[Seaside] Difference WAStaticHtmlCanvas >< WAHtmlCanvas

Ramon Leon ramon.leon at allresnet.com
Tue Mar 11 23:09:32 UTC 2008

> Today I had a look at The WACanvas hierarchy, but I do not 
> understand the difference between WAStaticHtmlCanvas and WAHtmlCanvas.
> Cheers,
> Claus

Look closer, WAHtmlCanvas is an abstract class, #document must be overridden
by subclasses.  They are mostly the same thing, WAStaticHtmlCanvas is just a
concrete implementation for it.  If WAStaticHtmlCanvas didn't exist and you
used WAHtmlCanvas directly, you'd have the WARenderCanvas inheriting from an
implementation class.  With the current implementation, WAStaticHtmlCanvas
is free to grow without messing up WARenderCanvas, it's cleaner the way it
is, one abstract class with two concrete implementations.  

I'm looking at 2.8 btw, it may have changed in 2.9.  It does look like
#textArea needs pushed up, it's the same in both subclasses.

Ramon Leon

More information about the seaside mailing list