gtkmm: Gtk::CellAreaContext Class Reference

This stores geometrical information for a series of rows in a CellArea . More...

#include <gtkmm/cellareacontext.h>

Inheritance diagram for Gtk::CellAreaContext:

Public Member Functions

CellAreaContext ( CellAreaContext && src) noexcept
CellAreaContext & operator= ( CellAreaContext && src) noexcept
~CellAreaContext () noexceptoverride
GtkCellAreaContext* gobj ()
Provides access to the underlying C GObject. More...

const GtkCellAreaContext* gobj () const
Provides access to the underlying C GObject. More...

GtkCellAreaContext* gobj_copy ()
Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

Glib::RefPtr < CellArea > get_area ()
Fetches the Gtk::CellArea this context was created by. More...

Glib::RefPtr < const CellArea > get_area () const
Fetches the Gtk::CellArea this context was created by. More...

void allocate (int width, int height)
Allocates a width and/or a height for all rows which are to be rendered with context . More...

void reset ()
Resets any previously cached request and allocation data. More...

void get_preferred_width (int& minimum_width, int& natural_width) const
Gets the accumulative preferred width for all rows which have been requested with this context. More...

void get_preferred_height (int& minimum_height, int& natural_height) const
Gets the accumulative preferred height for all rows which have been requested with this context. More...

void get_preferred_height_for_width (int width, int& minimum_height, int& natural_height) const
Gets the accumulative preferred height for width for all rows which have been requested for the same said width with this context. More...

void get_preferred_width_for_height (int height, int& minimum_width, int& natural_width) const
Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context. More...

void get_allocation (int& width, int& height) const
Fetches the current allocation size for context . More...

void push_preferred_width (int minimum_width, int natural_width)
Causes the minimum and/or natural width to grow if the new proposed sizes exceed the current minimum and natural width. More...

void push_preferred_height (int minimum_height, int natural_height)
Causes the minimum and/or natural height to grow if the new proposed sizes exceed the current minimum and natural height. More...

Glib::PropertyProxy_ReadOnly < CellArea * > property_area () const
The Gtk::CellArea this context was created by. More...

Glib::PropertyProxy_ReadOnly < int > property_minimum_width () const
The minimum width for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_width() . More...

Glib::PropertyProxy_ReadOnly < int > property_natural_width () const
The natural width for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_width() . More...

Glib::PropertyProxy_ReadOnly < int > property_minimum_height () const
The minimum height for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_height() . More...

Glib::PropertyProxy_ReadOnly < int > property_natural_height () const
The natural height for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_height() . More...

- Public Member Functions inherited from Glib::Object
Object (const Object &)=delete
Object & operator= (const Object &)=delete
Object ( Object &&src) noexcept
Object & operator= ( Object &&src) noexcept
void * get_data (const QueryQuark &key)
void set_data (const Quark &key, void *data)
void set_data (const Quark &key, void *data, DestroyNotify notify)
void remove_data (const QueryQuark &quark)
void * steal_data (const QueryQuark &quark)
Glib::RefPtr < Glib::Object > wrap (GObject *object, bool take_copy=false)
- Public Member Functions inherited from Glib::ObjectBase
ObjectBase (const ObjectBase &)=delete
ObjectBase & operator= (const ObjectBase &)=delete
void set_property_value (const Glib::ustring &property_name, const Glib::ValueBase &value)
void get_property_value (const Glib::ustring &property_name, Glib::ValueBase &value) const
void set_property (const Glib::ustring &property_name, const PropertyType &value)
void get_property (const Glib::ustring &property_name, PropertyType &value) const
void connect_property_changed (const Glib::ustring &property_name, const sigc::slot < void > &slot)
void connect_property_changed (const Glib::ustring &property_name, sigc::slot < void > &&slot)
sigc::connection connect_property_changed_with_return (const Glib::ustring &property_name, const sigc::slot < void > &slot)
sigc::connection connect_property_changed_with_return (const Glib::ustring &property_name, sigc::slot < void > &&slot)
void freeze_notify ()
void thaw_notify ()
virtual void reference () const
virtual void unreference () const
GObject * gobj ()
const GObject * gobj () const
GObject * gobj_copy () const
- Public Member Functions inherited from sigc::trackable
trackable () noexcept
trackable (const trackable &src) noexcept
trackable ( trackable &&src)
~trackable ()
void add_destroy_notify_callback (void *data, func_destroy_notify func) const
void notify_callbacks ()
trackable & operator= (const trackable &src)
trackable & operator= ( trackable &&src)
void remove_destroy_notify_callback (void *data) const

Static Public Member Functions

static GType get_type ()
Get the GType for this class, for use with the underlying GObject type system. More...

Related Functions

(Note that these are not member functions.)

Glib::RefPtr < Gtk::CellAreaContext > wrap (GtkCellAreaContext* object, bool take_copy=false)
A Glib::wrap() method for this object. More...

Additional Inherited Members

- Public Types inherited from Glib::Object
typedef void(*)(gpointer data DestroyNotify )
- Public Types inherited from sigc::trackable
typedef internal::func_destroy_notify func_destroy_notify
- Protected Member Functions inherited from Glib::Object
Object ()
Object (const Glib::ConstructParams &construct_params)
Object (GObject *castitem)
~Object () noexceptoverride
- Protected Member Functions inherited from Glib::ObjectBase
ObjectBase ()
ObjectBase (const char *custom_type_name)
ObjectBase (const std::type_info &custom_type_info)
ObjectBase ( ObjectBase &&src) noexcept
ObjectBase & operator= ( ObjectBase &&src) noexcept
virtual ~ObjectBase () noexcept=0
void initialize (GObject *castitem)
void initialize_move (GObject *castitem, Glib::ObjectBase *previous_wrapper)

Detailed Description

This stores geometrical information for a series of rows in a CellArea .

CellAreaContext is used by widgets such as TreeView and IconView , but application developers do not usually need to be aware of it.

The CellAreaContext object is created by a given CellArea and is used to store cell sizes and alignments for a series of TreeModel rows that are requested and rendered in the same context.

CellLayout widgets can create any number of contexts in which to request and render groups of data rows. However. it's important that the same context which was used to request sizes for a given TreeModel row also be used for the same row when calling other CellArea APIs such as gtk_cell_area_render() and gtk_cell_area_event().

Constructor & Destructor Documentation

Gtk::CellAreaContext::CellAreaContext ( CellAreaContext && src )
noexcept
Gtk::CellAreaContext::~CellAreaContext ( )
override noexcept

Member Function Documentation

void Gtk::CellAreaContext::allocate ( int width ,
int height
)

Allocates a width and/or a height for all rows which are to be rendered with context .

Usually allocation is performed only horizontally or sometimes vertically since a group of rows are usually rendered side by side vertically or horizontally and share either the same width or the same height. Sometimes they are allocated in both horizontal and vertical orientations producing a homogeneous effect of the rows. This is generally the case for Gtk::TreeView when Gtk::TreeView::property_fixed_height_mode() is enabled.

Since gtkmm 3.0:
Parameters
width The allocated width for all Gtk::TreeModel rows rendered with context , or -1.
height The allocated height for all Gtk::TreeModel rows rendered with context , or -1.
void Gtk::CellAreaContext::get_allocation ( int & width ,
int & height
) const

Fetches the current allocation size for context .

If the context was not allocated in width or height, or if the context was recently reset with reset() , the returned value will be -1.

Since gtkmm 3.0:
Parameters
width Location to store the allocated width, or nullptr .
height Location to store the allocated height, or nullptr .
Glib::RefPtr < CellArea > Gtk::CellAreaContext::get_area ( )

Fetches the Gtk::CellArea this context was created by.

This is generally unneeded by layouting widgets; however, it is important for the context implementation itself to fetch information about the area it is being used for.

For instance at Gtk::CellAreaContextClass.allocate() time it’s important to know details about any cell spacing that the Gtk::CellArea is configured with in order to compute a proper allocation.

Since gtkmm 3.0:
Returns
The Gtk::CellArea this context was created by.
Glib::RefPtr <const CellArea > Gtk::CellAreaContext::get_area ( ) const

Fetches the Gtk::CellArea this context was created by.

This is generally unneeded by layouting widgets; however, it is important for the context implementation itself to fetch information about the area it is being used for.

For instance at Gtk::CellAreaContextClass.allocate() time it’s important to know details about any cell spacing that the Gtk::CellArea is configured with in order to compute a proper allocation.

Since gtkmm 3.0:
Returns
The Gtk::CellArea this context was created by.
void Gtk::CellAreaContext::get_preferred_height ( int & minimum_height ,
int & natural_height
) const

Gets the accumulative preferred height for all rows which have been requested with this context.

After reset() is called and/or before ever requesting the size of a Gtk::CellArea , the returned values are 0.

Since gtkmm 3.0:
Parameters
minimum_height Location to store the minimum height, or nullptr .
natural_height Location to store the natural height, or nullptr .
void Gtk::CellAreaContext::get_preferred_height_for_width ( int width ,
int & minimum_height ,
int & natural_height
) const

Gets the accumulative preferred height for width for all rows which have been requested for the same said width with this context.

After reset() is called and/or before ever requesting the size of a Gtk::CellArea , the returned values are -1.

Since gtkmm 3.0:
Parameters
width A proposed width for allocation.
minimum_height Location to store the minimum height, or nullptr .
natural_height Location to store the natural height, or nullptr .
void Gtk::CellAreaContext::get_preferred_width ( int & minimum_width ,
int & natural_width
) const

Gets the accumulative preferred width for all rows which have been requested with this context.

After reset() is called and/or before ever requesting the size of a Gtk::CellArea , the returned values are 0.

Since gtkmm 3.0:
Parameters
minimum_width Location to store the minimum width, or nullptr .
natural_width Location to store the natural width, or nullptr .
void Gtk::CellAreaContext::get_preferred_width_for_height ( int height ,
int & minimum_width ,
int & natural_width
) const

Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context.

After reset() is called and/or before ever requesting the size of a Gtk::CellArea , the returned values are -1.

Since gtkmm 3.0:
Parameters
height A proposed height for allocation.
minimum_width Location to store the minimum width, or nullptr .
natural_width Location to store the natural width, or nullptr .
static GType Gtk::CellAreaContext::get_type ( )
static

Get the GType for this class, for use with the underlying GObject type system.

GtkCellAreaContext* Gtk::CellAreaContext::gobj ( )
inline

Provides access to the underlying C GObject.

const GtkCellAreaContext* Gtk::CellAreaContext::gobj ( ) const
inline

Provides access to the underlying C GObject.

GtkCellAreaContext* Gtk::CellAreaContext::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

CellAreaContext & Gtk::CellAreaContext::operator= ( CellAreaContext && src )
noexcept
Glib::PropertyProxy_ReadOnly < CellArea * > Gtk::CellAreaContext::property_area ( ) const

The Gtk::CellArea this context was created by.

Since gtkmm 3.0:
Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy_ReadOnly < int > Gtk::CellAreaContext::property_minimum_height ( ) const

The minimum height for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_height() .

Since gtkmm 3.0:
Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy_ReadOnly < int > Gtk::CellAreaContext::property_minimum_width ( ) const

The minimum width for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_width() .

Since gtkmm 3.0:
Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy_ReadOnly < int > Gtk::CellAreaContext::property_natural_height ( ) const

The natural height for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_height() .

Since gtkmm 3.0:
Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy_ReadOnly < int > Gtk::CellAreaContext::property_natural_width ( ) const

The natural width for the Gtk::CellArea in this context for all Gtk::TreeModel rows that this context was requested for using Gtk::CellArea::get_preferred_width() .

Since gtkmm 3.0:
Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
void Gtk::CellAreaContext::push_preferred_height ( int minimum_height ,
int natural_height
)

Causes the minimum and/or natural height to grow if the new proposed sizes exceed the current minimum and natural height.

This is used by Gtk::CellAreaContext implementations during the request process over a series of Gtk::TreeModel rows to progressively push the requested height over a series of get_preferred_height() requests.

Since gtkmm 3.0:
Parameters
minimum_height The proposed new minimum height for context .
natural_height The proposed new natural height for context .
void Gtk::CellAreaContext::push_preferred_width ( int minimum_width ,
int natural_width
)

Causes the minimum and/or natural width to grow if the new proposed sizes exceed the current minimum and natural width.

This is used by Gtk::CellAreaContext implementations during the request process over a series of Gtk::TreeModel rows to progressively push the requested width over a series of get_preferred_width() requests.

Since gtkmm 3.0:
Parameters
minimum_width The proposed new minimum width for context .
natural_width The proposed new natural width for context .
void Gtk::CellAreaContext::reset ( )

Resets any previously cached request and allocation data.

When underlying Gtk::TreeModel data changes its important to reset the context if the content size is allowed to shrink. If the content size is only allowed to grow (this is usually an option for views rendering large data stores as a measure of optimization), then only the row that changed or was inserted needs to be (re)requested with get_preferred_width() .

When the new overall size of the context requires that the allocated size changes (or whenever this allocation changes at all), the variable row sizes need to be re-requested for every row.

For instance, if the rows are displayed all with the same width from top to bottom then a change in the allocated width necessitates a recalculation of all the displayed row heights using get_preferred_height_for_width() .

Since gtkmm 3.0:

Friends And Related Function Documentation

Glib::RefPtr < Gtk::CellAreaContext > wrap ( GtkCellAreaContext * object ,
bool take_copy = false
)
related

A Glib::wrap() method for this object.

Parameters
object The C instance.
take_copy False if the result should take ownership of the C instance. True if it should take a new copy or ref.
Returns
A C++ instance that wraps this C instance.