drawing a generated bitmap

[kamil stachowski <kstachowski o2 pl>]

hello :)

i understand this is a basic question and am sorry for my ignorance. i really 
haven't managed to find an answer though i've searched quite a time.

i've actually got two problems (using nemerle (mono, i.e. gtk#)):

1. i'd like to generate a terrain heightmap and draw it onto a widget. should 
i be using drawingarea.gdkwindow.drawpixel (how to handle colours, then?), 
try to convert it to an xpm (how?) or what other method would be most 
appropriate? (please, read the second question before answering this one)

2. i'd like to be able to fluently change the colours while the heightmap is 
already generated. in the old days (i haven't written much for quite a time) 
it was possible to just draw a bitmap onto the screen and keep redefining the 
colours, which was pretty fast and looked nice in its way. is it still 
doable? i'd need it for altering the water level on the map.

any help would be appreciated :)