How to paint a background and place graphics on top of if?

[Thomas Gutzmann]

Hi,

before asking the list, I have tried quite some time - but I'm at my 
wits end.

I want to create a LARGE background image which is a sort of gutter. I 
think I can do this by creating a picture, but I don't find out how to 
draw lines of patterns in a picture under script control.

If I have this background image, it's very easy to group it so I can 
use scrollbars to scroll it. Once I have it...

Next I want to draw object son top of it. Ok, that's easy, once I know 
how to draw...

Then I want to replace parts of the picture, because the user must be 
able to move a virtual object by dragging it somewhere else. In RB this 
is quite simple - but how can I tell Rev to redraw patterns only in a 
specified rectangle (a sort of CliptRect)?

Back in the good old days of Pascal, I declared the CliptRect, painted 
the whole picture, and I was sure that only the ClitpRect was painted - 
performance was excellent event on a 68000. There was something as easy 
as lineTo - but what is the equivalent in Rev? It must be there, 
because I can use the paint tool to draw lines, patterns and so forth - 
but how to do it under script control?

Thank you for giving me some hints!

Thomas G.