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

#include <gtkmm/cellareacontext.h>

Inherits Glib::Object.

Public Member Functions
	CellAreaContext (CellAreaContext && src) noexcept

CellAreaContext &	operator= (CellAreaContext && src) noexcept

	~CellAreaContext () noexcept override

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...

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...

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

◆ CellAreaContext()

Gtk::CellAreaContext::CellAreaContext ( CellAreaContext && src )

noexcept

◆ ~CellAreaContext()

Gtk::CellAreaContext::~CellAreaContext ( )

overridenoexcept

Member Function Documentation

◆ allocate()

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.

◆ get_allocation()

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`.

◆ get_area() [1/2]

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.

◆ get_area() [2/2]

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.

◆ get_preferred_height()

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`.

◆ get_preferred_height_for_width()

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`.

◆ get_preferred_width()

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`.

◆ get_preferred_width_for_height()

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`.

◆ get_type()

static GType Gtk::CellAreaContext::get_type ( )

static

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

◆ gobj() [1/2]

GtkCellAreaContext * Gtk::CellAreaContext::gobj ( )

inline

Provides access to the underlying C GObject.

◆ gobj() [2/2]

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

inline

Provides access to the underlying C GObject.

◆ gobj_copy()

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.

◆ operator=()

CellAreaContext & Gtk::CellAreaContext::operator= ( CellAreaContext && src )

noexcept

◆ property_area()

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.

◆ property_minimum_height()

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:

Default value: -1

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_minimum_width()

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:

Default value: -1

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_natural_height()

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:

Default value: -1

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_natural_width()

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:

Default value: -1

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ push_preferred_height()

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.

◆ push_preferred_width()

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.

◆ reset()

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

◆ wrap()

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

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.

Public Member Functions

Static Public Member Functions

Related Functions

Detailed Description

Constructor & Destructor Documentation

◆ CellAreaContext()

◆ ~CellAreaContext()

Member Function Documentation

◆ allocate()

◆ get_allocation()

◆ get_area() [1/2]

◆ get_area() [2/2]

◆ get_preferred_height()

◆ get_preferred_height_for_width()

◆ get_preferred_width()

◆ get_preferred_width_for_height()

◆ get_type()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ operator=()

◆ property_area()

◆ property_minimum_height()

◆ property_minimum_width()

◆ property_natural_height()

◆ property_natural_width()

◆ push_preferred_height()

◆ push_preferred_width()

◆ reset()

Friends And Related Function Documentation

◆ wrap()