/****************************************/
/*	iiszoom		valdes 8 30 82	*/
/*					*/
/*	IIS zoom subroutines		*/
/****************************************/
#include	<stdio.h>
#include	"iisfv.h"

/*zoom window*/
iiszoom (window)
int     window;
{
    short   hdr[8], translate[2], *tmp;

    switch (iisdev) {
    case 1:
        iishdr (hdr, IWRITE + VRETRACE, 3, ZOOM, ADVXONTC, 0, 0, 0);
        iiswrite (hdr, iiswda[window].zoom, 6);
	break;
    case 2:
        tmp = iiswda[window].zoom;
        translate[0] = (tmp[0]<<12) + tmp[1];
        translate[1] = (tmp[0]<<12) + tmp[2];

	iishdr(hdr, IWRITE + VRETRACE, 2, M75_ZOOM, 0, 0,
               (1<<window) | 0200, 010001);
	iiswrite(hdr, translate, 4);
	break;
    }
}

/*zoom screen on cursor*/
iiszmsc (window)
int     window;
{
    int     pos[2];
    short  *wdp, *zoom;

    switch (iisdev) {
    case 1:
        zoom = iiswda[window].zoom;
        iiscrm (window, 0, pos);

        wdp = iiswda[window].wndw;
        zoom[0] = (zoom[0] + 1) % 4;
        zoom[1] = pos[0] + wdp[0];
        zoom[2] = pos[1] + wdp[1];
        iiszoom (window);
        iiscrm (window, 1, pos);
	break;
    case 2:
        zoom = iiswda[window].zoom;
        iiscrm (window, 0, pos);

        wdp = iiswda[window].wndw;
        zoom[0] = (zoom[0] + 1) % 4;
        zoom[1] = pos[0] + wdp[0];
        zoom[2] = pos[1] + wdp[1];
	zoom[1] = rework(zoom,0);
	zoom[2] = rework(zoom,1);
	iiszoom(window);
	iiscrm(window, 1, pos);
	break;
    }
}


/*zoom scroll memory*/
iiscroll (window)
int     window;
{
    static int  pos[2];
    short  *zoom, *status, *wdp;

    switch (iisdev) {
    case 1:
        zoom = iiswda[window].zoom;
        status = iiswda[window].cursor.status;
        iiscr (window, 1, pos);
        for (;;) {
	    iiscr (window, 0, pos);
	    if (M70_BD || M70_BA || M70_BB)
	        break;
	    if (M70_BC)
	        iiszmsc (window);
	    zoom[1] = pos[0];
	    zoom[2] = pos[1];
	    iiszoom (window);
        }
	break;
    case 2:
	zoom = iiswda[window].zoom;
	status = iiswda[window].cursor.status;
	iiscr(window, 1, pos);
	for (;;) {
	    iiscr(window, 0, pos);
	    if (M75_BD || M75_BA || M75_BB)
		break;
	    if (M75_BC){
		iiscrm(window, 0, pos);

		wdp = iiswda[window].wndw;
		zoom[0] = (zoom[0] + 1)%4;
		zoom[1] = pos[0] + wdp[0];
		zoom[2] = pos[1] + wdp[1];
		zoom[1] = rework(zoom,0);
		zoom[2] = rework(zoom,1);
		iiscr(window, 0, pos);
		iiszoom(window);
		iiscr(window, 1, pos);
	    } else {
		zoom[1] = pos[0];
		zoom[2] = pos[1];
		iiszoom(window);
	    }
	}
	break;
    }
}

/*zoom centered on window*/
iiszmw (window)
int     window;
{
    short  *wdp, *zoom;

    if (iisdev == 3)
	return;

    wdp = iiswda[window].wndw;
    zoom = iiswda[window].zoom;

    zoom[0] = (zoom[0] + 1) % 4;
    zoom[1] = (wdp[2] + wdp[0]) / 2;
    zoom[2] = (wdp[3] + wdp[1]) / 2;
    iiszoom (window);
}

/*zoom centered on xy in window*/
iiszmxy (window, pos)
int     window;
int     pos[2];
{
    short  *wdp, *zoom;

    if (iisdev == 3)
	return;

    wdp = iiswda[window].wndw;
    zoom = iiswda[window].zoom;

    zoom[0] = (zoom[0] + 1) % 4;
    zoom[1] = pos[0] + wdp[0];
    zoom[2] = pos[1] + wdp[1];
    iiszoom (window);
}

/* Routine to try to map model 70 zoom requests onto some sort of model
   75 sensibility.  Note this is not truly possible because of the severe
   change in model 75 architecture with respect to zoom and scroll.
   Model 70 I/O spec:
                      m70[0]    Magnification
                      m70[1]    X position
                      m70[2]    Y position
*/
rework(m70,y)
short int *m70, y;
{
short position, offset;

   if (m70[0] == 0) return(0); /* offset = 256; */
   if (m70[0] == 1 ) offset = 128;
   if (m70[0] == 2 ) offset =  64;
   if (m70[0] == 3 ) offset =  32;
         
   if (y) 
      position = m70[2] - offset;
   else 
      position = m70[1] - offset;

   return ( (position > 0) ? position : 0);
}