dpen6.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          */
/*                                                                       */
/*      DPEN6.c                                          1.9             */
/*                                                                       */
/* COMPONENT                                                             */
/*                                                                       */
/*      All                                                              */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This file contains the PenOffset function.                       */
/*                                                                       */
/* AUTHOR                                                                */
/*                                                                       */
/*      Robert G. Burrill, 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"


/* Function PenOffset defines the starting position within a dash sequence at
which to begin drawing the current dashed line style.  DASHOFFSET specifies
the dash sequence starting position, specified in units of horizontal pixels. */

void PenOffset(int DSHOFFSET)
{
	short grafErrValue;	/* error value */
	int dashListSize;
	int currDashRcd;
	int i;

	if ((grafPort.pnDash < 1) || (grafPort.pnDash > 7))
	{
		grafErrValue = c_PenOffse +  c_BadDash;
		nuGrafErr(grafErrValue);	/* report error */
		return;
	}

	currDashRcd = grafPort.pnDash;	/* current dashRcd # */
	dashListSize = grafPort.pnDashRcd[currDashRcd].dashSize;
	if (dashListSize == 0)	/* verify that the new dashRcd is okay */
	{	
		grafErrValue = c_PenOffse +  c_BadDashCnt;
		nuGrafErr(grafErrValue);	/* report error */
		return;
	}

	grafPort.pnFlags &= ~pnDashState;	/* set off because it gets flipped the
										first time */
	while (1)	/* note: this will be an infinite loop if all dash counts are 0.
				That is guarded against in DefineDash; any user who sets up dashing
				in the port themselves will just have to worry about it themselves! */
	{
		for (i = 0; i < dashListSize; i++)
		{
			grafPort.pnFlags ^= pnDashState;	/* flip the dash state */
			DSHOFFSET -= grafPort.pnDashRcd[currDashRcd].dashList[i];
			if (DSHOFFSET < 0) goto DP150;	/* count down dash sizes */
		}
	}

DP150:
	grafPort.pnDashCnt = -DSHOFFSET;	/* store the adjusted count remaining 
										in the shadow port */
	grafPort.pnDashNdx = i;	/* ditto for the dash # */
	thePort->pnDashCnt = grafPort.pnDashCnt;	/* set the real port, too */
	thePort->pnDashNdx = grafPort.pnDashNdx;
	thePort->pnFlags = grafPort.pnFlags;
	return;
}