#include <visual.h>

Inheritance diagram for Gdk::Visual:

Public Member Functions
virtual	~Visual ()

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

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

GdkVisual *	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< Screen >	get_screen ()

Glib::RefPtr< const Screen >	get_screen () const

VisualType	get_visual_type () const

int	get_depth () const

ByteOrder	get_byte_order ()

int	get_colormap_size () const

int	get_bits_per_rgb () const

void	get_red_pixel_details (guint32 &mask, int &shift, int &precision) const

void	get_green_pixel_details (guint32 &mask, int &shift, int &precision) const

void	get_blue_pixel_details (guint32 &mask, int &shift, int &precision) const

Static Public Member Functions
static GType	get_type () G_GNUC_CONST

static Glib::RefPtr< Visual >	get_system ()

static Glib::RefPtr< Visual >	get_best ()

static Glib::RefPtr< Visual >	get_best (int depth)

static Glib::RefPtr< Visual >	get_best (VisualType visual_type)

static Glib::RefPtr< Visual >	get_best (int depth, VisualType visual_type)

static int	get_best_depth ()

static VisualType	get_best_type ()

Protected Member Functions
	Visual ()

Related Functions
(Note that these are not member functions.)
Glib::RefPtr< Gdk::Visual >	wrap (GdkVisual *object, bool take_copy=false)

Detailed Description

A Gdk::Visual describes a particular video hardware display format. It includes information about the number of bits used for each color, the way the bits are translated into an RGB value for display, and the way the bits are stored in memory. For example, a piece of display hardware might support 24-bit color, 16-bit color, or 8-bit color; meaning 24/16/8-bit pixel sizes. For a given pixel size, pixels can be in different formats; for example the "red" element of an RGB pixel may be in the top 8 bits of the pixel, or may be in the lower 4 bits.

Usually you can avoid thinking about visuals in GTK+. Visuals are useful to interpret the contents of a GdkImage, but you should avoid Gdk::Image precisely because its contents depend on the display hardware; use Gdk::Pixbuf instead, for all but the most low-level purposes. Also, anytime you provide a Gdk::Colormap, the visual is implied as part of the colormap (Gdk::Colormap::get_visual()), so you won't have to provide a visual in addition.

There are several standard visuals. The visual returned by get_system() is the system's default visual. get_visual() returns the visual most suited to displaying full-color image data. If you use the calls in Gdk::RGB, you should create your windows using this visual (and the colormap returned by Gdk::Rgb::get_colormap()).

A number of methods are provided for determining the "best" available visual. For the purposes of making this determination, higher bit depths are considered better, and for visuals of the same bit depth, GDK_VISUAL_PSEUDO_COLOR is preferred at 8bpp, otherwise, the visual types are ranked in the order of (highest to lowest) GDK_VISUAL_DIRECT_COLOR, GDK_VISUAL_TRUE_COLOR, GDK_VISUAL_PSEUDO_COLOR, GDK_VISUAL_STATIC_COLOR, GDK_VISUAL_GRAYSCALE, then GDK_VISUAL_STATIC_GRAY.

Definition at line 112 of file visual.h.

Constructor & Destructor Documentation

◆ ~Visual()

virtual Gdk::Visual::~Visual ( )

virtual

◆ Visual()

Gdk::Visual::Visual ( )

protected

Member Function Documentation

◆ get_best() [1/4]

static Glib::RefPtr<Visual> Gdk::Visual::get_best ( )

static

Get the visual with the most available colors for the default GDK screen. The return value should not be freed.

Returns: Best visual.

◆ get_best() [2/4]

static Glib::RefPtr<Visual> Gdk::Visual::get_best ( int depth )

static

Get the best visual with depth depth for the default GDK screen. Color visuals and visuals with mutable colormaps are preferred over grayscale or fixed-colormap visuals. The return value should not be freed. 0 may be returned if no visual supports depth.

Parameters

depth A bit depth.

Returns: Best visual for the given depth.

◆ get_best() [3/4]

static Glib::RefPtr<Visual> Gdk::Visual::get_best	(	int	depth,
		VisualType	visual_type
	)

static

Combines get_best_with_depth() and get_best_with_type().

Parameters

depth	A bit depth.
visual_type	A visual type.

Returns: Best visual with both depth and visual_type, or 0 if none.

◆ get_best() [4/4]

static Glib::RefPtr<Visual> Gdk::Visual::get_best ( VisualType visual_type )

static

Get the best visual of the given visual_type for the default GDK screen. Visuals with higher color depths are considered better. The return value should not be freed. 0 may be returned if no visual has type visual_type.

Parameters

visual_type A visual type.

Returns: Best visual of the given type.

◆ get_best_depth()

static int Gdk::Visual::get_best_depth ( )

static

Get the best available depth for the default GDK screen. "Best" means "largest," i.e. 32 preferred over 24 preferred over 8 bits per pixel.

Returns: Best available depth.

◆ get_best_type()

static VisualType Gdk::Visual::get_best_type ( )

static

Return the best available visual type for the default GDK screen.

Returns: Best visual type.

◆ get_bits_per_rgb()

int Gdk::Visual::get_bits_per_rgb ( ) const

Returns the number of significant bits per red, green and blue value.

Returns: The number of significant bits per color value for visual.

◆ get_blue_pixel_details()

void Gdk::Visual::get_blue_pixel_details	(	guint32 &	mask,
		int &	shift,
		int &	precision
	)		const

Obtains values that are needed to calculate blue pixel values in TrueColor and DirectColor. The "mask" is the significant bits within the pixel. The "shift" is the number of bits left we must shift a primary for it to be in position (according to the "mask"). Finally, "precision" refers to how much precision the pixel value contains for a particular primary.

Parameters

mask	A pointer to a `guint32` to be filled in, or `0`.
shift	A pointer to a `int` to be filled in, or `0`.
precision	A pointer to a `int` to be filled in, or `0`.

◆ get_byte_order()

ByteOrder Gdk::Visual::get_byte_order ( )

Returns the byte order of this visual.

Returns: A Gdk::ByteOrder stating the byte order of visual.

◆ get_colormap_size()

int Gdk::Visual::get_colormap_size ( ) const

Returns the size of a colormap for this visual.

Returns: The size of a colormap that is suitable for visual.

◆ get_depth()

int Gdk::Visual::get_depth ( ) const

Returns the bit depth of this visual.

Returns: The bit depth of this visual.

◆ get_green_pixel_details()

void Gdk::Visual::get_green_pixel_details	(	guint32 &	mask,
		int &	shift,
		int &	precision
	)		const

Obtains values that are needed to calculate green pixel values in TrueColor and DirectColor. The "mask" is the significant bits within the pixel. The "shift" is the number of bits left we must shift a primary for it to be in position (according to the "mask"). Finally, "precision" refers to how much precision the pixel value contains for a particular primary.

Parameters

mask	A pointer to a `guint32` to be filled in, or `0`.
shift	A pointer to a `int` to be filled in, or `0`.
precision	A pointer to a `int` to be filled in, or `0`.

◆ get_red_pixel_details()

void Gdk::Visual::get_red_pixel_details	(	guint32 &	mask,
		int &	shift,
		int &	precision
	)		const

Obtains values that are needed to calculate red pixel values in TrueColor and DirectColor. The "mask" is the significant bits within the pixel. The "shift" is the number of bits left we must shift a primary for it to be in position (according to the "mask"). Finally, "precision" refers to how much precision the pixel value contains for a particular primary.

Parameters

mask	A pointer to a `guint32` to be filled in, or `0`.
shift	A pointer to a `int` to be filled in, or `0`.
precision	A pointer to a `int` to be filled in, or `0`.

◆ get_screen() [1/2]

Glib::RefPtr<Screen> Gdk::Visual::get_screen ( )

Gets the screen to which this visual belongs

Returns: The screen to which this visual belongs.

◆ get_screen() [2/2]

Glib::RefPtr<const Screen> Gdk::Visual::get_screen ( ) const

Gets the screen to which this visual belongs

Returns: The screen to which this visual belongs.

◆ get_system()

static Glib::RefPtr<Visual> Gdk::Visual::get_system ( )

static

Get the system's default visual for the default GDK screen. This is the visual for the root window of the display. The return value should not be freed.

Returns: System visual.

◆ get_type()

static GType Gdk::Visual::get_type ( )

static

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

◆ get_visual_type()

VisualType Gdk::Visual::get_visual_type ( ) const

Returns the type of visual this is (PseudoColor, TrueColor, etc).

Returns: A Gdk::VisualType stating the type of visual.

◆ gobj() [1/2]

GdkVisual* Gdk::Visual::gobj ( )

inline

Provides access to the underlying C GObject.

Definition at line 151 of file visual.h.

◆ gobj() [2/2]

const GdkVisual* Gdk::Visual::gobj ( ) const

inline

Provides access to the underlying C GObject.

Definition at line 154 of file visual.h.

◆ gobj_copy()

GdkVisual* Gdk::Visual::gobj_copy ( )

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

Friends And Related Function Documentation

◆ wrap()

Glib::RefPtr< Gdk::Visual > wrap	(	GdkVisual *	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.

The documentation for this class was generated from the following file:

visual.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Related Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~Visual()

◆ Visual()

Member Function Documentation

◆ get_best() [1/4]

◆ get_best() [2/4]

◆ get_best() [3/4]

◆ get_best() [4/4]

◆ get_best_depth()

◆ get_best_type()

◆ get_bits_per_rgb()

◆ get_blue_pixel_details()

◆ get_byte_order()

◆ get_colormap_size()

◆ get_depth()

◆ get_green_pixel_details()

◆ get_red_pixel_details()

◆ get_screen() [1/2]

◆ get_screen() [2/2]

◆ get_system()

◆ get_type()

◆ get_visual_type()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

Friends And Related Function Documentation

◆ wrap()