Why are Aspect-Ratio Considerations Tied to a Frame?

[Ami Tavory <atavory gmail com>]

  Hello,

  I would like to ask a question on aspect-ratio containers. 

  I'm writing an application that uses OpenGL widgets (via
gtkglextmm). All of these widgets rely on the fact that their aspect
ratio is fixed. I noticed that gtkmm includes AspectFrame, but since
I'm not using these widgets as part of any logical group, I don't need
any frame. I consequently used the documentation on custom containers
to write an aspect-ratio container.

  Everything about gtkmm is great, both classes and docs, but I
don't understand the rationale for AspectFrame. From "Design Patterns"
(by the GoF), it seems that aspect-ratio enforcements should be a
"decorator" for a different component (this is how I've implemented
it). Now if gtkmm had an AspectRatioContainer class, it would:
A. Allow to enforce aspect ratios on any other component.
B. As a special case, it could enforce aspect ratios on frames, or,
alternatively, a frame could contain an AspectRatioContainer object.
Put differently, I see AspectFrame as simply a decorator decorating
both frame and aspect-ratio.
  So were gtkmm to include something like AspectRatioContainer
instead of AspectFrame, it seems the number of classes would be the
same, but the applicability would be greater. I was wondering why
AspectFrame was chosen.

  Thanks,

  Ami