view src/scrollbar-x.c @ 617:af57a77cbc92

[xemacs-hg @ 2001-06-18 07:09:50 by ben] --------------------------------------------------------------- DOCUMENTATION FIXES: --------------------------------------------------------------- eval.c: Correct documentation. elhash.c: Doc correction. --------------------------------------------------------------- LISP OBJECT CLEANUP: --------------------------------------------------------------- bytecode.h, buffer.h, casetab.h, chartab.h, console-msw.h, console.h, database.c, device.h, eldap.h, elhash.h, events.h, extents.h, faces.h, file-coding.h, frame.h, glyphs.h, gui-x.h, gui.h, keymap.h, lisp-disunion.h, lisp-union.h, lisp.h, lrecord.h, lstream.h, mule-charset.h, objects.h, opaque.h, postgresql.h, process.h, rangetab.h, specifier.h, toolbar.h, tooltalk.h, ui-gtk.h: Add wrap_* to all objects (it was already there for a few of them) -- an expression to encapsulate a pointer into a Lisp object, rather than the inconvenient XSET*. "wrap" was chosen because "make" as in make_int(), make_char() is not appropriate. (It implies allocation. The issue does not exist for ints and chars because they are not allocated.) Full error checking has been added to these expressions. When used without error checking, non-union build, use of these expressions will incur no loss of efficiency. (In fact, XSET* is now defined in terms of wrap_* in a non-union build.) In a union build, you will also get no loss of efficiency provided that you have a decent optimizing compiler, and a compiler that either understands inlines or automatically inlines those particular functions. (And since people don't normally do their production builds on union, it doesn't matter.) Update the sample Lisp object definition in lrecord.h accordingly. dumper.c: Fix places in dumper that referenced wrap_object to reference its new name, wrap_pointer_1. buffer.c, bufslots.h, conslots.h, console.c, console.h, devslots.h, device.c, device.h, frame.c, frame.h, frameslots.h, window.c, window.h, winslots.h: -- Extract out the Lisp objects of `struct device' into devslots.h, just like for the other structures. -- Extract out the remaining (not copied into the window config) Lisp objects in `struct window' into winslots.h; use different macros (WINDOW_SLOT vs. WINDOW_SAVED_SLOT) to differentiate them. -- Eliminate the `dead' flag of `struct frame', since it duplicates information already available in `framemeths', and fix FRAME_LIVE_P accordingly. (Devices and consoles already work this way.) -- In *slots.h, switch to system where MARKED_SLOT is automatically undef'd at the end of the file. (Follows what winslots.h already does.) -- Update the comments at the beginning of *slots.h to be accurate. -- When making any of the above objects dead, zero it out entirely and reset all Lisp object slots to Qnil. (We were already doing this somewhat, but not consistently.) This (1) Eliminates the possibility of extra objects hanging around that ought to be GC'd, (2) Causes an immediate crash if anyone tries to access a structure in one of these objects, (3) Ensures consistent behavior wrt dead objects. dialog-msw.c: Use internal_object_printer, since this object should not escape. --------------------------------------------------------------- FIXING A CRASH THAT I HIT ONCE (AND A RELATED BAD BEHAVIOR): --------------------------------------------------------------- eval.c: Fix up some comments about the FSF implementation. Fix two nasty bugs: (1) condition_case_unwind frees the conses sitting in the catch->tag slot too quickly, resulting in a crash that I hit. (2) catches need to be unwound one at a time when calling unwind-protect code, rather than all at once at the end; otherwise, incorrect behavior can result. (A comment shows exactly how.) backtrace.h: Improve comment about FSF differences in the handler stack. --------------------------------------------------------------- FIXING A CRASH THAT I REPEATEDLY HIT WHEN USING THE MOUSE WHEEL UNDER MSWINDOWS: --------------------------------------------------------------- Basic idea: My crash is due either to a dead, non-marked, GC-collected frame inside of a window mirror, or a prematurely freed window mirror. We need to mark the Lisp objects inside of window mirrors. Tracking the lifespan of window mirrors and scrollbar instances is extremely hard, and there may well be lurking bugs where such objects are freed too soon. The only safe way to fix these problems (and it fixes both problems at once) is to make both of these structures Lisp objects. lrecord.h, emacs.c, inline.c, scrollbar-gtk.c, scrollbar-msw.c, scrollbar-x.c, scrollbar.c, scrollbar.h, symsinit.h: Make scrollbar instances actual Lisp objects. Mark the window mirrors in them. inline.c needs to know about scrollbar.h now. Record the new type in lrecord.h. Fix up scrollbar-*.c appropriately. Create a hash table in scrollbar-msw.c so that the scrollbar instances stored in scrollbar HWND's are properly GC-protected. Create complex_vars_of_scrollbar_mswindows() to create the hash table at startup, and call it from emacs.c. Don't store the scrollbar instance as a property of the GTK scrollbar, as it's not used and if we did this, we'd have to separately GC-protect it in a hash table, like in MS Windows. lrecord.h, frame.h, frame.c, frameslots.h, redisplay.c, window.c, window.h: Move mark_window_mirror from redisplay.c to window.c. Make window mirrors actual Lisp objects. Tell lrecord.h about them. Change the window mirror member of struct frame from a pointer to a Lisp object, and add XWINDOW_MIRROR in appropriate places. Mark the scrollbar instances in the window mirror. redisplay.c, redisplay.h, alloc.c: Delete mark_redisplay. Don't call mark_redisplay. We now mark frame-specific structures in mark_frame. NOTE: I also deleted an extremely questionable call to update_frame_window_mirrors(). It was extremely questionable before, and now totally impossible, since it will create Lisp objects during redisplay. frame.c: Mark the scrollbar instances, which are now Lisp objects. Call mark_gutter() here, not in mark_redisplay(). gutter.c: Update comments about correct marking. --------------------------------------------------------------- ISSUES BROUGHT UP BY MARTIN: --------------------------------------------------------------- buffer.h: Put back these macros the way Steve T and I think they ought to be. I already explained in a previous changelog entry why I think these macros should be the way I'd defined them. Once again: We fix these macros so they don't care about the type of their lvalues. The non-C-string equivalents of these already function in the same way, and it's correct because it should be OK to pass in a CBufbyte *, a BufByte *, a Char_Binary *, an UChar_Binary *, etc. The whole reason for these different types is to work around errors caused by signed-vs-unsigned non-matching types. Any possible error that might be caught in a DFC macro would also be caught wherever the argument is used elsewhere. So creating multiple macro versions would add no useful error-checking and just further complicate an already complicated area. As for Martin's "ANSI aliasing" bug, XEmacs is not ANSI-aliasing clean and probably never will be. Unless the board agrees to change XEmacs in this way (and we really don't want to go down that road), this is not a bug. sound.h: Undo Martin's type change. signal.c: Fix problem identified by Martin with Linux and g++ due to non-standard declaration of setitimer(). systime.h: Update the docs for "qxe_" to point out why making the encapsulation explicit is always the right way to go. (setitimer() itself serves as an example.) For 21.4: update-elc-2.el: Correct misplaced parentheses, making lisp/mule not get recompiled.
author ben
date Mon, 18 Jun 2001 07:10:32 +0000
parents abe6d1db359e
children e38acbeb1cae
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 "console-x.h"
#include "EmacsFrame.h"
#include "glyphs-x.h"
#include "gui-x.h"
#include "scrollbar-x.h"

#include "frame.h"
#include "window.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;

  XSETWINDOW (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" so that we abort() if Fsignal()
     gets called. */
  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
}