/**************************************************************************
 * GRFBLIT.C - grf_memblit() function.
 *************************************************************************/

#include "gemfintl.h"

static long dmyfdb = 0L; /* dummy "fdb" (0L) describes the physical screen */

/**************************************************************************
 * grf_blit - blit a rectangle between screen and buffer.
 *************************************************************************/

long grf_blit(options, buffer, prect)
	short			   options;
	void			*buffer;
	void			*prect;
{
	GRECT			scrnrect;	  /* rectangle on the screen			   */
	GRECT			memrect;	  /* rectangle in memory (x/y always zero) */
	FDB 			memfdb; 	  /* FDB describing memory buffer		   */
	register short	wdwidth;	  /* width of memory buffer in words	   */
	register long	mem_needed;   /* memory needed to do the blit		   */
	register FDB	*srcefdb;	  /* source FDB pointer 				   */
	register FDB	*destfdb;	  /* destination FDB pointer			   */
	register short	  vdi_handle;	/* Handle for temp VDI workstation		 */
	struct	{					  /* This is the 'pxy array' used in the   */
			VRECT	srce;		  /* VDI blit command; actually two VRECT- */
			VRECT	dest;		  /* type rectangles stuck back-to-back    */
			} blitcoords;		  /* so it looks like an array. 		   */

/*----------------------------------------------------------------------*
 * validate parms, open a vdi workstation...
 *----------------------------------------------------------------------*/

	mem_needed = 0; 			/* assume failure */

	wind_update(BEG_UPDATE);

	if (!(options & (GRF_BFROMSCREEN|GRF_BTOSCREEN|GRF_BMEMCALC))) {
		goto BYPASS_BLIT;
	}

	if (prect == NULL || (buffer == NULL && !(options & GRF_BMEMCALC))) {
		goto BYPASS_BLIT;
	}

	if (0 == (vdi_handle = apl_vshared())) {
		goto BYPASS_BLIT;
	}

/*----------------------------------------------------------------------*
 * get the screen rectangle, clip it to the physical screen...
 *----------------------------------------------------------------------*/

	if (options & GRF_BOBJTREE) {
		frm_sizes((OBJECT *)prect, &scrnrect);
	} else{
		rc_copy(prect, &scrnrect);
	}

	if (!rc_intersect(&gl_rfscrn, &scrnrect)) {
		goto BYPASS_BLIT;
	}

/*----------------------------------------------------------------------*
 * set up the buffer rectangle...
 *----------------------------------------------------------------------*/

	memrect.g_x = 0;
	memrect.g_y = 0;
	memrect.g_w = scrnrect.g_w;
	memrect.g_h = scrnrect.g_h;

/*----------------------------------------------------------------------*
 * set up the fdb describing the buffer.
 *----------------------------------------------------------------------*/

	wdwidth = (scrnrect.g_w + 15) / 16;

	memfdb.fd_nplanes = gl_vxout[4];
	memfdb.fd_stand   = 0;
	memfdb.fd_w 	  = scrnrect.g_w;
	memfdb.fd_h 	  = scrnrect.g_h;
	memfdb.fd_wdwidth = wdwidth;
	memfdb.fd_addr	  = buffer;

	mem_needed = (2 * (wdwidth * (long)(scrnrect.g_h * memfdb.fd_nplanes)));

	if ((options & GRF_BMEMCALC) || mem_needed == 0) {
		goto BYPASS_BLIT;
	}

/*----------------------------------------------------------------------*
 * do the blit.
 *----------------------------------------------------------------------*/

	if (options & GRF_BFROMSCREEN) {
		rc_gtov(&scrnrect, &blitcoords.srce);
		rc_gtov(&memrect,  &blitcoords.dest);
		srcefdb = (FDB *)&dmyfdb;
		destfdb = &memfdb;
	} else {
		rc_gtov(&memrect,  &blitcoords.srce);
		rc_gtov(&scrnrect, &blitcoords.dest);
		srcefdb = &memfdb;
		destfdb = (FDB *)&dmyfdb;
	}

	graf_mouse(M_OFF, 0L);
	vro_cpyfm(vdi_handle, S_ONLY, (short *)&blitcoords, srcefdb, destfdb);
	graf_mouse(M_ON, 0L);

/*----------------------------------------------------------------------*
 * all done, return.
 *----------------------------------------------------------------------*/

BYPASS_BLIT:

	wind_update(END_UPDATE);
	return mem_needed;
}