view src/scrollbar-x.c @ 1314:15a91d7ae2d1

[xemacs-hg @ 2003-02-20 08:16:21 by ben] check in makefile fixes et al Makefile.in.in: Major surgery. Move all stuff related to building anything in the src/ directory into src/. Simplify the dependencies -- everything in src/ is dependent on the single entry `src' in MAKE_SUBDIRS. Remove weirdo targets like `all-elc[s]', dump-elc[s], etc. mule/mule-msw-init.el: Removed. Delete this file. mule/mule-win32-init.el: New file, with stuff from mule-msw-init.el -- not just for MS Windows native, boys and girls! bytecomp.el: Change code inserted to catch trying to load a Mule-only .elc file in a non-Mule XEmacs. Formerly you got the rather cryptic "The required feature `mule' cannot be provided". Now you get "Loading this file requires Mule support". finder.el: Remove dependency on which directory this function is invoked from. update-elc.el: Don't mess around with ../src/BYTECOMPILE_CHANGE. Now that Makefile.in.in and xemacs.mak are in sync, both of them use NEEDTODUMP and the other one isn't used. dumped-lisp.el: Rewrite in terms of `list' and `nconc' instead of assemble-list, so we can have arbitrary forms, not just `when-feature'. very-early-lisp.el: Nuke this file. finder-inf.el, packages.el, update-elc.el, update-elc-2.el, loadup.el, make-docfile.el: Eliminate references to very-early-lisp. msw-glyphs.el: Comment clarification. xemacs.mak: Add macros DO_TEMACS, DO_XEMACS, and a few others; this macro section is now completely in sync with src/Makefile.in.in. Copy check-features, load-shadows, and rebuilding finder-inf.el from src/Makefile.in.in. The main build/dump/recompile process is now synchronized with src/Makefile.in.in. Change `WARNING' to `NOTE' and `error checking' to `error-checking' TO avoid tripping faux warnings and errors in the VC++ IDE. Makefile.in.in: Major surgery. Move all stuff related to building anything in the src/ directory from top-level Makefile.in.in to here. Simplify the dependencies. Rearrange into logical subsections. Synchronize the main compile/dump/build-elcs section with xemacs.mak, which is already clean and in good working order. Remove weirdo targets like `all-elc[s]', dump-elc[s], etc. Add additional levels of macros \(e.g. DO_TEMACS, DO_XEMACS, TEMACS_BATCH, XEMACS_BATCH, XEMACS_BATCH_PACKAGES) to factor out duplicated stuff. Clean up handling of "HEAP_IN_DATA" (Cygwin) so it doesn't need to ignore the return value from dumping. Add .NO_PARALLEL since various aspects of building and dumping must be serialized but do not always have dependencies between them (this is impossible in some cases). Everything related to src/ now gets built in one pass in this directory by just running `make' (except the Makefiles themselves and config.h, paths.h, Emacs.ad.h, and other generated .h files). console.c: Update list of possibly valid console types. emacs.c: Rationalize the specifying and handling of the type of the first frame. This was originally prompted by a workspace in which I got GTK to compile under C++ and in the process fixed it so it could coexist with X in the same build -- hence, a combined TTY/X/MS-Windows/GTK build is now possible under Cygwin. (However, you can't simultaneously *display* more than one kind of device connection -- but getting that to work is not that difficult. Perhaps a project for a bored grad student. I (ben) would do it but don't see the use.) To make sense of this, I added new switches that can be used to specifically indicate the window system: -x [aka --use-x], -tty \[aka --use-tty], -msw [aka --use-ms-windows], -gtk [aka --use-gtk], and -gnome [aka --use-gnome, same as --use-gtk]. -nw continues as an alias for -tty. When none have been given, XEmacs checks for other parameters implying particular device types (-t -> tty, -display -> x [or should it have same treatment as DISPLAY below?]), and has ad-hoc logic afterwards: if env var DISPLAY is set, use x (or gtk? perhaps should check whether gnome is running), else MS Windows if it exsits, else TTY if it exists, else stream, and you must be running in batch mode. This also fixes an existing bug whereby compiling with no x, no mswin, no tty, when running non- interactively (e.g. to dump) I get "sorry, must have TTY support". emacs.c: Turn on Vstack_trace_on_error so that errors are debuggable even when occurring extremely early in reinitialization. emacs.c: Try to make sure that the user can see message output under Windows (i.e. it doesn't just disappear right away) regardless of when it occurs, e.g. in the middle of creating the first frame. emacs.c: Define new function `emacs-run-status', indicating whether XEmacs is noninteractive or interactive, whether raw, post-dump/pdump-load or run-temacs, whether we are dumping, whether pdump is in effect. event-stream.c: It's "mommas are fat", not "momas are fat". Fix other typo. event-stream.c: Conditionalize in_menu_callback check on HAVE_MENUBARS, because it won't exist on w/o menubar support, lisp.h: More hackery on RETURN_NOT_REACHED. Cygwin v3.2 DOES complain here if RETURN_NOT_REACHED() is blank, as it is for GCC 2.5+. So make it blank only for GCC 2.5 through 2.999999999999999. Declare Vstack_trace_on_error. profile.c: Need to include "profile.h" to fix warnings. sheap.c: Don't fatal() when need to rerun Make, just stderr_out() and exit(0). That way we can distinguish between a dumping failing expectedly (due to lack of stack space, triggering another dump) and unexpectedly, in which case, we want to stop building. (or go on, if -K is given) syntax.c, syntax.h: Use ints where they belong, and enum syntaxcode's where they belong, and fix warnings thereby. syntax.h: Fix crash caused by an edge condition in the syntax-cache macros. text.h: Spacing fixes. xmotif.h: New file, to get around shadowing warnings. EmacsManager.c, event-Xt.c, glyphs-x.c, gui-x.c, input-method-motif.c, xmmanagerp.h, xmprimitivep.h: Include xmotif.h. alloc.c: Conditionalize in_malloc on ERROR_CHECK_MALLOC. config.h.in, file-coding.h, fileio.c, getloadavg.c, select-x.c, signal.c, sysdep.c, sysfile.h, systime.h, text.c, unicode.c: Eliminate HAVE_WIN32_CODING_SYSTEMS, use WIN32_ANY instead. Replace defined (WIN32_NATIVE) || defined (CYGWIN) with WIN32_ANY. lisp.h: More futile attempts to walk and chew gum at the same time when dealing with subr's that don't return.
author ben
date Thu, 20 Feb 2003 08:16:21 +0000
parents 37bdd24225ef
children b531bf8658e9
line wrap: on
line source

/* scrollbar implementation -- X interface.
   Copyright (C) 1994, 1995 Board of Trustees, University of Illinois.
   Copyright (C) 1994 Amdahl Corporation.
   Copyright (C) 1995 Sun Microsystems, Inc.
   Copyright (C) 1995 Darrell Kindred <dkindred+@cmu.edu>.

This file is part of XEmacs.

XEmacs is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.

XEmacs is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with XEmacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* Synched up with: Not in FSF. */

/* This file Mule-ized (more like Mule-verified) by Ben Wing, 7-8-00. */

#include <config.h>
#include "lisp.h"

#include "device-impl.h"
#include "frame-impl.h"
#include "window.h"

#include "console-x-impl.h"
#include "glyphs-x.h"
#include "gui-x.h"
#include "scrollbar-x.h"

#include "EmacsFrame.h"

static void x_update_vertical_scrollbar_callback (Widget widget, LWLIB_ID id,
						  XtPointer client_data);
static void x_update_horizontal_scrollbar_callback (Widget widget, LWLIB_ID id,
						    XtPointer client_data);

/* Used to prevent changing the size of the slider while drag
   scrolling, under Motif.  This is necessary because the Motif
   scrollbar is incredibly stupid about updating the slider and causes
   lots of flicker if it is done too often.  */
static int inhibit_slider_size_change;
int stupid_vertical_scrollbar_drag_hack;

/* Doesn't work with athena */
#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID)
static int vertical_drag_in_progress;
#endif


/* A device method. */
static int
x_inhibit_scrollbar_slider_size_change (void)
{
  /* Doesn't work with Athena */
#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID)
  return inhibit_slider_size_change;
#else
  return 0;
#endif
}

/* A device method. */
static void
x_free_scrollbar_instance (struct scrollbar_instance *instance)
{
  if (SCROLLBAR_X_NAME (instance))
    xfree (SCROLLBAR_X_NAME (instance));

  if (SCROLLBAR_X_WIDGET (instance))
    {
      if (XtIsManaged (SCROLLBAR_X_WIDGET (instance)))
	XtUnmanageChild (SCROLLBAR_X_WIDGET (instance));

      lw_destroy_all_widgets (SCROLLBAR_X_ID (instance));
    }

  if (instance->scrollbar_data)
    xfree (instance->scrollbar_data);
}

/* A device method. */
static void
x_release_scrollbar_instance (struct scrollbar_instance *instance)
{
  if (XtIsManaged (SCROLLBAR_X_WIDGET (instance)))
    XtUnmanageChild (SCROLLBAR_X_WIDGET (instance));
}

/* A device method. */
static void
x_create_scrollbar_instance (struct frame *f, int vertical,
			     struct scrollbar_instance *instance)
{
  char buffer[32];

  /* initialize the X specific data section. */
  instance->scrollbar_data = xnew_and_zero (struct x_scrollbar_data);

  SCROLLBAR_X_ID (instance) = new_lwlib_id ();
  sprintf (buffer, "scrollbar_%d", SCROLLBAR_X_ID (instance));
  SCROLLBAR_X_NAME (instance) = xstrdup (buffer);
#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID) || \
    defined (LWLIB_SCROLLBARS_ATHENA3D)
  SCROLLBAR_X_VDRAG_ORIG_VALUE (instance) = -1;
#endif

  if (vertical)
    {
      SCROLLBAR_X_WIDGET (instance) =
	lw_create_widget ("vertical-scrollbar", SCROLLBAR_X_NAME (instance),
			  SCROLLBAR_X_ID (instance),
			  NULL, FRAME_X_CONTAINER_WIDGET (f), 0,
			  x_update_vertical_scrollbar_callback, NULL, NULL);
    }
  else
    {
      SCROLLBAR_X_WIDGET (instance) =
	lw_create_widget ("horizontal-scrollbar", SCROLLBAR_X_NAME (instance),
			  SCROLLBAR_X_ID (instance),
			  NULL, FRAME_X_CONTAINER_WIDGET (f), 0,
			  x_update_horizontal_scrollbar_callback, NULL, NULL);
    }
}

#define UPDATE_DATA_FIELD(field)				\
  if (new_##field >= 0 &&					\
      SCROLLBAR_X_POS_DATA (inst).field != new_##field) {	\
    SCROLLBAR_X_POS_DATA (inst).field = new_##field;		\
    inst->scrollbar_instance_changed = 1;			\
  }

/* A device method. */
/* #### The -1 check is such a hack. */
static void
x_update_scrollbar_instance_values (struct window *w,
				    struct scrollbar_instance *inst,
				    int new_line_increment,
				    int new_page_increment,
				    int new_minimum, int new_maximum,
				    int new_slider_size,
				    int new_slider_position,
				    int new_scrollbar_width,
				    int new_scrollbar_height,
				    int new_scrollbar_x, int new_scrollbar_y)
{
  UPDATE_DATA_FIELD (line_increment);
  UPDATE_DATA_FIELD (page_increment);
  UPDATE_DATA_FIELD (minimum);
  UPDATE_DATA_FIELD (maximum);
  UPDATE_DATA_FIELD (slider_size);
  UPDATE_DATA_FIELD (slider_position);
  UPDATE_DATA_FIELD (scrollbar_width);
  UPDATE_DATA_FIELD (scrollbar_height);
  UPDATE_DATA_FIELD (scrollbar_x);
  UPDATE_DATA_FIELD (scrollbar_y);

  /* This doesn't work with Athena, why? */
#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID)
  if (w && !vertical_drag_in_progress)
    {
      int new_vov = SCROLLBAR_X_POS_DATA (inst).slider_position;
      int new_vows = marker_position (w->start[CURRENT_DISP]);

      if (SCROLLBAR_X_VDRAG_ORIG_VALUE (inst) != new_vov)
	{
	  SCROLLBAR_X_VDRAG_ORIG_VALUE (inst) = new_vov;
	  inst->scrollbar_instance_changed = 1;
	}
      if (SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (inst) != new_vows)
	{
	  SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (inst) = new_vows;
	  inst->scrollbar_instance_changed = 1;
	}
    }
#endif
}

/* Used by x_update_scrollbar_instance_status. */
static void
update_one_scrollbar_bs (struct frame *f, Widget sb_widget)
{
  Boolean use_backing_store;

  Xt_GET_VALUE (FRAME_X_TEXT_WIDGET (f), XtNuseBackingStore, &use_backing_store);

  if (use_backing_store && sb_widget)
    {
      unsigned long mask = CWBackingStore;
      XSetWindowAttributes attrs;

      attrs.backing_store = Always;
      XChangeWindowAttributes (XtDisplay (sb_widget),
			       XtWindow (sb_widget),
			       mask,
			       &attrs);
    }
}

/* Create a widget value structure for passing down to lwlib so that
   it can update the scrollbar widgets.  Used by
   x_update_scrollbar_instance_status. */
static widget_value *
scrollbar_instance_to_widget_value (struct scrollbar_instance *instance)
{
  widget_value *wv;

  wv = xmalloc_widget_value ();
  /* #### maybe should add malloc_scrollbar_values to resource these? */
  wv->scrollbar_data = xnew (scrollbar_values);

  wv->name = SCROLLBAR_X_NAME (instance);
  wv->name = xstrdup (wv->name);
  wv->value = 0;
  wv->key = 0;
  wv->enabled = instance->scrollbar_is_active;
  wv->selected = 0;
  wv->call_data = NULL;

  *wv->scrollbar_data = SCROLLBAR_X_POS_DATA (instance);

  wv->next = NULL;

  return wv;
}

/* Used by x_update_scrollbar_instance_status. */
static void
update_one_widget_scrollbar_pointer (struct window *w, Widget wid)
{
  if (POINTER_IMAGE_INSTANCEP (w->scrollbar_pointer))
    {
      XDefineCursor (XtDisplay (wid), XtWindow (wid),
		     XIMAGE_INSTANCE_X_CURSOR (w->scrollbar_pointer));
      XSync (XtDisplay (wid), False);
    }
}

/* A device method. */
static void
x_update_scrollbar_instance_status (struct window *w, int active, int size,
				    struct scrollbar_instance *instance)
{
  struct frame *f = XFRAME (w->frame);
  Boolean managed = XtIsManaged (SCROLLBAR_X_WIDGET (instance));

  if (active && size)
    {
      widget_value *wv = scrollbar_instance_to_widget_value (instance);

      if (instance->scrollbar_instance_changed)
	{
	  lw_modify_all_widgets (SCROLLBAR_X_ID (instance), wv, 0);
	  instance->scrollbar_instance_changed = 0;
	}

      if (!managed)
	{
	  XtManageChild (SCROLLBAR_X_WIDGET (instance));
	  if (XtWindow (SCROLLBAR_X_WIDGET (instance)))
	    {
	      /* Raise this window so that it's visible on top of the
                 text window below it. */
	      XRaiseWindow (XtDisplay (SCROLLBAR_X_WIDGET (instance)),
			    XtWindow (SCROLLBAR_X_WIDGET (instance)));
	      update_one_widget_scrollbar_pointer
		(w, SCROLLBAR_X_WIDGET (instance));
	      if (!SCROLLBAR_X_BACKING_STORE_INITIALIZED (instance))
		{
		  update_one_scrollbar_bs (f, SCROLLBAR_X_WIDGET (instance));
		  SCROLLBAR_X_BACKING_STORE_INITIALIZED (instance) = 1;
		}
	    }
	}

      if (!wv->scrollbar_data) abort ();
      free_widget_value_tree (wv);
    }
  else if (managed)
    {
#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID)
      /* This isn't needed with Athena Scrollbars.  It might not be needed */
      /* with Motif scrollbars (it is apparently needed with Lesstif). */
      XtUngrabKeyboard (SCROLLBAR_X_WIDGET (instance), CurrentTime);
#endif
      XtUnmanageChild (SCROLLBAR_X_WIDGET (instance));
    }
}

enum x_scrollbar_loop
{
  X_FIND_SCROLLBAR_WINDOW_MIRROR,
  X_SET_SCROLLBAR_POINTER,
  X_WINDOW_IS_SCROLLBAR,
  X_UPDATE_FRAME_SCROLLBARS
};

static struct window_mirror *
x_scrollbar_loop (enum x_scrollbar_loop type, Lisp_Object window,
		  struct window_mirror *mir,
		  LWLIB_ID id, Window x_win)
{
  struct window_mirror *retval = NULL;

  while (mir)
    {
      struct scrollbar_instance *vinstance = mir->scrollbar_vertical_instance;
      struct scrollbar_instance *hinstance = mir->scrollbar_horizontal_instance;
      struct window *w = XWINDOW (window);

      if (mir->vchild)
	retval = x_scrollbar_loop (type, w->vchild, mir->vchild, id, x_win);
      else if (mir->hchild)
	retval = x_scrollbar_loop (type, w->hchild, mir->hchild, id, x_win);
      if (retval)
	return retval;

      if (hinstance || vinstance)
	{
	  switch (type)
	    {
	    case X_FIND_SCROLLBAR_WINDOW_MIRROR:
	      if ((vinstance && SCROLLBAR_X_ID (vinstance) == id) ||
		  (hinstance && SCROLLBAR_X_ID (hinstance) == id))
		return mir;
	      break;
	    case X_UPDATE_FRAME_SCROLLBARS:
	      if (!mir->vchild && !mir->hchild)
		update_window_scrollbars (w, mir, 1, 0);
	      break;
	    case X_SET_SCROLLBAR_POINTER:
	      if (!mir->vchild && !mir->hchild)
		{
                  Widget widget;

		  widget = SCROLLBAR_X_WIDGET (hinstance);
		  if (widget && XtIsManaged (widget))
		    update_one_widget_scrollbar_pointer (w, widget);

		  widget = SCROLLBAR_X_WIDGET (vinstance);
		  if (widget && XtIsManaged (widget))
		    update_one_widget_scrollbar_pointer (w, widget);
		}
	      break;
	    case X_WINDOW_IS_SCROLLBAR:
	      if (!mir->vchild && !mir->hchild)
		{
		  Widget widget;

		  widget = SCROLLBAR_X_WIDGET (hinstance);
		  if (widget && XtIsManaged (widget) &&
		      XtWindow (widget) == x_win)
		    return (struct window_mirror *) 1;

		  widget = SCROLLBAR_X_WIDGET (vinstance);
		  if (widget && XtIsManaged (widget) &&
		      XtWindow (widget) == x_win)
		    return (struct window_mirror *) 1;
		}
	      break;
	    default:
	      abort ();
	    }
	}

      mir = mir->next;
      window = w->next;
    }

  return NULL;
}

/* Used by callbacks. */
static struct window_mirror *
find_scrollbar_window_mirror (struct frame *f, LWLIB_ID id)
{
  if (f->mirror_dirty)
    update_frame_window_mirror (f);
  return x_scrollbar_loop (X_FIND_SCROLLBAR_WINDOW_MIRROR, f->root_window,
			   XWINDOW_MIRROR (f->root_mirror), id, (Window) NULL);
}

/*
 * This is the only callback provided for vertical scrollbars.  It
 * should be able to handle all of the scrollbar events in
 * scroll_action (see lwlib.h).  The client data will be of type
 * scroll_event (see lwlib.h). */
static void
x_update_vertical_scrollbar_callback (Widget widget, LWLIB_ID id,
				      XtPointer client_data)
{
  /* This function can GC */
  scroll_event *data = (scroll_event *) client_data;
  struct device *d = get_device_from_display (XtDisplay (widget));
  struct frame *f = x_any_window_to_frame (d, XtWindow (widget));
  Lisp_Object win, frame;
  struct scrollbar_instance *instance;
  struct window_mirror *mirror;

  if (!f)
    return;

  mirror = find_scrollbar_window_mirror (f, id);
  if (!mirror)
    return;

  win = real_window (mirror, 1);

  if (NILP (win))
    return;
  instance = mirror->scrollbar_vertical_instance;
  frame = WINDOW_FRAME (XWINDOW (win));

  /* It seems that this is necessary whenever signal_special_Xt_user_event()
     is called.  #### Why??? */
  DEVICE_X_MOUSE_TIMESTAMP (d) = DEVICE_X_GLOBAL_MOUSE_TIMESTAMP (d);

  switch (data->action)
    {
    case SCROLLBAR_LINE_UP:
      signal_special_Xt_user_event (frame, Qscrollbar_line_up, win);
      break;

    case SCROLLBAR_LINE_DOWN:
      signal_special_Xt_user_event (frame, Qscrollbar_line_down, win);
      break;

      /* The Athena scrollbar paging behavior is that of xterms.
         Depending on where you click the size of the page varies.
         Motif always does a standard Emacs page. */
    case SCROLLBAR_PAGE_UP:
#if !defined (LWLIB_SCROLLBARS_MOTIF) && !defined (LWLIB_SCROLLBARS_LUCID) && \
    !defined (LWLIB_SCROLLBARS_ATHENA3D)
      {
	double tmp = ((double) data->slider_value /
		      (double) SCROLLBAR_X_POS_DATA(instance).scrollbar_height);
	double line = tmp *
	  (double) window_displayed_height (XWINDOW (win));

	if (line > -1.0)
	  line = -1.0;
	signal_special_Xt_user_event (frame, Qscrollbar_page_up,
				      Fcons (win, make_int ((int) line)));
      }
#else
      signal_special_Xt_user_event (frame, Qscrollbar_page_up,
				    Fcons (win, Qnil));
#endif
      break;

    case SCROLLBAR_PAGE_DOWN:
#if !defined (LWLIB_SCROLLBARS_MOTIF) && !defined (LWLIB_SCROLLBARS_LUCID) && \
    !defined (LWLIB_SCROLLBARS_ATHENA3D)
      {
	double tmp = ((double) data->slider_value /
		      (double) SCROLLBAR_X_POS_DATA(instance).scrollbar_height);
	double line = tmp *
	  (double) window_displayed_height (XWINDOW (win));

	if (SCROLLBAR_X_POS_DATA(instance).maximum >
	    (SCROLLBAR_X_POS_DATA(instance).slider_size + SCROLLBAR_X_POS_DATA(instance).slider_position))
	  {
	    if (line < 1.0)
	      line = 1.0;
	    signal_special_Xt_user_event (frame, Qscrollbar_page_down,
					  Fcons (win,
						 make_int ((int) line)));
	  }
      }
#else
      signal_special_Xt_user_event (frame, Qscrollbar_page_down,
				    Fcons (win, Qnil));
#endif
      break;

    case SCROLLBAR_TOP:
      signal_special_Xt_user_event (frame, Qscrollbar_to_top, win);
      break;

    case SCROLLBAR_BOTTOM:
      signal_special_Xt_user_event (frame, Qscrollbar_to_bottom, win);
      break;


    case SCROLLBAR_CHANGE:
      inhibit_slider_size_change = 0;
#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID)
      vertical_drag_in_progress = 0;
      SCROLLBAR_X_VDRAG_ORIG_VALUE (instance) = data->slider_value;
      SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (instance) =
	XINT (Fwindow_start (win));
#else
      stupid_vertical_scrollbar_drag_hack = 0;
#endif
      break;

    case SCROLLBAR_DRAG:
      {
	int value;

	inhibit_slider_size_change = 1;

#if defined (LWLIB_SCROLLBARS_MOTIF) || defined (LWLIB_SCROLLBARS_LUCID)
	/* Doing drags with Motif-like scrollbars is a mess, since we
	   want to avoid having the window position jump when you
	   first grab the scrollbar, but we also want to ensure that
	   you can scroll all the way to the top or bottom of the
	   buffer.  This can all be replaced with something sane when
	   we get line-based scrolling. */

	vertical_drag_in_progress = 1;

	if (SCROLLBAR_X_VDRAG_ORIG_VALUE (instance) < 0)
	  {
	    SCROLLBAR_X_VDRAG_ORIG_VALUE (instance) = data->slider_value;
	    SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (instance) =
	      XINT (Fwindow_start (win));
	  }

	/* Could replace this piecewise linear scrolling with a
	   quadratic through the three points, but I'm not sure that
	   would feel any nicer in practice. */
	if (data->slider_value < SCROLLBAR_X_VDRAG_ORIG_VALUE (instance))
	  {
	    /* We've dragged up; slide linearly from original position to
	       window-start=data.minimum, slider-value=data.minimum. */

	    if (SCROLLBAR_X_VDRAG_ORIG_VALUE (instance)
		<= SCROLLBAR_X_POS_DATA (instance).minimum)
	      {
		/* shouldn't get here, but just in case */
		value = SCROLLBAR_X_POS_DATA (instance).minimum;
	      }
	    else
	      {
		value = (int)
		  (SCROLLBAR_X_POS_DATA (instance).minimum
		   + (((double)
		       (SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (instance)
			- SCROLLBAR_X_POS_DATA (instance).minimum)
		       * (data->slider_value -
			  SCROLLBAR_X_POS_DATA (instance).minimum))
		      / (SCROLLBAR_X_VDRAG_ORIG_VALUE (instance)
			 - SCROLLBAR_X_POS_DATA (instance).minimum)));
	      }
	  }
	else
	  {
	    /* We've dragged down; slide linearly from original position to
	       window-start=data.maximum, slider-value=data.maximum. */

	    if (SCROLLBAR_X_VDRAG_ORIG_VALUE (instance)
		>= (SCROLLBAR_X_POS_DATA (instance).maximum -
		    SCROLLBAR_X_POS_DATA (instance).slider_size))
	      {
		/* avoid divide by zero */
		value = SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (instance);
	      }
	    else
	      {
		value = (int)
		  (SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (instance)
		   + (((double)
		       (SCROLLBAR_X_POS_DATA (instance).maximum
			- SCROLLBAR_X_VDRAG_ORIG_WINDOW_START (instance))
		       * (data->slider_value
			  - SCROLLBAR_X_VDRAG_ORIG_VALUE (instance)))
		      / (SCROLLBAR_X_POS_DATA (instance).maximum
			 - SCROLLBAR_X_POS_DATA (instance).slider_size
			 - SCROLLBAR_X_VDRAG_ORIG_VALUE (instance))));
	      }
	  }
#else
	stupid_vertical_scrollbar_drag_hack = 0;
	value = data->slider_value;
#endif

	if (value >= SCROLLBAR_X_POS_DATA (instance).maximum)
	  value = SCROLLBAR_X_POS_DATA (instance).maximum - 1;
	if (value < SCROLLBAR_X_POS_DATA (instance).minimum)
	  value = SCROLLBAR_X_POS_DATA (instance).minimum;

	signal_special_Xt_user_event (frame, Qscrollbar_vertical_drag,
				      Fcons (win, make_int (value)));
      }
      break;

    }
}

/*
 * This is the only callback provided for horizontal scrollbars.  It
 * should be able to handle all of the scrollbar events in
 * scroll_action (see lwlib.h).  The client data will be of type
 * scroll_event (see lwlib.h). */
static void
x_update_horizontal_scrollbar_callback (Widget widget, LWLIB_ID id,
					XtPointer client_data)
{
  scroll_event *data = (scroll_event *) client_data;
  struct device *d = get_device_from_display (XtDisplay (widget));
  struct frame *f = x_any_window_to_frame (d, XtWindow (widget));
  Lisp_Object win, frame;
  struct window_mirror *mirror;

  if (!f)
    return;

  mirror = find_scrollbar_window_mirror (f, id);
  if (!mirror)
    return;

  win = real_window (mirror, 1);

  if (NILP (win))
    return;
  frame = WINDOW_FRAME (XWINDOW (win));

  /* It seems that this is necessary whenever signal_special_Xt_user_event()
     is called.  #### Why??? */
  DEVICE_X_MOUSE_TIMESTAMP (d) = DEVICE_X_GLOBAL_MOUSE_TIMESTAMP (d);

  switch (data->action)
    {
    case SCROLLBAR_LINE_UP:
      signal_special_Xt_user_event (frame, Qscrollbar_char_left, win);
      break;
    case SCROLLBAR_LINE_DOWN:
      signal_special_Xt_user_event (frame, Qscrollbar_char_right, win);
      break;
    case SCROLLBAR_PAGE_UP:
      signal_special_Xt_user_event (frame, Qscrollbar_page_left, win);
      break;
    case SCROLLBAR_PAGE_DOWN:
      signal_special_Xt_user_event (frame, Qscrollbar_page_right, win);
      break;
    case SCROLLBAR_TOP:
      signal_special_Xt_user_event (frame, Qscrollbar_to_left, win);
      break;
    case SCROLLBAR_BOTTOM:
      signal_special_Xt_user_event (frame, Qscrollbar_to_right, win);
      break;
    case SCROLLBAR_CHANGE:
      inhibit_slider_size_change = 0;
      break;
    case SCROLLBAR_DRAG:
      inhibit_slider_size_change = 1;
      /* #### Fix the damn toolkit code so they all work the same way.
         Lucid is the one mostly wrong.*/
#if defined (LWLIB_SCROLLBARS_LUCID) || defined (LWLIB_SCROLLBARS_ATHENA3D)
      signal_special_Xt_user_event (frame, Qscrollbar_horizontal_drag,
				    (Fcons
				     (win, make_int (data->slider_value))));
#else
      signal_special_Xt_user_event (frame, Qscrollbar_horizontal_drag,
				    (Fcons
				     (win,
				      make_int (data->slider_value - 1))));
#endif
      break;
    default:
      break;
    }
}

static void
x_scrollbar_pointer_changed_in_window (struct window *w)
{
  Lisp_Object window = wrap_window (w);

  x_scrollbar_loop (X_SET_SCROLLBAR_POINTER, window, find_window_mirror (w),
		    0, (Window) NULL);
}

/* Make sure that all scrollbars on frame are up-to-date.  Called
   directly from x_set_frame_properties in frame-x.c*/
void
x_update_frame_scrollbars (struct frame *f)
{
  /* Consider this code to be "in_display" (in a critical section) so we
     abort() if elisp or QUIT is not properly wrapped -- see
     enter_redisplay_critical_section(). */
  in_display++;
  x_scrollbar_loop (X_UPDATE_FRAME_SCROLLBARS, f->root_window,
		    XWINDOW_MIRROR (f->root_mirror), 0, (Window) NULL);
  in_display--;
  if (in_display < 0) abort ();
}

#ifdef MEMORY_USAGE_STATS

static int
x_compute_scrollbar_instance_usage (struct device *d,
				    struct scrollbar_instance *inst,
				    struct overhead_stats *ovstats)
{
  int total = 0;

  while (inst)
    {
      struct x_scrollbar_data *data =
	(struct x_scrollbar_data *) inst->scrollbar_data;

      total += malloced_storage_size (data, sizeof (*data), ovstats);
      total += malloced_storage_size (data->name, 1 + strlen (data->name),
				      ovstats);
      inst = inst->next;
    }

  return total;
}

#endif /* MEMORY_USAGE_STATS */


/************************************************************************/
/*                            initialization                            */
/************************************************************************/

void
console_type_create_scrollbar_x (void)
{
  CONSOLE_HAS_METHOD (x, inhibit_scrollbar_slider_size_change);
  CONSOLE_HAS_METHOD (x, free_scrollbar_instance);
  CONSOLE_HAS_METHOD (x, release_scrollbar_instance);
  CONSOLE_HAS_METHOD (x, create_scrollbar_instance);
  CONSOLE_HAS_METHOD (x, update_scrollbar_instance_values);
  CONSOLE_HAS_METHOD (x, update_scrollbar_instance_status);
  CONSOLE_HAS_METHOD (x, scrollbar_pointer_changed_in_window);
#ifdef MEMORY_USAGE_STATS
  CONSOLE_HAS_METHOD (x, compute_scrollbar_instance_usage);
#endif /* MEMORY_USAGE_STATS */
}

void
reinit_vars_of_scrollbar_x (void)
{
  stupid_vertical_scrollbar_drag_hack = 1;
}

void
vars_of_scrollbar_x (void)
{
  reinit_vars_of_scrollbar_x ();

#if defined (LWLIB_SCROLLBARS_LUCID)
  Fprovide (intern ("lucid-scrollbars"));
#elif defined (LWLIB_SCROLLBARS_MOTIF)
  Fprovide (intern ("motif-scrollbars"));
#elif defined (LWLIB_SCROLLBARS_ATHENA)
  Fprovide (intern ("athena-scrollbars"));
#endif
}