On 21/04/16 13:08, Carsten Haitzler wrote:
> On Thu, 21 Apr 2016 10:17:16 +0100 Tom Hacohen <t...@osg.samsung.com> said:
>
>> On 21/04/16 02:43, Carsten Haitzler wrote:
>>> On Mon, 18 Apr 2016 14:18:06 +0100 Tom Hacohen <t...@osg.samsung.com> said:
>>>
>>>> On 12/04/16 12:36, Carsten Haitzler wrote:
>>>>> On Tue, 12 Apr 2016 12:27:02 +0100 Tom Hacohen <t...@osg.samsung.com>
>>>>> said:
>>>>>
>>>>>> On 12/04/16 10:57, Carsten Haitzler wrote:
>>>>>>> just realized... Eo_Event *....
>>>>>>>
>>>>>>> it has obj. shouldn't it ALSO have src too? for event propagation we
>>>>>>> really want to maintain src to be the original object the event happened
>>>>>>> on AND obj to be the event the callback is being called on...
>>>>>>>
>>>>>>> ... comments?
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> Let me start by saying that the magic of the Eo_Event structure is that
>>>>>> we can add to it when we need to. Like now. :)
>>>>>
>>>>> yeah - i know. but let's add to it now... :)
>>>>>
>>>>>> At the moment we just overwrite obj (as you may know) and send a
>>>>>> "native" event. The problem I have with src is that I feel like it's
>>>>>> exposing internals of widgets for no apparent benefit. Having src feels
>>>>>> useful to me as well, but I don't have a usecase in mind.
>>>>>
>>>>> you can't otherwise know where the event really originated. you only know
>>>>> you got it. if it propagated... there would be cases you want to know - if
>>>>> you are the original src of the event or just got a propagation -
>>>>> otherwise it could be handled multiple times like
>>>>>
>>>>> if (event->src != event->obj) // propagated event
>>>>
>>>> I understand how it can be used, what I don't know is the purpose. A
>>>> purpose like: "you can check if it's a propagated event" is not a real
>>>> purpose, it's a method. Why would you want to know if it's a propagated
>>>> event? What's the real use case where knowing that is useful?
>>>>
>>>>>
>>>>>> In cases where it's really needed, src could be added to the event info.
>>>>>
>>>>> i think that's really too special/manual. i think it likely should be a
>>>>> core feature. right now we have event forwarders ... and here src would
>>>>> need to change. currently that's gore. i think we should also add
>>>>> propagation to parent too like evas already does. that would necessitate
>>>>> this feature in core. we currently dont have a propagate flag. in fact
>>>>> you likely want to propagate some events and not others.
>>>>>
>>>>> anyway - i remember int he past doing code and going "shit. i dont know
>>>>> where the event came from. i can't fix this simply. i have to do some
>>>>> weird stuff instead". i remember making a mental note to fix this in
>>>>> future. :) i'm now voicing that note. :)
>>>>
>>>> I'm not strictly against, just lacking an example... Got one you can
>>>> describe?
>>>
>>> another example:
>>>
>>> struct _Evas_Event_Mouse_Down /** Mouse button press event */
>>> {
>>> int button; /**< Mouse button number that went down (1 -
>>> 32) *$
>>>
>>> Evas_Point output; /**< The X/Y location of the cursor */
>>> Evas_Coord_Point canvas; /**< The X/Y location of the cursor */
>>>
>>> void *data;
>>> Evas_Modifier *modifiers; /**< modifier keys pressed during the
>>> event */ Evas_Lock *locks;
>>>
>>> Evas_Button_Flags flags; /**< button flags set during the event */
>>> unsigned int timestamp;
>>> Evas_Event_Flags event_flags;
>>> Evas_Device *dev;
>>> Evas_Object *event_src; /**< The Evas Object which actually
>>> triggered t$ };
>>>
>>> ... event_src. we already have it. and we are doing it adhoc event by event.
>>> this is why it should be core.
>>>
>>
>> It means something else in this example than what you want to add.
>>
>> Here, in this case, event_src is actually ->obj! The canvas is the one
>> emitting the event and if anything, the object repeats it. So exactly
>> the opposite. You'll have to add this field anyway.
>>
>> Furthermore, as I've mentioned before, we should use struct inheritance
>> for the event->info properties of things when they are shared, so it
>> won't really be duplication.
>
> if you use struct inheritance you can't extend structs that are inherited from
> in future. beware.
>
>
Yes, you can't. It's a common event struct that has all of what the
input events have at the moment (in common). Maybe it's a good idea to
add an extension slot to the base just in case. Though many of those are
unlikely to change.
--
Tom.
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