[NTG-context] Equivalent in ConTeXt mkiv for LaTeX's picture environment?

The headline says it: As a convert from LaTeX I'm looking for the functionality of LaTeX's picture environment, i.e. the placing of boxes et al. according to absolute coordinates, possibly with calculating measurements and coordinates on the go, like the stuff provided by the picture package on LaTeX. (It's labels for cider bottles this time.) Cheers -- Thomas