The brackets/slide tubes and poles I used are just aluminum tubing which can be sourced from many metal suppliers and can even be found on ebay.
I recommend that you use anodized tubing.

Hey I making a shade similar to yours, I was wondering where you got those aluminum poles and the bracket to attach them? I rigged mine using zip ties for now and using aluminum window cleaning poles so I could get an idea how it would look and what size canvas I would want. Your aluminum poles look a lot nicer than the window cleaning ones. any info I'd greatly appreciate. Thanks
Andrew