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GObject ╰── GInitiallyUnowned ╰── GtkObject ╰── GwyDataViewLayer ╰── GwyVectorLayer
GwyVectorLayer is a base class for GwyDataViewLayers displaying selections and handling user input. It is a GwyDataView component and it is not normally usable outside of it.
The layer takes the selection to display from its parent GwyDataView's
container. The key under which the selection is found is set with
gwy_vector_layer_set_selection_key()
. The selection either can be put
there beforehand (the corresponding selection type can be obtained with
gwy_vector_layer_class_get_selection_type()
) or
gwy_vector_layer_ensure_selection()
can be used to create it if it doesn't
exist.
GwyVectorLayer provides two independent means to restrict user interaction
with displayed selection: editability and focus. When a layer is set
noneditable (see gwy_vector_layer_set_editable()
), the user cannot modify
displayed objects, however "object-chosen" is emitted normally. Focus
(see gwy_vector_layer_set_focus()
) on the other hand limits all possible
interactions to a single selection object. It is possible although not
very useful to combine both restrictions.
The other methods are rarely useful outside GwyDataView and/or layer implementation.
GType
gwy_vector_layer_class_get_selection_type
(GwyVectorLayerClass *klass
);
Returns the selection type of a vector layer class.
Note this is a class method, to get the type from an instance one can use
gwy_vector_layer_get_selection_type()
. To get the type from layer's
GType one has to use g_type_class_peek()
.
#define gwy_vector_layer_get_selection_type(layer)
Gets the selection type of a vector layer.
This is a convenience wrapper around
gwy_vector_layer_class_get_selection_type()
.
void gwy_vector_layer_set_selection_key (GwyVectorLayer *layer
,const gchar *key
);
Sets the selection object to use by a vector layer.
const gchar *
gwy_vector_layer_get_selection_key (GwyVectorLayer *layer
);
Gets the key identifying selection this vector layer displays.
GwySelection *
gwy_vector_layer_ensure_selection (GwyVectorLayer *layer
);
Ensures a vector layer's selection exist in data container.
This method can be called only when layer is plugged into a data view and it has a selection key set. If the data container contains a selection under the specified key the selection is returned. If there is none, a selection of appropriate type is created and put to the container first.
Provided the above conditions are met this method is suitable for just obtaining the selection object a vector layer uses too.
gint
gwy_vector_layer_get_focus (GwyVectorLayer *layer
);
Gets focused object index.
gboolean gwy_vector_layer_set_focus (GwyVectorLayer *layer
,gint focus
);
Focues on one selection object.
When a selection object is focused, it becomes the only one user can interact with. More precisely, "object-chosen" signal is emitted only for this object, and if the layer is editable only this object can be modified by the user.
gboolean
gwy_vector_layer_get_editable (GwyVectorLayer *layer
);
Gets editability of a vector layer.
void gwy_vector_layer_set_editable (GwyVectorLayer *layer
,gboolean editable
);
Sets a vector layer editability.
It is an error to attempt to set a layer non-editabile while it is being edited.
When a layer is set noneditable, the user cannot change the selection. However, "object-chosen" signal is still emitted.
void gwy_vector_layer_draw (GwyVectorLayer *layer
,GdkDrawable *drawable
,GwyRenderingTarget target
);
Draws layer
on given drawable (which should be a GwyDataView window).
gboolean gwy_vector_layer_button_press (GwyVectorLayer *layer
,GdkEventButton *event
);
Sends a mouse button press event to a layer.
This method primarily exists for GwyDataView to forward events to layers. You should rarely need it.
gboolean gwy_vector_layer_button_release (GwyVectorLayer *layer
,GdkEventButton *event
);
Sends a mouse button release event to a layer.
This method primarily exists for GwyDataView to forward events to layers. You should rarely need it.
gboolean gwy_vector_layer_motion_notify (GwyVectorLayer *layer
,GdkEventMotion *event
);
Sends a mouse pointer motion notification event to a layer.
This method primarily exists for GwyDataView to forward events to layers. You should rarely need it.
gboolean gwy_vector_layer_key_press (GwyVectorLayer *layer
,GdkEventKey *event
);
Sends a key press event to a layer.
This method primarily exists for GwyDataView to forward events to layers. You should rarely need it.
gboolean gwy_vector_layer_key_release (GwyVectorLayer *layer
,GdkEventKey *event
);
Sends a key release event to a layer.
This method primarily exists for GwyDataView to forward events to layers. You should rarely need it.
void gwy_vector_layer_object_chosen (GwyVectorLayer *layer
,gint id
);
Emits "object-chosen" signal on a vector layer.
This function is primarily intended for layer implementations.
struct GwyVectorLayerClass { GwyDataViewLayerClass parent_class; GType selection_type; /* Signals */ gboolean (*object_chosen)(GwyVectorLayer *layer, gint id); /* Virtual table */ void (*draw)(GwyVectorLayer *layer, GdkDrawable *drawable, GwyRenderingTarget target); gboolean (*button_press)(GwyVectorLayer *layer, GdkEventButton *event); gboolean (*button_release)(GwyVectorLayer *layer, GdkEventButton *event); gboolean (*motion_notify)(GwyVectorLayer *layer, GdkEventMotion *event); gboolean (*key_press)(GwyVectorLayer *layer, GdkEventKey *event); gboolean (*key_release)(GwyVectorLayer *layer, GdkEventKey *event); gboolean (*set_focus)(GwyVectorLayer *layer, gint object); void (*reserved1)(void); void (*reserved2)(void); void (*reserved3)(void); void (*reserved4)(void); };
“editable”
property“editable” gboolean
Whether selection objects are editable.
Owner: GwyVectorLayer
Flags: Read / Write
Default value: TRUE
“focus”
property “focus” int
The id of focused object, or -1 if all objects are active.
Owner: GwyVectorLayer
Flags: Read / Write
Allowed values: >= -1
Default value: -1
“object-chosen”
signalvoid user_function (GwyVectorLayer *gwyvectorlayer, int arg1, gpointer user_data)
The ::object-chosen signal is emitted when user starts interacting with a selection object, even before modifying it. It is emitted even if the layer is not editable, but it is not emitted when focus is set and the user attempts to choose a different object.
gwyvectorlayer |
The GwyVectorLayer which received the signal. |
|
arg1 |
The number (index) of the chosen selection object. |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run First