LBitmapRgn::SetRgnPolygon

#include "ltwrappr.h"

virtual L_INT LBitmapRgn::SetRgnPolygon(pPoints, uPoints, uFillMode=L_POLY_WINDING)

POINT L_FAR * pPoints;	/* pointer to an array of POINT structures */
L_UINT uPoints;	/* number of points in the array */
L_UINT uFillMode;	/* flag that indicates how to handle complex crossing lines */

Creates or updates the associated class object's bitmap region by adding a polygonal region.

Parameter	Description
pPoints	Pointer to an array of POINT structures. The points in the array must be in the order in which the vertices of the polygon are connected. To create the line that closes the polygon, the last point in the array is connected to the first point of the array.
uPoints	The number of points in the array specified by the pPoints parameter.
uFillMode	Flag that indicates how to handle complex crossing lines. The following are valid values, which are illustrated below:
	Value	Meaning
	L_POLY_WINDING	[0] All pixels that are inside the resulting exterior lines are in the region.
	L_POLY_ALTERNATE	[1] The region includes the area between odd-numbered and even-numbered polygon sides on each scan line.
	$image\winding.gif$

Returns

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

Comments

To update an existing region, you specify how the new region is to be combined with the existing one. For descriptions of the possibilities, refer to Creating a Bitmap Region.

Required DLLs and Libraries

LTDIS

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

See Also

Elements:	LBitmapRgn::SetRgnColor, LBitmapRgn::SetRgnEllipse, LBitmapRgn::SetRgnRect, LBitmapRgn::SetRgnRoundRect, LBitmapRgn::SetRgnColorHSVRange, LBitmapRgn::SetRgnColorRGBRange, Class Members
Topics:	Raster Image Functions: Creating and Using a Region
	Raster Image Functions: Region Processing
	Defining and Using a Bitmap Region
	Saving a Region

Example

L_VOID TestFunction(HWND hWnd)
{
   RGNXFORM XFormBtmp; // Structure for transforming display coordinates
   RECT rClientArea; // Client area of the current window
   L_INT nRet = 0;
   LBitmapRgn lBmpRgn ;
   LBitmapBase lBmpBase ;
   LBitmapBase lBmpMask ;
   HRGN hRgn ;
   POINT PolyPt[5]; // Array of points that defines the polygon
   POINT L_FAR *pPolyPt = PolyPt; // Pointer to the array of points

   // Get the client area of the current window
   GetClientRect(hWnd,&rClientArea);

   // Load a bitmap
   nRet = lBmpBase.Load(TEXT("IMAGE1.CMP"), 32, ORDER_BGR);

   if (nRet == SUCCESS)
   {
      lBmpRgn.SetBitmap(&lBmpBase) ;

      L_UINT uCombineMode = lBmpRgn.GetRgnCombineMode() ;
      uCombineMode |= L_RGN_OR ;

      lBmpRgn.SetRgnCombineMode(uCombineMode) ;

      lBmpRgn.SetRgnColor(RGB(0,0,0)) ;

      // create mask region from bitmap
      nRet = lBmpRgn.CreateMaskFromBitmapRgn(&lBmpMask, sizeof(lBmpMask)) ;

      if (nRet == SUCCESS)
         // set region from mask bitmap
         lBmpRgn.SetRgnFromMask(lBmpMask) ;

      // get the region transform used with region function
      lBmpRgn.GetRgnXForm(&XFormBtmp) ;

      /* Set RGNXFORM fields, assuming that the display rectangle is the same
      as the client area of the current window */
      XFormBtmp.uViewPerspective = TOP_LEFT;
      XFormBtmp.nXScalarNum = lBmpBase.GetWidth();
      XFormBtmp.nXScalarDen = rClientArea.right;
      XFormBtmp.nYScalarNum = lBmpBase.GetHeight() ;
      XFormBtmp.nYScalarDen = rClientArea.bottom;
      XFormBtmp.nXOffset = 0;
      XFormBtmp.nYOffset = 0;

      // set the region transform to be used in region functions
      lBmpRgn.SetRgnXForm(&XFormBtmp) ;

      // Specify the vertices of the polygon (a 5-pointed star)
      pPolyPt[0].x = 0;
      pPolyPt[0].y = 0;

      pPolyPt[1].x = rClientArea.right / 3;
      pPolyPt[1].y = rClientArea.bottom / 2;

      pPolyPt[2].x = rClientArea.right / 3;
      pPolyPt[2].y = 0;

      pPolyPt[3].x = 0;
      pPolyPt[3].y = rClientArea.bottom / 3;

      pPolyPt[4].x = rClientArea.right / 2;
      pPolyPt[4].y = rClientArea.bottom / 3;

      // Create a polygonal region
      lBmpRgn.SetRgnPolygon( pPolyPt, 5, L_POLY_ALTERNATE);

      // Save the first polygonal region
      hRgn = lBmpRgn.GetRgnHandle();

      // Free the region
      lBmpRgn.Free();

      // Add the saved region to the new one
      lBmpRgn.SetRgnHandle(hRgn);

      /*
      ...
      ...
      ...
      */

      // Delete the HRGN object
      DeleteObject(hRgn);
   }
}