dtk_draw_shape man page
dtk_draw_shape — Draw a shape in the window
void dtk_draw_shape(const dtk_hshape shp);
dtk_draw_shape() draw the shape referenced by shp in the current window. The position of the drawing depends on the rotation and translation previously set by dtk_*move_shape() and dtk_*rotate_shape() (the rotation is first applied to the shape and then the translation).
This function assumes there is a valid OpenGL rendering context in the calling thread. So a successfull call to dtk_make_current_window() should have been performed previously in the current thread.
dtk_create_composite_shape(3), dtk_make_current_window(3), dtk_move_shape(3).