[cvs-nhc98] Refactor the expression-squashing code into the paintOne r

malcolm: Mon Jul 1 19:00:20 CEST 2002 Update of /usr/src/master/nhc/src/hat/tools In directory hinken:/tmp/cvs-serv12973 Modified Files: HatTrail.hs Log Message: Refactor the expression-squashing code into the paintOne routine, so that the expression is pretty-printed only once at the final size, instead of twice. Also, make some fixes to the shrink/expand behaviour when an expression has been squashed. Previously, this led to a garbled screen, and sometimes a disappearing selection.