gtk2/gtk/gtkrange.c

/* GTK - The GIMP Toolkit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 * Copyright (C) 2001 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it 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.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Modified by the GTK+ Team and others 1997-2004.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

#include "config.h"

#include <stdio.h>
#include <math.h>

#include "gtkrange.h"
#include "gtkrangeprivate.h"

#include "gtkadjustmentprivate.h"
#include "gtkboxgadgetprivate.h"
#include "gtkbuiltiniconprivate.h"
#include "gtkcsscustomgadgetprivate.h"
#include "gtkcolorscaleprivate.h"
#include "gtkintl.h"
#include "gtkgesturelongpressprivate.h"
#include "gtkmain.h"
#include "gtkmarshalers.h"
#include "gtkorientableprivate.h"
#include "gtkprivate.h"
#include "gtkscale.h"
#include "gtkscrollbar.h"
#include "gtktypebuiltins.h"
#include "gtkwindow.h"
#include "gtkwidgetprivate.h"
#include "a11y/gtkrangeaccessible.h"
#include "gtkcssstylepropertyprivate.h"

/**
 * SECTION:gtkrange
 * @Short_description: Base class for widgets which visualize an adjustment
 * @Title: GtkRange
 *
 * #GtkRange is the common base class for widgets which visualize an
 * adjustment, e.g #GtkScale or #GtkScrollbar.
 *
 * Apart from signals for monitoring the parameters of the adjustment,
 * #GtkRange provides properties and methods for influencing the sensitivity
 * of the “steppers”. It also provides properties and methods for setting a
 * “fill level” on range widgets. See gtk_range_set_fill_level().
 */


#define TIMEOUT_INITIAL     500
#define TIMEOUT_REPEAT      250
#define AUTOSCROLL_FACTOR   20
#define SCROLL_EDGE_SIZE    15
#define MARK_SNAP_LENGTH    12

typedef struct _GtkRangeStepTimer GtkRangeStepTimer;

struct _GtkRangePrivate
{
  GtkCssGadget *mouse_location;
  /* last mouse coords we got, or G_MININT if mouse is outside the range */
  gint  mouse_x;
  gint  mouse_y;
  GtkCssGadget *grab_location;   /* "grabbed" mouse location, NULL for no grab */

  GtkRangeStepTimer *timer;

  GtkAdjustment     *adjustment;
  GtkSensitivityType lower_sensitivity;
  GtkSensitivityType upper_sensitivity;

  /* Steppers are: < > ---- < >
   *               a b      c d
   */
  GtkCssGadget *contents_gadget;
  GtkCssGadget *stepper_a_gadget;
  GtkCssGadget *stepper_b_gadget;
  GtkCssGadget *stepper_c_gadget;
  GtkCssGadget *stepper_d_gadget;
  GtkCssGadget *trough_gadget;
  GtkCssGadget *fill_gadget;
  GtkCssGadget *highlight_gadget;
  GtkCssGadget *slider_gadget;

  GtkOrientation     orientation;

  gdouble  fill_level;
  gdouble *marks;

  gint *mark_pos;
  gint  n_marks;
  gint  round_digits;                /* Round off value to this many digits, -1 for no rounding */
  gint  slide_initial_slider_position;
  gint  slide_initial_coordinate_delta;

  guint flippable              : 1;
  guint inverted               : 1;
  guint slider_size_fixed      : 1;
  guint trough_click_forward   : 1;  /* trough click was on the forward side of slider */

  /* Stepper sensitivity */
  guint lower_sensitive        : 1;
  guint upper_sensitive        : 1;

  /* The range has an origin, should be drawn differently. Used by GtkScale */
  guint has_origin             : 1;

  /* Whether we're doing fine adjustment */
  guint zoom                   : 1;

  /* Fill level */
  guint show_fill_level        : 1;
  guint restrict_to_fill_level : 1;

  /* Whether dragging is ongoing */
  guint in_drag                : 1;

  GtkGesture *long_press_gesture;
  GtkGesture *multipress_gesture;
  GtkGesture *drag_gesture;

  GtkScrollType autoscroll_mode;
  guint autoscroll_id;
};


enum {
  PROP_0,
  PROP_ADJUSTMENT,
  PROP_INVERTED,
  PROP_LOWER_STEPPER_SENSITIVITY,
  PROP_UPPER_STEPPER_SENSITIVITY,
  PROP_SHOW_FILL_LEVEL,
  PROP_RESTRICT_TO_FILL_LEVEL,
  PROP_FILL_LEVEL,
  PROP_ROUND_DIGITS,
  PROP_ORIENTATION,
  LAST_PROP = PROP_ORIENTATION
};

enum {
  VALUE_CHANGED,
  ADJUST_BOUNDS,
  MOVE_SLIDER,
  CHANGE_VALUE,
  LAST_SIGNAL
};

static void gtk_range_set_property   (GObject          *object,
                                      guint             prop_id,
                                      const GValue     *value,
                                      GParamSpec       *pspec);
static void gtk_range_get_property   (GObject          *object,
                                      guint             prop_id,
                                      GValue           *value,
                                      GParamSpec       *pspec);
static void gtk_range_finalize       (GObject          *object);
static void gtk_range_destroy        (GtkWidget        *widget);
static void gtk_range_measure        (GtkWidget      *widget,
                                      GtkOrientation  orientation,
                                      int             for_size,
                                      int            *minimum,
                                      int            *natural,
                                      int            *minimum_baseline,
                                      int            *natural_baseline);
static void gtk_range_size_allocate  (GtkWidget        *widget,
                                      GtkAllocation    *allocation);
static void gtk_range_unmap          (GtkWidget        *widget);
static void gtk_range_snapshot       (GtkWidget        *widget,
                                      GtkSnapshot      *snapshot);

static void gtk_range_multipress_gesture_pressed  (GtkGestureMultiPress *gesture,
                                                   guint                 n_press,
                                                   gdouble               x,
                                                   gdouble               y,
                                                   GtkRange             *range);
static void gtk_range_multipress_gesture_released (GtkGestureMultiPress *gesture,
                                                   guint                 n_press,
                                                   gdouble               x,
                                                   gdouble               y,
                                                   GtkRange             *range);
static void gtk_range_drag_gesture_begin          (GtkGestureDrag       *gesture,
                                                   gdouble               offset_x,
                                                   gdouble               offset_y,
                                                   GtkRange             *range);
static void gtk_range_drag_gesture_update         (GtkGestureDrag       *gesture,
                                                   gdouble               offset_x,
                                                   gdouble               offset_y,
                                                   GtkRange             *range);
static void gtk_range_long_press_gesture_pressed  (GtkGestureLongPress  *gesture,
                                                   gdouble               x,
                                                   gdouble               y,
                                                   GtkRange             *range);


static gboolean gtk_range_scroll_event   (GtkWidget        *widget,
                                      GdkEventScroll   *event);
static gboolean gtk_range_event       (GtkWidget       *widget,
                                       GdkEvent        *event);
static void update_slider_position   (GtkRange	       *range,
				      gint              mouse_x,
				      gint              mouse_y);
static void stop_scrolling           (GtkRange         *range);
static void add_autoscroll           (GtkRange         *range);
static void remove_autoscroll        (GtkRange         *range);

/* Range methods */

static void gtk_range_move_slider              (GtkRange         *range,
                                                GtkScrollType     scroll);

/* Internals */
static void          gtk_range_compute_slider_position  (GtkRange      *range,
                                                         gdouble        adjustment_value,
                                                         GdkRectangle  *slider_rect);
static gboolean      gtk_range_scroll                   (GtkRange      *range,
                                                         GtkScrollType  scroll);
static void          gtk_range_update_mouse_location    (GtkRange      *range);
static void          gtk_range_calc_slider              (GtkRange      *range);
static void          gtk_range_calc_stepper_sensitivity (GtkRange      *range);
static void          gtk_range_calc_marks               (GtkRange      *range);
static void          gtk_range_adjustment_value_changed (GtkAdjustment *adjustment,
                                                         gpointer       data);
static void          gtk_range_adjustment_changed       (GtkAdjustment *adjustment,
                                                         gpointer       data);
static void          gtk_range_add_step_timer           (GtkRange      *range,
                                                         GtkScrollType  step);
static void          gtk_range_remove_step_timer        (GtkRange      *range);
static gboolean      gtk_range_real_change_value        (GtkRange      *range,
                                                         GtkScrollType  scroll,
                                                         gdouble        value);
static gboolean      gtk_range_key_press                (GtkWidget     *range,
							 GdkEventKey   *event);
static void          gtk_range_state_flags_changed      (GtkWidget     *widget,
                                                         GtkStateFlags  previous_state);
static void          gtk_range_direction_changed        (GtkWidget     *widget,
                                                         GtkTextDirection  previous_direction);
static void          gtk_range_measure_trough           (GtkCssGadget   *gadget,
                                                         GtkOrientation  orientation,
                                                         gint            for_size,
                                                         gint           *minimum,
                                                         gint           *natural,
                                                         gint           *minimum_baseline,
                                                         gint           *natural_baseline,
                                                         gpointer        user_data);
static void          gtk_range_allocate_trough          (GtkCssGadget        *gadget,
                                                         const GtkAllocation *allocation,
                                                         int                  baseline,
                                                         GtkAllocation       *out_clip,
                                                         gpointer             data);
static gboolean      gtk_range_render_trough            (GtkCssGadget *gadget,
                                                         GtkSnapshot  *snapshot,
                                                         int           x,
                                                         int           y,
                                                         int           width,
                                                         int           height,
                                                         gpointer      user_data);

G_DEFINE_TYPE_WITH_CODE (GtkRange, gtk_range, GTK_TYPE_WIDGET,
                         G_ADD_PRIVATE (GtkRange)
                         G_IMPLEMENT_INTERFACE (GTK_TYPE_ORIENTABLE,
                                                NULL))

static guint signals[LAST_SIGNAL];
static GParamSpec *properties[LAST_PROP];

static void
gtk_range_class_init (GtkRangeClass *class)
{
  GObjectClass   *gobject_class;
  GtkWidgetClass *widget_class;

  gobject_class = G_OBJECT_CLASS (class);
  widget_class = (GtkWidgetClass*) class;

  gobject_class->set_property = gtk_range_set_property;
  gobject_class->get_property = gtk_range_get_property;
  gobject_class->finalize = gtk_range_finalize;

  widget_class->destroy = gtk_range_destroy;
  widget_class->measure = gtk_range_measure;
  widget_class->size_allocate = gtk_range_size_allocate;
  widget_class->unmap = gtk_range_unmap;
  widget_class->snapshot = gtk_range_snapshot;
  widget_class->event = gtk_range_event;
  widget_class->scroll_event = gtk_range_scroll_event;
  widget_class->key_press_event = gtk_range_key_press;
  widget_class->state_flags_changed = gtk_range_state_flags_changed;
  widget_class->direction_changed = gtk_range_direction_changed;

  class->move_slider = gtk_range_move_slider;
  class->change_value = gtk_range_real_change_value;

  /**
   * GtkRange::value-changed:
   * @range: the #GtkRange that received the signal
   *
   * Emitted when the range value changes.
   */
  signals[VALUE_CHANGED] =
    g_signal_new (I_("value-changed"),
                  G_TYPE_FROM_CLASS (gobject_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (GtkRangeClass, value_changed),
                  NULL, NULL,
                  NULL,
                  G_TYPE_NONE, 0);

  /**
   * GtkRange::adjust-bounds:
   * @range: the #GtkRange that received the signal
   * @value: the value before we clamp
   *
   * Emitted before clamping a value, to give the application a
   * chance to adjust the bounds.
   */
  signals[ADJUST_BOUNDS] =
    g_signal_new (I_("adjust-bounds"),
                  G_TYPE_FROM_CLASS (gobject_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (GtkRangeClass, adjust_bounds),
                  NULL, NULL,
                  NULL,
                  G_TYPE_NONE, 1,
                  G_TYPE_DOUBLE);

  /**
   * GtkRange::move-slider:
   * @range: the #GtkRange that received the signal
   * @step: how to move the slider
   *
   * Virtual function that moves the slider. Used for keybindings.
   */
  signals[MOVE_SLIDER] =
    g_signal_new (I_("move-slider"),
                  G_TYPE_FROM_CLASS (gobject_class),
                  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
                  G_STRUCT_OFFSET (GtkRangeClass, move_slider),
                  NULL, NULL,
                  NULL,
                  G_TYPE_NONE, 1,
                  GTK_TYPE_SCROLL_TYPE);

  /**
   * GtkRange::change-value:
   * @range: the #GtkRange that received the signal
   * @scroll: the type of scroll action that was performed
   * @value: the new value resulting from the scroll action
   *
   * The #GtkRange::change-value signal is emitted when a scroll action is
   * performed on a range.  It allows an application to determine the
   * type of scroll event that occurred and the resultant new value.
   * The application can handle the event itself and return %TRUE to
   * prevent further processing.  Or, by returning %FALSE, it can pass
   * the event to other handlers until the default GTK+ handler is
   * reached.
   *
   * The value parameter is unrounded.  An application that overrides
   * the GtkRange::change-value signal is responsible for clamping the
   * value to the desired number of decimal digits; the default GTK+
   * handler clamps the value based on #GtkRange:round-digits.
   *
   * Returns: %TRUE to prevent other handlers from being invoked for
   *     the signal, %FALSE to propagate the signal further
   *
   * Since: 2.6
   */
  signals[CHANGE_VALUE] =
    g_signal_new (I_("change-value"),
                  G_TYPE_FROM_CLASS (gobject_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (GtkRangeClass, change_value),
                  _gtk_boolean_handled_accumulator, NULL,
                  _gtk_marshal_BOOLEAN__ENUM_DOUBLE,
                  G_TYPE_BOOLEAN, 2,
                  GTK_TYPE_SCROLL_TYPE,
                  G_TYPE_DOUBLE);

  g_object_class_override_property (gobject_class, PROP_ORIENTATION, "orientation");

  properties[PROP_ADJUSTMENT] =
      g_param_spec_object ("adjustment",
                           P_("Adjustment"),
                           P_("The GtkAdjustment that contains the current value of this range object"),
                           GTK_TYPE_ADJUSTMENT,
                           GTK_PARAM_READWRITE|G_PARAM_CONSTRUCT);

  properties[PROP_INVERTED] =
      g_param_spec_boolean ("inverted",
                            P_("Inverted"),
                            P_("Invert direction slider moves to increase range value"),
                            FALSE,
                            GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  properties[PROP_LOWER_STEPPER_SENSITIVITY] =
      g_param_spec_enum ("lower-stepper-sensitivity",
                         P_("Lower stepper sensitivity"),
                         P_("The sensitivity policy for the stepper that points to the adjustment’s lower side"),
                         GTK_TYPE_SENSITIVITY_TYPE,
                         GTK_SENSITIVITY_AUTO,
                         GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  properties[PROP_UPPER_STEPPER_SENSITIVITY] =
      g_param_spec_enum ("upper-stepper-sensitivity",
                         P_("Upper stepper sensitivity"),
                         P_("The sensitivity policy for the stepper that points to the adjustment’s upper side"),
                         GTK_TYPE_SENSITIVITY_TYPE,
                         GTK_SENSITIVITY_AUTO,
                         GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  /**
   * GtkRange:show-fill-level:
   *
   * The show-fill-level property controls whether fill level indicator
   * graphics are displayed on the trough. See
   * gtk_range_set_show_fill_level().
   *
   * Since: 2.12
   **/
  properties[PROP_SHOW_FILL_LEVEL] =
      g_param_spec_boolean ("show-fill-level",
                            P_("Show Fill Level"),
                            P_("Whether to display a fill level indicator graphics on trough."),
                            FALSE,
                            GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  /**
   * GtkRange:restrict-to-fill-level:
   *
   * The restrict-to-fill-level property controls whether slider
   * movement is restricted to an upper boundary set by the
   * fill level. See gtk_range_set_restrict_to_fill_level().
   *
   * Since: 2.12
   **/
  properties[PROP_RESTRICT_TO_FILL_LEVEL] =
      g_param_spec_boolean ("restrict-to-fill-level",
                            P_("Restrict to Fill Level"),
                            P_("Whether to restrict the upper boundary to the fill level."),
                            TRUE,
                            GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  /**
   * GtkRange:fill-level:
   *
   * The fill level (e.g. prebuffering of a network stream).
   * See gtk_range_set_fill_level().
   *
   * Since: 2.12
   **/
  properties[PROP_FILL_LEVEL] =
      g_param_spec_double ("fill-level",
                           P_("Fill Level"),
                           P_("The fill level."),
                           -G_MAXDOUBLE, G_MAXDOUBLE,
                           G_MAXDOUBLE,
                           GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  /**
   * GtkRange:round-digits:
   *
   * The number of digits to round the value to when
   * it changes, or -1. See #GtkRange::change-value.
   *
   * Since: 2.24
   */
  properties[PROP_ROUND_DIGITS] =
      g_param_spec_int ("round-digits",
                        P_("Round Digits"),
                        P_("The number of digits to round the value to."),
                        -1, G_MAXINT,
                        -1,
                        GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);

  g_object_class_install_properties (gobject_class, LAST_PROP, properties);

  gtk_widget_class_set_accessible_type (widget_class, GTK_TYPE_RANGE_ACCESSIBLE);
}

static void
gtk_range_sync_orientation (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  GtkOrientation orientation;

  orientation = gtk_orientable_get_orientation (GTK_ORIENTABLE (range));
  _gtk_orientable_set_style_classes (GTK_ORIENTABLE (range));
  gtk_box_gadget_set_orientation (GTK_BOX_GADGET (priv->contents_gadget), orientation);
}

static void
gtk_range_set_property (GObject      *object,
			guint         prop_id,
			const GValue *value,
			GParamSpec   *pspec)
{
  GtkRange *range = GTK_RANGE (object);
  GtkRangePrivate *priv = range->priv;

  switch (prop_id)
    {
    case PROP_ORIENTATION:
      if (priv->orientation != g_value_get_enum (value))
        {
          priv->orientation = g_value_get_enum (value);
          gtk_range_sync_orientation (range);
          gtk_widget_queue_resize (GTK_WIDGET (range));
          g_object_notify_by_pspec (object, pspec);
        }
      break;
    case PROP_ADJUSTMENT:
      gtk_range_set_adjustment (range, g_value_get_object (value));
      break;
    case PROP_INVERTED:
      gtk_range_set_inverted (range, g_value_get_boolean (value));
      break;
    case PROP_LOWER_STEPPER_SENSITIVITY:
      gtk_range_set_lower_stepper_sensitivity (range, g_value_get_enum (value));
      break;
    case PROP_UPPER_STEPPER_SENSITIVITY:
      gtk_range_set_upper_stepper_sensitivity (range, g_value_get_enum (value));
      break;
    case PROP_SHOW_FILL_LEVEL:
      gtk_range_set_show_fill_level (range, g_value_get_boolean (value));
      break;
    case PROP_RESTRICT_TO_FILL_LEVEL:
      gtk_range_set_restrict_to_fill_level (range, g_value_get_boolean (value));
      break;
    case PROP_FILL_LEVEL:
      gtk_range_set_fill_level (range, g_value_get_double (value));
      break;
    case PROP_ROUND_DIGITS:
      gtk_range_set_round_digits (range, g_value_get_int (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
gtk_range_get_property (GObject      *object,
			guint         prop_id,
			GValue       *value,
			GParamSpec   *pspec)
{
  GtkRange *range = GTK_RANGE (object);
  GtkRangePrivate *priv = range->priv;

  switch (prop_id)
    {
    case PROP_ORIENTATION:
      g_value_set_enum (value, priv->orientation);
      break;
    case PROP_ADJUSTMENT:
      g_value_set_object (value, priv->adjustment);
      break;
    case PROP_INVERTED:
      g_value_set_boolean (value, priv->inverted);
      break;
    case PROP_LOWER_STEPPER_SENSITIVITY:
      g_value_set_enum (value, gtk_range_get_lower_stepper_sensitivity (range));
      break;
    case PROP_UPPER_STEPPER_SENSITIVITY:
      g_value_set_enum (value, gtk_range_get_upper_stepper_sensitivity (range));
      break;
    case PROP_SHOW_FILL_LEVEL:
      g_value_set_boolean (value, gtk_range_get_show_fill_level (range));
      break;
    case PROP_RESTRICT_TO_FILL_LEVEL:
      g_value_set_boolean (value, gtk_range_get_restrict_to_fill_level (range));
      break;
    case PROP_FILL_LEVEL:
      g_value_set_double (value, gtk_range_get_fill_level (range));
      break;
    case PROP_ROUND_DIGITS:
      g_value_set_int (value, gtk_range_get_round_digits (range));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
gtk_range_init (GtkRange *range)
{
  GtkRangePrivate *priv;
  GtkCssNode *widget_node;

  range->priv = gtk_range_get_instance_private (range);
  priv = range->priv;

  gtk_widget_set_has_window (GTK_WIDGET (range), FALSE);

  priv->orientation = GTK_ORIENTATION_HORIZONTAL;
  priv->adjustment = NULL;
  priv->inverted = FALSE;
  priv->flippable = FALSE;
  priv->round_digits = -1;
  priv->mouse_x = G_MININT;
  priv->mouse_y = G_MININT;
  priv->lower_sensitivity = GTK_SENSITIVITY_AUTO;
  priv->upper_sensitivity = GTK_SENSITIVITY_AUTO;
  priv->lower_sensitive = TRUE;
  priv->upper_sensitive = TRUE;
  priv->has_origin = FALSE;
  priv->show_fill_level = FALSE;
  priv->restrict_to_fill_level = TRUE;
  priv->fill_level = G_MAXDOUBLE;
  priv->timer = NULL;

  _gtk_orientable_set_style_classes (GTK_ORIENTABLE (range));

  widget_node = gtk_widget_get_css_node (GTK_WIDGET (range));
  priv->contents_gadget = gtk_box_gadget_new ("contents",
                                              GTK_WIDGET (range),
                                              NULL, NULL);
  gtk_css_node_set_parent (gtk_css_gadget_get_node (priv->contents_gadget),
                           widget_node);

  priv->trough_gadget = gtk_css_custom_gadget_new ("trough",
                                                   GTK_WIDGET (range),
                                                   NULL, NULL,
                                                   gtk_range_measure_trough,
                                                   gtk_range_allocate_trough,
                                                   gtk_range_render_trough,
                                                   NULL, NULL);
  gtk_css_gadget_set_state (priv->trough_gadget,
                            gtk_css_node_get_state (widget_node));
  gtk_box_gadget_insert_gadget (GTK_BOX_GADGET (priv->contents_gadget), -1, priv->trough_gadget,
                                TRUE, GTK_ALIGN_CENTER);

  priv->slider_gadget = gtk_builtin_icon_new ("slider",
                                              GTK_WIDGET (range),
                                              priv->trough_gadget, NULL);
  gtk_css_gadget_set_state (priv->slider_gadget,
                            gtk_css_node_get_state (widget_node));

  /* Note: Order is important here.
   * The ::drag-begin handler relies on the state set up by the
   * multipress ::pressed handler. Gestures are handling events
   * in the oppposite order in which they are added to their
   * widget.
   */
  priv->drag_gesture = gtk_gesture_drag_new (GTK_WIDGET (range));
  gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (priv->drag_gesture), 0);
  g_signal_connect (priv->drag_gesture, "drag-begin",
                    G_CALLBACK (gtk_range_drag_gesture_begin), range);
  g_signal_connect (priv->drag_gesture, "drag-update",
                    G_CALLBACK (gtk_range_drag_gesture_update), range);

  priv->multipress_gesture = gtk_gesture_multi_press_new (GTK_WIDGET (range));
  gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (priv->multipress_gesture), 0);
  gtk_gesture_group (priv->drag_gesture, priv->multipress_gesture);
  g_signal_connect (priv->multipress_gesture, "pressed",
                    G_CALLBACK (gtk_range_multipress_gesture_pressed), range);
  g_signal_connect (priv->multipress_gesture, "released",
                    G_CALLBACK (gtk_range_multipress_gesture_released), range);

  priv->long_press_gesture = gtk_gesture_long_press_new (GTK_WIDGET (range));
  g_object_set (priv->long_press_gesture, "delay-factor", 2.0, NULL);
  gtk_gesture_group (priv->drag_gesture, priv->long_press_gesture);
  g_signal_connect (priv->long_press_gesture, "pressed",
                    G_CALLBACK (gtk_range_long_press_gesture_pressed), range);
}

/**
 * gtk_range_get_adjustment:
 * @range: a #GtkRange
 * 
 * Get the #GtkAdjustment which is the “model” object for #GtkRange.
 * See gtk_range_set_adjustment() for details.
 * The return value does not have a reference added, so should not
 * be unreferenced.
 * 
 * Returns: (transfer none): a #GtkAdjustment
 **/
GtkAdjustment*
gtk_range_get_adjustment (GtkRange *range)
{
  GtkRangePrivate *priv;

  g_return_val_if_fail (GTK_IS_RANGE (range), NULL);

  priv = range->priv;

  if (!priv->adjustment)
    gtk_range_set_adjustment (range, NULL);

  return priv->adjustment;
}

/**
 * gtk_range_set_adjustment:
 * @range: a #GtkRange
 * @adjustment: a #GtkAdjustment
 *
 * Sets the adjustment to be used as the “model” object for this range
 * widget. The adjustment indicates the current range value, the
 * minimum and maximum range values, the step/page increments used
 * for keybindings and scrolling, and the page size. The page size
 * is normally 0 for #GtkScale and nonzero for #GtkScrollbar, and
 * indicates the size of the visible area of the widget being scrolled.
 * The page size affects the size of the scrollbar slider.
 **/
void
gtk_range_set_adjustment (GtkRange      *range,
			  GtkAdjustment *adjustment)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  if (!adjustment)
    adjustment = gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
  else
    g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));

  if (priv->adjustment != adjustment)
    {
      if (priv->adjustment)
	{
	  g_signal_handlers_disconnect_by_func (priv->adjustment,
						gtk_range_adjustment_changed,
						range);
	  g_signal_handlers_disconnect_by_func (priv->adjustment,
						gtk_range_adjustment_value_changed,
						range);
	  g_object_unref (priv->adjustment);
	}

      priv->adjustment = adjustment;
      g_object_ref_sink (adjustment);
      
      g_signal_connect (adjustment, "changed",
			G_CALLBACK (gtk_range_adjustment_changed),
			range);
      g_signal_connect (adjustment, "value-changed",
			G_CALLBACK (gtk_range_adjustment_value_changed),
			range);
      
      gtk_range_adjustment_changed (adjustment, range);
      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_ADJUSTMENT]);
    }
}

static gboolean
should_invert (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;

  if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)
    return
      (priv->inverted && !priv->flippable) ||
      (priv->inverted && priv->flippable && gtk_widget_get_direction (GTK_WIDGET (range)) == GTK_TEXT_DIR_LTR) ||
      (!priv->inverted && priv->flippable && gtk_widget_get_direction (GTK_WIDGET (range)) == GTK_TEXT_DIR_RTL);
  else
    return priv->inverted;
}

static void
update_highlight_position (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;

  if (!priv->highlight_gadget)
    return;

  if (should_invert (range))
    {
      gtk_css_gadget_remove_class (priv->highlight_gadget, GTK_STYLE_CLASS_TOP);
      gtk_css_gadget_add_class (priv->highlight_gadget, GTK_STYLE_CLASS_BOTTOM);
    }
  else
    {
      gtk_css_gadget_remove_class (priv->highlight_gadget, GTK_STYLE_CLASS_BOTTOM);
      gtk_css_gadget_add_class (priv->highlight_gadget, GTK_STYLE_CLASS_TOP);
    }
}

static void
update_fill_position (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;

  if (!priv->fill_gadget)
    return;

  if (should_invert (range))
    {
      gtk_css_gadget_remove_class (priv->fill_gadget, GTK_STYLE_CLASS_TOP);
      gtk_css_gadget_add_class (priv->fill_gadget, GTK_STYLE_CLASS_BOTTOM);
    }
  else
    {
      gtk_css_gadget_remove_class (priv->fill_gadget, GTK_STYLE_CLASS_BOTTOM);
      gtk_css_gadget_add_class (priv->fill_gadget, GTK_STYLE_CLASS_TOP);
    }
}

static void
update_stepper_state (GtkRange     *range,
                      GtkCssGadget *gadget)
{
  GtkRangePrivate *priv = range->priv;
  GtkStateFlags state;
  gboolean arrow_sensitive;

  state = gtk_widget_get_state_flags (GTK_WIDGET (range));

  if ((!priv->inverted &&
       (gadget == priv->stepper_a_gadget || gadget == priv->stepper_c_gadget)) ||
      (priv->inverted &&
       (gadget == priv->stepper_b_gadget || gadget == priv->stepper_d_gadget)))
    arrow_sensitive = priv->lower_sensitive;
  else
    arrow_sensitive = priv->upper_sensitive;

  state &= ~(GTK_STATE_FLAG_ACTIVE | GTK_STATE_FLAG_PRELIGHT);

  if ((state & GTK_STATE_FLAG_INSENSITIVE) || !arrow_sensitive)
    {
      state |= GTK_STATE_FLAG_INSENSITIVE;
    }
  else
    {
      if (priv->grab_location == gadget)
        state |= GTK_STATE_FLAG_ACTIVE;
      if (priv->mouse_location == gadget)
        state |= GTK_STATE_FLAG_PRELIGHT;
    }

  gtk_css_gadget_set_state (gadget, state);
}

static void
update_steppers_state (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;

  if (priv->stepper_a_gadget)
    update_stepper_state (range, priv->stepper_a_gadget);
  if (priv->stepper_b_gadget)
    update_stepper_state (range, priv->stepper_b_gadget);
  if (priv->stepper_c_gadget)
    update_stepper_state (range, priv->stepper_c_gadget);
  if (priv->stepper_d_gadget)
    update_stepper_state (range, priv->stepper_d_gadget);
}

/**
 * gtk_range_set_inverted:
 * @range: a #GtkRange
 * @setting: %TRUE to invert the range
 *
 * Ranges normally move from lower to higher values as the
 * slider moves from top to bottom or left to right. Inverted
 * ranges have higher values at the top or on the right rather than
 * on the bottom or left.
 **/
void
gtk_range_set_inverted (GtkRange *range,
                        gboolean  setting)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  setting = setting != FALSE;

  if (setting != priv->inverted)
    {
      priv->inverted = setting;

      update_steppers_state (range);
      update_fill_position (range);
      update_highlight_position (range);

      gtk_widget_queue_resize (GTK_WIDGET (range));

      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_INVERTED]);
    }
}

/**
 * gtk_range_get_inverted:
 * @range: a #GtkRange
 * 
 * Gets the value set by gtk_range_set_inverted().
 * 
 * Returns: %TRUE if the range is inverted
 **/
gboolean
gtk_range_get_inverted (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), FALSE);

  return range->priv->inverted;
}

/**
 * gtk_range_set_flippable:
 * @range: a #GtkRange
 * @flippable: %TRUE to make the range flippable
 *
 * If a range is flippable, it will switch its direction if it is
 * horizontal and its direction is %GTK_TEXT_DIR_RTL.
 *
 * See gtk_widget_get_direction().
 *
 * Since: 2.18
 **/
void
gtk_range_set_flippable (GtkRange *range,
                         gboolean  flippable)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  flippable = flippable ? TRUE : FALSE;

  if (flippable != priv->flippable)
    {
      priv->flippable = flippable;
      update_fill_position (range);
      update_highlight_position (range);

      gtk_widget_queue_allocate (GTK_WIDGET (range));
    }
}

/**
 * gtk_range_get_flippable:
 * @range: a #GtkRange
 *
 * Gets the value set by gtk_range_set_flippable().
 *
 * Returns: %TRUE if the range is flippable
 *
 * Since: 2.18
 **/
gboolean
gtk_range_get_flippable (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), FALSE);

  return range->priv->flippable;
}

/**
 * gtk_range_set_slider_size_fixed:
 * @range: a #GtkRange
 * @size_fixed: %TRUE to make the slider size constant
 *
 * Sets whether the range’s slider has a fixed size, or a size that
 * depends on its adjustment’s page size.
 *
 * This function is useful mainly for #GtkRange subclasses.
 *
 * Since: 2.20
 **/
void
gtk_range_set_slider_size_fixed (GtkRange *range,
                                 gboolean  size_fixed)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  if (size_fixed != priv->slider_size_fixed)
    {
      priv->slider_size_fixed = size_fixed ? TRUE : FALSE;

      if (priv->adjustment && gtk_widget_get_mapped (GTK_WIDGET (range)))
        gtk_css_gadget_queue_allocate (priv->slider_gadget);
    }
}

/**
 * gtk_range_get_slider_size_fixed:
 * @range: a #GtkRange
 *
 * This function is useful mainly for #GtkRange subclasses.
 *
 * See gtk_range_set_slider_size_fixed().
 *
 * Returns: whether the range’s slider has a fixed size.
 *
 * Since: 2.20
 **/
gboolean
gtk_range_get_slider_size_fixed (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), FALSE);

  return range->priv->slider_size_fixed;
}

static void
measure_one_gadget (GtkCssGadget *gadget,
                    int          *width_out,
                    int          *height_out)
{
  gtk_css_gadget_get_preferred_size (gadget,
                                     GTK_ORIENTATION_HORIZONTAL, -1,
                                     width_out, NULL,
                                     NULL, NULL);
  gtk_css_gadget_get_preferred_size (gadget,
                                     GTK_ORIENTATION_VERTICAL, -1,
                                     height_out, NULL,
                                     NULL, NULL);
}

/**
 * gtk_range_get_range_rect:
 * @range: a #GtkRange
 * @range_rect: (out): return location for the range rectangle
 *
 * This function returns the area that contains the range’s trough
 * and its steppers, in widget->window coordinates.
 *
 * This function is useful mainly for #GtkRange subclasses.
 *
 * Since: 2.20
 **/
void
gtk_range_get_range_rect (GtkRange     *range,
                          GdkRectangle *range_rect)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));
  g_return_if_fail (range_rect != NULL);

  priv = range->priv;

  gtk_css_gadget_get_margin_box (priv->contents_gadget, range_rect);
}

/**
 * gtk_range_get_slider_range:
 * @range: a #GtkRange
 * @slider_start: (out) (allow-none): return location for the slider's
 *     start, or %NULL
 * @slider_end: (out) (allow-none): return location for the slider's
 *     end, or %NULL
 *
 * This function returns sliders range along the long dimension,
 * in widget->window coordinates.
 *
 * This function is useful mainly for #GtkRange subclasses.
 *
 * Since: 2.20
 **/
void
gtk_range_get_slider_range (GtkRange *range,
                            gint     *slider_start,
                            gint     *slider_end)
{
  GtkRangePrivate *priv;
  GtkAllocation slider_alloc;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  gtk_css_gadget_get_margin_box (priv->slider_gadget, &slider_alloc);

  if (priv->orientation == GTK_ORIENTATION_VERTICAL)
    {
      if (slider_start)
        *slider_start = slider_alloc.y;
      if (slider_end)
        *slider_end = slider_alloc.y + slider_alloc.height;
    }
  else
    {
      if (slider_start)
        *slider_start = slider_alloc.x;
      if (slider_end)
        *slider_end = slider_alloc.x + slider_alloc.width;
    }
}

/**
 * gtk_range_set_lower_stepper_sensitivity:
 * @range:       a #GtkRange
 * @sensitivity: the lower stepper’s sensitivity policy.
 *
 * Sets the sensitivity policy for the stepper that points to the
 * 'lower' end of the GtkRange’s adjustment.
 *
 * Since: 2.10
 **/
void
gtk_range_set_lower_stepper_sensitivity (GtkRange           *range,
                                         GtkSensitivityType  sensitivity)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  if (priv->lower_sensitivity != sensitivity)
    {
      priv->lower_sensitivity = sensitivity;

      gtk_range_calc_stepper_sensitivity (range);

      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_LOWER_STEPPER_SENSITIVITY]);
    }
}

/**
 * gtk_range_get_lower_stepper_sensitivity:
 * @range: a #GtkRange
 *
 * Gets the sensitivity policy for the stepper that points to the
 * 'lower' end of the GtkRange’s adjustment.
 *
 * Returns: The lower stepper’s sensitivity policy.
 *
 * Since: 2.10
 **/
GtkSensitivityType
gtk_range_get_lower_stepper_sensitivity (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), GTK_SENSITIVITY_AUTO);

  return range->priv->lower_sensitivity;
}

/**
 * gtk_range_set_upper_stepper_sensitivity:
 * @range:       a #GtkRange
 * @sensitivity: the upper stepper’s sensitivity policy.
 *
 * Sets the sensitivity policy for the stepper that points to the
 * 'upper' end of the GtkRange’s adjustment.
 *
 * Since: 2.10
 **/
void
gtk_range_set_upper_stepper_sensitivity (GtkRange           *range,
                                         GtkSensitivityType  sensitivity)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  if (priv->upper_sensitivity != sensitivity)
    {
      priv->upper_sensitivity = sensitivity;

      gtk_range_calc_stepper_sensitivity (range);

      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_UPPER_STEPPER_SENSITIVITY]);
    }
}

/**
 * gtk_range_get_upper_stepper_sensitivity:
 * @range: a #GtkRange
 *
 * Gets the sensitivity policy for the stepper that points to the
 * 'upper' end of the GtkRange’s adjustment.
 *
 * Returns: The upper stepper’s sensitivity policy.
 *
 * Since: 2.10
 **/
GtkSensitivityType
gtk_range_get_upper_stepper_sensitivity (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), GTK_SENSITIVITY_AUTO);

  return range->priv->upper_sensitivity;
}

/**
 * gtk_range_set_increments:
 * @range: a #GtkRange
 * @step: step size
 * @page: page size
 *
 * Sets the step and page sizes for the range.
 * The step size is used when the user clicks the #GtkScrollbar
 * arrows or moves #GtkScale via arrow keys. The page size
 * is used for example when moving via Page Up or Page Down keys.
 **/
void
gtk_range_set_increments (GtkRange *range,
                          gdouble   step,
                          gdouble   page)
{
  GtkAdjustment *adjustment;

  g_return_if_fail (GTK_IS_RANGE (range));

  adjustment = range->priv->adjustment;

  gtk_adjustment_configure (adjustment,
                            gtk_adjustment_get_value (adjustment),
                            gtk_adjustment_get_lower (adjustment),
                            gtk_adjustment_get_upper (adjustment),
                            step,
                            page,
                            gtk_adjustment_get_page_size (adjustment));
}

/**
 * gtk_range_set_range:
 * @range: a #GtkRange
 * @min: minimum range value
 * @max: maximum range value
 * 
 * Sets the allowable values in the #GtkRange, and clamps the range
 * value to be between @min and @max. (If the range has a non-zero
 * page size, it is clamped between @min and @max - page-size.)
 **/
void
gtk_range_set_range (GtkRange *range,
                     gdouble   min,
                     gdouble   max)
{
  GtkRangePrivate *priv;
  GtkAdjustment *adjustment;
  gdouble value;
  
  g_return_if_fail (GTK_IS_RANGE (range));
  g_return_if_fail (min <= max);

  priv = range->priv;
  adjustment = priv->adjustment;

  value = gtk_adjustment_get_value (adjustment);
  if (priv->restrict_to_fill_level)
    value = MIN (value, MAX (gtk_adjustment_get_lower (adjustment),
                             priv->fill_level));

  gtk_adjustment_configure (adjustment,
                            value,
                            min,
                            max,
                            gtk_adjustment_get_step_increment (adjustment),
                            gtk_adjustment_get_page_increment (adjustment),
                            gtk_adjustment_get_page_size (adjustment));
}

/**
 * gtk_range_set_value:
 * @range: a #GtkRange
 * @value: new value of the range
 *
 * Sets the current value of the range; if the value is outside the
 * minimum or maximum range values, it will be clamped to fit inside
 * them. The range emits the #GtkRange::value-changed signal if the 
 * value changes.
 **/
void
gtk_range_set_value (GtkRange *range,
                     gdouble   value)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  if (priv->restrict_to_fill_level)
    value = MIN (value, MAX (gtk_adjustment_get_lower (priv->adjustment),
                             priv->fill_level));

  gtk_adjustment_set_value (priv->adjustment, value);
}

/**
 * gtk_range_get_value:
 * @range: a #GtkRange
 * 
 * Gets the current value of the range.
 * 
 * Returns: current value of the range.
 **/
gdouble
gtk_range_get_value (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), 0.0);

  return gtk_adjustment_get_value (range->priv->adjustment);
}

/**
 * gtk_range_set_show_fill_level:
 * @range:           A #GtkRange
 * @show_fill_level: Whether a fill level indicator graphics is shown.
 *
 * Sets whether a graphical fill level is show on the trough. See
 * gtk_range_set_fill_level() for a general description of the fill
 * level concept.
 *
 * Since: 2.12
 **/
void
gtk_range_set_show_fill_level (GtkRange *range,
                               gboolean  show_fill_level)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  show_fill_level = show_fill_level ? TRUE : FALSE;

  if (show_fill_level == priv->show_fill_level)
    return;

  priv->show_fill_level = show_fill_level;

  if (show_fill_level)
    {
      priv->fill_gadget = gtk_css_custom_gadget_new ("fill",
                                                     GTK_WIDGET (range),
                                                     priv->trough_gadget, NULL,
                                                     NULL, NULL, NULL,
                                                     NULL, NULL);
      gtk_css_gadget_set_state (priv->fill_gadget,
                                gtk_css_node_get_state (gtk_css_gadget_get_node (priv->trough_gadget)));

      update_fill_position (range);
    }
  else
    {
      gtk_css_node_set_parent (gtk_css_gadget_get_node (priv->fill_gadget), NULL);
      g_clear_object (&priv->fill_gadget);
    }

  g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_SHOW_FILL_LEVEL]);
  gtk_widget_queue_allocate (GTK_WIDGET (range));
}

/**
 * gtk_range_get_show_fill_level:
 * @range: A #GtkRange
 *
 * Gets whether the range displays the fill level graphically.
 *
 * Returns: %TRUE if @range shows the fill level.
 *
 * Since: 2.12
 **/
gboolean
gtk_range_get_show_fill_level (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), FALSE);

  return range->priv->show_fill_level;
}

/**
 * gtk_range_set_restrict_to_fill_level:
 * @range:                  A #GtkRange
 * @restrict_to_fill_level: Whether the fill level restricts slider movement.
 *
 * Sets whether the slider is restricted to the fill level. See
 * gtk_range_set_fill_level() for a general description of the fill
 * level concept.
 *
 * Since: 2.12
 **/
void
gtk_range_set_restrict_to_fill_level (GtkRange *range,
                                      gboolean  restrict_to_fill_level)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  restrict_to_fill_level = restrict_to_fill_level ? TRUE : FALSE;

  if (restrict_to_fill_level != priv->restrict_to_fill_level)
    {
      priv->restrict_to_fill_level = restrict_to_fill_level;
      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_RESTRICT_TO_FILL_LEVEL]);

      gtk_range_set_value (range, gtk_range_get_value (range));
    }
}

/**
 * gtk_range_get_restrict_to_fill_level:
 * @range: A #GtkRange
 *
 * Gets whether the range is restricted to the fill level.
 *
 * Returns: %TRUE if @range is restricted to the fill level.
 *
 * Since: 2.12
 **/
gboolean
gtk_range_get_restrict_to_fill_level (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), FALSE);

  return range->priv->restrict_to_fill_level;
}

/**
 * gtk_range_set_fill_level:
 * @range: a #GtkRange
 * @fill_level: the new position of the fill level indicator
 *
 * Set the new position of the fill level indicator.
 *
 * The “fill level” is probably best described by its most prominent
 * use case, which is an indicator for the amount of pre-buffering in
 * a streaming media player. In that use case, the value of the range
 * would indicate the current play position, and the fill level would
 * be the position up to which the file/stream has been downloaded.
 *
 * This amount of prebuffering can be displayed on the range’s trough
 * and is themeable separately from the trough. To enable fill level
 * display, use gtk_range_set_show_fill_level(). The range defaults
 * to not showing the fill level.
 *
 * Additionally, it’s possible to restrict the range’s slider position
 * to values which are smaller than the fill level. This is controller
 * by gtk_range_set_restrict_to_fill_level() and is by default
 * enabled.
 *
 * Since: 2.12
 **/
void
gtk_range_set_fill_level (GtkRange *range,
                          gdouble   fill_level)
{
  GtkRangePrivate *priv;

  g_return_if_fail (GTK_IS_RANGE (range));

  priv = range->priv;

  if (fill_level != priv->fill_level)
    {
      priv->fill_level = fill_level;
      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_FILL_LEVEL]);

      if (priv->show_fill_level)
        gtk_widget_queue_allocate (GTK_WIDGET (range));

      if (priv->restrict_to_fill_level)
        gtk_range_set_value (range, gtk_range_get_value (range));
    }
}

/**
 * gtk_range_get_fill_level:
 * @range: A #GtkRange
 *
 * Gets the current position of the fill level indicator.
 *
 * Returns: The current fill level
 *
 * Since: 2.12
 **/
gdouble
gtk_range_get_fill_level (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), 0.0);

  return range->priv->fill_level;
}

static void
gtk_range_destroy (GtkWidget *widget)
{
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;

  gtk_range_remove_step_timer (range);

  if (priv->adjustment)
    {
      g_signal_handlers_disconnect_by_func (priv->adjustment,
					    gtk_range_adjustment_changed,
					    range);
      g_signal_handlers_disconnect_by_func (priv->adjustment,
					    gtk_range_adjustment_value_changed,
					    range);
      g_object_unref (priv->adjustment);
      priv->adjustment = NULL;
    }

  if (priv->n_marks)
    {
      g_free (priv->marks);
      priv->marks = NULL;
      g_free (priv->mark_pos);
      priv->mark_pos = NULL;
      priv->n_marks = 0;
    }

  GTK_WIDGET_CLASS (gtk_range_parent_class)->destroy (widget);
}

static void
gtk_range_finalize (GObject *object)
{
  GtkRange *range = GTK_RANGE (object);
  GtkRangePrivate *priv = range->priv;

  g_clear_object (&priv->drag_gesture);
  g_clear_object (&priv->multipress_gesture);
  g_clear_object (&priv->long_press_gesture);

  g_clear_object (&priv->contents_gadget);
  g_clear_object (&priv->trough_gadget);
  g_clear_object (&priv->fill_gadget);
  g_clear_object (&priv->highlight_gadget);
  g_clear_object (&priv->slider_gadget);
  g_clear_object (&priv->stepper_a_gadget);
  g_clear_object (&priv->stepper_b_gadget);
  g_clear_object (&priv->stepper_c_gadget);
  g_clear_object (&priv->stepper_d_gadget);

  G_OBJECT_CLASS (gtk_range_parent_class)->finalize (object);
}

static void
gtk_range_measure_trough (GtkCssGadget   *gadget,
                          GtkOrientation  orientation,
                          gint            for_size,
                          gint           *minimum,
                          gint           *natural,
                          gint           *minimum_baseline,
                          gint           *natural_baseline,
                          gpointer        user_data)
{
  GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;
  gint min, nat;

  gtk_css_gadget_get_preferred_size (priv->slider_gadget,
                                     orientation, -1,
                                     minimum, natural,
                                     NULL, NULL);

  if (priv->fill_gadget)
    {
      gtk_css_gadget_get_preferred_size (priv->fill_gadget,
                                         orientation, for_size,
                                         &min, &nat,
                                         NULL, NULL);
      *minimum = MAX (*minimum, min);
      *natural = MAX (*natural, nat);
    }

  if (priv->highlight_gadget)
    {
      gtk_css_gadget_get_preferred_size (priv->highlight_gadget,
                                         orientation, for_size,
                                         &min, &nat,
                                         NULL, NULL);
      *minimum = MAX (*minimum, min);
      *natural = MAX (*natural, nat);
    }
}

static void gtk_range_measure (GtkWidget     *widget,
                               GtkOrientation  orientation,
                               int             for_size,
                               int            *minimum,
                               int            *natural,
                               int            *minimum_baseline,
                               int            *natural_baseline)
{
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;
  GtkBorder border = { 0 };

  /* Measure the main box */
  gtk_css_gadget_get_preferred_size (priv->contents_gadget,
                                     orientation,
                                     -1,
                                     minimum, natural,
                                     NULL, NULL);

  if (GTK_RANGE_GET_CLASS (range)->get_range_border)
    GTK_RANGE_GET_CLASS (range)->get_range_border (range, &border);

  /* Add the border */
  if (orientation == GTK_ORIENTATION_HORIZONTAL)
    {
      *minimum += border.left + border.right;
      *natural += border.left + border.right;
    }
  else
    {
      *minimum += border.top + border.bottom;
      *natural += border.top + border.bottom;
    }

  if (GTK_RANGE_GET_CLASS (range)->get_range_size_request)
    {
      gint min, nat;

      GTK_RANGE_GET_CLASS (range)->get_range_size_request (range, orientation,
                                                           &min, &nat);

      *minimum = MAX (*minimum, min);
      *natural = MAX (*natural, nat);
    }
}

static void
gtk_range_allocate_trough (GtkCssGadget        *gadget,
                           const GtkAllocation *allocation,
                           int                  baseline,
                           GtkAllocation       *out_clip,
                           gpointer             data)
{
  GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;
  GtkAllocation slider_alloc, widget_alloc;

  /* Slider */
  gtk_range_calc_marks (range);
  gtk_range_calc_stepper_sensitivity (range);

  gtk_widget_get_allocation (widget, &widget_alloc);
  gtk_range_compute_slider_position (range,
                                     gtk_adjustment_get_value (priv->adjustment),
                                     &slider_alloc);
  slider_alloc.x += widget_alloc.x;
  slider_alloc.y += widget_alloc.y;

  gtk_css_gadget_allocate (priv->slider_gadget,
                           &slider_alloc,
                           gtk_widget_get_allocated_baseline (widget),
                           out_clip);

  if (priv->show_fill_level &&
      gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment) -
      gtk_adjustment_get_lower (priv->adjustment) != 0)
    {
      gdouble level, fill;
      GtkAllocation fill_alloc, fill_clip;

      fill_alloc = *allocation;

      level = CLAMP (priv->fill_level,
                     gtk_adjustment_get_lower (priv->adjustment),
                     gtk_adjustment_get_upper (priv->adjustment) -
                     gtk_adjustment_get_page_size (priv->adjustment));

      fill = (level - gtk_adjustment_get_lower (priv->adjustment)) /
        (gtk_adjustment_get_upper (priv->adjustment) -
         gtk_adjustment_get_lower (priv->adjustment) -
         gtk_adjustment_get_page_size (priv->adjustment));

      if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)
        {
          fill_alloc.width *= fill;

          if (should_invert (range))
            fill_alloc.x += allocation->width - fill_alloc.width;
        }
      else
        {
          fill_alloc.height *= fill;

          if (should_invert (range))
            fill_alloc.y += allocation->height - fill_alloc.height;
        }

      gtk_css_gadget_allocate (priv->fill_gadget,
                               &fill_alloc,
                               baseline,
                               &fill_clip);
      gdk_rectangle_union (out_clip, &fill_clip, out_clip);
    }

  if (priv->has_origin)
    {
      GtkAllocation highlight_alloc, highlight_clip;
      int min, nat;

      gtk_css_gadget_get_preferred_size (priv->highlight_gadget,
                                         priv->orientation, -1,
                                         &min, &nat,
                                         NULL, NULL);

      highlight_alloc = *allocation;

      if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)
        {
          int x = slider_alloc.x + slider_alloc.width / 2;

          if (!should_invert (range))
            {
              highlight_alloc.x = allocation->x;
              highlight_alloc.width = MAX (x - allocation->x, min);
            }
          else
            {
              highlight_alloc.width = MAX (allocation->x + allocation->width - x, min);
              highlight_alloc.x = allocation->x + allocation->width - highlight_alloc.width;
            }
        }
      else
        {
          int y = slider_alloc.y + slider_alloc.height / 2;

          if (!should_invert (range))
            {
              highlight_alloc.y = allocation->y;
              highlight_alloc.height = MAX (y - allocation->y, min);
            }
          else
            {
              highlight_alloc.height = MAX (allocation->y + allocation->height - y, min);
              highlight_alloc.y = allocation->y + allocation->height - highlight_alloc.height;
            }
        }

      gtk_css_gadget_allocate (priv->highlight_gadget,
                               &highlight_alloc,
                               baseline,
                               &highlight_clip);
      gdk_rectangle_union (out_clip, &highlight_clip, out_clip);
    }
}

/* Clamp dimensions and border inside allocation, such that we prefer
 * to take space from border not dimensions in all directions, and prefer to
 * give space to border over dimensions in one direction.
 */
static void
clamp_dimensions (const GtkAllocation *allocation,
                  int                 *width,
                  int                 *height,
                  GtkBorder           *border,
                  gboolean             border_expands_horizontally)
{
  gint extra, shortage;

  /* Width */
  extra = allocation->width - border->left - border->right - *width;
  if (extra > 0)
    {
      if (border_expands_horizontally)
        {
          border->left += extra / 2;
          border->right += extra / 2 + extra % 2;
        }
      else
        {
          *width += extra;
        }
    }
  
  /* See if we can fit rect, if not kill the border */
  shortage = *width - allocation->width;
  if (shortage > 0)
    {
      *width = allocation->width;
      /* lose the border */
      border->left = 0;
      border->right = 0;
    }
  else
    {
      /* See if we can fit rect with borders */
      shortage = *width + border->left + border->right - allocation->width;
      if (shortage > 0)
        {
          /* Shrink borders */
          border->left -= shortage / 2;
          border->right -= shortage / 2 + shortage % 2;
        }
    }

  /* Height */
  extra = allocation->height - border->top - border->bottom - *height;
  if (extra > 0)
    {
      if (border_expands_horizontally)
        {
          /* don't expand border vertically */
          *height += extra;
        }
      else
        {
          border->top += extra / 2;
          border->bottom += extra / 2 + extra % 2;
        }
    }
  
  /* See if we can fit rect, if not kill the border */
  shortage = *height - allocation->height;
  if (shortage > 0)
    {
      *height = allocation->height;
      /* lose the border */
      border->top = 0;
      border->bottom = 0;
    }
  else
    {
      /* See if we can fit rect with borders */
      shortage = *height + border->top + border->bottom - allocation->height;
      if (shortage > 0)
        {
          /* Shrink borders */
          border->top -= shortage / 2;
          border->bottom -= shortage / 2 + shortage % 2;
        }
    }
}

static void
gtk_range_size_allocate (GtkWidget     *widget,
                         GtkAllocation *allocation)
{
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;
  GtkAllocation clip = *allocation;
  GtkAllocation child_clip;
  GtkBorder border = { 0 };
  GtkAllocation box_alloc;
  int box_min_width, box_min_height;

  if (GTK_RANGE_GET_CLASS (range)->get_range_border)
    GTK_RANGE_GET_CLASS (range)->get_range_border (range, &border);

  measure_one_gadget (priv->contents_gadget, &box_min_width, &box_min_height);

  if (priv->orientation == GTK_ORIENTATION_VERTICAL)
    clamp_dimensions (allocation, &box_min_width, &box_min_height, &border, TRUE);
  else
    clamp_dimensions (allocation, &box_min_width, &box_min_height, &border, FALSE);

  box_alloc.x = border.left + allocation->x;
  box_alloc.y = border.top + allocation->y;
  box_alloc.width = box_min_width;
  box_alloc.height = box_min_height;

  gtk_css_gadget_allocate (priv->contents_gadget,
                           &box_alloc,
                           gtk_widget_get_allocated_baseline (widget),
                           &child_clip);

  /* TODO: we should compute a proper clip from get_range_border(),
   * but this will at least give us outset shadows.
   */
  gdk_rectangle_union (&child_clip, &clip, &clip);
  gtk_widget_set_clip (widget, &clip);
}

static void
gtk_range_unmap (GtkWidget *widget)
{
  GtkRange *range = GTK_RANGE (widget);

  stop_scrolling (range);

  GTK_WIDGET_CLASS (gtk_range_parent_class)->unmap (widget);
}

static void
update_slider_state (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  GtkStateFlags state;

  state = gtk_widget_get_state_flags (GTK_WIDGET (range));

  state &= ~(GTK_STATE_FLAG_PRELIGHT | GTK_STATE_FLAG_ACTIVE);

  if (priv->mouse_location == priv->slider_gadget &&
      !(state & GTK_STATE_FLAG_INSENSITIVE))
    state |= GTK_STATE_FLAG_PRELIGHT;

  if (priv->grab_location == priv->slider_gadget)
    state |= GTK_STATE_FLAG_ACTIVE;

  gtk_css_gadget_set_state (priv->slider_gadget, state);
}

static void
update_trough_state (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  GtkStateFlags state;

  state = gtk_widget_get_state_flags (GTK_WIDGET (range));

  state &= ~(GTK_STATE_FLAG_PRELIGHT | GTK_STATE_FLAG_ACTIVE);

  gtk_css_gadget_set_state (priv->contents_gadget, state);

  if (priv->mouse_location == priv->trough_gadget &&
      !(state & GTK_STATE_FLAG_INSENSITIVE))
    state |= GTK_STATE_FLAG_PRELIGHT;

  if (priv->grab_location == priv->trough_gadget)
    state |= GTK_STATE_FLAG_ACTIVE;

  gtk_css_gadget_set_state (priv->trough_gadget, state);
  if (priv->highlight_gadget)
    gtk_css_gadget_set_state (priv->highlight_gadget, state);
  if (priv->fill_gadget)
    gtk_css_gadget_set_state (priv->fill_gadget, state);
}

static void
gtk_range_direction_changed (GtkWidget        *widget,
                             GtkTextDirection  previous_direction)
{
  GtkRange *range = GTK_RANGE (widget);

  update_fill_position (range);
  update_highlight_position (range);

  GTK_WIDGET_CLASS (gtk_range_parent_class)->direction_changed (widget, previous_direction);
}

static void
gtk_range_state_flags_changed (GtkWidget     *widget,
                               GtkStateFlags  previous_state)
{
  GtkRange *range = GTK_RANGE (widget);

  update_trough_state (range);
  update_slider_state (range);
  update_steppers_state (range);

  GTK_WIDGET_CLASS (gtk_range_parent_class)->state_flags_changed (widget, previous_state);
}

static gboolean
gtk_range_render_trough (GtkCssGadget *gadget,
                         GtkSnapshot  *snapshot,
                         int           x,
                         int           y,
                         int           width,
                         int           height,
                         gpointer      user_data)
{
  GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;

  /* HACK: GtkColorScale wants to draw its own trough
   * so we let it...
   */
  if (GTK_IS_COLOR_SCALE (widget))
    gtk_color_scale_snapshot_trough (GTK_COLOR_SCALE (widget), snapshot, x, y, width, height);

  if (priv->show_fill_level &&
      gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment) -
      gtk_adjustment_get_lower (priv->adjustment) != 0)
    gtk_css_gadget_snapshot (priv->fill_gadget, snapshot);

  if (priv->has_origin)
    gtk_css_gadget_snapshot (priv->highlight_gadget, snapshot);

  return gtk_widget_has_visible_focus (widget);
}

static void
gtk_range_snapshot (GtkWidget   *widget,
                    GtkSnapshot *snapshot)
{
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;

  gtk_css_gadget_snapshot (priv->contents_gadget, snapshot);

  /* Draw the slider last, so that e.g. the focus ring stays below it */
  gtk_css_gadget_snapshot (priv->slider_gadget, snapshot);
}

static void
range_grab_add (GtkRange      *range,
                GtkCssGadget  *location)
{
  GtkRangePrivate *priv = range->priv;
  GtkStyleContext *context;

  context = gtk_widget_get_style_context (GTK_WIDGET (range));

  /* Don't perform any GDK/GTK+ grab here. Since a button
   * is down, there's an ongoing implicit grab on
   * the widget, which pretty much guarantees this
   * is the only widget receiving the pointer events.
   */
  priv->grab_location = location;
  gtk_css_gadget_queue_allocate (location);

  update_trough_state (range);
  update_slider_state (range);
  update_steppers_state (range);

  gtk_style_context_add_class (context, "dragging");
}

static void
update_zoom_state (GtkRange *range,
                   gboolean  enabled)
{
  GtkStyleContext *context;

  context = gtk_widget_get_style_context (GTK_WIDGET (range));

  if (enabled)
    gtk_style_context_add_class (context, "fine-tune");
  else
    gtk_style_context_remove_class (context, "fine-tune");

  range->priv->zoom = enabled;
}

static void
range_grab_remove (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  GtkStyleContext *context;

  if (!priv->grab_location)
    return;

  context = gtk_widget_get_style_context (GTK_WIDGET (range));

  gtk_css_gadget_queue_allocate (priv->grab_location);
  priv->grab_location = NULL;

  gtk_range_update_mouse_location (range);

  update_slider_state (range);
  update_steppers_state (range);
  update_zoom_state (range, FALSE);

  gtk_style_context_remove_class (context, "dragging");
}

static GtkScrollType
range_get_scroll_for_grab (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  guint grab_button;
  gboolean invert;

  invert = should_invert (range);
  grab_button = gtk_gesture_single_get_current_button (GTK_GESTURE_SINGLE (range->priv->multipress_gesture));

  if (!priv->grab_location)
    return GTK_SCROLL_NONE;

  /* Backward stepper */
  if (priv->grab_location == priv->stepper_a_gadget ||
      priv->grab_location == priv->stepper_c_gadget)
    {
      switch (grab_button)
        {
        case GDK_BUTTON_PRIMARY:
          return invert ? GTK_SCROLL_STEP_FORWARD : GTK_SCROLL_STEP_BACKWARD;
          break;
        case GDK_BUTTON_SECONDARY:
          return invert ? GTK_SCROLL_PAGE_FORWARD : GTK_SCROLL_PAGE_BACKWARD;
          break;
        case GDK_BUTTON_MIDDLE:
          return invert ? GTK_SCROLL_END : GTK_SCROLL_START;
          break;
        default:
          return GTK_SCROLL_NONE;
        }
    }

  /* Forward stepper */
  if (priv->grab_location == priv->stepper_b_gadget ||
      priv->grab_location == priv->stepper_d_gadget)
    {
      switch (grab_button)
        {
        case GDK_BUTTON_PRIMARY:
          return invert ? GTK_SCROLL_STEP_BACKWARD : GTK_SCROLL_STEP_FORWARD;
          break;
        case GDK_BUTTON_SECONDARY:
          return invert ? GTK_SCROLL_PAGE_BACKWARD : GTK_SCROLL_PAGE_FORWARD;
          break;
        case GDK_BUTTON_MIDDLE:
          return invert ? GTK_SCROLL_START : GTK_SCROLL_END;
          break;
        default:
          return GTK_SCROLL_NONE;
        }
    }

  /* In the trough */
  if (priv->grab_location == priv->trough_gadget)
    {
      if (priv->trough_click_forward)
        return GTK_SCROLL_PAGE_FORWARD;
      else
        return GTK_SCROLL_PAGE_BACKWARD;
    }

  return GTK_SCROLL_NONE;
}

static gdouble
coord_to_value (GtkRange *range,
                gdouble   coord)
{
  GtkRangePrivate *priv = range->priv;
  gdouble frac;
  gdouble value;
  gint    trough_length;
  gint    trough_start;
  gint    slider_length;
  GtkAllocation slider_alloc, trough_alloc;

  gtk_css_gadget_get_margin_box (priv->slider_gadget, &slider_alloc);
  gtk_css_gadget_get_content_box (priv->trough_gadget, &trough_alloc);

  if (priv->orientation == GTK_ORIENTATION_VERTICAL)
    {
      trough_length = trough_alloc.height;
      trough_start  = trough_alloc.y;
      slider_length = slider_alloc.height;
    }
  else
    {
      trough_length = trough_alloc.width;
      trough_start  = trough_alloc.x;
      slider_length = slider_alloc.width;
    }

  if (trough_length == slider_length)
    frac = 1.0;
  else
    frac = (MAX (0, coord - trough_start) /
            (gdouble) (trough_length - slider_length));

  if (should_invert (range))
    frac = 1.0 - frac;

  value = gtk_adjustment_get_lower (priv->adjustment) + frac * (gtk_adjustment_get_upper (priv->adjustment) -
                                            gtk_adjustment_get_lower (priv->adjustment) -
                                            gtk_adjustment_get_page_size (priv->adjustment));
  return value;
}

static gboolean
gtk_range_key_press (GtkWidget   *widget,
		     GdkEventKey *event)
{
  GdkDevice *device;
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;

  device = gdk_event_get_device ((GdkEvent *) event);
  device = gdk_device_get_associated_device (device);

  if (gtk_gesture_is_active (priv->drag_gesture) &&
      device == gtk_gesture_get_device (priv->drag_gesture) &&
      event->keyval == GDK_KEY_Escape &&
      priv->grab_location != NULL)
    {
      stop_scrolling (range);

      return GDK_EVENT_STOP;
    }
  else if (priv->in_drag &&
           (event->keyval == GDK_KEY_Shift_L ||
            event->keyval == GDK_KEY_Shift_R))
    {
      GtkAllocation slider_alloc;

      gtk_css_gadget_get_margin_box (priv->slider_gadget, &slider_alloc);

      if (priv->orientation == GTK_ORIENTATION_VERTICAL)
        priv->slide_initial_slider_position = slider_alloc.y;
      else
        priv->slide_initial_slider_position = slider_alloc.x;
      update_zoom_state (range, !priv->zoom);

      return GDK_EVENT_STOP;
    }

  return GTK_WIDGET_CLASS (gtk_range_parent_class)->key_press_event (widget, event);
}

static void
update_initial_slider_position (GtkRange      *range,
                                gdouble        x,
                                gdouble        y,
                                GtkAllocation *slider_alloc)
{
  GtkRangePrivate *priv = range->priv;

  if (priv->orientation == GTK_ORIENTATION_VERTICAL)
    {
      priv->slide_initial_slider_position = MAX (0, slider_alloc->y);
      priv->slide_initial_coordinate_delta = y - priv->slide_initial_slider_position;
    }
  else
    {
      priv->slide_initial_slider_position = MAX (0, slider_alloc->x);
      priv->slide_initial_coordinate_delta = x - priv->slide_initial_slider_position;
    }
}

static void
gtk_range_long_press_gesture_pressed (GtkGestureLongPress *gesture,
                                      gdouble              x,
                                      gdouble              y,
                                      GtkRange            *range)
{
  GtkRangePrivate *priv = range->priv;

  gtk_range_update_mouse_location (range);

  if (priv->mouse_location == priv->slider_gadget && !priv->zoom)
    {
      GtkAllocation slider_alloc;

      gtk_css_gadget_get_margin_box (priv->slider_gadget, &slider_alloc);
      update_initial_slider_position (range, x, y, &slider_alloc);
      update_zoom_state (range, TRUE);
    }
}

static void
gtk_range_multipress_gesture_pressed (GtkGestureMultiPress *gesture,
                                      guint                 n_press,
                                      gdouble               x,
                                      gdouble               y,
                                      GtkRange             *range)
{
  GtkWidget *widget = GTK_WIDGET (range);
  GtkRangePrivate *priv = range->priv;
  GdkDevice *source_device;
  GdkEventSequence *sequence;
  const GdkEvent *event;
  GdkInputSource source;
  gboolean primary_warps;
  gboolean shift_pressed;
  guint button;
  GdkModifierType state_mask;
  GtkAllocation slider_alloc;

  if (!gtk_widget_has_focus (widget))
    gtk_widget_grab_focus (widget);

  sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
  button = gtk_gesture_single_get_current_button (GTK_GESTURE_SINGLE (gesture));
  event = gtk_gesture_get_last_event (GTK_GESTURE (gesture), sequence);
  gdk_event_get_state (event, &state_mask);
  shift_pressed = (state_mask & GDK_SHIFT_MASK) != 0;

  source_device = gdk_event_get_source_device ((GdkEvent *) event);
  source = gdk_device_get_source (source_device);

  priv->mouse_x = x;
  priv->mouse_y = y;

  gtk_range_update_mouse_location (range);
  gtk_css_gadget_get_margin_box (priv->slider_gadget, &slider_alloc);

  g_object_get (gtk_widget_get_settings (widget),
                "gtk-primary-button-warps-slider", &primary_warps,
                NULL);

  if (priv->mouse_location == priv->slider_gadget &&
      gdk_event_triggers_context_menu (event))
    {
      gboolean handled;

      gtk_gesture_set_state (priv->multipress_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
      g_signal_emit_by_name (widget, "popup-menu", &handled);
      return;
    }

  if (priv->mouse_location == priv->slider_gadget)
    {
      /* Shift-click in the slider = fine adjustment */
      if (shift_pressed)
        update_zoom_state (range, TRUE);

      update_initial_slider_position (range, x, y, &slider_alloc);
      range_grab_add (range, priv->slider_gadget);

      gtk_widget_queue_draw (widget);
    }
  else if (priv->mouse_location == priv->stepper_a_gadget ||
           priv->mouse_location == priv->stepper_b_gadget ||
           priv->mouse_location == priv->stepper_c_gadget ||
           priv->mouse_location == priv->stepper_d_gadget)
    {
      GtkScrollType scroll;

      range_grab_add (range, priv->mouse_location);

      scroll = range_get_scroll_for_grab (range);
      if (scroll == GTK_SCROLL_START || scroll == GTK_SCROLL_END)
        gtk_range_scroll (range, scroll);
      else if (scroll != GTK_SCROLL_NONE)
        {
          remove_autoscroll (range);
          range->priv->autoscroll_mode = scroll;
          add_autoscroll (range);
        }
    }
  else if (priv->mouse_location == priv->trough_gadget &&
           (source == GDK_SOURCE_TOUCHSCREEN ||
            (button == GDK_BUTTON_PRIMARY &&
             ((primary_warps && !shift_pressed) ||
              (!primary_warps && shift_pressed)))))
    {
      /* warp to location */
      GdkRectangle slider;
      gdouble slider_low_value, slider_high_value, new_value;

      slider_high_value =
        coord_to_value (range,
                        priv->orientation == GTK_ORIENTATION_VERTICAL ?
                        y : x);
      slider_low_value =
        coord_to_value (range,
                        priv->orientation == GTK_ORIENTATION_VERTICAL ?
                        y - slider_alloc.height :
                        x - slider_alloc.width);

      /* compute new value for warped slider */
      new_value = (slider_low_value + slider_high_value) / 2;

      gtk_range_compute_slider_position (range, new_value, &slider);
      update_initial_slider_position (range, x, y, &slider);

      range_grab_add (range, priv->slider_gadget);

      gtk_widget_queue_draw (widget);

      update_slider_position (range, x, y);
    }
  else if (priv->mouse_location == priv->trough_gadget &&
           button == GDK_BUTTON_PRIMARY &&
           ((primary_warps && shift_pressed) ||
            (!primary_warps && !shift_pressed)))
    {
      /* jump by pages */
      GtkScrollType scroll;
      gdouble click_value;

      click_value = coord_to_value (range,
                                    priv->orientation == GTK_ORIENTATION_VERTICAL ?
                                    y : x);

      priv->trough_click_forward = click_value > gtk_adjustment_get_value (priv->adjustment);
      range_grab_add (range, priv->trough_gadget);

      scroll = range_get_scroll_for_grab (range);
      gtk_range_add_step_timer (range, scroll);
    }
  else if (priv->mouse_location == priv->trough_gadget &&
           button == GDK_BUTTON_SECONDARY)
    {
      /* autoscroll */
      gdouble click_value;

      click_value = coord_to_value (range,
                                    priv->orientation == GTK_ORIENTATION_VERTICAL ?
                                    y : x);

      priv->trough_click_forward = click_value > gtk_adjustment_get_value (priv->adjustment);
      range_grab_add (range, priv->trough_gadget);

      remove_autoscroll (range);
      range->priv->autoscroll_mode = priv->trough_click_forward ? GTK_SCROLL_END : GTK_SCROLL_START;
      add_autoscroll (range);
    }

  if (priv->grab_location == priv->slider_gadget);
    /* leave it to ::drag-begin to claim the sequence */
  else if (priv->grab_location != NULL)
    gtk_gesture_set_state (priv->multipress_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
}

static void
gtk_range_multipress_gesture_released (GtkGestureMultiPress *gesture,
                                       guint                 n_press,
                                       gdouble               x,
                                       gdouble               y,
                                       GtkRange             *range)
{
  GtkRangePrivate *priv = range->priv;

  priv->mouse_x = x;
  priv->mouse_y = y;
  range->priv->in_drag = FALSE;
  stop_scrolling (range);
}

/* During a slide, move the slider as required given new mouse position */
static void
update_slider_position (GtkRange *range,
                        gint      mouse_x,
                        gint      mouse_y)
{
  GtkRangePrivate *priv = range->priv;
  gdouble delta;
  gdouble c;
  gdouble new_value;
  gboolean handled;
  gdouble next_value;
  gdouble mark_value;
  gdouble mark_delta;
  gdouble zoom;
  gint i;

  if (priv->zoom)
    {
      GtkAllocation trough_alloc;

      gtk_css_gadget_get_margin_box (priv->trough_gadget, &trough_alloc);

      zoom = MIN(1.0, (priv->orientation == GTK_ORIENTATION_VERTICAL ?
                       trough_alloc.height : trough_alloc.width) /
                       (gtk_adjustment_get_upper (priv->adjustment) -
                        gtk_adjustment_get_lower (priv->adjustment) -
                        gtk_adjustment_get_page_size (priv->adjustment)));
      /* the above is ineffective for scales, so just set a zoom factor */
      if (zoom == 1.0)
        zoom = 0.25;
    }
  else
    zoom = 1.0;

  /* recalculate the initial position from the current position */
  if (priv->slide_initial_slider_position == -1)
    {
      GtkAllocation slider_alloc;

      gtk_css_gadget_get_margin_box (priv->slider_gadget, &slider_alloc);

      if (priv->orientation == GTK_ORIENTATION_VERTICAL)
        priv->slide_initial_slider_position = (zoom * (mouse_y - priv->slide_initial_coordinate_delta) - slider_alloc.y) / (zoom - 1.0);
      else
        priv->slide_initial_slider_position = (zoom * (mouse_x - priv->slide_initial_coordinate_delta) - slider_alloc.x) / (zoom - 1.0);
    }

  if (priv->orientation == GTK_ORIENTATION_VERTICAL)
    delta = mouse_y - (priv->slide_initial_coordinate_delta + priv->slide_initial_slider_position);
  else
    delta = mouse_x - (priv->slide_initial_coordinate_delta + priv->slide_initial_slider_position);

  c = priv->slide_initial_slider_position + zoom * delta;

  new_value = coord_to_value (range, c);
  next_value = coord_to_value (range, c + 1);
  mark_delta = fabs (next_value - new_value);

  for (i = 0; i < priv->n_marks; i++)
    {
      mark_value = priv->marks[i];

      if (fabs (gtk_adjustment_get_value (priv->adjustment) - mark_value) < 3 * mark_delta)
        {
          if (fabs (new_value - mark_value) < MARK_SNAP_LENGTH * mark_delta)
            {
              new_value = mark_value;
              break;
            }
        }
    }

  g_signal_emit (range, signals[CHANGE_VALUE], 0, GTK_SCROLL_JUMP, new_value, &handled);
}

static void
remove_autoscroll (GtkRange *range)
{
  if (range->priv->autoscroll_id)
    {
      gtk_widget_remove_tick_callback (GTK_WIDGET (range),
                                       range->priv->autoscroll_id);
      range->priv->autoscroll_id = 0;
    }

  /* unset initial position so it can be calculated */
  range->priv->slide_initial_slider_position = -1;

  range->priv->autoscroll_mode = GTK_SCROLL_NONE;
}

static gboolean
autoscroll_cb (GtkWidget     *widget,
               GdkFrameClock *frame_clock,
               gpointer       data)
{
  GtkRange *range = GTK_RANGE (data);
  GtkRangePrivate *priv = range->priv;
  GtkAdjustment *adj = priv->adjustment;
  gdouble increment;
  gdouble value;
  gboolean handled;
  gdouble step, page;

  step = gtk_adjustment_get_step_increment (adj);
  page = gtk_adjustment_get_page_increment (adj);

  switch (priv->autoscroll_mode)
    {
    case GTK_SCROLL_STEP_FORWARD:
      increment = step / AUTOSCROLL_FACTOR;
      break;
    case GTK_SCROLL_PAGE_FORWARD:
      increment = page / AUTOSCROLL_FACTOR;
      break;
    case GTK_SCROLL_STEP_BACKWARD:
      increment = - step / AUTOSCROLL_FACTOR;
      break;
    case GTK_SCROLL_PAGE_BACKWARD:
      increment = - page / AUTOSCROLL_FACTOR;
      break;
    case GTK_SCROLL_START:
    case GTK_SCROLL_END:
      {
        gdouble x, y;
        gdouble distance, t;

        /* Vary scrolling speed from slow (ie step) to fast (2 * page),
         * based on the distance of the pointer from the widget. We start
         * speeding up if the pointer moves at least 20 pixels away, and
         * we reach maximum speed when it is 220 pixels away.
         */
        if (!gtk_gesture_drag_get_offset (GTK_GESTURE_DRAG (priv->drag_gesture), &x, &y))
          {
            x = 0.0;
            y = 0.0;
          }
        if (gtk_orientable_get_orientation (GTK_ORIENTABLE (range)) == GTK_ORIENTATION_HORIZONTAL)
          distance = fabs (y);
        else
          distance = fabs (x);
        distance = CLAMP (distance - 20, 0.0, 200);
        t = distance / 100.0;
        step = (1 - t) * step + t * page;
        if (priv->autoscroll_mode == GTK_SCROLL_END)
          increment = step / AUTOSCROLL_FACTOR;
        else
          increment = - step / AUTOSCROLL_FACTOR;
      }
      break;
    default:
      g_assert_not_reached ();
      break;
    }

  value = gtk_adjustment_get_value (adj);
  value += increment;

  g_signal_emit (range, signals[CHANGE_VALUE], 0, GTK_SCROLL_JUMP, value, &handled);

  return G_SOURCE_CONTINUE;
}

static void
add_autoscroll (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;

  if (priv->autoscroll_id != 0 ||
      priv->autoscroll_mode == GTK_SCROLL_NONE)
    return;

  priv->autoscroll_id = gtk_widget_add_tick_callback (GTK_WIDGET (range),
                                                      autoscroll_cb, range, NULL);
}

static void
stop_scrolling (GtkRange *range)
{
  range_grab_remove (range);
  gtk_range_remove_step_timer (range);
  remove_autoscroll (range);
}

/**
 * _gtk_range_get_wheel_delta:
 * @range: a #GtkRange
 * @event: A #GdkEventScroll
 *
 * Returns a good step value for the mouse wheel.
 *
 * Returns: A good step value for the mouse wheel.
 *
 * Since: 2.4
 **/
gdouble
_gtk_range_get_wheel_delta (GtkRange       *range,
                            GdkEventScroll *event)
{
  GtkRangePrivate *priv = range->priv;
  GtkAdjustment *adjustment = priv->adjustment;
  gdouble dx, dy;
  gdouble delta = 0;
  gdouble page_size;
  gdouble page_increment;
  gdouble scroll_unit;
  GdkScrollDirection direction;

  page_size = gtk_adjustment_get_page_size (adjustment);
  page_increment = gtk_adjustment_get_page_increment (adjustment);

  if (GTK_IS_SCROLLBAR (range))
    scroll_unit = pow (page_size, 2.0 / 3.0);
  else
    scroll_unit = page_increment;

  if (gdk_event_get_scroll_deltas ((GdkEvent *) event, &dx, &dy))
    {
#ifdef GDK_WINDOWING_QUARTZ
      scroll_unit = 1;
#endif

      if (gtk_orientable_get_orientation (GTK_ORIENTABLE (range)) == GTK_ORIENTATION_HORIZONTAL)
        delta = - (dx ? dx : dy) * scroll_unit;
      else
        delta = dy * scroll_unit;
    }
  else if (gdk_event_get_scroll_direction ((GdkEvent *) event, &direction))
    {
      if (direction == GDK_SCROLL_UP ||
          direction == GDK_SCROLL_LEFT)
        delta = - scroll_unit;
      else
        delta = scroll_unit;
    }

  if (priv->inverted)
    delta = - delta;

  return delta;
}

static gboolean
gtk_range_scroll_event (GtkWidget      *widget,
			GdkEventScroll *event)
{
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;

  if (gtk_widget_get_realized (widget))
    {
      gdouble delta;
      gboolean handled;

      delta = _gtk_range_get_wheel_delta (range, event);

      g_signal_emit (range, signals[CHANGE_VALUE], 0,
                     GTK_SCROLL_JUMP, gtk_adjustment_get_value (priv->adjustment) + delta,
                     &handled);
    }

  return GDK_EVENT_STOP;
}

static void
update_autoscroll_mode (GtkRange *range)
{
  GtkScrollType mode = GTK_SCROLL_NONE;

  if (range->priv->zoom)
    {
      GtkAllocation allocation;
      gint size, pos;

      gtk_widget_get_allocation (GTK_WIDGET (range), &allocation);

      if (range->priv->orientation == GTK_ORIENTATION_VERTICAL)
        {
          size = allocation.height;
          pos = range->priv->mouse_y;
        }
      else
        {
          size = allocation.width;
          pos = range->priv->mouse_x;
        }

      if (pos < SCROLL_EDGE_SIZE)
        mode = range->priv->inverted ? GTK_SCROLL_STEP_FORWARD : GTK_SCROLL_STEP_BACKWARD;
      else if (pos > (size - SCROLL_EDGE_SIZE))
        mode = range->priv->inverted ? GTK_SCROLL_STEP_BACKWARD : GTK_SCROLL_STEP_FORWARD;
    }

  if (mode != range->priv->autoscroll_mode)
    {
      remove_autoscroll (range);
      range->priv->autoscroll_mode = mode;
      add_autoscroll (range);
    }
}

static void
gtk_range_drag_gesture_update (GtkGestureDrag *gesture,
                               gdouble         offset_x,
                               gdouble         offset_y,
                               GtkRange       *range)
{
  GtkRangePrivate *priv = range->priv;
  gdouble start_x, start_y;

  if (priv->grab_location == priv->slider_gadget)
    {
      gtk_gesture_drag_get_start_point (gesture, &start_x, &start_y);
      priv->mouse_x = start_x + offset_x;
      priv->mouse_y = start_y + offset_y;
      priv->in_drag = TRUE;
      update_autoscroll_mode (range);

      if (priv->autoscroll_mode == GTK_SCROLL_NONE)
        update_slider_position (range, priv->mouse_x, priv->mouse_y);
    }
}

static void
gtk_range_drag_gesture_begin (GtkGestureDrag *gesture,
                              gdouble         offset_x,
                              gdouble         offset_y,
                              GtkRange       *range)
{
  GtkRangePrivate *priv = range->priv;

  if (priv->grab_location == priv->slider_gadget)
    gtk_gesture_set_state (priv->drag_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
}

static gboolean
gtk_range_event (GtkWidget *widget,
                 GdkEvent  *event)
{
  GtkRange *range = GTK_RANGE (widget);
  GtkRangePrivate *priv = range->priv;
  gdouble x, y;

  if (event->type == GDK_LEAVE_NOTIFY)
    {
      priv->mouse_x = G_MININT;
      priv->mouse_y = G_MININT;
    }
  else if (gdk_event_get_coords (event, &x, &y))
    {
      priv->mouse_x = x;
      priv->mouse_y = y;
    }

  gtk_range_update_mouse_location (range);

  return GDK_EVENT_PROPAGATE;
}

static void
gtk_range_adjustment_changed (GtkAdjustment *adjustment,
			      gpointer       data)
{
  GtkRange *range = GTK_RANGE (data);

  gtk_range_calc_slider (range);
  gtk_range_calc_stepper_sensitivity (range);

  /* Note that we don't round off to priv->round_digits here.
   * that's because it's really broken to change a value
   * in response to a change signal on that value; round_digits
   * is therefore defined to be a filter on what the GtkRange
   * can input into the adjustment, not a filter that the GtkRange
   * will enforce on the adjustment.
   */
}

static void
gtk_range_adjustment_value_changed (GtkAdjustment *adjustment,
				    gpointer       data)
{
  GtkRange *range = GTK_RANGE (data);

  gtk_range_calc_slider (range);
  gtk_range_calc_stepper_sensitivity (range);
  
  /* now check whether the layout changed  */
  if (GTK_IS_SCALE (range) && gtk_scale_get_draw_value (GTK_SCALE (range)))
    {
      gtk_widget_queue_draw (GTK_WIDGET (range));
    }

  /* Note that we don't round off to priv->round_digits here.
   * that's because it's really broken to change a value
   * in response to a change signal on that value; round_digits
   * is therefore defined to be a filter on what the GtkRange
   * can input into the adjustment, not a filter that the GtkRange
   * will enforce on the adjustment.
   */

  g_signal_emit (range, signals[VALUE_CHANGED], 0);
}

static void
apply_marks (GtkRange *range, 
             gdouble   oldval,
             gdouble  *newval)
{
  GtkRangePrivate *priv = range->priv;
  gint i;
  gdouble mark;

  for (i = 0; i < priv->n_marks; i++)
    {
      mark = priv->marks[i];
      if ((oldval < mark && mark < *newval) ||
          (oldval > mark && mark > *newval))
        {
          *newval = mark;
          return;
        }
    }
}

static void
step_back (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gdouble newval;
  gboolean handled;

  newval = gtk_adjustment_get_value (priv->adjustment) - gtk_adjustment_get_step_increment (priv->adjustment);
  apply_marks (range, gtk_adjustment_get_value (priv->adjustment), &newval);
  g_signal_emit (range, signals[CHANGE_VALUE], 0,
                 GTK_SCROLL_STEP_BACKWARD, newval, &handled);
}

static void
step_forward (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gdouble newval;
  gboolean handled;

  newval = gtk_adjustment_get_value (priv->adjustment) + gtk_adjustment_get_step_increment (priv->adjustment);
  apply_marks (range, gtk_adjustment_get_value (priv->adjustment), &newval);
  g_signal_emit (range, signals[CHANGE_VALUE], 0,
                 GTK_SCROLL_STEP_FORWARD, newval, &handled);
}


static void
page_back (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gdouble newval;
  gboolean handled;

  newval = gtk_adjustment_get_value (priv->adjustment) - gtk_adjustment_get_page_increment (priv->adjustment);
  apply_marks (range, gtk_adjustment_get_value (priv->adjustment), &newval);
  g_signal_emit (range, signals[CHANGE_VALUE], 0,
                 GTK_SCROLL_PAGE_BACKWARD, newval, &handled);
}

static void
page_forward (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gdouble newval;
  gboolean handled;

  newval = gtk_adjustment_get_value (priv->adjustment) + gtk_adjustment_get_page_increment (priv->adjustment);
  apply_marks (range, gtk_adjustment_get_value (priv->adjustment), &newval);
  g_signal_emit (range, signals[CHANGE_VALUE], 0,
                 GTK_SCROLL_PAGE_FORWARD, newval, &handled);
}

static void
scroll_begin (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gboolean handled;

  g_signal_emit (range, signals[CHANGE_VALUE], 0,
                 GTK_SCROLL_START, gtk_adjustment_get_lower (priv->adjustment),
                 &handled);
}

static void
scroll_end (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gdouble newval;
  gboolean handled;

  newval = gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment);
  g_signal_emit (range, signals[CHANGE_VALUE], 0, GTK_SCROLL_END, newval,
                 &handled);
}

static gboolean
gtk_range_scroll (GtkRange     *range,
                  GtkScrollType scroll)
{
  GtkRangePrivate *priv = range->priv;
  gdouble old_value = gtk_adjustment_get_value (priv->adjustment);

  switch (scroll)
    {
    case GTK_SCROLL_STEP_LEFT:
      if (should_invert (range))
        step_forward (range);
      else
        step_back (range);
      break;
                    
    case GTK_SCROLL_STEP_UP:
      if (should_invert (range))
        step_forward (range);
      else
        step_back (range);
      break;

    case GTK_SCROLL_STEP_RIGHT:
      if (should_invert (range))
        step_back (range);
      else
        step_forward (range);
      break;
                    
    case GTK_SCROLL_STEP_DOWN:
      if (should_invert (range))
        step_back (range);
      else
        step_forward (range);
      break;
                  
    case GTK_SCROLL_STEP_BACKWARD:
      step_back (range);
      break;
                  
    case GTK_SCROLL_STEP_FORWARD:
      step_forward (range);
      break;

    case GTK_SCROLL_PAGE_LEFT:
      if (should_invert (range))
        page_forward (range);
      else
        page_back (range);
      break;
                    
    case GTK_SCROLL_PAGE_UP:
      if (should_invert (range))
        page_forward (range);
      else
        page_back (range);
      break;

    case GTK_SCROLL_PAGE_RIGHT:
      if (should_invert (range))
        page_back (range);
      else
        page_forward (range);
      break;
                    
    case GTK_SCROLL_PAGE_DOWN:
      if (should_invert (range))
        page_back (range);
      else
        page_forward (range);
      break;
                  
    case GTK_SCROLL_PAGE_BACKWARD:
      page_back (range);
      break;
                  
    case GTK_SCROLL_PAGE_FORWARD:
      page_forward (range);
      break;

    case GTK_SCROLL_START:
      scroll_begin (range);
      break;

    case GTK_SCROLL_END:
      scroll_end (range);
      break;

    case GTK_SCROLL_JUMP:
      /* Used by CList, range doesn't use it. */
      break;

    case GTK_SCROLL_NONE:
      break;
    }

  return gtk_adjustment_get_value (priv->adjustment) != old_value;
}

static void
gtk_range_move_slider (GtkRange     *range,
                       GtkScrollType scroll)
{
  if (! gtk_range_scroll (range, scroll))
    gtk_widget_error_bell (GTK_WIDGET (range));
}

static gboolean
rectangle_contains_point (GdkRectangle *rect,
                          gint          x,
                          gint          y)
{
  return (x >= rect->x) && (x < rect->x + rect->width) &&
         (y >= rect->y) && (y < rect->y + rect->height);
}

/* Update mouse location, return TRUE if it changes */
static void
gtk_range_update_mouse_location (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gint x, y;
  GtkCssGadget *old_location;
  GtkWidget *widget = GTK_WIDGET (range);
  GdkRectangle trough_alloc, slider_alloc, slider_trace;

  old_location = priv->mouse_location;

  x = priv->mouse_x;
  y = priv->mouse_y;

  gtk_css_gadget_get_border_box (priv->trough_gadget, &trough_alloc);
  gtk_css_gadget_get_border_box (priv->slider_gadget, &slider_alloc);
  gdk_rectangle_union (&slider_alloc, &trough_alloc, &slider_trace);

  if (priv->grab_location != NULL)
    priv->mouse_location = priv->grab_location;
  else if (priv->stepper_a_gadget &&
           gtk_css_gadget_border_box_contains_point (priv->stepper_a_gadget, x, y))
    priv->mouse_location = priv->stepper_a_gadget;
  else if (priv->stepper_b_gadget &&
           gtk_css_gadget_border_box_contains_point (priv->stepper_b_gadget, x, y))
    priv->mouse_location = priv->stepper_b_gadget;
  else if (priv->stepper_c_gadget &&
           gtk_css_gadget_border_box_contains_point (priv->stepper_c_gadget, x, y))
    priv->mouse_location = priv->stepper_c_gadget;
  else if (priv->stepper_d_gadget &&
           gtk_css_gadget_border_box_contains_point (priv->stepper_d_gadget, x, y))
    priv->mouse_location = priv->stepper_d_gadget;
  else if (gtk_css_gadget_border_box_contains_point (priv->slider_gadget, x, y))
    priv->mouse_location = priv->slider_gadget;
  else if (rectangle_contains_point (&slider_trace, x, y))
    priv->mouse_location = priv->trough_gadget;
#if 0
  else if (gtk_css_gadget_margin_box_contains_point (priv->gadget, x, y))
    priv->mouse_location = priv->gadget;
#endif
  else
    priv->mouse_location = NULL;

  if (old_location != priv->mouse_location)
    {
      if (old_location != NULL)
        gtk_css_gadget_queue_allocate (old_location);

      if (priv->mouse_location != NULL)
        {
          gtk_widget_set_state_flags (widget, GTK_STATE_FLAG_PRELIGHT, FALSE);
          gtk_css_gadget_queue_allocate (priv->mouse_location);
        }
      else
        {
          gtk_widget_unset_state_flags (widget, GTK_STATE_FLAG_PRELIGHT);
        }

      update_trough_state (range);
      update_slider_state (range);
      update_steppers_state (range);
    }
}

static void
gtk_range_compute_slider_position (GtkRange     *range,
                                   gdouble       adjustment_value,
                                   GdkRectangle *slider_rect)
{
  GtkRangePrivate *priv = range->priv;
  GtkAllocation trough_content_alloc;
  int slider_width, slider_height, min_slider_size;

  measure_one_gadget (priv->slider_gadget, &slider_width, &slider_height);
  gtk_css_gadget_get_content_box (priv->trough_gadget, &trough_content_alloc);

  if (priv->orientation == GTK_ORIENTATION_VERTICAL)
    {
      gint y, bottom, top, height;
        
      /* Slider fits into the trough, with stepper_spacing on either side,
       * and the size/position based on the adjustment or fixed, depending.
       */
      slider_rect->x = trough_content_alloc.x + (int) floor ((trough_content_alloc.width - slider_width) / 2);
      slider_rect->width = slider_width;

      min_slider_size = slider_height;

      /* Compute slider position/length */
      top = trough_content_alloc.y;
      bottom = top + trough_content_alloc.height;

      /* Scale slider half extends over the trough edge */
      if (GTK_IS_SCALE (range))
        {
          top -= min_slider_size / 2;
          bottom += min_slider_size / 2;
        }

      /* slider height is the fraction (page_size /
       * total_adjustment_range) times the trough height in pixels
       */

      if (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment) != 0)
        height = ((bottom - top) * (gtk_adjustment_get_page_size (priv->adjustment) /
                                     (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment))));
      else
        height = min_slider_size;

      if (height < min_slider_size ||
          priv->slider_size_fixed)
        height = min_slider_size;

      height = MIN (height, trough_content_alloc.height);
      
      y = top;

      if (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment) != 0)
        y += (bottom - top - height) * ((adjustment_value - gtk_adjustment_get_lower (priv->adjustment)) /
                                        (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment)));

      y = CLAMP (y, top, bottom);
      
      if (should_invert (range))
        y = bottom - (y - top + height);
      
      slider_rect->y = y;
      slider_rect->height = height;
    }
  else
    {
      gint x, left, right, width;
        
      /* Slider fits into the trough, with stepper_spacing on either side,
       * and the size/position based on the adjustment or fixed, depending.
       */
      slider_rect->y = trough_content_alloc.y + (int) floor ((trough_content_alloc.height - slider_height) / 2);
      slider_rect->height = slider_height;

      min_slider_size = slider_width;

      /* Compute slider position/length */
      left = trough_content_alloc.x;
      right = left + trough_content_alloc.width;

      /* Scale slider half extends over the trough edge */
      if (GTK_IS_SCALE (range))
        {
          left -= min_slider_size / 2;
          right += min_slider_size / 2;
        }

      /* slider width is the fraction (page_size /
       * total_adjustment_range) times the trough width in pixels
       */

      if (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment) != 0)
        width = ((right - left) * (gtk_adjustment_get_page_size (priv->adjustment) /
                                 (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment))));
      else
        width = min_slider_size;

      if (width < min_slider_size ||
          priv->slider_size_fixed)
        width = min_slider_size;

      width = MIN (width, trough_content_alloc.width);

      x = left;

      if (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment) != 0)
        x += (right - left - width) * ((adjustment_value - gtk_adjustment_get_lower (priv->adjustment)) /
                                       (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_lower (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment)));
      
      x = CLAMP (x, left, right);
      
      if (should_invert (range))
        x = right - (x - left + width);
      
      slider_rect->x = x;
      slider_rect->width = width;
    }
}

static void
gtk_range_calc_slider (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gboolean visible;

  if (GTK_IS_SCALE (range) &&
      gtk_adjustment_get_upper (priv->adjustment) == gtk_adjustment_get_lower (priv->adjustment))
    visible = FALSE;
  else
    visible = TRUE;

  gtk_css_gadget_set_visible (priv->slider_gadget, visible);

  gtk_css_gadget_queue_allocate (priv->slider_gadget);

  if (priv->has_origin)
    gtk_css_gadget_queue_allocate (priv->trough_gadget);

  gtk_range_update_mouse_location (range);
}

static void
gtk_range_calc_stepper_sensitivity (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  gboolean was_upper_sensitive, was_lower_sensitive;

  was_upper_sensitive = priv->upper_sensitive;
  switch (priv->upper_sensitivity)
    {
    case GTK_SENSITIVITY_AUTO:
      priv->upper_sensitive =
        (gtk_adjustment_get_value (priv->adjustment) <
         (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment)));
      break;

    case GTK_SENSITIVITY_ON:
      priv->upper_sensitive = TRUE;
      break;

    case GTK_SENSITIVITY_OFF:
      priv->upper_sensitive = FALSE;
      break;
    }

  was_lower_sensitive = priv->lower_sensitive;
  switch (priv->lower_sensitivity)
    {
    case GTK_SENSITIVITY_AUTO:
      priv->lower_sensitive =
        (gtk_adjustment_get_value (priv->adjustment) > gtk_adjustment_get_lower (priv->adjustment));
      break;

    case GTK_SENSITIVITY_ON:
      priv->lower_sensitive = TRUE;
      break;

    case GTK_SENSITIVITY_OFF:
      priv->lower_sensitive = FALSE;
      break;
    }

  /* Too many side effects can influence which stepper reacts to wat condition.
   * So we just invalidate them all.
   */
  if (was_upper_sensitive != priv->upper_sensitive ||
      was_lower_sensitive != priv->lower_sensitive)
    {
      update_steppers_state (range);

      if (priv->stepper_a_gadget)
        gtk_css_gadget_queue_allocate (priv->stepper_a_gadget);
      if (priv->stepper_b_gadget)
        gtk_css_gadget_queue_allocate (priv->stepper_b_gadget);
      if (priv->stepper_c_gadget)
        gtk_css_gadget_queue_allocate (priv->stepper_c_gadget);
      if (priv->stepper_d_gadget)
        gtk_css_gadget_queue_allocate (priv->stepper_d_gadget);
    }
}

static void
gtk_range_calc_marks (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;
  GdkRectangle slider;
  gint i;

  for (i = 0; i < priv->n_marks; i++)
    {
      gtk_range_compute_slider_position (range, priv->marks[i], &slider);

      if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)
        priv->mark_pos[i] = slider.x + slider.width / 2;
      else
        priv->mark_pos[i] = slider.y + slider.height / 2;
    }
}

static gboolean
gtk_range_real_change_value (GtkRange      *range,
                             GtkScrollType  scroll,
                             gdouble        value)
{
  GtkRangePrivate *priv = range->priv;

  /* potentially adjust the bounds _before_ we clamp */
  g_signal_emit (range, signals[ADJUST_BOUNDS], 0, value);

  if (priv->restrict_to_fill_level)
    value = MIN (value, MAX (gtk_adjustment_get_lower (priv->adjustment),
                             priv->fill_level));

  value = CLAMP (value, gtk_adjustment_get_lower (priv->adjustment),
                 (gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment)));

  if (priv->round_digits >= 0)
    {
      gdouble power;
      gint i;

      i = priv->round_digits;
      power = 1;
      while (i--)
        power *= 10;

      value = floor ((value * power) + 0.5) / power;
    }

  if (priv->in_drag || priv->autoscroll_id)
    gtk_adjustment_set_value (priv->adjustment, value);
  else
    gtk_adjustment_animate_to_value (priv->adjustment, value);

  return FALSE;
}

struct _GtkRangeStepTimer
{
  guint timeout_id;
  GtkScrollType step;
};

static gboolean
second_timeout (gpointer data)
{
  GtkRange *range = GTK_RANGE (data);
  GtkRangePrivate *priv = range->priv;

  gtk_range_scroll (range, priv->timer->step);

  return G_SOURCE_CONTINUE;
}

static gboolean
initial_timeout (gpointer data)
{
  GtkRange *range = GTK_RANGE (data);
  GtkRangePrivate *priv = range->priv;

  priv->timer->timeout_id = gdk_threads_add_timeout (TIMEOUT_REPEAT,
                                                     second_timeout,
                                                     range);
  g_source_set_name_by_id (priv->timer->timeout_id, "[gtk+] second_timeout");
  return G_SOURCE_REMOVE;
}

static void
gtk_range_add_step_timer (GtkRange      *range,
                          GtkScrollType  step)
{
  GtkRangePrivate *priv = range->priv;

  g_return_if_fail (priv->timer == NULL);
  g_return_if_fail (step != GTK_SCROLL_NONE);

  priv->timer = g_new (GtkRangeStepTimer, 1);

  priv->timer->timeout_id = gdk_threads_add_timeout (TIMEOUT_INITIAL,
                                                     initial_timeout,
                                                     range);
  g_source_set_name_by_id (priv->timer->timeout_id, "[gtk+] initial_timeout");
  priv->timer->step = step;

  gtk_range_scroll (range, priv->timer->step);
}

static void
gtk_range_remove_step_timer (GtkRange *range)
{
  GtkRangePrivate *priv = range->priv;

  if (priv->timer)
    {
      if (priv->timer->timeout_id != 0)
        g_source_remove (priv->timer->timeout_id);

      g_free (priv->timer);

      priv->timer = NULL;
    }
}

void
_gtk_range_set_has_origin (GtkRange *range,
                           gboolean  has_origin)
{
  GtkRangePrivate *priv = range->priv;

  range->priv->has_origin = has_origin;

  if (has_origin)
    {
      priv->highlight_gadget = gtk_css_custom_gadget_new ("highlight",
                                                          GTK_WIDGET (range),
                                                          priv->trough_gadget, NULL,
                                                          NULL, NULL,
                                                          NULL,
                                                          NULL, NULL);
      gtk_css_gadget_set_state (priv->highlight_gadget,
                                gtk_css_node_get_state (gtk_css_gadget_get_node (priv->trough_gadget)));

      update_highlight_position (range);
    }
  else
    {
      gtk_css_node_set_parent (gtk_css_gadget_get_node (priv->highlight_gadget), NULL);
      g_clear_object (&priv->highlight_gadget);
    }
}

gboolean
_gtk_range_get_has_origin (GtkRange *range)
{
  return range->priv->has_origin;
}

void
_gtk_range_set_stop_values (GtkRange *range,
                            gdouble  *values,
                            gint      n_values)
{
  GtkRangePrivate *priv = range->priv;
  gint i;

  g_free (priv->marks);
  priv->marks = g_new (gdouble, n_values);

  g_free (priv->mark_pos);
  priv->mark_pos = g_new (gint, n_values);

  priv->n_marks = n_values;

  for (i = 0; i < n_values; i++) 
    priv->marks[i] = values[i];

  gtk_range_calc_marks (range);
}

gint
_gtk_range_get_stop_positions (GtkRange  *range,
                               gint     **values)
{
  GtkRangePrivate *priv = range->priv;

  gtk_range_calc_marks (range);

  if (values)
    *values = g_memdup (priv->mark_pos, priv->n_marks * sizeof (gint));

  return priv->n_marks;
}

/**
 * gtk_range_set_round_digits:
 * @range: a #GtkRange
 * @round_digits: the precision in digits, or -1
 *
 * Sets the number of digits to round the value to when
 * it changes. See #GtkRange::change-value.
 *
 * Since: 2.24
 */
void
gtk_range_set_round_digits (GtkRange *range,
                            gint      round_digits)
{
  g_return_if_fail (GTK_IS_RANGE (range));
  g_return_if_fail (round_digits >= -1);

  if (range->priv->round_digits != round_digits)
    {
      range->priv->round_digits = round_digits;
      g_object_notify_by_pspec (G_OBJECT (range), properties[PROP_ROUND_DIGITS]);
    }
}

/**
 * gtk_range_get_round_digits:
 * @range: a #GtkRange
 *
 * Gets the number of digits to round the value to when
 * it changes. See #GtkRange::change-value.
 *
 * Returns: the number of digits to round to
 *
 * Since: 2.24
 */
gint
gtk_range_get_round_digits (GtkRange *range)
{
  g_return_val_if_fail (GTK_IS_RANGE (range), -1);

  return range->priv->round_digits;
}

static void
sync_stepper_gadget (GtkRange                *range,
                     gboolean                 should_have_stepper,
                     GtkCssGadget           **gadget_ptr,
                     const gchar             *class,
                     GtkCssImageBuiltinType   image_type,
                     GtkCssGadget            *prev_sibling)
{
  GtkWidget *widget;
  GtkCssGadget *gadget;
  GtkCssNode *widget_node;
  gboolean has_stepper;
  GtkRangePrivate *priv = range->priv;

  has_stepper = (*gadget_ptr != NULL);
  if (has_stepper == should_have_stepper)
    return;

  if (!should_have_stepper)
    {
      if (*gadget_ptr != NULL)
        {
          if (*gadget_ptr == priv->grab_location)
            stop_scrolling (range);
          if (*gadget_ptr == priv->mouse_location)
            priv->mouse_location = NULL;
          gtk_css_node_set_parent (gtk_css_gadget_get_node (*gadget_ptr), NULL);
          gtk_box_gadget_remove_gadget (GTK_BOX_GADGET (priv->contents_gadget), *gadget_ptr);
        }
      g_clear_object (gadget_ptr);
      return;
    }

  widget = GTK_WIDGET (range);
  widget_node = gtk_widget_get_css_node (widget);
  gadget = gtk_builtin_icon_new ("button",
                                 widget,
                                 NULL, NULL);
  gtk_builtin_icon_set_image (GTK_BUILTIN_ICON (gadget), image_type);
  gtk_css_gadget_add_class (gadget, class);
  gtk_css_gadget_set_state (gadget, gtk_css_node_get_state (widget_node));

  gtk_box_gadget_insert_gadget_after (GTK_BOX_GADGET (priv->contents_gadget), prev_sibling,
                                      gadget, FALSE, GTK_ALIGN_FILL);
  *gadget_ptr = gadget;
}

void
_gtk_range_set_steppers (GtkRange *range,
                         gboolean  has_a,
                         gboolean  has_b,
                         gboolean  has_c,
                         gboolean  has_d)
{
  GtkRangePrivate *priv = range->priv;

  sync_stepper_gadget (range,
                       has_a, &priv->stepper_a_gadget,
                       "up",
                       priv->orientation == GTK_ORIENTATION_VERTICAL ?
                       GTK_CSS_IMAGE_BUILTIN_ARROW_UP : GTK_CSS_IMAGE_BUILTIN_ARROW_LEFT,
                       NULL);

  sync_stepper_gadget (range,
                       has_b, &priv->stepper_b_gadget,
                       "down",
                       priv->orientation == GTK_ORIENTATION_VERTICAL ?
                       GTK_CSS_IMAGE_BUILTIN_ARROW_DOWN : GTK_CSS_IMAGE_BUILTIN_ARROW_RIGHT,
                       priv->stepper_a_gadget);

  sync_stepper_gadget (range,
                       has_c, &priv->stepper_c_gadget,
                       "up",
                       priv->orientation == GTK_ORIENTATION_VERTICAL ?
                       GTK_CSS_IMAGE_BUILTIN_ARROW_UP : GTK_CSS_IMAGE_BUILTIN_ARROW_LEFT,
                       priv->trough_gadget);

  sync_stepper_gadget (range,
                       has_d, &priv->stepper_d_gadget,
                       "down",
                       priv->orientation == GTK_ORIENTATION_VERTICAL ?
                       GTK_CSS_IMAGE_BUILTIN_ARROW_DOWN : GTK_CSS_IMAGE_BUILTIN_ARROW_RIGHT,
                       priv->stepper_c_gadget ? priv->stepper_c_gadget : priv->trough_gadget);

  gtk_widget_queue_resize (GTK_WIDGET (range));
}

GtkCssGadget *
gtk_range_get_slider_gadget (GtkRange *range)
{
  return range->priv->slider_gadget;
}