The textbuffer test is calling into a function defined by the AT-SPI
accessibility backend. As of commit 4ddf1b70 we only build and run the
test on Linux, but the function in question isn't really
accessibility-related: it's just a serialization function.
To build a better world sometimes means having to tear the old one down.
-- Alexander Pierce, "Captain America: The Winter Soldier"
ATK served us well for nearly 20 years, but the world has changed, and
GTK has changed with it. Now ATK is mostly a hindrance towards improving
the accessibility stack:
- it maps to a very specific implementation, AT-SPI, which is Linux and
Unix specific
- it requires implementing the same functionality in three different
layers of the stack: AT-SPI, ATK, and GTK
- only GTK uses it; every other Linux and Unix toolkit and application
talks to AT-SPI directly, including assistive technologies
Sadly, we cannot incrementally port GTK to a new accessibility stack;
since ATK insulates us entirely from the underlying implementation, we
cannot replace it piecemeal. Instead, we're going to remove everything
and then incrementally build on a clean slate:
- add an "accessible" interface, implemented by GTK objects directly,
which describe the accessible role and state changes for every UI
element
- add an "assistive technology context" to proxy a native accessibility
API, and assign it to every widget
- implement the AT context depending on the platform
For more information, see: https://gitlab.gnome.org/GNOME/gtk/-/issues/2833
These functions are implementations of the AtkText api on top
of a PangoLayout, and are intended to replace GailTextUtil.
Since gtkpango.h is a private header, also remove the individual
inclusion prohibition.
This includes the addition of a "small" helper function,
_gtk_pango_fill_layout() that ignores color information. This
functionality is not available inside Pango and until that happens, we
need this fix. The bug is filed at:
https://bugzilla.gnome.org/show_bug.cgi?id=624917
