C++ ST_SCROLL_VIEW函数代码示例

static void
st_scroll_view_fade_paint_target (ClutterOffscreenEffect *effect)
{
  StScrollViewFade *self = ST_SCROLL_VIEW_FADE (effect);
  ClutterOffscreenEffectClass *parent;
  CoglHandle material;

  gdouble value, lower, upper, page_size;
  ClutterActor *vscroll = st_scroll_view_get_vscroll_bar (ST_SCROLL_VIEW (self->actor));
  ClutterActor *hscroll = st_scroll_view_get_hscroll_bar (ST_SCROLL_VIEW (self->actor));
  gboolean h_scroll_visible, v_scroll_visible;

  g_object_get (ST_SCROLL_VIEW (self->actor),
                "hscrollbar-visible", &h_scroll_visible,
                "vscrollbar-visible", &v_scroll_visible,
                NULL);

  if (self->program == COGL_INVALID_HANDLE)
    goto out;

  st_adjustment_get_values (self->vadjustment, &value, &lower, &upper, NULL, NULL, &page_size);

  if (self->offset_top_uniform > -1) {
    if (value > lower + 0.1)
      cogl_program_set_uniform_1f (self->program, self->offset_top_uniform, self->fade_offset);
    else
      cogl_program_set_uniform_1f (self->program, self->offset_top_uniform, 0.0f);
  }

  if (self->offset_bottom_uniform > -1) {
    if (value < upper - page_size - 0.1)
      cogl_program_set_uniform_1f (self->program, self->offset_bottom_uniform, self->fade_offset);
    else
      cogl_program_set_uniform_1f (self->program, self->offset_bottom_uniform, 0.0f);
  }

  if (self->tex_uniform > -1)
    cogl_program_set_uniform_1i (self->program, self->tex_uniform, 0);
  if (self->height_uniform > -1)
    cogl_program_set_uniform_1f (self->program, self->height_uniform, clutter_actor_get_height (self->actor));
  if (self->width_uniform > -1)
    cogl_program_set_uniform_1f (self->program, self->width_uniform, clutter_actor_get_width (self->actor));
  if (self->scrollbar_width_uniform > -1)
    cogl_program_set_uniform_1f (self->program, self->scrollbar_width_uniform, v_scroll_visible ? clutter_actor_get_width (vscroll) : 0);
  if (self->scrollbar_height_uniform > -1)
    cogl_program_set_uniform_1f (self->program, self->scrollbar_height_uniform, h_scroll_visible ? clutter_actor_get_height (hscroll) : 0);
  if (self->rtl_uniform > -1)
    cogl_program_set_uniform_1i (self->program, self->rtl_uniform, (st_widget_get_direction (ST_WIDGET (self->actor)) == ST_TEXT_DIRECTION_RTL));

  material = clutter_offscreen_effect_get_target (effect);
  cogl_material_set_user_program (material, self->program);

out:
  parent = CLUTTER_OFFSCREEN_EFFECT_CLASS (st_scroll_view_fade_parent_class);
  parent->paint_target (effect);
}

static void
st_scroll_view_get_preferred_width (ClutterActor *actor,
                                    gfloat        for_height,
                                    gfloat       *min_width_p,
                                    gfloat       *natural_width_p)
{
  StScrollViewPrivate *priv = ST_SCROLL_VIEW (actor)->priv;
  StThemeNode *theme_node = st_widget_get_theme_node (ST_WIDGET (actor));
  gfloat min_width = 0, natural_width;
  gfloat child_min_width, child_natural_width;

  if (!priv->child)
    return;

  st_theme_node_adjust_for_height (theme_node, &for_height);

  clutter_actor_get_preferred_width (priv->child, -1,
                                     &child_min_width, &child_natural_width);

  natural_width = child_natural_width;

  switch (priv->hscrollbar_policy)
    {
    case GTK_POLICY_NEVER:
      min_width = child_min_width;
      break;
    case GTK_POLICY_ALWAYS:
    case GTK_POLICY_AUTOMATIC:
    case GTK_POLICY_EXTERNAL:
      /* Should theoretically use the min width of the hscrollbar,
       * but that's not cleanly defined at the moment */
      min_width = 0;
      break;
    default:
      g_warn_if_reached();
      break;
    }

  if (priv->vscrollbar_policy != GTK_POLICY_NEVER)
    {
      float sb_width = get_scrollbar_width (ST_SCROLL_VIEW (actor), for_height);

      min_width += sb_width;
      natural_width += sb_width;
    }

  if (min_width_p)
    *min_width_p = min_width;

  if (natural_width_p)
    *natural_width_p = natural_width;

  st_theme_node_adjust_preferred_width (theme_node, min_width_p, natural_width_p);
}

void
st_scroll_view_set_auto_scrolling (StScrollView *scroll,
                                   gboolean      enabled)
{
  StScrollViewPrivate *priv;

  g_return_if_fail (ST_IS_SCROLL_VIEW (scroll));

  priv = ST_SCROLL_VIEW (scroll)->priv;

  if (priv->auto_scroll != enabled)
    {
      priv->auto_scroll = enabled;

      /* make sure we can receive mouse wheel events */
      if (enabled) {
        clutter_actor_set_reactive ((ClutterActor *) scroll, TRUE);
        g_signal_connect (scroll, "motion-event",
                          G_CALLBACK (motion_event_cb), scroll);
      } else {
        g_signal_handlers_disconnect_by_func (scroll, motion_event_cb, scroll);
        if (priv->auto_scroll_timeout_id > 0) {
            g_source_remove (priv->auto_scroll_timeout_id);
            priv->auto_scroll_timeout_id = 0;
        }
      }
    }
}

/**
 * st_scroll_view_update_vfade_effect:
 * @self: a #StScrollView
 * @fade_offset: The length of the fade effect, in pixels.
 *
 * Sets the height of the fade area area in pixels. A value of 0
 * disables the effect.
 */
static void
st_scroll_view_update_vfade_effect (StScrollView *self,
                                    float fade_offset)
{
  StScrollViewPrivate *priv = ST_SCROLL_VIEW (self)->priv;

  /* A fade amount of more than 0 enables the effect. */
  if (fade_offset > 0.)
    {
      if (priv->vfade_effect == NULL) {
        priv->vfade_effect = g_object_new (ST_TYPE_SCROLL_VIEW_FADE, NULL);

        clutter_actor_add_effect_with_name (CLUTTER_ACTOR (self), "vfade",
                                            CLUTTER_EFFECT (priv->vfade_effect));
      }

      g_object_set (priv->vfade_effect,
                    "fade-offset", fade_offset,
                    NULL);
    }
   else
    {
      if (priv->vfade_effect != NULL) {
        clutter_actor_remove_effect (CLUTTER_ACTOR (self), CLUTTER_EFFECT (priv->vfade_effect));
        priv->vfade_effect = NULL;
      }
    }

  clutter_actor_queue_redraw (CLUTTER_ACTOR (self));
}

static void
st_scroll_view_remove (ClutterContainer *container,
                       ClutterActor     *actor)
{
  StScrollView *self = ST_SCROLL_VIEW (container);
  StScrollViewPrivate *priv = self->priv;

  if (actor == priv->child)
    {
      g_object_ref (priv->child);

      /* chain up to StBin::remove() */
      st_scroll_view_parent_iface->remove (container, actor);

      st_scrollable_set_adjustments (ST_SCROLLABLE (priv->child),
                                     NULL, NULL);

      g_object_unref (priv->child);
      priv->child = NULL;
    }
  else
    {
      if (actor == priv->vscroll)
        priv->vscroll = NULL;
      else if (actor == priv->hscroll)
        priv->hscroll = NULL;
      else
        g_assert ("Unknown child removed from StScrollView");

      clutter_actor_unparent (actor);
    }
}

static void
calculate_and_scroll (ClutterActor  *self,
                             gint    mouse_x,
                             gint    mouse_y,
                             gfloat  box_x,
                             gfloat  box_y,
                             gfloat  width,
                             gfloat  height)
{
    StScrollViewPrivate *priv = ST_SCROLL_VIEW (self)->priv;
    gboolean up;
    gint sub_region;
    gdouble delta, vvalue;

    up = get_sub_region_y (mouse_y, box_y, height, &sub_region);

    if (up)
        delta = sub_region * -1.0 / AUTO_SCROLL_SPEED_DIVISOR;
    else
        delta = sub_region / AUTO_SCROLL_SPEED_DIVISOR;

    g_object_get (priv->vadjustment,
                    "value", &vvalue,
                    NULL);
    st_adjustment_set_value (priv->vadjustment, vvalue + delta);
}

static void
st_scroll_view_set_property (GObject      *object,
                             guint         property_id,
                             const GValue *value,
                             GParamSpec   *pspec)
{
  StScrollView *self = ST_SCROLL_VIEW (object);
  StScrollViewPrivate *priv = self->priv;

  switch (property_id)
    {
    case PROP_MOUSE_SCROLL:
      st_scroll_view_set_mouse_scrolling (self,
                                          g_value_get_boolean (value));
      break;
    case PROP_HSCROLLBAR_POLICY:
      st_scroll_view_set_policy (self,
                                 g_value_get_enum (value),
                                 priv->vscrollbar_policy);
      break;
    case PROP_VSCROLLBAR_POLICY:
      st_scroll_view_set_policy (self,
                                 priv->hscrollbar_policy,
                                 g_value_get_enum (value));
      break;
    case PROP_AUTO_SCROLL:
      st_scroll_view_set_auto_scrolling (self,
                                         g_value_get_boolean (value));
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
    }
}

static void
st_scroll_view_add (ClutterContainer *container,
                    ClutterActor     *actor)
{
  StScrollView *self = ST_SCROLL_VIEW (container);
  StScrollViewPrivate *priv = self->priv;

  if (ST_IS_SCROLLABLE (actor))
    {
      priv->child = actor;

      /* chain up to StBin::add() */
      st_scroll_view_parent_iface->add (container, actor);

      st_scrollable_set_adjustments (ST_SCROLLABLE (actor),
                                     priv->hadjustment, priv->vadjustment);
    }
  else
    {
      g_warning ("Attempting to add an actor of type %s to "
                 "a StScrollView, but the actor does "
                 "not implement StScrollable.",
                 g_type_name (G_OBJECT_TYPE (actor)));
    }
}

/**
 * st_scroll_view_set_policy:
 * @scroll: A #StScrollView
 * @hscroll: Whether to enable horizontal scrolling
 * @vscroll: Whether to enable vertical scrolling
 *
 * Set the scroll policy.
 */
void
st_scroll_view_set_policy (StScrollView   *scroll,
                           GtkPolicyType   hscroll,
                           GtkPolicyType   vscroll)
{
  StScrollViewPrivate *priv;

  g_return_if_fail (ST_IS_SCROLL_VIEW (scroll));

  priv = ST_SCROLL_VIEW (scroll)->priv;

  if (priv->hscrollbar_policy == hscroll && priv->vscrollbar_policy == vscroll)
    return;

  g_object_freeze_notify ((GObject *) scroll);

  if (priv->hscrollbar_policy != hscroll)
    {
      priv->hscrollbar_policy = hscroll;
      g_object_notify ((GObject *) scroll, "hscrollbar-policy");
    }

  if (priv->vscrollbar_policy != vscroll)
    {
      priv->vscrollbar_policy = vscroll;
      g_object_notify ((GObject *) scroll, "vscrollbar-policy");
    }

  clutter_actor_queue_relayout (CLUTTER_ACTOR (scroll));

  g_object_thaw_notify ((GObject *) scroll);
}

static gboolean
st_scroll_view_scroll_event (ClutterActor       *self,
                             ClutterScrollEvent *event)
{
  StScrollViewPrivate *priv = ST_SCROLL_VIEW (self)->priv;

  /* don't handle scroll events if requested not to */
  if (!priv->mouse_scroll)
    return FALSE;

  if (clutter_event_is_pointer_emulated ((ClutterEvent *) event))
    return TRUE;

  switch (event->direction)
    {
    case CLUTTER_SCROLL_SMOOTH:
      {
        gdouble delta_x, delta_y;
        clutter_event_get_scroll_delta ((ClutterEvent *)event, &delta_x, &delta_y);
        st_adjustment_adjust_for_scroll_event (priv->hadjustment, delta_x);
        st_adjustment_adjust_for_scroll_event (priv->vadjustment, delta_y);
      }
      break;
    case CLUTTER_SCROLL_UP:
    case CLUTTER_SCROLL_DOWN:
      adjust_with_direction (priv->vadjustment, event->direction);
      break;
    case CLUTTER_SCROLL_LEFT:
    case CLUTTER_SCROLL_RIGHT:
      adjust_with_direction (priv->hadjustment, event->direction);
      break;
    }

  return TRUE;
}

static void
st_scroll_view_dispose (GObject *object)
{
  StScrollViewPrivate *priv = ST_SCROLL_VIEW (object)->priv;

  if (priv->vfade_effect)
    {
      clutter_actor_remove_effect (CLUTTER_ACTOR (object), CLUTTER_EFFECT (priv->vfade_effect));
      priv->vfade_effect = NULL;
    }

  if (priv->vscroll)
    clutter_actor_destroy (priv->vscroll);

  if (priv->hscroll)
    clutter_actor_destroy (priv->hscroll);

  /* For most reliable freeing of memory, an object with signals
   * like StAdjustment should be explicitly disposed. Since we own
   * the adjustments, we take care of that. This also disconnects
   * the signal handlers that we established on creation.
   */
  if (priv->hadjustment)
    {
      g_object_run_dispose (G_OBJECT (priv->hadjustment));
      g_object_unref (priv->hadjustment);
      priv->hadjustment = NULL;
    }

  if (priv->vadjustment)
    {
      g_object_run_dispose (G_OBJECT (priv->vadjustment));
      g_object_unref (priv->vadjustment);
      priv->vadjustment = NULL;
    }

  if (priv->setting_connect_id > 0) {
    g_signal_handler_disconnect (priv->settings, priv->setting_connect_id);
    priv->setting_connect_id = 0;
  }

  g_signal_handlers_disconnect_by_func (ST_SCROLL_VIEW (object), motion_event_cb, ST_SCROLL_VIEW (object));

  G_OBJECT_CLASS (st_scroll_view_parent_class)->dispose (object);
}

static void
st_scroll_view_fade_set_actor (ClutterActorMeta *meta,
                               ClutterActor *actor)
{
  StScrollViewFade *self = ST_SCROLL_VIEW_FADE (meta);
  ClutterActorMetaClass *parent;

  g_return_if_fail (actor == NULL || ST_IS_SCROLL_VIEW (actor));

  if (self->shader == COGL_INVALID_HANDLE)
    {
      clutter_actor_meta_set_enabled (meta, FALSE);
      return;
    }

  if (self->vadjustment)
    {
      g_signal_handlers_disconnect_by_func (self->vadjustment,
                                            (gpointer)on_adjustment_changed,
                                            self);
      self->vadjustment = NULL;
    }

  if (self->hadjustment)
    {
      g_signal_handlers_disconnect_by_func (self->hadjustment,
                                            (gpointer)on_adjustment_changed,
                                            self);
      self->hadjustment = NULL;
    }


  if (actor)
    {
        StScrollView *scroll_view = ST_SCROLL_VIEW (actor);
        StScrollBar *vscroll = ST_SCROLL_BAR (st_scroll_view_get_vscroll_bar (scroll_view));
        StScrollBar *hscroll = ST_SCROLL_BAR (st_scroll_view_get_hscroll_bar (scroll_view));
        self->vadjustment = ST_ADJUSTMENT (st_scroll_bar_get_adjustment (vscroll));
        self->hadjustment = ST_ADJUSTMENT (st_scroll_bar_get_adjustment (hscroll));

        g_signal_connect (self->vadjustment, "changed",
                          G_CALLBACK (on_adjustment_changed),
                          self);

        g_signal_connect (self->hadjustment, "changed",
                          G_CALLBACK (on_adjustment_changed),
                          self);

        on_adjustment_changed (NULL, CLUTTER_EFFECT (self));
    }

  parent = CLUTTER_ACTOR_META_CLASS (st_scroll_view_fade_parent_class);
  parent->set_actor (meta, actor);

  /* we keep a back pointer here, to avoid going through the ActorMeta */
  self->actor = clutter_actor_meta_get_actor (meta);
}

/**
 * st_scroll_view_get_overlay_scrollbars:
 * @scroll: A #StScrollView
 *
 * Gets the value set by st_scroll_view_set_overlay_scrollbars().
 */
gboolean
st_scroll_view_get_overlay_scrollbars (StScrollView *scroll)
{
  StScrollViewPrivate *priv;

  g_return_val_if_fail (ST_IS_SCROLL_VIEW (scroll), FALSE);

  priv = ST_SCROLL_VIEW (scroll)->priv;

  return priv->overlay_scrollbars;
}

gboolean
st_scroll_view_get_auto_scrolling (StScrollView *scroll)
{
  StScrollViewPrivate *priv;

  g_return_val_if_fail (ST_IS_SCROLL_VIEW (scroll), FALSE);

  priv = ST_SCROLL_VIEW (scroll)->priv;

  return priv->auto_scroll;
}

static void
st_scroll_view_paint (ClutterActor *actor)
{
  StScrollViewPrivate *priv = ST_SCROLL_VIEW (actor)->priv;

  st_widget_paint_background (ST_WIDGET (actor));

  if (priv->child)
    clutter_actor_paint (priv->child);
  if (priv->hscrollbar_visible)
    clutter_actor_paint (priv->hscroll);
  if (priv->vscrollbar_visible)
    clutter_actor_paint (priv->vscroll);
}