Content providers are meant to be immutable, apart from very special
cases, but in those cases they need to emit
gdk_content_provider_content_changed().
Having a constructor that just uses a get_func invites abuse of this
by not making developers aware of those requirments.
In fact, all users in GTK failed to do this.
Instead, code should use the GtkDragSource::prepare signal to create
content providers when needed.
The same problem exists with gdk_content_provider_new_with_formats(),
but this commit doesn't touch that.
Instead, rely on people passing fallbacks explicitly.
Alternatively, GThemedIcon provides the functionality to create
fallbacks, which is what GtkImage and the testsuite now use.
That method is slightly better, too, so the expected test results
have been updated accordingly.
Most users were just forgetting to set the proper flags.
And flags aren't the right way to set this anyway, it was just
acceptable as a workaround during GTK3 to not break API.
Remove arguments from the constructor.
For actions, we now default to COPY, which is the most common one
that we should enable by default (MOVE requires handling deletion
on the the source side, and ASK only makes sense if we have
multiple actions).
For the content provider, we add a new ::prepare signal where
it should be provided just-in-time.
This is to go along with the newly introduced GdkDrop.
This commit includes the necessary updates to the X11, Wayland
and Broadway backends. Other backends have to be updated separately.
This is in preparation of using input streams to show that these
coordinates aren't needed most of the time and can otherwise be saved
during GtkWidget::drag-drop.
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.
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.
