Graphics package needed
I'm looking for a graphics package for designing various diagrams for my thesis. It doesn't need to be incredibly flash, as most of my diagrams are black outlines, with possibly block colours. What it does need to have is the ability to turn snapping on/off, plus a range of boxes and lines, tools which allow you to easily reproduce segments of the picture, put circles round numbers, save as jpeg etc etc.
I've tried using Powerpoint in the past, but don't have it on this machine... plus found it a bit limiting (although I can't remember quite why now).
I can't be much more specific than this about my requirements. I guess the closest I could come would be to say I need to take sketches in my notebooks, and make them look neat!
Preferably it needs to be free, because I have absolutely no spare money. I only need it for maximum three months, so maybe software offering a free trial period would work.
Thanks for any help...
Oh, and Windows XP.