GocItem

typedef struct _GocItem GocItem;

GocItem contains the following fields:

The various fields should not be accessed directly except from children objects which must update x0, y0, x1, and y1 from their update_bounds method. All other fields are read-only and not documented.

GocItemClass

typedef struct {
	GObjectClass	 base;

	double			(*distance) (GocItem *item,
					     double x, double y, GocItem **near_item);
	void			(*draw) (GocItem const *item, cairo_t *cr);
	gboolean		(*draw_region) (GocItem const *item, cairo_t *cr,
						double x0, double y0, double x1, double y1);
	void			(*update_bounds) (GocItem *item);
	/* events related functions */
	gboolean		(*button_pressed) (GocItem *item, int button, double x, double y);
	gboolean		(*button2_pressed) (GocItem *item, int button, double x, double y);
	gboolean		(*button_released) (GocItem *item, int button, double x, double y);
	gboolean		(*motion) (GocItem *item, double x, double y);
	gboolean		(*enter_notify) (GocItem *item, double x, double y);
	gboolean		(*leave_notify) (GocItem *item, double x, double y);
	void			(*realize) (GocItem *item);
	void			(*unrealize) (GocItem *item);
	gboolean		(*key_pressed) (GocItem *item, GdkEventKey* ev);
	gboolean		(*key_released) (GocItem *item, GdkEventKey* ev);
	void			(*notify_scrolled) (GocItem *item);
} GocItemClass;

The base class for all canvas items.

goc_item_new ()

GocItem *           goc_item_new                        (GocGroup *parent,
                                                         GType type,
                                                         const gchar *first_arg_name,
                                                         ...);

Creates a new item of type type in group group. Properties can be set just the same way they are in g_object_new.

goc_item_destroy ()

void                goc_item_destroy                    (GocItem *item);

Destroys item, removes it from its parent group and updates the canvas accordingly.

goc_item_set ()

void                goc_item_set                        (GocItem *item,
                                                         const gchar *first_arg_name,
                                                         ...);

Set properties and updates the canvas. Using g_object_set instead would set the properties, but not update the canvas.

goc_item_distance ()

double              goc_item_distance                   (GocItem *item,
                                                         double x,
                                                         double y,
                                                         GocItem **near_item);

Evaluates the distance between the point with canvas coordinates x,y and the nearest point of item. near_item is set with either item or its appropriate child.

goc_item_draw ()

void                goc_item_draw                       (GocItem const *item,
                                                         cairo_t *cr);

Renders item using cr. There is no need to call this function directly. Invalidating the item is the way to go.

goc_item_draw_region ()

gboolean            goc_item_draw_region                (GocItem const *item,
                                                         cairo_t *cr,
                                                         double x0,
                                                         double y0,
                                                         double x1,
                                                         double y1);

Renders item using cr, limiting all drawings to the region limited by x0, y0, x1, and y1. If this function returns FALSE, goc_item_draw should be called. There is no need to call this function directly. Invalidating the item is the way to go.

goc_item_invalidate ()

void                goc_item_invalidate                 (GocItem *item);

Force a redraw of item bounding region.

goc_item_show ()

void                goc_item_show                       (GocItem *item);

Makes item visible.

goc_item_hide ()

void                goc_item_hide                       (GocItem *item);

Hides item.

goc_item_is_visible ()

gboolean            goc_item_is_visible                 (GocItem *item);

goc_item_get_bounds ()

void                goc_item_get_bounds                 (GocItem const *item,
                                                         double *x0,
                                                         double *y0,
                                                         double *x1,
                                                         double *y1);

Retrieves the bounds of item in canvas coordinates.

goc_item_bounds_changed ()

void                goc_item_bounds_changed             (GocItem *item);

This function needs to be called each time the bounds of item change. It is normally called from inside the implementation of items derived classes.

goc_item_grab ()

void                goc_item_grab                       (GocItem *item);

Grabs the item. This function will fail if another item is grabbed.

goc_item_ungrab ()

void                goc_item_ungrab                     (GocItem *item);

Ungrabs the item. This function will fail if item is not grabbed.

goc_item_raise ()

void                goc_item_raise                      (GocItem *item,
                                                         int n);

Raises item by n steps inside its parent GocGroup (or less if the list is too short) in the item list so that it is displayed nearer the top of the items stack.

goc_item_lower ()

void                goc_item_lower                      (GocItem *item,
                                                         int n);

Lowers item by n steps inside its parent GocGroup (or less if the list is too short) in the item list so that it is displayed more deeply in the items stack.

goc_item_lower_to_bottom ()

void                goc_item_lower_to_bottom            (GocItem *item);

Lowers item to bottom inside its parent GocGroup so that it will be at least partly hidden by any overlapping item.

goc_item_raise_to_top ()

void                goc_item_raise_to_top               (GocItem *item);

Raises item to front so that it becomes the toplevel item inside its parent GocGroup.

The "canvas" property

  "canvas"                   GocCanvas*            : Read

The canvas object on which the item resides.

The "parent" property

  "parent"                   GocGroup*             : Read

The group in which the item resides.