and a more complex shape


I am using map tiles as created by with my own application. I can use a bounding box to reduce the rendering to an area of interest. In my case I only want to render a country at once - say Germany ;-).
osmosis for example has an option to load a complex shape of a country and produce a osm-file of this country. But am I able to render only the parts in this country?

Greetings from Germany!