Hey
GapiDraw 1.0 will work safely with OpenTrek. You could also probably use a later version and avoid using any window resizing and only use normal display orientation.
OpenTrek NG (Next Generation of course) will soon be announced that will itself be built upon GapiDraw.
In the mean time. Either use GD100 with OpenTrek or develop the graphics separately and wait for OTNG.
/Johan