L_PntSetTransformation

L_INT PntSetTransformationExample(HWND          hWnd, 
                                                    pBITMAPHANDLE pBitmap, 
                                                    L_INT *g_nZoomFactor, 
                                                    L_INT *g_nHScroll, /* current scroll bar horzontal value */ 
                                                    L_INT *g_nVScroll /* current scroll bar vertical value */) 
{ 
   L_INT nRet; 
   pPAINTHANDLE pPaint ; 
   HDC          hDC; 
   RECT         rcView ; 
   L_INT        nXOffset, nYOffset ; 
   RECT         rcShapeRect ; 
   PAINTXFORM   PntXForm ; 
    
   /* Initiate the Paint toolkit */ 
   nRet = L_PntInit ( &pPaint ); 
   if ( SUCCESS != nRet ) 
   { 
         return nRet;  
   } 
 
   /* set the painting rectangel */ 
   SetRect ( &rcView, 0, 0, BITMAPWIDTH ( pBitmap ), BITMAPHEIGHT ( pBitmap ) ) ; 
 
   if ( *g_nZoomFactor < 100 ) 
   { 
      nXOffset = - MulDiv ( *g_nHScroll, 100, *g_nZoomFactor ) ;   
      nYOffset = - MulDiv ( *g_nVScroll, 100, *g_nZoomFactor ) ; 
   } 
   else 
   { 
      nXOffset = - *g_nHScroll ; 
      nYOffset = - *g_nVScroll ; 
   } 
 
   OffsetRect ( &rcView, nXOffset, nYOffset ) ; 
 
   rcView.left   = MulDiv ( rcView.left,   *g_nZoomFactor, 100 ) ; 
   rcView.top    = MulDiv ( rcView.top,    *g_nZoomFactor, 100 ) ; 
   rcView.right  = MulDiv ( rcView.right,  *g_nZoomFactor, 100 ) ; 
   rcView.bottom = MulDiv ( rcView.bottom, *g_nZoomFactor, 100 ) ; 
 
   // set the paintin transformatoins values. 
   PntXForm.nZoom    = *g_nZoomFactor ; 
   PntXForm.nXOffset = - rcView.left ; 
   PntXForm.nYOffset = - rcView.top ; 
 
   /* Set the painting transformations to reflect a zoom-in by 5:1 */ 
   nRet = L_PntSetTransformation ( pPaint, &PntXForm ) ;  
   if(nRet != SUCCESS) 
      return nRet; 
 
   /* Get the device context */ 
   hDC = GetDC ( hWnd ) ; 
 
   /* paint the bitmap */ 
   nRet = L_PaintDC( hDC, pBitmap, NULL, NULL, &rcView, NULL, SRCCOPY ) ; 
   if(nRet != SUCCESS) 
      return nRet; 
 
   /* Set the rectangle coordinates with respect to the DC dimensions*/ 
   SetRect ( &rcShapeRect, 10, 10, 150, 150 ) ; 
 
    /* Set the DC Extents */ 
   RECT rcClient; 
   GetClientRect(hWnd, &rcClient); 
   nRet = L_PntSetDCExtents ( pPaint, &rcClient ); 
 
   /* Use the current shape properties to draw a rectangle to DC (hDC) */ 
   nRet = L_PntDrawShapeRectangle ( pPaint, hDC, &rcShapeRect ) ; 
   if(nRet != SUCCESS) 
      return nRet; 
 
   /* Release the device context */ 
   ReleaseDC ( hWnd, hDC ) ; 
 
   /* Free the paint tools handle */ 
   L_PntFree ( pPaint ) ; 
 
   return SUCCESS ; 
}