As an example, the `PixbufDisplayer` needs packed RGB888 data,
while the `XvDisplayer` expects YUV (MPEG-style) pixels.
The research setup is not well equipped to handle any kind of content
or format negotiation; yet for the experimentation, the connections can
be wired as !SigC-Signals. After the preceding refactorings,
`DummyImageGenerator` can be configured to perform the conversion to YUV
only when necessary, and to use the working buffer flexibly.
When supplied with packed RGB pixel data, the display in the Gtk::Image
is now correct, and also handles layout and scaling appropriately.
Ichthyostega
8abeb02397