It seems the suggested way is doable.
It also seems, that using
OpenGL ES as the base is a rather platform independent way.
Making work freetype fonts and ftgles to be done.
The complete implementation of themed
Tk support is not yet started, it should be relatively easy using enough time to do the work, as the existing implementation for
Tk is available.
It seems not to be possible to use native fonts with
OpenGL ES.
The implementation of the widgets using
OpenGL ES commands is at the beginning.
There is the need for test cases.
There is also the need for examples/demos.