Now that we have a frame clock in place, we should be able to drop
the beam-sync penalty prevention code as we should be aligning our
draws with CVDisplayLink.
Originally by Christian Hergert <chergert@redhat.com>, flushWindow
corrections and improvements by John Ralls.
If we get consecutive preedit string updates that announce a NULL
string, we still do end up issuing ::preedit-changed with those.
Ignore changes from NULL to NULL, it is the other combinations which
must issue this signal.
For reasons that only apply to the old serial handling, asking for
the surrounding after IM changes resulted in lazy handling of
commit() afterwards.
With the recent interpretation of serials, this problem became more
apparent, since it is in fact very likely that the last interaction
step after an IM change is notifying of the changed surrounding
text after the IM change was applied.
Make handling of surrounding text similar to caret position changes,
always commit() after the state change, but skip through non-changes.
This makes the compositor state fully up-to-date after an IM change.
(cherry-picked from commit eb7c78aa4896b1d36fa09a3e68c942730b233f74)
Similarly, uses casts in `gtk_image_definition_unref()`. Compilation
succeeds without them, unlike in `gtk_image_definition_ref()`, because
`gtk_image_definition_unref()` is not called internally, unlike
`gtk_image_definition_ref()`. But the build would fail if some function
defined in the module were changed in the future to call
`gtk_image_definition_unref()`, and we can future-proof it now. This
also removes an inconsistency in how we access the members of the union.
`jhbuild build gtk+-3` with GCC 12 fails with:
```
In function ‘gtk_image_definition_ref’,
inlined from ‘gtk_image_definition_new_empty’
at ../../../../jhbuild/checkout/gtk+-3/gtk/gtkimagedefinition.c:107:10:
../../../../jhbuild/checkout/gtk+-3/gtk/gtkimagedefinition.c:241:13: error:
array subscript ‘GtkImageDefinition {aka union _GtkImageDefinition}[0]’
is partly outside array bounds of ‘GtkImageDefinitionEmpty[1]’
{aka ‘struct _GtkImageDefinitionEmpty[1]’} [-Werror=array-bounds]
241 | def->empty.ref_count++;
| ~~~~~~~~~~^~~~~~~~~~
../../../../jhbuild/checkout/gtk+-3/gtk/gtkimagedefinition.c:
In function ‘gtk_image_definition_new_empty’:
../../../../jhbuild/checkout/gtk+-3/gtk/gtkimagedefinition.c:105:34: note:
object ‘empty’ of size 8
105 | static GtkImageDefinitionEmpty empty = { GTK_IMAGE_EMPTY, 1 };
| ^~~~~
```
and many similar errors.
Fix it by casting `GtkImageDefinition` to `GtkImageDefinitionEmpty` or
similar, as appropriate.
Essentially backports 4dcd02e85315f487310e2e01fe9412706a77dc35 from main to gtk-3-24.
