This allows us not just to pass any mime type to the read function, but
it also makes it possible to pass multiple mime types and the clipboard
can then try them in order until it finds a supported one.
This is so far not implemented though.
It's unused. Plain text is not using that framework, neither is
in-process same-display transmission.
So it was only useful for sharing text with custom tags across
applications, and nobody is doing that.
This is not used by anything yet, but add it now, so people looking at
this new code can make sense of it.
Plus, the documentation mentions it, so better have the docs make sense.
It will be used once we add support for conversions to GDK and allow
doing cipboard/dnd by GValue.
Make sure the API reflects the idea that GdkContentFormats is a set
containing mime types. In particular, treat the object itself as a
plural - it's named content format`S' after all - and therefor use
the correct verb form.
Also make GdkContentFormats keep an array instead of a list, now that
it's immutable.
Instead of allowing people to pass a uint user-data, insist on them
comparing mime types.
The user data was a uint instead of a pointer anyway, so uniqueness
could not be guaranteed and it caused more issues than it was worth.
And that's ignoring the fact that it basically wasn't used.
Instead, add a function gtk_image_set_icon_size() for the cases where
overriding the icon size is necessary.
Treat icon sizes the same way as pixel sizes, too. So gtk_image_clear()
no longer unsets the icon size.
Instead of returning the icon size with them, make
gtk_image_get_icon_name() and gtk_image_get_gicon() only return the icon
itself.
As a benefit, we can turn them into regular getters that return values
instead of requiring out parameters.
Instead, provide gtk_image_get_icon_size() to query the icon size.
Change constructors to reflect that.
While doing so, also add a fallback argument to the cursor constructors,
so it is now possible to create cursors with fallback.
And have a priv->display instead of a priv->screen.
Includes turning gtk_menu_set_screen() into gtk_menu_set_display(),
because that function just forwards to its window.
This drops the pixbuf property and the pixbuf getters. We keep
gtk_image_new/set_from_pixbuf, but these are small helpers that
immediately convert to a surface, and there is no way to later get
back the pixbuf you passed in.
The from file/resource codepaths are also changed to load a surface
instead of a pixbuf.
