Re[2]: [cgmo-webcgm] ISSUE: should no-target-object block event dispatch?

[Benoit Bezaire <benoit@itedo.com>]

Hi,

See inline...

Wednesday, August 24, 2005, 4:36:00 AM, Dieter wrote:

DW> Hi Lofton,

DW> see inline. 

>> -----Original Message-----
>> From: Lofton Henderson [mailto:lofton@rockynet.com] 
>> Sent: Wednesday, August 24, 2005 12:51 AM
>> To: cgmo-webcgm@lists.oasis-open.org
>> Subject: [cgmo-webcgm] ISSUE: should no-target-object block 
>> event dispatch?
>> 
>> 
>> 5.7.10
>> ----------
>> There are some things in the 2nd bullet list that I don't understand:
>> 
>> >* If there are no graphics objects whose interactive region is under
>> >the mouse (i.e., there is no target object), the event is 
>> not dispatched.
DW> In 5.7.10, explanation of event types, the expression "if any" is used a
DW> lot. That suggests that the event _is_ in fact dispatched if there is no
DW> APS under the mouse.
DW> Option 1:  remove the "if any" in various locations, change the bullet point
DW> 	     above to "the event is discarded."
DW> Option 2:  change the above to support events outside of an APS.
DW> My recollection is that we didn't want to handle events outside of an APS,
DW> if this is right, we should go for option 1.
I apologies, but I don't understand what you are trying to say.

>> >* Otherwise, there is a target object. If there is an event 
>> handler at 
>> >the Picture level with event capturing for the given event, then the
>> >event is dispatched to the Picture.
DW> There can't be an event handler at the Picture level, because the
DW> addEventListener funtion is on the metafile interface.
DW> Suggestion: change to reflect this.
Right, Picture needs to change to Metafile.

>> >* Otherwise, if the target object has an appropriate event 
>> handler for 
>> >the given event, the event is dispatched to the target object.
DW> There is no way to add an event listener to an individual object,
DW> so this needs to be removed.
I agree.

>> >* Otherwise, the Picture is checked to see if it has an appropriate
>> >event handler. The event is dispatched to the Picture if one 
>> is found.
DW> Again, change Picture to Metafile.
DW> However, this doesn't make sense, as Lofton pointed out.

>> >* Otherwise, the event is discarded.
DW> No. We still have internal link handling, i.e. linking by linkURI
DW> attributes found in the file.
Yes, but Lofton only extracted a small section of that chapter, we
do cover this in:
The processing order for user interface events is as follows:
...

-- 
 Benoit   mailto:benoit@itedo.com

DW> Regards,
DW> Dieter


>> 
>> (Long story short ... draw a flowchart of the above, with 
>> four Y/N decision branches ... something is wrong.  In words, 
>> the long story is...)
>> 
>> I don't understand how the 2nd sentence of 2nd bullet relates 
>> to the 4th bullet.  If there is an appropriate event handler 
>> at the Picture level, how would the event-dispatch algorithm 
>> ever get past the 2nd bullet?  2nd bullet says that eligible 
>> Picture gets the event before eligible target object 
>> (eligible = has handler), while 4th says eligible picture gets it
>> *after* eligible target object.  I would think that we mean 
>> the 4th, right?  I.e., most specific wins?  I.e., closest to 
>> leaf wins?
>> 
>> I'm unclear why the dispatch-to-Picture (if eligible) of the 
>> 2nd bullet should be contingent upon there being a target 
>> object.  It basically
>> says:  if you click on a blank area of the picture, the event 
>> is not dispatched (so Picture could not receive the event).  
>> Is that what we intended?
>> 
>> (Btw, the first bullet is effectively the same as SVG1.1.  
>> SVG is now debating whether to change it, even at the expense 
>> of being non-backward compatible[!], so that the containing 
>> SVG element [i.e., our "Picture"] gets a chance at the event 
>> if there is no target object.)
>> 
>> Thoughts?
>> 
>> Regards,
>> -Lofton.