Just created an account here to say that for me this is a deal-breaker. It's heart-breaking because I've been playing with the AP trial for an hour or two and I was so excited to have finally found a package I could use like Photoshop (but without the subscription/ridiculous price) ... and then it tripped up on this simple feature of all things. That's pretty shocking.
Serif: Seriously, this missing feature just lost you a sale from an otherwise keen customer :'( I'm off to look at Photoshop yearly subscription prices so that I can draw a horizontal line.
tommy_g003 got a reaction from 4EverMaAT in Affinity Photo - Constrain drawing tools to straight lines