gtkmm  4.8.0
Public Member Functions | Static Public Member Functions | Protected Member Functions | Related Functions | List of all members
Gdk::DrawContext Class Reference

Drawing context base class. More...

#include <gdkmm/drawcontext.h>

Inheritance diagram for Gdk::DrawContext:
Inheritance graph
[legend]

Public Member Functions

 DrawContext (DrawContext && src) noexcept
 
DrawContextoperator= (DrawContext && src) noexcept
 
 ~DrawContext () noexcept override
 
GdkDrawContext * gobj ()
 Provides access to the underlying C GObject. More...
 
const GdkDrawContext * gobj () const
 Provides access to the underlying C GObject. More...
 
GdkDrawContext * 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< Displayget_display ()
 Retrieves the Gdk::Display the context is created for. More...
 
Glib::RefPtr< const Displayget_display () const
 Retrieves the Gdk::Display the context is created for. More...
 
Glib::RefPtr< Surfaceget_surface ()
 Retrieves the surface that context is bound to. More...
 
Glib::RefPtr< const Surfaceget_surface () const
 Retrieves the surface that context is bound to. More...
 
void begin_frame (const ::Cairo::RefPtr< const ::Cairo::Region > & region)
 Indicates that you are beginning the process of redrawing region on the context's surface. More...
 
void end_frame ()
 Ends a drawing operation started with begin_frame(). More...
 
bool is_in_frame () const
 Returns true if context is in the process of drawing to its surface. More...
 
::Cairo::RefPtr< const ::Cairo::Region > get_frame_region () const
 Retrieves the region that is currently being repainted. More...
 
Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Display > > property_display () const
 The Gdk::Display used to create the Gdk::DrawContext. More...
 
Glib::PropertyProxy_ReadOnly< Glib::RefPtr< Surface > > property_surface () const
 The Gdk::Surface the context is bound to. More...
 

Static Public Member Functions

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

Protected Member Functions

 DrawContext ()
 This constructor is protected because only derived classes shall be instantiated. More...
 

Related Functions

(Note that these are not member functions.)

Glib::RefPtr< Gdk::DrawContextwrap (GdkDrawContext * object, bool take_copy=false)
 A Glib::wrap() method for this object. More...
 

Detailed Description

Drawing context base class.

Gdk::DrawContext is the base object used by contexts implementing different rendering methods, such as GLContext or VulkanContext. It provides shared functionality between those contexts.

You will always interact with one of those subclasses.

Since gtkmm 3.90:

Constructor & Destructor Documentation

◆ DrawContext() [1/2]

Gdk::DrawContext::DrawContext ( DrawContext &&  src)
noexcept

◆ ~DrawContext()

Gdk::DrawContext::~DrawContext ( )
overridenoexcept

◆ DrawContext() [2/2]

Gdk::DrawContext::DrawContext ( )
protected

This constructor is protected because only derived classes shall be instantiated.

Member Function Documentation

◆ begin_frame()

void Gdk::DrawContext::begin_frame ( const ::Cairo::RefPtr< const ::Cairo::Region > &  region)

Indicates that you are beginning the process of redrawing region on the context's surface.

Calling this function begins a drawing operation using context on the surface that context was created from. The actual requirements and guarantees for the drawing operation vary for different implementations of drawing, so a Gdk::CairoContext and a Gdk::GLContext need to be treated differently.

A call to this function is a requirement for drawing and must be followed by a call to end_frame(), which will complete the drawing operation and ensure the contents become visible on screen.

Note that the region passed to this function is the minimum region that needs to be drawn and depending on implementation, windowing system and hardware in use, it might be necessary to draw a larger region. Drawing implementation must use get_frame_region() to query the region that must be drawn.

When using GTK, the widget system automatically places calls to begin_frame() and end_frame() via the use of Gsk::Renderers, so application code does not need to call these functions explicitly.

Parameters
regionMinimum region that should be drawn.

◆ end_frame()

void Gdk::DrawContext::end_frame ( )

Ends a drawing operation started with begin_frame().

This makes the drawing available on screen. See begin_frame() for more details about drawing.

When using a Gdk::GLContext, this function may call glFlush() implicitly before returning; it is not recommended to call glFlush() explicitly before calling this function.

◆ get_display() [1/2]

Glib::RefPtr<Display> Gdk::DrawContext::get_display ( )

Retrieves the Gdk::Display the context is created for.

Returns
The Gdk::Display.

◆ get_display() [2/2]

Glib::RefPtr<const Display> Gdk::DrawContext::get_display ( ) const

Retrieves the Gdk::Display the context is created for.

Returns
The Gdk::Display.

◆ get_frame_region()

::Cairo::RefPtr<const ::Cairo::Region> Gdk::DrawContext::get_frame_region ( ) const

Retrieves the region that is currently being repainted.

After a call to begin_frame() this function will return a union of the region passed to that function and the area of the surface that the context determined needs to be repainted.

If context is not in between calls to begin_frame() and end_frame(), nullptr will be returned.

Returns
A Cairo region.

◆ get_surface() [1/2]

Glib::RefPtr<Surface> Gdk::DrawContext::get_surface ( )

Retrieves the surface that context is bound to.

Returns
A Gdk::Surface.

◆ get_surface() [2/2]

Glib::RefPtr<const Surface> Gdk::DrawContext::get_surface ( ) const

Retrieves the surface that context is bound to.

Returns
A Gdk::Surface.

◆ get_type()

static GType Gdk::DrawContext::get_type ( )
static

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

◆ gobj() [1/2]

GdkDrawContext* Gdk::DrawContext::gobj ( )
inline

Provides access to the underlying C GObject.

◆ gobj() [2/2]

const GdkDrawContext* Gdk::DrawContext::gobj ( ) const
inline

Provides access to the underlying C GObject.

◆ gobj_copy()

GdkDrawContext* Gdk::DrawContext::gobj_copy ( )

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

◆ is_in_frame()

bool Gdk::DrawContext::is_in_frame ( ) const

Returns true if context is in the process of drawing to its surface.

This is the case between calls to begin_frame() and end_frame(). In this situation, drawing commands may be effecting the contents of the context's surface.

Returns
true if the context is between begin_frame() and end_frame() calls.

◆ operator=()

DrawContext& Gdk::DrawContext::operator= ( DrawContext &&  src)
noexcept

◆ property_display()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr<Display> > Gdk::DrawContext::property_display ( ) const

The Gdk::Display used to create the Gdk::DrawContext.

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_surface()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr<Surface> > Gdk::DrawContext::property_surface ( ) const

The Gdk::Surface the context is bound to.

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

Friends And Related Function Documentation

◆ wrap()

Glib::RefPtr< Gdk::DrawContext > wrap ( GdkDrawContext *  object,
bool  take_copy = false 
)
related

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

Parameters
objectThe C instance.
take_copyFalse 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.