Re: Use composition for embedding PangoMatrix in Transform (issue 555610043 by address@hidden)

[dak]

"PangoMatrix is a struct, so there is no value in using inheritance" is
a non-sequitur.  A struct just is a class with public members.

The motivation for choosing inheritance here was that this allows
passing Transform directly into Pango for operations.  This advantage is
not realised in our current code base, and doing so does not appear like
the best long-term plan since a good long-term plan would likely rather
involve using the transform matrices of Cairo since it would make a lot
more sense to route the bulk of graphics operations through Cairo than
maintaining our own limited and maintenance-intensive set of backends
and/or relying on Ghostscript as comparatively computationally expensive
intermediary.

So while I don't see any objective of value achieved here (the objective
of not using multiple inheritance went out the window long ago since it
is needed, for example, for determining initialisation order for
GC-marked objects), I don't see anything adversely impacted, either.

https://codereview.appspot.com/555610043/