docs: add Gtk*Class docs

https://bugzilla.gnome.org/show_bug.cgi?id=81006

gtk/deprecated/gtkaction.h

@@ -56,13 +56,22 @@ struct _GtkAction
   GtkActionPrivate *private_data;
 };
 
+/**
+ * GtkActionClass:
+ * @parent_class: The parent class.
+ * @activate: Signal emitted when the action is activated.
+ */
 struct _GtkActionClass
 {
   GObjectClass parent_class;
 
+  /*< public >*/
+
   /* activation signal */
   void       (* activate)           (GtkAction    *action);
 
+  /*< private >*/
+
   GType      menu_item_type;
   GType      toolbar_item_type;
 

gtk/deprecated/gtkactiongroup.h

@@ -60,6 +60,11 @@ struct _GtkActionGroup
   GtkActionGroupPrivate *priv;
 };
 
+/**
+ * GtkActionGroupClass:
+ * @parent_class: The parent class.
+ * @get_action: Looks up an action in the action group by name.
+ */
 struct _GtkActionGroupClass
 {
   GObjectClass parent_class;
@@ -67,6 +72,8 @@ struct _GtkActionGroupClass
   GtkAction *(* get_action) (GtkActionGroup *action_group,
                              const gchar    *action_name);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/deprecated/gtkcolorsel.h

@@ -70,12 +70,19 @@ struct _GtkColorSelection
   GtkColorSelectionPrivate *private_data;
 };
 
+/**
+ * GtkColorSelectionClass:
+ * @parent_class: The parent class.
+ * @color_changed:
+ */
 struct _GtkColorSelectionClass
 {
   GtkBoxClass parent_class;
 
   void (*color_changed)	(GtkColorSelection *color_selection);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/deprecated/gtkhandlebox.h

@@ -57,6 +57,14 @@ struct _GtkHandleBox
   GtkHandleBoxPrivate *priv;
 };
 
+/**
+ * GtkHandleBoxClass:
+ * @parent_class: The parent class.
+ * @child_attached: Signal emitted when the contents of the handlebox
+ *    are reattached to the main window. Deprecated: 3.4.
+ * @child_detached: Signal emitted when the contents of the handlebox
+ *    are detached from the main window. Deprecated: 3.4.
+ */
 struct _GtkHandleBoxClass
 {
   GtkBinClass parent_class;
@@ -66,6 +74,8 @@ struct _GtkHandleBoxClass
   void	(*child_detached)	(GtkHandleBox	*handle_box,
 				 GtkWidget	*child);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/deprecated/gtkiconfactory.h

@@ -57,10 +57,16 @@ struct _GtkIconFactory
   GtkIconFactoryPrivate *priv;
 };
 
+/**
+ * GtkIconFactoryClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkIconFactoryClass
 {
   GObjectClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/deprecated/gtkimagemenuitem.h

@@ -55,10 +55,16 @@ struct _GtkImageMenuItem
   GtkImageMenuItemPrivate *priv;
 };
 
+/**
+ * GtkImageMenuItemClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkImageMenuItemClass
 {
   GtkMenuItemClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/deprecated/gtkrc.h

@@ -100,10 +100,21 @@ struct _GtkRcStyle
   guint engine_specified : 1;   /* The RC file specified the engine */
 };
 
+/**
+ * GtkRcStyleClass:
+ * @parent_class: The parent class.
+ * @create_rc_style: 
+ * @parse: 
+ * @merge: 
+ * @create_style: 
+ * @create_style: 
+ */
 struct _GtkRcStyleClass
 {
   GObjectClass parent_class;
 
+  /*< public >*/
+
   /* Create an empty RC style of the same type as this RC style.
    * The default implementation, which does
    * g_object_new (G_OBJECT_TYPE (style), NULL);
@@ -129,6 +140,8 @@ struct _GtkRcStyleClass
    */
   GtkStyle * (*create_style) (GtkRcStyle *rc_style);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/deprecated/gtkstyle.h

@@ -98,10 +98,43 @@ struct _GtkStyle
   GSList         *icon_factories; /* of type GtkIconFactory* */
 };
 
+/**
+ * GtkStyleClass:
+ * @parent_class: The parent class.
+ * @realize: 
+ * @unrealize: 
+ * @copy: 
+ * @clone: 
+ * @init_from_rc: 
+ * @set_background: 
+ * @render_icon: 
+ * @draw_hline: 
+ * @draw_vline: 
+ * @draw_shadow: 
+ * @draw_arrow: 
+ * @draw_diamond: 
+ * @draw_box: 
+ * @draw_flat_box: 
+ * @draw_check: 
+ * @draw_option: 
+ * @draw_tab: 
+ * @draw_shadow_gap: 
+ * @draw_box_gap: 
+ * @draw_extension: 
+ * @draw_focus: 
+ * @draw_slider: 
+ * @draw_handle: 
+ * @draw_expander: 
+ * @draw_layout: 
+ * @draw_resize_grip: 
+ * @draw_spinner: 
+ */
 struct _GtkStyleClass
 {
   GObjectClass parent_class;
 
+  /*< public >*/
+
   /* Initialize for a particular visual. style->visual
    * will have been set at this point. Will typically chain
    * to parent.
@@ -352,6 +385,8 @@ struct _GtkStyleClass
                                  gint                    width,
                                  gint                    height);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1)  (void);
   void (*_gtk_reserved2)  (void);

gtk/deprecated/gtktearoffmenuitem.h

@@ -53,10 +53,16 @@ struct _GtkTearoffMenuItem
   GtkTearoffMenuItemPrivate *priv;
 };
 
+/**
+ * GtkTearoffMenuItemClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkTearoffMenuItemClass
 {
   GtkMenuItemClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkaccelgroup.h

@@ -88,15 +88,25 @@ struct _GtkAccelGroup
   GtkAccelGroupPrivate *priv;
 };
 
+/**
+ * GtkAccelGroupClass:
+ * @parent_class: The parent class.
+ * @accel_changed: Signal emitted when an entry is added to or removed
+ *    from the accel group.
+ */
 struct _GtkAccelGroupClass
 {
   GObjectClass parent_class;
 
+  /*< public >*/
+
   void	(*accel_changed)	(GtkAccelGroup	*accel_group,
 				 guint           keyval,
 				 GdkModifierType modifier,
 				 GClosure       *accel_closure);
-  
+
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkalignment.h

@@ -55,10 +55,16 @@ struct _GtkAlignment
   GtkAlignmentPrivate *priv;
 };
 
+/**
+ * GtkAlignmentClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkAlignmentClass
 {
   GtkBinClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkappchooserbutton.h

@@ -49,12 +49,23 @@ struct _GtkAppChooserButton {
   GtkAppChooserButtonPrivate *priv;
 };
 
+/**
+ * GtkAppChooserButtonClass:
+ * @parent_class: The parent class.
+ * @custom_item_activated: Signal emitted when a custom item,
+ *    previously added with gtk_app_chooser_button_append_custom_item(),
+ *    is activated from the dropdown menu.
+ */
 struct _GtkAppChooserButtonClass {
   GtkComboBoxClass parent_class;
 
+  /*< public >*/
+
   void (* custom_item_activated) (GtkAppChooserButton *self,
                                   const gchar *item_name);
 
+  /*< private >*/
+
   /* padding for future class expansion */
   gpointer padding[16];
 };

gtk/gtkappchooserdialog.h

@@ -52,9 +52,15 @@ struct _GtkAppChooserDialog {
   GtkAppChooserDialogPrivate *priv;
 };
 
+/**
+ * GtkAppChooserDialogClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkAppChooserDialogClass {
   GtkDialogClass parent_class;
 
+  /*< private >*/
+
   /* padding for future class expansion */
   gpointer padding[16];
 };

gtk/gtkappchooserwidget.h

@@ -53,9 +53,21 @@ struct _GtkAppChooserWidget {
   GtkAppChooserWidgetPrivate *priv;
 };
 
+/**
+ * GtkAppChooserWidgetClass:
+ * @parent_class: The parent class.
+ * @application_selected: Signal emitted when an application item is
+ *    selected from the widget's list.
+ * @application_activated: Signal emitted when an application item is
+ *    activated from the widget's list.
+ * @populate_popup: Signal emitted when a context menu is about to
+ *    popup over an application item.
+ */
 struct _GtkAppChooserWidgetClass {
   GtkBoxClass parent_class;
 
+  /*< public >*/
+
   void (* application_selected)  (GtkAppChooserWidget *self,
                                   GAppInfo            *app_info);
 
@@ -66,6 +78,8 @@ struct _GtkAppChooserWidgetClass {
                                   GtkMenu             *menu,
                                   GAppInfo            *app_info);
 
+  /*< private >*/
+
   /* padding for future class expansion */
   gpointer padding[16];
 };

gtk/gtkapplication.h

@@ -48,10 +48,21 @@ struct _GtkApplication
   GtkApplicationPrivate *priv;
 };
 
+/**
+ * GtkApplicationClass:
+ * @parent_class: The parent class.
+ * @window_added: Signal emitted when a #GtkWindow is added to
+ *    application through gtk_application_add_window().
+ * @window_removed: Signal emitted when a #GtkWindow is removed from
+ *    application, either as a side-effect of being destroyed or
+ *    explicitly through gtk_application_remove_window().
+ */
 struct _GtkApplicationClass
 {
   GApplicationClass parent_class;
 
+  /*< public >*/
+
   void (*window_added)   (GtkApplication *application,
                           GtkWindow      *window);
   void (*window_removed) (GtkApplication *application,

gtk/gtkapplicationwindow.h

@@ -48,6 +48,10 @@ struct _GtkApplicationWindow
   GtkApplicationWindowPrivate *priv;
 };
 
+/**
+ * GtkApplicationWindowClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkApplicationWindowClass
 {
   GtkWindowClass parent_class;

gtk/gtkaspectframe.h

@@ -54,10 +54,16 @@ struct _GtkAspectFrame
   GtkAspectFramePrivate *priv;
 };
 
+/**
+ * GtkAspectFrameClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkAspectFrameClass
 {
   GtkFrameClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkassistant.h

@@ -89,15 +89,27 @@ struct _GtkAssistant
   GtkAssistantPrivate *priv;
 };
 
+/**
+ * GtkAssistantClass:
+ * @parent_class: The parent class.
+ * @prepare: Signal emitted when a new page is set as the assistant's current page, before making the new page visible.
+ * @apply: Signal emitted when the apply button is clicked.
+ * @close: Signal emitted either when the close button or last page apply button is clicked.
+ * @cancel: Signal emitted when the cancel button is clicked.
+ */
 struct _GtkAssistantClass
 {
   GtkWindowClass parent_class;
 
+  /*< public >*/
+
   void (* prepare) (GtkAssistant *assistant, GtkWidget *page);
   void (* apply)   (GtkAssistant *assistant);
   void (* close)   (GtkAssistant *assistant);
   void (* cancel)  (GtkAssistant *assistant);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkbbox.h

@@ -54,10 +54,16 @@ struct _GtkButtonBox
   GtkButtonBoxPrivate *priv;
 };
 
+/**
+ * GtkButtonBoxClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkButtonBoxClass
 {
   GtkBoxClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkbin.h

@@ -55,10 +55,16 @@ struct _GtkBin
   GtkBinPrivate *priv;
 };
 
+/**
+ * GtkBinClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkBinClass
 {
   GtkContainerClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkbox.h

@@ -56,10 +56,16 @@ struct _GtkBox
   GtkBoxPrivate *priv;
 };
 
+/**
+ * GtkBoxClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkBoxClass
 {
   GtkContainerClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkbutton.h

@@ -55,17 +55,33 @@ struct _GtkButton
   GtkButtonPrivate *priv;
 };
 
+/**
+ * GtkButtonClass:
+ * @parent_class: The parent class.
+ * @pressed: Signal emitted when the button is pressed. Deprecated: 2.8.
+ * @released: Signal emitted when the button is released. Deprecated: 2.8.
+ * @clicked: Signal emitted when the button has been activated (pressed and released).
+ * @enter: Signal emitted when the pointer enters the button. Deprecated: 2.8.
+ * @leave: Signal emitted when the pointer leaves the button. Deprecated: 2.8.
+ * @activate: Signal that causes the button to animate press then
+ *    release. Applications should never connect to this signal, but use
+ *    the @clicked signal.
+ */
 struct _GtkButtonClass
 {
   GtkBinClass        parent_class;
-  
+
+  /*< public >*/
+
   void (* pressed)  (GtkButton *button);
   void (* released) (GtkButton *button);
   void (* clicked)  (GtkButton *button);
   void (* enter)    (GtkButton *button);
   void (* leave)    (GtkButton *button);
   void (* activate) (GtkButton *button);
-  
+
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkcellareabox.h

@@ -49,6 +49,9 @@ struct _GtkCellAreaBox
   GtkCellAreaBoxPrivate *priv;
 };
 
+/**
+ * GtkCellAreaBoxClass:
+ */
 struct _GtkCellAreaBoxClass
 {
   /*< private >*/

gtk/gtkcellrenderer.h

@@ -90,10 +90,29 @@ struct _GtkCellRenderer
   GtkCellRendererPrivate *priv;
 };
 
+/**
+ * GtkCellRendererClass:
+ * @get_request_mode: Called to gets whether the cell renderer prefers
+ *    a height-for-width layout or a width-for-height layout.
+ * @get_preferred_width: Called to get a renderer's natural width.
+ * @get_preferred_height_for_width: Called to get a renderer's natural height for width.
+ * @get_preferred_height: Called to get a renderer's natural height.
+ * @get_preferred_width_for_height: Called to get a renderer's natural width for height.
+ * @get_aligned_area: Called to get the aligned area used by @cell inside @cell_area.
+ * @get_size: Called to get the width and height needed to render the cell. Deprecated: 3.0.
+ * @render: Called to render the content of the #GtkCellRenderer.
+ * @activate: Called to activate the content of the #GtkCellRenderer.
+ * @start_editing: Called to initiate editing the content of the #GtkCellRenderer.
+ * @editing_canceled: Signal gets emitted when the user cancels the process of editing a cell.
+ * @editing_started: Signal gets emitted when a cell starts to be edited.
+ */
 struct _GtkCellRendererClass
 {
+  /*< private >*/
   GInitiallyUnownedClass parent_class;
 
+  /*< public >*/
+
   /* vtable - not signals */
   GtkSizeRequestMode (* get_request_mode)                (GtkCellRenderer      *cell);
   void               (* get_preferred_width)             (GtkCellRenderer      *cell,
@@ -153,6 +172,8 @@ struct _GtkCellRendererClass
 			     GtkCellEditable *editable,
 			     const gchar     *path);
 
+  /*< private >*/
+
   GtkCellRendererClassPrivate *priv;
 
   /* Padding for future expansion */

gtk/gtkcellview.h

@@ -49,10 +49,16 @@ struct _GtkCellView
   GtkCellViewPrivate *priv;
 };
 
+/**
+ * GtkCellViewClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkCellViewClass
 {
   GtkWidgetClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkcheckmenuitem.h

@@ -55,14 +55,24 @@ struct _GtkCheckMenuItem
   GtkCheckMenuItemPrivate *priv;
 };
 
+/**
+ * GtkCheckMenuItemClass:
+ * @parent_class: The parent class.
+ * @toggled: Signal emitted when the state of the check box is changed.
+ * @draw_indicator: Called to draw the check indicator.
+ */
 struct _GtkCheckMenuItemClass
 {
   GtkMenuItemClass parent_class;
 
+  /*< public >*/
+
   void (* toggled)	  (GtkCheckMenuItem *check_menu_item);
   void (* draw_indicator) (GtkCheckMenuItem *check_menu_item,
 			   cairo_t          *cr);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkcolorchooserwidget.h

@@ -45,10 +45,16 @@ struct _GtkColorChooserWidget
   GtkColorChooserWidgetPrivate *priv;
 };
 
+/**
+ * GtkColorChooserWidgetClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkColorChooserWidgetClass
 {
   GtkBoxClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkcombobox.h

@@ -47,15 +47,26 @@ struct _GtkComboBox
   GtkComboBoxPrivate *priv;
 };
 
+/**
+ * GtkComboBoxClass:
+ * @parent_class: The parent class.
+ * @changed: Signal is emitted when the active item is changed.
+ * @format_entry_text: Signal which allows you to change how the text
+ *    displayed in a combo box's entry is displayed.
+ */
 struct _GtkComboBoxClass
 {
   GtkBinClass parent_class;
 
+  /*< public >*/
+
   /* signals */
   void     (* changed)           (GtkComboBox *combo_box);
   gchar   *(* format_entry_text) (GtkComboBox *combo_box,
 				  const gchar *path);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkcontainer.h

@@ -55,10 +55,28 @@ struct _GtkContainer
   GtkContainerPrivate *priv;
 };
 
+/**
+ * GtkContainerClass:
+ * @parent_class: The parent class.
+ * @add: Signal emitted when a widget is added to container.
+ * @remove: Signal emitted when a widget is removed from container.
+ * @check_resize: Signal emitted when a size recalculation is needed.
+ * @forall: Invokes callback on each child of container.
+ * @set_focus_child: Sets the focused child of container.
+ * @child_type: Returns the type of the children supported by the container.
+ * @composite_name: Gets a widget's composite name. Deprecated: 3.10.
+ * @set_child_property: Set a property on a child of container.
+ * @get_path_for_child: Get path representing entire widget hierarchy
+ *    from the toplevel down to and including @child.
+ *
+ * Base class for containers.
+ */
 struct _GtkContainerClass
 {
   GtkWidgetClass parent_class;
 
+  /*< public >*/
+
   void    (*add)       		(GtkContainer	 *container,
 				 GtkWidget	 *widget);
   void    (*remove)    		(GtkContainer	 *container,

gtk/gtkcustompaperunixdialog.h

@@ -41,10 +41,16 @@ struct _GtkCustomPaperUnixDialog
   GtkCustomPaperUnixDialogPrivate *priv;
 };
 
+/**
+ * GtkCustomPaperUnixDialogClass:
+ * @parent_class: The parent class.
+ */
 struct _GtkCustomPaperUnixDialogClass
 {
   GtkDialogClass parent_class;
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkdialog.h

@@ -114,16 +114,26 @@ struct _GtkDialog
   GtkDialogPrivate *priv;
 };
 
+/**
+ * GtkDialogClass:
+ * @parent_class: The parent class.
+ * @response: Signal emitted when an action widget is activated.
+ * @close: Signal emitted when the user uses a keybinding to close the dialog.
+ */
 struct _GtkDialogClass
 {
   GtkWindowClass parent_class;
 
+  /*< public >*/
+
   void (* response) (GtkDialog *dialog, gint response_id);
 
   /* Keybinding signals */
 
   void (* close)    (GtkDialog *dialog);
 
+  /*< private >*/
+
   /* Padding for future expansion */
   void (*_gtk_reserved1) (void);
   void (*_gtk_reserved2) (void);

gtk/gtkeventbox.h

@@ -54,10 +54,16 @@ struct _GtkEventBox