of the destination */   
   L_INT XSize;/* Pixel width of the rectangle to combine */   
   L_INT YSize;/* Pixel height of the rectangle to combine */   
   L_INT XSrc; /* Column offset of the source */   
   L_INT YSrc; /* Column offset of the source */ 

4. Load two images as follows:

   L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("sample1.cmp")), &BitmapDst, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);   
   L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("sample2.cmp")), &BitmapSrc, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 

5. Get the client area of the current child window as follows:

   GetClientRect(hWndClient, &rClientArea); 

6. Set RGNXFORM fields, assuming that the display rectangle is the same as the client area of the current child window as follows:

   XForm.uViewPerspective = TOP_LEFT;   
   XForm.nXScalarNum = BITMAPWIDTH(&BitmapDst);   
   XForm.nXScalarDen = rClientArea.right;   
   XForm.nYScalarNum = BITMAPHEIGHT(&BitmapDst);   
   XForm.nYScalarDen = rClientArea.bottom;   
   XForm.nXOffset = 0;   
   XForm.nYOffset = 0; 

7. Specify a rectangle to define the region and then create a rectangular region as follows:

   SetRect(&rRgnRect, rClientArea.right/8, rClientArea.bottom/8, rClientArea.right/2, rClientArea.bottom/2);   
   L_SetBitmapRgnRect(&BitmapDst, &XForm, &rRgnRect, L_RGN_SET); 

8. Specify a position in the top left part of the displayed image and use the full size of the source bitmap as follows:

   XDst = BITMAPWIDTH(&BitmapDst) / 8;   
   YDst = BITMAPHEIGHT(&BitmapDst) / 8;   
   YSize = BITMAPHEIGHT(&BitmapSrc);   
   XSize = BITMAPWIDTH(&BitmapSrc);   
   XSrc = 0;   
   YSrc = 0; 

9. Combine BitmapDst with &BitmapSrc, using flags for an ordinary paste, and save the results:

   L_CombineBitmap(&BitmapDst, XSize, YSize, XDst, YDst,  &BitmapSrc, XSrc, YSrc, CB_OP_ADD | CB_DST_0);   
   L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("test_region.bmp")), &BitmapDst, FILE_BMP, 0, 2, NULL); 

10. At the end you should free the rectangle:

    L_FreeBitmapRgn(&BitmapDst);