BeRTOS graphics library was designed to run on systems with severe resource constraints and this reflects on its features:
- Images are 1bpp to save the maximum RAM and ROM space
- Vertical or horizontal pixel disposition to make blit operations faster depending on the underlying hardware
- Only basic drawing algorithms are provided
- Only integer arithmetics is supported
I think that comparing it to GDI+ is a bit unfair!
We have plans to introduce a more complete library in the mid-term (read, this year). This library will probably support RGBA surfaces, image loading from file, more painting algorithms.
Please contact me in private if you or your company would like to fund such developments.
Regarding the integration with external libraries, I have never tried to integrate external toolkits. Let me know if you need help with BeRTOS internals.