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L_PntRegionEllipse

Summary

Creates an elliptical region using the bounding rectangle, specified in prcRect.

Syntax

#include "LtPnt.h"

L_LTPNT_API L_INT L_PntRegionEllipse(pPaint, UserDC, prcRect, phDestRgn)

Parameters

pPAINTHANDLE pPaint

Pointer to a paint handle.

L_HDC UserDC

Handle to a device context, such as a screen, to use as a display surface. This parameter can also be NULL. The mapping mode of the device context must be MM_TEXT.

const LPRECT prcRect

Pointer to a RECT structure that specifies the region boundaries.

pHRGN phDestRgn

Pointer to the region handle to be updated with the resulting region.

Returns

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

Comments

The region creation procedure will be carried out using the current region properties. To determine the current region properties, call L_PntGetProperty. To set or change the current region properties, call L_PntSetProperty. For more information on the region properties, refer to the PAINTREGION structure.

This function will also use the current painting transformation information when creating the new region. To get the current painting transformation information, call L_PntGetTransformation. To change or set the painting transformation information, call L_PntSetTransformation.

If the user has set a bitmap in the toolkit, using the function L_PntSetMetrics, then the toolkit will create the region for the bitmap. Otherwise, the toolkit will create the region for the specified device context.

Required DLLs and Libraries

LTPNT
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

L_INT PntRegionEllipseExample(HWND           hWnd, 
                                                pBITMAPHANDLE  pBitmap, 
                                                L_INT *g_nZoomFactor , 
                                                L_INT *g_nHScroll, 
                                                L_INT *g_nVScroll ) 
{ 
   L_INT nRet; 
   pPAINTHANDLE pPaint ; 
   HDC          hDC ; 
   RECT         rcView ; 
   PAINTXFORM   PntXForm ; 
   L_INT        nXOffset, nYOffset ; 
   HRGN         hRgn ;  
   RECT         rcRegionRect ; 
 
   /* Initiate the Paint toolkit */ 
   nRet = L_PntInit ( &pPaint ); 
   if ( SUCCESS != nRet ) 
   { 
      return nRet; 
   } 
 
   PntXForm.nZoom    = *g_nZoomFactor;  
   PntXForm.nXOffset = *g_nHScroll;  
   PntXForm.nYOffset = *g_nVScroll;  
 
   /* Set the painting transformations to relfect a zoom-in by 3:1 */ 
   nRet = L_PntSetTransformation ( pPaint, &PntXForm ) ;  
   if(nRet != SUCCESS) 
      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 ) ; 
 
   /* 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*/ 
   /* Set the rectangle coordinates with respect to the DC dimensions*/ 
   SetRect ( &rcRegionRect, 10, 10, 110, 110 ) ; 
 
   /* Use the current region properties and the current painting */ 
   /* transformations to create an ellipse region */ 
   nRet = L_PntRegionEllipse ( pPaint, hDC, &rcRegionRect, &hRgn ) ; 
   if(nRet != SUCCESS) 
      return nRet; 
 
   /* Display the resulted region */ 
   FrameRgn ( hDC, hRgn, ( HBRUSH ) GetStockObject ( BLACK_BRUSH ), 1, 1 ) ; 
    
   /* Release the device context */ 
   ReleaseDC ( hWnd, hDC ) ; 
 
  /* Delete the region */ 
   DeleteObject ( hRgn ) ; 
 
   /* Free the paint tools handle */ 
   L_PntFree ( pPaint ) ; 
 
   return SUCCESS ; 
}