http://qiita.com/yusukefurukawa/items/8774a2fc38799915790b
It is a sample taking screenshot using any font on docker.
docker build -t test_xvfb_with_alpine .
docker run -it -v `pwd`:/host test_xvfb_with_alpine
The font used the thing of the following sites. Thank you for a splendid font!