/* $XConsortium: ScroVis.c /main/6 1995/09/19 23:07:44 cde-sun $ */
/*
 * Motif
 *
 * Copyright (c) 1987-2012, The Open Group. All rights reserved.
 *
 * These libraries and programs are free software; you can
 * redistribute them and/or modify them under the terms of the GNU
 * Lesser General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * These libraries and programs are distributed in the hope that
 * they will be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE. See the GNU Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with these librararies and programs; if not, write
 * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
 * Floor, Boston, MA 02110-1301 USA
 * 
 */
/*
 * HISTORY
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


#include <Xm/ScrolledWP.h>
#include <Xm/NavigatorT.h>
#include "ScrollFramTI.h"
#include "MessagesI.h"
#include "XmI.h"

#define SWMessage1      _XmMMsgScrollVis_0000 

/************************************************************************
 *									*
 * XmScrollVisible -  TraverseObscureCallback helper                    *
 *									*
 ************************************************************************/
void
XmScrollVisible(
		Widget      	scrw,
		Widget          wid,
		Dimension       hor_margin, 
		Dimension       ver_margin)
/*********************
 * A function that makes visible a unvisible or partially visible descendant 
 * of an AUTOMATIC scrolledwindow workwindow.
 *********************
 * - scrw is the ScrolledWindow whose workwindow act as the origin of the move.
 * - wid is the widget to be made visible.
 * - hor_margin, ver_margin are the margins between the widget in its new 
 *   position and the scrolledwindow clipwindow.
**********************/
{
    XmScrolledWindowWidget sw = (XmScrolledWindowWidget) scrw ;
    register 
    Position newx, newy,      /* new workwindow position */
             wx, wy  ;        /* current workwindow position */
    register 
    unsigned short tw, th,         /* widget sizes */
              cw, ch ;        /* clipwindow sizes */
    Position dx, dy ;         /* position inside the workwindow */
    Position src_x, src_y, dst_x, dst_y ;
    Widget w ;
    XmScrolledWindowConstraint swc;
    XmNavigatorDataRec nav_data ;
    _XmWidgetToAppContext(scrw);

    _XmAppLock(app);
    /* check param */
    if (!((scrw) && (XmIsScrolledWindow(scrw)) &&
	  (sw->swindow.ScrollPolicy == XmAUTOMATIC))) {
	XmeWarning(scrw, SWMessage1);
	_XmAppUnlock(app);
	return ;
    }

    /* loop up in search for a "workwindow" */
    w = wid;
    while (w && (XtParent(w) != (Widget) sw->swindow.ClipWindow))
      w = XtParent(w);
    if (!w) {
	XmeWarning(scrw, SWMessage1);
	_XmAppUnlock(app);
	return ;
    }

    /* w is the potentially scrollable ascendant of wid that needs to 
       be scrolled, its parent is the clip window */
    /* In the new scheme, w might not be able to scroll at all,
       or even in the direction the margins point to. There is
       nothing much we can do about that except document that
       traversing to an unvisible kid of unscrollable workwindow will
       not scroll it, resulting in unvisible focus widget. We could
       check for NO_SCROLL in w, but since we cannot check for SCROLL_HOR
       or SCROLL_VERT - depend on the traversal layout - I'd rather do 
       nothing */

    /* we need to get the position of wid relative to w, 
       so we use 2 XtTranslateCoords */
    
    XtTranslateCoords(wid, 0, 0, &src_x, &src_y);
    XtTranslateCoords(w, 0, 0, &dst_x, &dst_y);
    dx = src_x - dst_x ;
    dy = src_y - dst_y ;

    swc = GetSWConstraint(w);
   
    /* get the other positions and sizes */
    cw = XtWidth((Widget) sw->swindow.ClipWindow) ;
    ch = XtHeight((Widget) sw->swindow.ClipWindow) ;
    wx = swc->orig_x - XtX(w) ;  
    wy = swc->orig_y - XtY(w) ; /* both always positive */
    tw = XtWidth(wid) ;
    th = XtHeight(wid) ;
    
    /* find out the zone where the widget lies and set newx,newy (neg) for
       the workw */
    /* if the widget is bigger than the clipwindow, we put it on
       the left, top or top/left, depending on the zone it was */

    if (dy < wy) {                                       /* North */
	newy = dy - (Position)ver_margin ;      /* stuck it on top + margin */
    } else 
    if ((dy + th) <= (ch - XtY(w))) {
	newy = wy ;               /* in the middle : don't move y */
    } else {                                             /* South */
	if (th > ch)
	    newy = dy - (Position)ver_margin ; /* stuck it on top if too big */
	else
	    newy = swc->orig_y + dy - ch + th + (Position)ver_margin;
    } 
	
    if (dx < wx) {                              /* West */
	newx = dx - (Position)hor_margin ; /* stuck it on left + margin */
    } else
    if ((dx + tw) <= (cw - XtX(w))) {
	newx = wx ;  /* in the middle : don't move x */
    } else {                                     /* East */
	if (tw > cw)
	    newx = dx - (Position)hor_margin ; /* stuck it on left if too big */
	else
	    newx = swc->orig_x + dx - cw + tw + (Position)hor_margin;
    } 

    /* a last check */
    if (newx > sw->swindow.hmax - sw->swindow.hExtent) 
	newx = sw->swindow.hmax - sw->swindow.hExtent;
    if (newy > sw->swindow.vmax - sw->swindow.vExtent) 
	newy = sw->swindow.vmax - sw->swindow.vExtent;
    if (newx < sw->swindow.hmin) newx =  sw->swindow.hmin ;
    if (newy < sw->swindow.vmin) newy =  sw->swindow.vmin ;

    nav_data.valueMask = NavValue ;
    nav_data.value.x = newx ;
    nav_data.value.y = newy ;
    nav_data.dimMask = NavigDimensionX|NavigDimensionY ;
    _XmSFUpdateNavigatorsValue((Widget)sw, &nav_data, True);
    _XmAppUnlock(app);
}