view src/scrollbar-x.c @ 502:7039e6323819

[xemacs-hg @ 2001-05-04 22:41:46 by ben] ----------------------- byte-comp warning fixes ----------------- New functions for cleanly eliminating byte-compiler warnings. Their definitions require no changes at all in bytecomp.el, meaning that any package that wants to use them and be compatible with older versions of XEmacs need only copy the code and rename the functions (i.e. prefix them with the package name). Eliminate byte-compiler warnings using the new functions in bytecomp-runtime.el. Move coding-system-put,get,category, since they're not Mule-specific and are used in prefer-coding-system. font.el was incredibly ugly. Clean it up. Avoid using defsubst for any exported functions, to avoid possible compatibility problems if we later change the internal interface. (It happened before, with face accessors, between 19.8 and 19.9). Fix tons of warnings. Clean up (new function gpm-is-supported-p eliminates duplicate code in gpm-create/delete-device-hook) and eliminate warnings. ---------- make byte-recompile-directory work in the --------- core `lisp' dir, even in the absence of a Mule XEmacs (i.e. make it skip the Mule files rather than trying to compile them). now you should be able to do `touch *.el' in the `lisp' dir, then M-x byte-recompile-directory, and get no warnings. Avoid trying to compile Mule files in byte-recompile-directory when we're not in a Mule XEmacs, since we're highly likely to get syntax errors. Add a coding-system cookie to all Mule files so that byte-recompile-directory ignores them. Magic cookie function moved to files.el from code-files.el (for use by bytecomp even in a non-coding-system XEmacs), and changed names and semantics for use by bytecomp. NOTE: IMO this is an internal function that we can change as we like (and there is absolutely no code anywhere else using the function). ---------------- GUI improvements: menus, help ------------------- Rearrange order of keymap declarations to be alphabetical. Improve help on help to include all bindings, and group by category. Add bindings for new Info commands. Remove warnings. Use command-hyper-apropos in place of command-apropos. Add a function to do the equivalent of command-apropos. Evals its help-text argument so you can put expressions there. Used now by help-for-help. Add binding to continue text searches. Expand index searches to work over multiple info documents. Add commands to search text/index in User and Lispref. Add new entry, "Uncomment Region" (parallels "Comment Out Region"). Redo Help menu; add bindings for new Info commands to search the index or text of the User and Lispref manuals. Add command for mark-paragraph, activate-region. Make Edit->R accelerator be rectangle, not register (more commonly used), and put rectangle first. Fix the Edit Init File entry to never load the .elc file. Simplify the default-popup-menu. Add Cmds->Tabs menu. Use kp-left not kp_left, etc. ---------------- Miscellaneous bug fixes/cleanup ------------------- byte-compiler-options: Correct doc string. easy-menu-do-define: fix extra quote. fill-paragraph-or-region:Rewrite to be more correct -- use call-interactively so that we always get exactly the same behavior as if the functions were called directly. No need to fiddle with zmacs-region-stays, now that bogus clearing of it (2001-04-28 src/ChangeLog) is removed. Put dialog titles back in -- this time correctly. Fix various other problems with leaks and such. key-sequence-list-description: Clean up fun to always correctly canonicalize. Clean up Kinsoku comments, synch comment-region with FSF 20.7. * simple.el (region-exists-p): * simple.el (region-active-p): Add comment about which one is correct to use in menu specs. * sound.el (load-sound-file): Minor code clean up. * startup.el: * startup.el (command-line-early): * startup.el (initial-scratch-message): Comment changes. Add info about sample.init.el to splash screen. Improve initial-scratch-message and clarify purpose of Scratch buffer. Fix byte-compile warning. ------------------------ Added features ------------------------- Add new variable to control whether etags checks all parent directories for tag files. (On by default.) * hash-table.el: New file, useful utility functions. * dumped-lisp.el (preloaded-file-list): Dump hash-table.el. ------------ notable bug fix: Windows event code -------------- Get critical quit working. ------------ notable bug fix and new feature: regex code -------------- Shy groups were implemented in a horrible, half-assed way that would cause them to screw up regex searching in most cases. Fixed to work correctly. Also extended back-reference syntax past 9. Only is recognized as such if there are at least that many non-shy groups; and optionally will warn about such uses, to catch old code that might be using them differently. (Added variable to control this in search.c -- `warn-about-possibly-incompatible-back- references', on by default for the moment. Declared in lisp.h. ---------------- process/SIGIO improvements ------------------- define USE_GETADDRINFO to replace more complex conditional, and use it. the code conditionalized on this in unix_open_network_stream had *serious* problems handling errors. it's now fixed, and major amounts of duplicate code between the two versions were combined. don't disable SIGIO and other interrupts unless CONNECT_NEEDS_SLOWED_INTERRUPTS is defined -- don't penalize OS's without bugs. similarly for a freebsd bug that was affecting all OS's. * s\ultrix.h: define CONNECT_NEEDS_SLOWED_INTERRUPTS, since that's the OS mentioned as having a kernel bug. * sysdep.c (request_sigio_on_device): * sysdep.c (unrequest_sigio_on_device): fix SIGIO problems on Linux. add check for O_ASYNC in case it's defined and FASYNC isn't. add comment about other ways to do SIGIO on Linux. * callproc.c (Fold_call_process_internal): * process.c (Fstart_process_internal): Deal with the possibility that `default-directory' doesn't have terminating slash. Correct comments about vfork. ---------------- Miscellaneous bug fixes/cleanup ------------------- * callint.c (Finteractive): Add lots of documentation -- exactly what the Lisp equivalents of all the interactive specs are. * console.h (struct console): change type of quit_char to Emchar. * event-msw.c (lstream_type_create_mswindows_selectable): spacing change. Eliminate events-mod.h and combine into events.h. * emacs.c: * emacs.c (make_arg_list_1): * emacs.c (main_1): A couple of char->Extbyte changes, add a comment. * glyphs-msw.c: Correct indentation of function defns to not exceed 80 cols. Try (sort of) to fix some code that sets the colors of the progress gauge. (Commented out) * keymap.c (syms_of_keymap): use DEFSYMBOL. * process.c (read_process_output): No need to fiddle with zmacs_region_stays, now that bogus clearing of it (see below) is removed. * search.c (Freplace_match): warning fix.
author ben
date Fri, 04 May 2001 22:42:35 +0000
parents abe6d1db359e
children af57a77cbc92
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,
			   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, 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
}