This is another step in the gobjectification of the internal library
of gstreamer-vaapi. Now it is the turn of GstVaapiWindow and its
derivates.
The idea is to minimize the changeset keeping the same design as
much as possible.
GstVaapiWindow is defined as an abstract class with two properties:
the GstVaapiDisplay and the native ID. Thus, many of the
GstVaapiObject macros were copied as GstVaapiWindow macros.
The function gst_vaapi_window_new_internal() is kept as a decorator
of for calling gst_vaapi_window_create() and the possibility of
failure.
The descendant classes, such as glx, still use the private
structures, but through the gobject mechanism.
Add GstVaapiWindowClass::get_colormap() hook to help determine the
currently active colormap bound to the supplied window, or actually
create it if it does not already exist yet.
Add GstVaapiWindowClass::get_visual_id() function hook to help find
the best suitable visual id for the supplied window. While doing so,
also simplify the process by which an X11 window is created with a
desired Visual, i.e. now use a visual id instead of a Visual object.
Add a new generic helper function gst_vaapi_window_new() to create
a window without having the caller to check for the display type
himself. i.e. internally, there is now a GstVaapiDisplayClass hook
to create windows, and the actual backend implementation fills it in.
Add new generic helper functions gst_vaapi_texture_new_wrapped()
This is a simplification in view to supporting EGL.
Record the underlying native display instance into the toplevel
GstVaapiDisplay object. This is useful for fast lookups to the
underlying native display, e.g. for creating an EGL display.
Fix formts for various GST_DEBUG et al. invocations. More precisely,
make size_t arguments use the %zu format specifier accordingly; force
XID formats to be a 32-bit unsigned integer; and fix the format used
for gst_vaapi_create_surface_with_format() error cases since we have
been using strings nowadays.
Make sure to create the GLX context once the window object has completed
its creation. Since gl_resize() relies on the newly created window size,
then we cannot simply overload the GstVaapiWindowClass::create() hook.
So, we just call into gst_vaapi_window_glx_ensure_context() once the
window object is created in the gst_vaapi_window_glx_new*() functions.
Drop obsolete GST_VAAPI_IS_xxx() helper macros since we are no longer
deriving from GObject and so those were only checking for whether the
argument was NULL or not. This is now irrelevant, and even confusing
to some extent, because we no longer have type checking.
Note: this incurs more type checking (review) but the libgstvaapi is
rather small, so this is manageable.
