Comments on: Changing a MovieClip’s registration point painlessly

By: Zeh

Zeh — Wed, 01 Apr 2009 14:13:43 +0000

Hassan: if both classes were implemented using a decorator pattern (or even a pseudo-decorator with composition), yeah, it’d work.

The way they are now, in the examples, for you to combine the functionality, you’d have to merge the two classes, adding all the functions and methods from one class to the other, or extending from one class to the other.

By: Hassan

Hassan — Wed, 01 Apr 2009 13:24:11 +0000

Thanks Zeh! I thought that this way will be easier for end-developer, but it seems that I was wrong. Using this method:

var mc:MovieClip = new MovieClip();
var pmc:PointMovieClip = new PointMovieClip(mc);

is good, but can I use a code like this? var dmc:DesignerMovieClip = new DesignerMovieClip(pmc);? To have both functionality of DesignerMovieClip and pmc:PointMovieClip? Is it a good way to do this or not?

Thanks! I really appreciate your notes!

By: Zeh

Zeh — Tue, 31 Mar 2009 21:35:34 +0000

Hassan: it’s a bigger problem, but the right thing to do would probably be using a decorator pattern. You’d still need a separate class, and to use it instead of your MC, but at least in this case you could apply it to *any* class. It’d work like that:

var mc:MovieClip = new MovieClip();
var pmc:PointMovieClip = new PointMovieClip(mc);

Using decorators actually makes a lot more sense when you need to add features like registration points, coloring and such to existing classes – specially MC classes since it’s a lot more common for people to have their own display classes and they can choose *which* features to add.

Remember this example is supposed to be an example of how you can extend properties and override original properties, it’s a getter/setter syntax example, instead of the best practice ever to add registration points to movieclips.

PS. Your english is fine, don’t worry.

By: Hassan

Hassan — Tue, 31 Mar 2009 21:13:58 +0000

I was thinking it would be better if could extend the class itself to add these methods to. I mean, use something like var mc:MovieClip = new MovieClip() and mc had the functionality that var mc:PointMovieClip = new PointMovieClip() has. Is that possible? I can’t speak english very well, sorry for my english.

By: Ryan

Ryan — Sun, 29 Mar 2009 04:10:21 +0000

Oleg you could just take this class and pass in the movieclip reference to the constructor, an init method, or add a property that sets it for composition usage.

By: Zeh

Zeh — Mon, 16 Mar 2009 14:11:00 +0000

Olegs: feel free to post your implementation to serve as an example.

By: Olegs Balss

Olegs Balss — Mon, 16 Mar 2009 09:35:41 +0000

It would be much more usable if you would choose composition over inheritance.