reg05.c

nucleus 文件系统,内核和彩色图形系统,在小系统上非常好用

/*************************************************************************/
/*                                                                       */
/*         Copyright (c) 1997 - 1999 Accelerated Technology, Inc.        */
/*                                                                       */
/* PROPRIETARY RIGHTS of Accelerated Technology are involved in the      */
/* subject matter of this material.  All manufacturing, reproduction,    */
/* use, and sales rights pertaining to this subject matter are governed  */
/* by the license agreement.  The recipient of this software implicitly  */
/* accepts the terms of the license.                                     */
/*                                                                       */
/*************************************************************************/

/*************************************************************************/
/*                                                                       */
/* FILE NAME                                            VERSION          */
/*                                                                       */
/*      REG05.c                                          1.9             */
/*                                                                       */
/* COMPONENT                                                             */
/*                                                                       */
/*      All                                                              */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This file contains the SubtractRegion function.                  */
/*                                                                       */
/* AUTHOR                                                                */
/*                                                                       */
/*      Giac Dinh, Accelerated Technology, Inc.                          */
/*                                                                       */
/* DATA STRUCTURES                                                       */
/*                                                                       */
/*      None                                                             */
/*                                                                       */
/* FUNCTIONS                                                             */
/*                                                                       */
/*      None                                                             */
/*                                                                       */
/* DEPENDENCIES                                                          */
/*                                                                       */
/*      None                                                             */
/*                                                                       */
/* HISTORY                                                               */
/*                                                                       */
/*         NAME            DATE                    REMARKS               */
/*                                                                       */
/*                                                                       */
/*************************************************************************/

#include "meta_wnd.h"
#include "metconst.h"    /* MetaWINDOW Constant & Stucture Definitions */
#include "metports.h"    /* MetaWINDOW Port & Bitmap Definitions */
#include "grafdata.h"
#include "metmacs3.h"


/* Function SubtractRegion() creates a region that is the area of REGION1
which is not part of REGION2 (i.e. the area of REGION1 with REGION2
subtracted from it.  If an error occurs during SubtractRegion() (e.g.
insufficient memory), a QueryError() status is posted and a NULL pointer
is returned.

Memory for the new region definition is allocated dynamically using the
MetaWINDOW GrafAlloc() function.  When finished using the region, the program
should call GrafFree() with the region pointer to release the memory occupied
by the region definition.  */
region *SubtractRegion( region *rgn1, region *rgn2 )
{
unsigned int mwMergeRegion (int numRects1, rect *rectList1,
	   						int numRects2, rect *rectList2,
		     				int sizeRGN,  region *destRGN, int rgnOP );
	void *GrafAlloc(int memSize);	
	rect *ptrList1;
	rect *ptrList2;
	int  numList1;
	int  numList2;
	region *ptrRgn;
	unsigned int  sizRgn;
	short grafErrValue;

	ptrList1 = rgn1->rgnList;
/* Calculate number of rects in list 1  */
	numList1 = (rgn1->rgnSize - sizeof(region) - 2*sizeof(rect)) >> 3;

	ptrList2 = rgn2->rgnList;
/* Calculate number of rects in list 2  */
	numList2 = (rgn2->rgnSize - sizeof(region) - 2*sizeof(rect)) >> 3;

/* Determine how much memory is needed for new region  */

	sizRgn = mwMergeRegion(numList1,ptrList1,numList2,ptrList2,0,0,2);

	ptrRgn = (region *) GrafAlloc (sizRgn);
	if(ptrRgn == 0)
	{
		grafErrValue = c_UnionReg + c_OutofMem;
		nuGrafErr(grafErrValue);
		return(0);
	}

	mwMergeRegion(numList1,ptrList1,numList2,ptrList2,sizRgn, ptrRgn,2);

	return(ptrRgn);
}