Tizen Native API
7.0
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Functions relating to canvas events that report on changes of its internal states (an object got focused, the rendering is updated, etc).
Some of the functions in this group are exemplified here.
Functions | |
void | evas_event_callback_add (Evas *e, Evas_Callback_Type type, Evas_Event_Cb func, const void *data) |
void | evas_event_callback_priority_add (Evas *e, Evas_Callback_Type type, Evas_Callback_Priority priority, Evas_Event_Cb func, const void *data) |
void * | evas_event_callback_del (Evas *e, Evas_Callback_Type type, Evas_Event_Cb func) |
void * | evas_event_callback_del_full (Evas *e, Evas_Callback_Type type, Evas_Event_Cb func, const void *data) |
void | evas_post_event_callback_push (Evas *e, Evas_Object_Event_Post_Cb func, const void *data) |
void | evas_post_event_callback_remove (Evas *e, Evas_Object_Event_Post_Cb func) |
void | evas_post_event_callback_remove_full (Evas *e, Evas_Object_Event_Post_Cb func, const void *data) |
Typedefs | |
typedef struct _Evas_Event_Mouse_Down | Evas_Event_Mouse_Down |
typedef struct _Evas_Event_Mouse_Up | Evas_Event_Mouse_Up |
typedef struct _Evas_Event_Mouse_In | Evas_Event_Mouse_In |
typedef struct _Evas_Event_Mouse_Out | Evas_Event_Mouse_Out |
typedef struct _Evas_Event_Mouse_Move | Evas_Event_Mouse_Move |
typedef struct _Evas_Event_Mouse_Wheel | Evas_Event_Mouse_Wheel |
typedef struct _Evas_Event_Multi_Down | Evas_Event_Multi_Down |
typedef struct _Evas_Event_Multi_Up | Evas_Event_Multi_Up |
typedef struct _Evas_Event_Multi_Move | Evas_Event_Multi_Move |
typedef struct _Evas_Event_Key_Down | Evas_Event_Key_Down |
typedef struct _Evas_Event_Key_Up | Evas_Event_Key_Up |
typedef struct _Evas_Event_Hold | Evas_Event_Hold |
typedef struct _Evas_Event_Axis_Update | Evas_Event_Axis_Update |
typedef enum _Evas_Axis_Label | Evas_Axis_Label |
Typedef Documentation
typedef enum _Evas_Axis_Label Evas_Axis_Label |
Types of recognized device axes
- Since (EFL) :
- 1.13
typedef struct _Evas_Event_Axis_Update Evas_Event_Axis_Update |
Event structure for #EVAS_CALLBACK_AXIS_UPDATE event callbacks
- Since (EFL) :
- 1.13
typedef struct _Evas_Event_Hold Evas_Event_Hold |
Event structure for #EVAS_CALLBACK_HOLD event callbacks
typedef struct _Evas_Event_Key_Down Evas_Event_Key_Down |
Event structure for #EVAS_CALLBACK_KEY_DOWN event callbacks
typedef struct _Evas_Event_Key_Up Evas_Event_Key_Up |
Event structure for #EVAS_CALLBACK_KEY_UP event callbacks
typedef struct _Evas_Event_Mouse_Down Evas_Event_Mouse_Down |
Event structure for #EVAS_CALLBACK_MOUSE_DOWN event callbacks
typedef struct _Evas_Event_Mouse_In Evas_Event_Mouse_In |
Event structure for #EVAS_CALLBACK_MOUSE_IN event callbacks
typedef struct _Evas_Event_Mouse_Move Evas_Event_Mouse_Move |
Event structure for #EVAS_CALLBACK_MOUSE_MOVE event callbacks
typedef struct _Evas_Event_Mouse_Out Evas_Event_Mouse_Out |
Event structure for #EVAS_CALLBACK_MOUSE_OUT event callbacks
typedef struct _Evas_Event_Mouse_Up Evas_Event_Mouse_Up |
Event structure for #EVAS_CALLBACK_MOUSE_UP event callbacks
typedef struct _Evas_Event_Mouse_Wheel Evas_Event_Mouse_Wheel |
Event structure for #EVAS_CALLBACK_MOUSE_WHEEL event callbacks
typedef struct _Evas_Event_Multi_Down Evas_Event_Multi_Down |
Event structure for #EVAS_CALLBACK_MULTI_DOWN event callbacks
typedef struct _Evas_Event_Multi_Move Evas_Event_Multi_Move |
Event structure for #EVAS_CALLBACK_MULTI_MOVE event callbacks
typedef struct _Evas_Event_Multi_Up Evas_Event_Multi_Up |
Event structure for #EVAS_CALLBACK_MULTI_UP event callbacks
Enumeration Type Documentation
enum _Evas_Axis_Label |
- Enumerator:
Function Documentation
void evas_event_callback_add | ( | Evas * | e, |
Evas_Callback_Type | type, | ||
Evas_Event_Cb | func, | ||
const void * | data | ||
) |
Add (register) a callback function to a given canvas event.
- Parameters:
-
e Canvas to attach a callback to type The type of event that will trigger the callback func The (callback) function to be called when the event is triggered data The data pointer to be passed to func
This function adds a function callback to the canvas e
when the event of type type
occurs on it. The function pointer is func
.
In the event of a memory allocation error during the addition of the callback to the canvas, evas_alloc_error() should be used to determine the nature of the error, if any, and the program should sensibly try and recover.
A callback function must have the ::Evas_Event_Cb prototype definition. The first parameter (data
) in this definition will have the same value passed to evas_event_callback_add() as the data
parameter, at runtime. The second parameter e
is the canvas pointer on which the event occurred. The third parameter event_info
is a pointer to a data structure that may or may not be passed to the callback, depending on the event type that triggered the callback. This is so because some events don't carry extra context with them, but others do.
The event type type
to trigger the function may be one of #EVAS_CALLBACK_RENDER_FLUSH_PRE, #EVAS_CALLBACK_RENDER_FLUSH_POST, #EVAS_CALLBACK_CANVAS_FOCUS_IN, #EVAS_CALLBACK_CANVAS_FOCUS_OUT, #EVAS_CALLBACK_CANVAS_OBJECT_FOCUS_IN and #EVAS_CALLBACK_CANVAS_OBJECT_FOCUS_OUT. This determines the kind of event that will trigger the callback to be called. Only the last two of the event types listed here provide useful event information data -- a pointer to the recently focused Evas object. For the others the event_info
pointer is going to be NULL
.
Example:
evas_event_callback_add(d.canvas, EVAS_CALLBACK_RENDER_FLUSH_PRE, _render_flush_cb, NULL); if (evas_alloc_error() != EVAS_ALLOC_ERROR_NONE) { fprintf(stderr, "ERROR: Callback registering failed! Aborting.\n"); goto panic; } evas_event_callback_add(d.canvas, EVAS_CALLBACK_CANVAS_OBJECT_FOCUS_IN, _object_focus_in_cb, NULL); if (evas_alloc_error() != EVAS_ALLOC_ERROR_NONE) { fprintf(stderr, "ERROR: Callback registering failed! Aborting.\n"); goto panic; } /* two canvas event callbacks */
Looking to the callbacks registered above,
/* called when our rectangle gets focus */ static void _object_focus_in_cb(void *data EINA_UNUSED, Evas *e, void *event_info) { printf("An object got focused: %s\n", evas_object_name_get(event_info)); printf("Let's recheck it: %s\n", evas_object_name_get(evas_focus_get(e))); printf("And again: %s\n", evas_object_focus_get(event_info) ? "OK!" : "Oops, something is bad."); } /* render flush callback */ static void _render_flush_cb(void *data EINA_UNUSED, Evas *e EINA_UNUSED, void *event_info EINA_UNUSED) { printf("Canvas is about to flush its rendering pipeline!\n"); } /* put some action in the canvas */ static Eina_Bool _resize_cb(void *data EINA_UNUSED) { int w, h, cw, ch; evas_object_geometry_get(d.img, NULL, NULL, &w, &h); ecore_evas_geometry_get(d.ee, NULL, NULL, &cw, &ch); if (w < cw) evas_object_resize(d.img, cw, ch); else evas_object_resize(d.img, cw / 2, ch / 2); return EINA_TRUE; /* re-issue the timer */ } /* let's have our events back */
we see that the canvas flushes its rendering pipeline (#EVAS_CALLBACK_RENDER_FLUSH_PRE) whenever the _resize_cb
routine takes place: it has to redraw that image at a different size. Also, the callback on an object being focused comes just after we focus it explicitly, on code.
See the full example.
- Note:
- Be careful not to add the same callback multiple times, if that's not what you want, because Evas won't check if a callback existed before exactly as the one being registered (and thus, call it more than once on the event, in this case). This would make sense if you passed different functions and/or callback data, only.
- Since :
- 2.3.1
- Examples:
- ecore_imf_example.c, and evas-events.c.
void* evas_event_callback_del | ( | Evas * | e, |
Evas_Callback_Type | type, | ||
Evas_Event_Cb | func | ||
) |
Delete a callback function from the canvas.
- Parameters:
-
e Canvas to remove a callback from type The type of event that was triggering the callback func The function that was to be called when the event was triggered
- Returns:
- The data pointer that was to be passed to the callback
This function removes the most recently added callback from the canvas e
which was triggered by the event type type
and was calling the function func
when triggered. If the removal is successful it will also return the data pointer that was passed to evas_event_callback_add() when the callback was added to the canvas. If not successful NULL
will be returned.
Example:
extern Evas *e; void *my_data; void focus_in_callback(void *data, Evas *e, void *event_info); my_data = evas_event_callback_del(ebject, EVAS_CALLBACK_CANVAS_FOCUS_IN, focus_in_callback);
- Since :
- 2.3.1
void* evas_event_callback_del_full | ( | Evas * | e, |
Evas_Callback_Type | type, | ||
Evas_Event_Cb | func, | ||
const void * | data | ||
) |
Delete (unregister) a callback function registered to a given canvas event.
- Parameters:
-
e Canvas to remove an event callback from type The type of event that was triggering the callback func The function that was to be called when the event was triggered data The data pointer that was to be passed to the callback
- Returns:
- The data pointer that was to be passed to the callback
This function removes the first added callback from the canvas e
matching the event type type
, the registered function pointer func
and the callback data pointer data
. If the removal is successful it will also return the data pointer that was passed to evas_event_callback_add() (that will be the same as the parameter) when the callback(s) was(were) added to the canvas. If not successful NULL
will be returned. A common use would be to remove an exact match of a callback.
Example:
evas_event_callback_del_full(evas, EVAS_CALLBACK_RENDER_FLUSH_PRE, _render_flush_cb, NULL); evas_event_callback_del_full( evas, EVAS_CALLBACK_CANVAS_OBJECT_FOCUS_IN, _object_focus_in_cb, NULL);
See the full example.
- Note:
- For deletion of canvas events callbacks filtering by just type and function pointer, user evas_event_callback_del().
- Since :
- 2.3.1
- Examples:
- ecore_imf_example.c, and evas-events.c.
void evas_event_callback_priority_add | ( | Evas * | e, |
Evas_Callback_Type | type, | ||
Evas_Callback_Priority | priority, | ||
Evas_Event_Cb | func, | ||
const void * | data | ||
) |
Add (register) a callback function to a given canvas event with a non-default priority set. Except for the priority field, it's exactly the same as evas_event_callback_add
- Parameters:
-
e Canvas to attach a callback to type The type of event that will trigger the callback priority The priority of the callback, lower values called first. func The (callback) function to be called when the event is triggered data The data pointer to be passed to func
- See also:
- evas_event_callback_add
- Since (EFL) :
- 1.1
- Since :
- 2.3.1
void evas_post_event_callback_push | ( | Evas * | e, |
Evas_Object_Event_Post_Cb | func, | ||
const void * | data | ||
) |
Push a callback on the post-event callback stack
- Parameters:
-
e Canvas to push the callback on func The function that to be called when the stack is unwound data The data pointer to be passed to the callback
Evas has a stack of callbacks that get called after all the callbacks for an event have triggered (all the objects it triggers on and all the callbacks in each object triggered). When all these have been called, the stack is unwound from most recently to least recently pushed item and removed from the stack calling the callback set for it.
This is intended for doing reverse logic-like processing, example - when a child object that happens to get the event later is meant to be able to "steal" functions from a parent and thus on unwind of this stack have its function called first, thus being able to set flags, or return 0 from the post-callback that stops all other post-callbacks in the current stack from being called (thus basically allowing a child to take control, if the event callback prepares information ready for taking action, but the post callback actually does the action).
This function should only be called from inside an evas input event callback. The event_info data may be kept up until func
is called, in order to check the state of the "on-hold" flag for instance. Do not modify the canvas or otherwise trigger or feed a events to the canvas from inside func
. Use jobs to safely modify the canvas.
- Warning:
- Only use this function if you know exactly what you are doing!
- Since :
- 2.3.1
void evas_post_event_callback_remove | ( | Evas * | e, |
Evas_Object_Event_Post_Cb | func | ||
) |
Remove a callback from the post-event callback stack
- Parameters:
-
e Canvas to push the callback on func The function that to be called when the stack is unwound
This removes a callback from the stack added with evas_post_event_callback_push(). The first instance of the function in the callback stack is removed from being executed when the stack is unwound. Further instances may still be run on unwind.
- Since :
- 2.3.1
void evas_post_event_callback_remove_full | ( | Evas * | e, |
Evas_Object_Event_Post_Cb | func, | ||
const void * | data | ||
) |
Remove a callback from the post-event callback stack
- Parameters:
-
e Canvas to push the callback on func The function that to be called when the stack is unwound data The data pointer to be passed to the callback
This removes a callback from the stack added with evas_post_event_callback_push(). The first instance of the function and data in the callback stack is removed from being executed when the stack is unwound. Further instances may still be run on unwind.
- Since :
- 2.3.1