Evas_Output_Method(3)

NAME
Evas_Output_Method - Render Engine Functions

 - Functions that are used to set the render engine for a given function, and then get that engine working.

SYNOPSIS

  Functions
EVAS_API int evas_render_method_lookup (const char *name)
Look up a numeric ID from a string name of a rendering engine.
EVAS_API Eina_List * evas_render_method_list (void)
List all the rendering engines compiled into the copy of the Evas library.
EVAS_API void evas_render_method_list_free (Eina_List *list)
This function should be called to free a list of engine names.

Detailed Description

Functions that are used to set the render engine for a given function, and then get that engine working. The following code snippet shows how they can be used to initialise an evas that uses the X11 software engine:

Evas *evas;
Evas_Engine_Info_Software_X11 *einfo;
extern Display *display;
extern Window win;
evas_init();
evas = evas_new();
evas_output_method_set(evas, evas_render_method_lookup("software_x11"));
evas_output_size_set(evas, 640, 480);
evas_output_viewport_set(evas, 0, 0, 640, 480);
einfo = (Evas_Engine_Info_Software_X11 *)evas_engine_info_get(evas);
einfo->info.display = display;
einfo->info.visual = DefaultVisual(display, DefaultScreen(display));
einfo->info.colormap = DefaultColormap(display, DefaultScreen(display));
einfo->info.drawable = win;
einfo->info.depth = DefaultDepth(display, DefaultScreen(display));
evas_engine_info_set(evas, (Evas_Engine_Info *)einfo);

Function Documentation

  EVAS_API int evas_render_method_lookup (const char * name)

Look up a numeric ID from a string name of a rendering engine.

Parameters
    name the name string of an engine

Returns
    A numeric (opaque) ID for the rendering engine

This function looks up a numeric return value for the named engine in the string name. This is a normal C string, NUL byte terminated. The name is case sensitive. If the rendering engine is available, a numeric ID for that engine is returned that is not 0. If the engine is not available, 0 is returned, indicating an invalid engine.

The programmer should NEVER rely on the numeric ID of an engine unless it is returned by this function. Programs should NOT be written accessing render method ID's directly, without first obtaining it from this function.

Attention
    it is mandatory that one calls evas_init() before looking up the render method.

Example:

int engine_id;
Evas *evas;
evas_init();
evas = evas_new();
if (!evas)
  {
    fprintf(stderr, "ERROR: Canvas creation failed. Fatal error.);
    exit(-1);
  }
engine_id = evas_render_method_lookup("software_x11");
if (!engine_id)
  {
    fprintf(stderr, "ERROR: Requested rendering engine is absent.);
    exit(-1);
  }
evas_output_method_set(evas, engine_id);

Referenced by ecore_evas_buffer_allocfunc_new(), and ecore_evas_object_image_new().

  EVAS_API Eina_List* evas_render_method_list (void)

List all the rendering engines compiled into the copy of the Evas library.

Returns
    A linked list whose data members are C strings of engine names

Calling this will return a handle (pointer) to an Evas linked list. Each node in the linked list will have the data pointer be a (char *) pointer to the name string of the rendering engine available. The strings should never be modified, neither should the list be modified. This list should be cleaned up as soon as the program no longer needs it using evas_render_method_list_free(). If no engines are available from Evas, NULL will be returned.

Example:

Eina_List *engine_list, *l;
char *engine_name;
engine_list = evas_render_method_list();
if (!engine_list)
  {
    fprintf(stderr, "ERROR: Evas supports no engines! Exit.);
    exit(-1);
  }
printf("Available Evas Engines:);
EINA_LIST_FOREACH(engine_list, l, engine_name)
  printf("%s, engine_name);
evas_render_method_list_free(engine_list);

  EVAS_API void evas_render_method_list_free (Eina_List * list)

This function should be called to free a list of engine names.

Parameters
    list The Eina_List base pointer for the engine list to be freed

When this function is called it will free the engine list passed in as list. The list should only be a list of engines generated by calling evas_render_method_list(). If list is NULL, nothing will happen.

Example:

Eina_List *engine_list, *l;
char *engine_name;
engine_list = evas_render_method_list();
if (!engine_list)
  {
    fprintf(stderr, "ERROR: Evas supports no engines! Exit.);
    exit(-1);
  }
printf("Available Evas Engines:);
EINA_LIST_FOREACH(engine_list, l, engine_name)
  printf("%s, engine_name);
evas_render_method_list_free(engine_list);

References EINA_LIST_FREE, and eina_stringshare_del().

Author

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