Design Question: Delegation vs. callbacks

[Henning Hasemann]

>    Normally, I'd expect thing (or widget) to be a base class for many 
> graphics objects.

Ok, Ill give some more detail here:
My project is an engine for classical 2D adventures (like the old
LucasArts ones).
A thing is everything the player can interact with. I.e it might be
another character, or something to pick up or to push, ...

A thing needs an area to be able to receive mouse clicks, but I need
areas in other places, too (for example in 'regions' when I want to
trigger events as soon as the character stands at a certain place)

>    If you want a coherent architecture that doesn't confuse the user, 
> I'd recommend avoiding differing types of functionality with the same 
> function name.  Maybe it's best to rename one or both of your isIn 
> functions?

Are you talking about something like isInRelative() and isInAbsolute()?
Sounds like a good idea for the delegate approach.

>    If position is defined to be the upper left corner of a bounding
> box (or some similar definition), one of two things should result:
>    a. The position to change if a component has been changed.  The 
> object has changed, so its properties changed.  The user must live
> with it. b. The containing object forces everything inside it to
> conform to its dimensions.  Drawing a circle that goes outside of a
> window shouldn't leave a mark on the desktop...

A thing can also define its alignment relative to its position.
For example most things have their position ad middle-bottom (center of
feet) which hos some advantages when finding out the z-order of objects.

Thanks so far for your answer. It already helped me much to see the
thing a bit clearer.


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