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[gef-dev] Re: [Issue 1048] Allow manual adjustment of text label positions on edges

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Author dthompson
Full name Dave Thompson
Date 2008-12-19 07:48:43 PST
Message Continuing this discussion on gef dev list...

Yes, you are right, the new ModeFactories should make this easier. I do feel
that there may be some contention or possibly inefficiencies that could arise
from using it too much though.

Contention: Inevitably a new mode implementation will be to add some
additional functionality on top of the existing feature set. For this reason
anyone creating a new custom mode will probably want his mode to be first in
the stack. In an application where everyone assumes that their mode is still
the first, and takes precedence over the others, we may have a conflict, or
unexpected behaviour. It probably just means we need to manage this
carefully, and do thorough regression testing any time we add new Modes.

Inefficiencies: As I understand it, most of the modes in the stack
effectively scan the whole of the active diagram in the editor, one Fig at a
time, in order to see if that Fig was under the mouse for a given click. If
no event is consumed, the event goes to the next Mode in the stack. My
concern is that for a large diagram with a lot of modes, there might be a lot
of scanning before any match was found. This might slow down the UI's
responsiveness to mouse clicks, worsening the user experience. But we
needn't worry about this unless it becomes a problem.

My experience is mostly with embedded systems, where efficiencies are
important. I often forget that PC applications can perform several million
instructions in one millisecond, so maybe this doesn't matter to GEF/ArgoUML.

Regards,

Dave


Bob Tarling wrote:
> Yes, Modes are very useful in separating responsibilities to different classes.
>
> They're much underused. The new framework provided by the
> ModeFactories will hopefully allow us to more easily implement other
> interactions.
>
> I'm thinking about using this to allow the user to drag activations
> around on the new sequence diagrams.
>
> Cheers
>
> Bob.
>
>
> 2008/12/17 Dave Thompson <argouml at davet dot org>:
>> Hi Bob,
>>
>> I think the new mode seemed the safest way to go, because it allows me
>> to isolate the new behaviour to one specific action. The way it was
>> working the other way, seemed to be a side-effect, and although it
>> appeared to work, it didn't really, and probably created more problems
>> than it solved.
>>
>> Anyway, I'll keep at it, but I've not been able to spend much time on it
>> over the last week.
>>
>> Dave

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[gef-dev] Re: [Issue 1048] Allow manual adjustment of text label positions on edges dthompson Dave Thompson 2008-12-19 07:48:43 PST
     Re: [gef-dev] Re: [Issue 1048] Allow manual adjustment of text label positions on edges bobtarling Bob Tarling 2008-12-19 08:05:23 PST
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