This group provides low level Evas canvas functions. Sub-groups present more high level ones, though.

Remarks:

Most of these functions deal with low level Evas actions, like:

creating or destroying raw canvases, not bound to any displaying engine
telling a canvas that it got focused (in a windowing context, for example)
telling a canvas that a region should not be calculated anymore in rendering
telling a canvas to render its contents, immediately

You mostly use Evas with the Ecore_Evas wrapper, which deals with all the above mentioned issues automatically. Thus, you need this section only if you are building low level stuff.

The groups present you functions that deal with the canvas directly, too, and not yet with its objects. They are the functions you need to use at a minimum to get a working canvas.

Functions
Evas *	evas_new (void)
	Creates a new empty evas.
void	evas_free (Evas *e)
	Frees the given evas and any objects created on it.
void	evas_focus_in (Evas *e)
	Informs evas that it has got focus.
void	evas_focus_out (Evas *e)
	Informs the evas that it has lost focus.
Eina_Bool	evas_focus_state_get (const Evas *e)
	Gets the focus state of the given evas.
void	evas_nochange_push (Evas *e)
	Pushes the nochange flag up `1`.
void	evas_nochange_pop (Evas *e)
	Pops the nochange flag down `1`.
void	evas_data_attach_set (Evas e, void data)
	Attaches a specific pointer to evas for fetching later.
void *	evas_data_attach_get (const Evas *e)
	Gets the pointer attached by evas_data_attach_set().
void	evas_damage_rectangle_add (Evas *e, int x, int y, int w, int h)
	Adds a damage rectangle.
void	evas_obscured_rectangle_add (Evas *e, int x, int y, int w, int h)
	Adds an "obscured region" to an Evas canvas.
void	evas_obscured_clear (Evas *e)
	Removes all "obscured regions" from an Evas canvas.
Eina_List *	evas_render_updates (Evas *e)
	Forces immediate renderization of the given Evas canvas.
void	evas_render_updates_free (Eina_List *updates)
	Frees the rectangles returned by evas_render_updates().
void	evas_render (Evas *e)
	Forces rendering of the given canvas.
void	evas_norender (Evas *e)
	Updates the canvas internal objects but does not trigger immediate rendering.
void	evas_render_idle_flush (Evas *e)
	Makes the canvas discard internally cached data used for rendering.
void	evas_render_dump (Evas *e)
	Makes the canvas discard as much data as possible used by the engine at runtime.
Typedefs
typedef struct _Evas	Evas
	An opaque handle to an Evas canvas.

Typedef Documentation

Evas

An opaque handle to an Evas canvas.

See also:: evas_new(); evas_free()

Function Documentation

void evas_damage_rectangle_add	(	Evas *	e,
		int	x,
		int	y,
		int	w,
		int	h
	)

Adds a damage rectangle.

You can use this function to inform evas that a part of the canvas has to be repainted.

Since :: 2.3.1

Remarks:: All newly created Evas rectangles get the default color values of 255 255 255 255 (opaque white).

Parameters:

[in]	e	The given canvas pointer
[in]	x	The rectangle's left position
[in]	y	The rectangle's top position
[in]	w	The rectangle's width
[in]	h	The rectangle's height

void* evas_data_attach_get ( const Evas * e )

Gets the pointer attached by evas_data_attach_set().

Since :: 2.3.1

Parameters:

[in] e The canvas to attach the pointer to

Returns:: The pointer attached

void evas_data_attach_set	(	Evas *	e,
		void *	data
	)

Attaches a specific pointer to evas for fetching later.

Since :: 2.3.1

Parameters:

[in]	e	The canvas to attach the pointer to
[in]	data	The pointer to attach

void evas_focus_in ( Evas * e )

Informs evas that it has got focus.

Since :: 2.3.1

Parameters:

[in] e The evas to inform

void evas_focus_out ( Evas * e )

Informs the evas that it has lost focus.

Since :: 2.3.1

Parameters:

[in] e The evas to inform

Eina_Bool evas_focus_state_get ( const Evas * e )

Gets the focus state of the given evas.

Since :: 2.3.1

Parameters:

[in] e The evas to query information

Returns:: EINA_TRUE if it is focused, otherwise EINA_FALSE.

void evas_free ( Evas * e )

Frees the given evas and any objects created on it.

Since :: 2.3.1

Remarks:: Any objects with 'free' callbacks have those callbacks called in this function.

Parameters:

[in] e The given evas

Evas* evas_new ( void )

Creates a new empty evas.

Since :: 2.3.1

Remarks:: This function should only fail if the memory allocation fails.; This function is a very low level function.

Returns:: A new uninitialised Evas canvas on success,
otherwise NULL on failure

Precondition:

Note that before you can use evas, you have to:

Set its render method with evas_output_method_set.
Set its viewport size with evas_output_viewport_set.
Set its size of the canvas with evas_output_size_set.
Ensure that the render engine is given the correct settings with evas_engine_info_set.

void evas_nochange_pop ( Evas * e )

Pops the nochange flag down 1.

Since :: 2.3.1

Remarks:: This tells evas that while the nochange flag is greater than 0, do not mark objects as "changed" when making changes.

Parameters:

[in] e The evas to change information

void evas_nochange_push ( Evas * e )

Pushes the nochange flag up 1.

Since :: 2.3.1

Remarks:: This tells evas that while the nochange flag is greater than 0, do not mark objects as "changed" when making changes.

Parameters:

[in] e The evas to changes information

void evas_norender ( Evas * e )

Updates the canvas internal objects but does not trigger immediate rendering.

This function updates the canvas internal objects not triggering rendering. To force rendering, use evas_render().

Since :: 2.3.1

Parameters:

[in] e The given canvas pointer

See also:: evas_render

void evas_obscured_clear ( Evas * e )

Removes all "obscured regions" from an Evas canvas.

This function removes all the rectangles from the obscured regions list of the canvas e. It takes obscured areas added with evas_obscured_rectangle_add() and make them again a regions that have to be repainted on rendering updates.

Since :: 2.3.1

Remarks:: This is a very low level function, which you may not use.; This function does not flag the canvas as having its state changed. If you want to re-render it afterwards expecting new contents, you have to add "damage" regions yourself (see evas_damage_rectangle_add()).

Parameters:

[in] e The given canvas pointer

See also:: evas_obscured_rectangle_add() for an example; evas_render_updates()

void evas_obscured_rectangle_add	(	Evas *	e,
		int	x,
		int	y,
		int	w,
		int	h
	)

Adds an "obscured region" to an Evas canvas.

Since :: 2.3.1

Remarks:: You can use this function to inform an Evas canvas that a part of it must not be repainted. The region must be rectangular and its coordinates inside the canvas viewport are passed in the call. After this call, the region specified do not participate in any form in Evas' calculations and actions during its rendering updates, having its displaying content frozen as it is just after this function is executed.; This is called "obscured region" because the most common use case for this rendering (partial) freeze is something else (most probably other canvas) being on top of the specified rectangular region, thus shading it completely from the user's final scene in a display. To avoid unnecessary processing, one should indicate to the obscured canvas not to bother about the non-important area.; The majority of users do not have to worry about this function, as they use just one canvas in their applications, with nothing inset or on top of it in any form.; To make this region one that has to be repainted again, call the function evas_obscured_clear().; This is a very low level function, which you may not use.; This function does not flag the canvas as having its state changed. If you want to re-render it afterwards expecting new contents, you have to add "damage" regions yourself (see evas_damage_rectangle_add()).

Parameters:

[in]	e	The given canvas pointer
[in]	x	The rectangle's top left corner's horizontal coordinate
[in]	y	The rectangle's top left corner's vertical coordinate
[in]	w	The rectangle's width
[in]	h	The rectangle's height

See also:: evas_obscured_clear(); evas_render_updates()

void evas_render ( Evas * e )

Forces rendering of the given canvas.

Since :: 2.3.1

Parameters:

[in] e The given canvas pointer

void evas_render_dump ( Evas * e )

Makes the canvas discard as much data as possible used by the engine at runtime.

This function unloads images, deletes textures and much more, where possible. You may also want to call evas_render_idle_flush() immediately prior to this to perhaps discard a little more, though evas_render_dump() should implicitly delete most of what evas_render_idle_flush() might discard too.

Since :: 2.3.1

Parameters:

[in] e The given canvas pointer

void evas_render_idle_flush ( Evas * e )

Makes the canvas discard internally cached data used for rendering.

This function flushes the arrays of delete, active and render objects. The other things it may discard include shared memory segments, temporary scratch buffers, and cached data to avoid re-compute of that data.

Since :: 2.3.1

Parameters:

[in] e The given canvas pointer

Eina_List* evas_render_updates ( Evas * e )

Forces immediate renderization of the given Evas canvas.

This function forces an immediate renderization update of the given canvas e.

Since :: 2.3.1

Remarks:: This is a very low level function, which you may not use. You would use it, for example, to grab an Evas' canvas update regions and paint them back, using the canvas' pixmap, on a displaying system working below Evas.; Evas is a stateful canvas. If no operations changing its state took place since the last rendering action, you do not see any changes and this call becomes a no-op.

Parameters:

[in] e The given canvas pointer

Returns:: A newly allocated list of updated rectangles of the canvas (Eina_Rectangle structs)
Free this list with evas_render_updates_free().

void evas_render_updates_free ( Eina_List * updates )

Frees the rectangles returned by evas_render_updates().

This function removes the region from the render updates list. The region does not get render updated anymore.

Since :: 2.3.1

Parameters:

[in] updates The list of updated rectangles of the canvas

See also:: evas_render_updates() for an example

Functions

Typedefs

Typedef Documentation

Function Documentation