[PATCH 03/10 v4] gdiplus: Add functions for managing metafile objects id

[Vincent Povirk]

This seems like overkill to me?

I don't see the need for per-object refcounting. Every drawing
operation that uses an object is just going to end with a series of
releases, and after it returns all refcounts should be 0.

+    /* TODO: object id should be released on object dispose */
I don't think this approach is possible. It would require every object
to be aware of which metafiles are using it, and every operation that
modifies the object would have to release them. Bitmap objects can
refer to an application buffer that could be modified without any call
into gdiplus. (Or, Bitmaps could be modified by an ImageAttributes, in
which case we can't reuse them except with an identical
ImageAttributes.)

If we wanted to reuse Bitmaps, we'd have to compare the data. For
other large types like Paths, maybe keeping an id to detect whether it
changed would make sense. For types of bounded size, it probably would
be easier to store a complete copy.