the bounds of the item, in device space.
the canvas.
The sequence of commands describing the clip path of the item, specified
as a string using the same syntax
as in the
The color to use to paint the interior of the item, specified as a GdkRGBA. To disable painting set the 'fill-pattern' property to NULL.
the item's model, if it has one.
if all descendants need to be updated.
if the item needs to recompute its bounds and redraw.
the parent item.
data that is common to both the model and view classes. If the canvas item has a model, this will point to the model's #GooCanvasItemSimpleData, otherwise the canvas item will have its own #GooCanvasItemSimpleData.
The color to use for the item's perimeter, specified as a GdkRGBA. To disable painting set the 'stroke-pattern' property to NULL.
The tooltip to display for the item, or %NULL to display no tooltip.
Note that this property has no effect unless the #GtkWidget:has-tooltip property is set to %TRUE on the #GooCanvas containing this item.
Adds a child item to a container item at the given stack position.
the item to add.
the position of the item, or -1 to place it last (at the top of the stacking order).
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It allocates an area to a child #GooCanvasItem.
Note that the parent layout item will use a transform to move each of its children for the layout, so there is no need for the child item to reposition itself. It only needs to recalculate its device bounds.
To help recalculate the item's device bounds, the x_offset and y_offset
of the child item's allocated position from its requested position are
provided. Simple items can just add these to their bounds.
a cairo context.
the area that the item originally requested, in the parent's coordinate space.
the area that the item has been allocated, in the parent's coordinate space.
the x offset of the allocated area from the requested area in the device coordinate space.
the y offset of the allocated area from the requested area in the device coordinate space.
Animates an item from its current position to the given offsets, scale and rotation.
the final x coordinate.
the final y coordinate.
the final scale.
the final rotation. This can be negative to rotate anticlockwise, and can also be greater than 360 to rotate a number of times.
if the x, y, scale and degrees values are absolute, or relative to the current transform. Note that absolute animations only work if the item currently has a simple transform. If the item has a shear or some other complicated transform it may result in strange animations.
the duration of the animation, in milliseconds (1/1000ths of a second).
the time between each animation step, in milliseconds.
specifies what happens when the animation finishes.
Creates a binding between source_property on source and target_property
on target.
Whenever the source_property is changed the target_property is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property on target changes then the source_property on source
will be updated as well.
The binding will automatically be removed when either the source or the
target instances are finalized. To remove the binding without affecting the
source and the target you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source and target are only used from a single thread and it
is clear that both source and target outlive the binding. Especially it
is not safe to rely on this if the binding, source or target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
Creates a binding between source_property on source and target_property
on target, allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default
a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default
This function is intended to be used by subclasses of #GooCanvasItemSimple.
It is used as a callback for the "changed" signal of the item models. It requests an update or redraw of the item as appropriate.
if the item's bounds need to be recomputed.
This function is intended to be used by subclasses of #GooCanvasItemSimple.
It checks if the given point is in the current path, using the item's style settings.
the x coordinate of the point.
the y coordinate of the point.
a cairo context.
specifies which parts of the path to check.
This function is intended to be used by subclasses of #GooCanvasItemSimple, typically in their update() or get_requested_area() methods.
It ensures that the item's style is setup correctly. If the item has its own #GooCanvasStyle it makes sure the parent is set correctly. If it doesn't have its own style it uses the parent item's style.
This function is only intended to be used when implementing new canvas items.
It updates the canvas immediately, if an update is scheduled. This ensures that all item bounds are up-to-date.
Attempts to find the given child item with the container's stack.
the child item to find.
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object. If the freeze count is
non-zero, the emission of "notify" signals on object is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Gets the bounds of the item.
Note that the bounds includes the entire fill and stroke extents of the item, whether they are painted or not.
Gets the child item at the given stack position.
the position of a child in the container's stack.
Gets a child property of child.
a child #GooCanvasItem.
the name of the child property to get.
a location to return the value.
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Returns %TRUE if the item is static. Static items do not move or change size when the canvas is scrolled or the scale changes.
This function is only intended to be used when implementing new canvas items, specifically container items such as #GooCanvasGroup.
It gets the items at the given point.
the x coordinate of the point.
the y coordinate of the point.
a cairo contect.
%TRUE if the "pointer-events" properties of items should be used to determine which parts of the item are tested.
%TRUE if the parent item is visible (which implies that all ancestors are also visible).
the list of items found so far.
Gets the item's line width.
Gets the model of the given canvas item.
Gets the number of children of the container.
Gets the parent of the given item.
This function is intended to be used by subclasses of #GooCanvasItemSimple, typically in their update() or get_requested_area() methods.
It calculates the bounds of the current path, using the item's style settings, and stores the results in the given #GooCanvasBounds struct.
The returned bounds contains the bounding box of the path in device space, converted to user space coordinates. To calculate the bounds completely in user space, use cairo_identity_matrix() to temporarily reset the current transformation matrix to the identity matrix.
a cairo context.
the #GooCanvasBounds struct to store the resulting bounding box.
Gets a property of an object.
The value can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It gets the requested area of a child item.
a cairo context.
a #GooCanvasBounds to return the requested area in, in the parent's coordinate space.
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It gets the requested area of a child item, assuming it is allocated the given width. This is useful for text items whose requested height may change depending on the allocated width.
a cairo context.
the allocated width.
a #GooCanvasBounds to return the requested area in, in the parent's coordinate space. If %FALSE is returned, this is undefined.
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It gets the requested height of a child item, assuming it is allocated the given width. This is useful for text items whose requested height may change depending on the allocated width.
This function can be used to get the position, scale and rotation of an item, providing that the item has a simple transformation matrix (e.g. set with goo_canvas_item_set_simple_transform(), or using a combination of simple translate, scale and rotate operations). If the item has a complex transformation matrix the results will be incorrect.
Gets the item's style. If the item doesn't have its own style it will return its parent's style.
Gets the transformation matrix of an item combined with any special transform needed for the given child. These special transforms are used by layout items such as #GooCanvasTable.
a child of item.
Gets n_properties properties for an object.
Obtained properties will be set to values. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Tests to see if the given item is a container.
Checks whether object has a [floating][floating-ref] reference.
Checks if the item is visible.
This entails checking the item's own visibility setting, as well as those of its ancestors.
Note that the item may be scrolled off the screen and so may not be actually visible to the user.
Lowers an item in the stacking order.
the item to lower item below, or %NULL to lower item to the bottom of the stack.
Moves a child item to a new stack position within the container.
the current position of the child item.
the new position of the child item.
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object.
Emits a "notify" signal for the property specified by pspec on object.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object.
This function is only intended to be used when implementing new canvas items, specifically container items such as #GooCanvasGroup.
It paints the item and all children if they intersect the given bounds.
Note that the scale argument may be different to the current scale in the
#GooCanvasItem, e.g. when the canvas is being printed.
a cairo context.
the bounds that need to be repainted, in device space.
the scale to use to determine whether an item should be painted. See #GooCanvasItem:visibility-threshold.
Raises an item in the stacking order.
the item to raise item above, or %NULL to raise item to the top of the stack.
Increase the reference count of object, and possibly remove the
[floating][floating-ref] reference, if object has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object will be propagated to the return type
under the same conditions as for g_object_ref().
Removes an item from its parent. If the item is in a canvas it will be removed.
This would normally also result in the item being freed.
Removes the child item at the given position.
the position of the child item to remove.
This function is only intended to be used when implementing new canvas items.
It requests that an update of the item is scheduled. It will be performed as soon as the application is idle, and before the canvas is redrawn.
Rotates the item's coordinate system by the given amount, about the given origin.
the clockwise angle of rotation.
the x coordinate of the origin of the rotation.
the y coordinate of the origin of the rotation.
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
Scales the item's coordinate system by the given amounts.
the amount to scale the horizontal axis.
the amount to scale the vertical axis.
Sets a child property of child.
a child #GooCanvasItem.
the name of the child property to set.
the value to set the property to.
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key is converted to a #GQuark using g_quark_from_string().
This means a copy of key is kept permanently (even after object has been
finalized) — so it is recommended to only use a small, bounded set of values
for key in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Notifies the item that it is static. Static items do not move or change size when the canvas is scrolled or the scale changes.
Container items such as #GooCanvasGroup should call this function when children are added, to notify children whether they are static or not. Containers should also pass on any changes in their own status to children.
if the item is static.
This function should be called by subclasses of #GooCanvasItemSimple in their set_model() method.
the model that item will view.
This function is only intended to be used when implementing new canvas items (specifically container items such as #GooCanvasGroup). It sets the parent of the child item.
the new parent item.
Sets a property on an object.
the name of the property to set
the value
A convenience function to set the item's transformation matrix.
the x coordinate of the origin of the item's coordinate space.
the y coordinate of the origin of the item's coordinate space.
the scale of the item.
the clockwise rotation of the item, in degrees.
Sets the item's style, by copying the properties from the given style.
a style.
Skews the item's coordinate system along the x axis by the given amount, about the given origin.
the skew angle.
the x coordinate of the origin of the skew transform.
the y coordinate of the origin of the skew transform.
Skews the item's coordinate system along the y axis by the given amount, about the given origin.
the skew angle.
the x coordinate of the origin of the skew transform.
the y coordinate of the origin of the skew transform.
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Stops any current animation for the given item, leaving it at its current position.
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Translates the origin of the item's coordinate system by the given amounts.
the amount to move the origin in the horizontal direction.
the amount to move the origin in the vertical direction.
Decreases the reference count of object. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.
This function is only intended to be used when implementing new canvas items, specifically container items such as #GooCanvasGroup.
Updates the item, if needed, and any children.
if the entire subtree should be updated.
a cairo context.
a #GooCanvasBounds to return the new bounds in.
This function is intended to be used by subclasses of #GooCanvasItemSimple, typically in their update() or get_requested_area() methods.
It converts the item's bounds to a bounding box in the canvas (device) coordinate space.
a cairo context.
the bounds of the item, in the item's coordinate space.
This function is intended to be used by subclasses of #GooCanvasItemSimple, typically in their get_requested_area() method.
It converts the item's bounds to a bounding box in its parent's coordinate space. If the item has no transformation matrix set then no conversion is needed.
a cairo context.
the bounds of the item, in the item's coordinate space.
Adds a child item to a container item at the given stack position.
the item to add.
the position of the item, or -1 to place it last (at the top of the stacking order).
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It allocates an area to a child #GooCanvasItem.
Note that the parent layout item will use a transform to move each of its children for the layout, so there is no need for the child item to reposition itself. It only needs to recalculate its device bounds.
To help recalculate the item's device bounds, the x_offset and y_offset
of the child item's allocated position from its requested position are
provided. Simple items can just add these to their bounds.
a cairo context.
the area that the item originally requested, in the parent's coordinate space.
the area that the item has been allocated, in the parent's coordinate space.
the x offset of the allocated area from the requested area in the device coordinate space.
the y offset of the allocated area from the requested area in the device coordinate space.
Gets the bounds of the item.
Note that the bounds includes the entire fill and stroke extents of the item, whether they are painted or not.
Gets the child item at the given stack position.
the position of a child in the container's stack.
Returns %TRUE if the item is static. Static items do not move or change size when the canvas is scrolled or the scale changes.
This function is only intended to be used when implementing new canvas items, specifically container items such as #GooCanvasGroup.
It gets the items at the given point.
the x coordinate of the point.
the y coordinate of the point.
a cairo contect.
%TRUE if the "pointer-events" properties of items should be used to determine which parts of the item are tested.
%TRUE if the parent item is visible (which implies that all ancestors are also visible).
the list of items found so far.
Gets the model of the given canvas item.
Gets the number of children of the container.
Gets the parent of the given item.
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It gets the requested area of a child item.
a cairo context.
a #GooCanvasBounds to return the requested area in, in the parent's coordinate space.
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It gets the requested area of a child item, assuming it is allocated the given width. This is useful for text items whose requested height may change depending on the allocated width.
a cairo context.
the allocated width.
a #GooCanvasBounds to return the requested area in, in the parent's coordinate space. If %FALSE is returned, this is undefined.
This function is only intended to be used when implementing new canvas items, specifically layout items such as #GooCanvasTable.
It gets the requested height of a child item, assuming it is allocated the given width. This is useful for text items whose requested height may change depending on the allocated width.
Gets the item's style. If the item doesn't have its own style it will return its parent's style.
Gets the transformation matrix of an item combined with any special transform needed for the given child. These special transforms are used by layout items such as #GooCanvasTable.
a child of item.
Checks if the item is visible.
This entails checking the item's own visibility setting, as well as those of its ancestors.
Note that the item may be scrolled off the screen and so may not be actually visible to the user.
Moves a child item to a new stack position within the container.
the current position of the child item.
the new position of the child item.
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
This function is only intended to be used when implementing new canvas items, specifically container items such as #GooCanvasGroup.
It paints the item and all children if they intersect the given bounds.
Note that the scale argument may be different to the current scale in the
#GooCanvasItem, e.g. when the canvas is being printed.
a cairo context.
the bounds that need to be repainted, in device space.
the scale to use to determine whether an item should be painted. See #GooCanvasItem:visibility-threshold.
Removes the child item at the given position.
the position of the child item to remove.
This function is only intended to be used when implementing new canvas items.
It requests that an update of the item is scheduled. It will be performed as soon as the application is idle, and before the canvas is redrawn.
Notifies the item that it is static. Static items do not move or change size when the canvas is scrolled or the scale changes.
Container items such as #GooCanvasGroup should call this function when children are added, to notify children whether they are static or not. Containers should also pass on any changes in their own status to children.
if the item is static.
Sets the model of the given canvas item.
a #GooCanvasItemModel.
This function is only intended to be used when implementing new canvas items (specifically container items such as #GooCanvasGroup). It sets the parent of the child item.
the new parent item.
Sets the item's style, by copying the properties from the given style.
a style.
This function is only intended to be used when implementing new canvas items, specifically container items such as #GooCanvasGroup.
Updates the item, if needed, and any children.
if the entire subtree should be updated.
a cairo context.
a #GooCanvasBounds to return the new bounds in.
This function essentially limits the life time of the closure to
the life time of the object. That is, when the object is finalized,
the closure is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure, to ensure that an extra
reference count is held on object during invocation of the
closure. Usually, this function will be called on closures that
use this object as closure data.
#GClosure to watch
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init member of
#GTypeInfo.) It must not be called after after class_init has
been called for any object types implementing this interface.
If pspec is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
GooCanvasEllipse represents an ellipse item.
It is a subclass of #GooCanvasItemSimple and so inherits all of the style properties such as "stroke-color", "fill-color" and "line-width".
It also implements the #GooCanvasItem interface, so you can use the #GooCanvasItem functions such as goo_canvas_item_raise() and goo_canvas_item_rotate().
To create a #GooCanvasEllipse use goo_canvas_ellipse_new().
To get or set the properties of an existing #GooCanvasEllipse, use g_object_get() and g_object_set().
The ellipse can be specified either with the "center-x", "center-y", "radius-x" and "radius-y" properties, or with the "x", "y", "width" and "height" properties.