Display

Displays can be created by a backend, which returns a pix_display_t handle. More...

Collaboration diagram for Display:

Macros
#define	PIX_DISPLAY_POOL_CAPACITY   1u
	Maximum number of concurrently active displays. More...
#define	PIX_DISPLAY_CONTEXT_SIZE   64u
	Size in bytes of backend-private state embedded in each display. More...

Typedefs
typedef struct pix_display_t	pix_display_t
	Opaque display descriptor.
typedef void(*	pix_display_draw_t) (pix_display_t *display, pix_bitmap_t *bitmap, void *userdata)
	Draw callback signature. More...

Methods
void	pix_display_set_callback (pix_display_t *display, pix_display_draw_t callback, void *userdata)
	Register the function that draws this display's contents. More...
void	pix_display_deinit (pix_display_t *display)
	Deinitialize a display and release it back to the pool. More...

Detailed Description

Displays can be created by a backend, which returns a pix_display_t handle.

The backends are:

• SDL: dev_sdl_init()

A display is usually backed by a bitmap buffer of a specific pixel format, but how that's implemented is up to the backend.

Macro Definition Documentation

PIX_DISPLAY_CONTEXT_SIZE

#define PIX_DISPLAY_CONTEXT_SIZE   64u

Size in bytes of backend-private state embedded in each display.

Default fits the SDL backend's context, the largest today. Must be defined identically everywhere pix_display_t is used - override by defining PIX_DISPLAY_CONTEXT_SIZE globally at compile time.

Definition at line 45 of file display.h.

PIX_DISPLAY_POOL_CAPACITY

#define PIX_DISPLAY_POOL_CAPACITY   1u

Maximum number of concurrently active displays.

Displays come from a small fixed-size pool, not the heap. Override by defining PIX_DISPLAY_POOL_CAPACITY at compile time.

Definition at line 33 of file display.h.

Typedef Documentation

pix_display_draw_t

typedef void(* pix_display_draw_t) (pix_display_t *display, pix_bitmap_t *bitmap, void *userdata)

Draw callback signature.

Parameters

display	The display being drawn.
bitmap	The display's bitmap, already locked for direct pixel access - the callback should draw into it, but never lock/unlock it itself.
userdata	Opaque pointer, as passed to pix_display_set_callback().

Called internally, from within pix_poll(), whenever this display's backend reports it's due a redraw - never called directly.

Definition at line 60 of file display.h.

Function Documentation

pix_display_deinit()

void pix_display_deinit

(

pix_display_t *

display

)

Deinitialize a display and release it back to the pool.

Parameters

display

The display to deinitialize. Safe to call on NULL.

pix_display_set_callback()

void pix_display_set_callback	(	pix_display_t *	display,
		pix_display_draw_t	callback,
		void *	userdata
	)

Register the function that draws this display's contents.

Parameters

display	The display to set the callback on. A no-op if invalid.
callback	Called whenever display is due a redraw, or NULL to clear a previously registered callback.
userdata	Opaque pointer passed back to callback unchanged.