@mbc66, providing hex colors is definitely something I'd like to support. I actually have an open issue tracking this. I just opened this issue but I remember that I started to work on this a while ago. Something about it was difficult. Obviously the conversion isn't difficult at all, but there was some issue with how the GUI was structured. I can't remember what the issue was, but I'd like to finish this one up pretty soon, The open issue can be found here: https://github.com/srm985/axure-redline-tool/issues/12
@ophiliuim, could you give me an example of how you would use 100% as the value for a dimension? I haven't used Axure in a while and don't have any memory of this. Let me give a scenario and you tell me if it's what you mean. I thought Axure only supported fixed dimensions - or are you writing custom CSS after Axure exports its components? I'm not sure I understand this. As far as fixed items, could you give an example here too? With these, what do you mean by "adapt"? Do you mean, will the artboard display correctly or do you mean will it give the correct measurements?
I'll explain a little bit about how the tool works - in hopes that I might answer some of your questions. To create the artboard dimensions, the tool scans all of the elements that Axure has placed on the page. It then determines what the furthest elements are from "center". It then sizes the artboard based on these elements. So, if you were to draw a square that was 100px x 100px your artboard should be displayed as 100px x 100px. If you then added a square directly to the right of the first square, that had dimensions of 10px x 10px, your new artboard should now be 110px wide and still 100px high. The tool has to do some tricky stuff to determine element measurements, but in the end, it is pretty much just measuring the size of the element. So if you have a square that is 10px x 10px, the tool will just measure its outer bounds and report a square of 10px x 10px. Some things are impossible to measure correctly though because of how Axure renders certain components in HTML. For example, if you create a circle in your Axure file, Axure doesn't export this as a square with border radius of 50% - instead they export an image. Of course, we can't accurately measure an in or easily extract attributes. Maybe Axure has since changed this though.
As far as the floating buttons go, I have opened an issue to track this and it can be found here: https://github.com/srm985/axure-redline-tool/issues/10