Krita gives you quick access to the Line Tool and it’s great for testing out perspective theories. However, I came across one limitation in Krita with the way the program handles straight line. Other softwares keep the line straight when you draw it while holding down the Shift key. I found out today that you can change Krita’s profile to function like Photoshop! Once you change the profile, the “Shift” will allow you to draw straight lines. But upon closer look, it’s actually a Line Tool. That’s where the limitation is.
On the left image, if you want to draw a perfectly straight line that covers both top and bottom, starting at the center, you can’t with a line tool. You would have to lift up your pen and repeat, and the problem is that it might not align with the first line perfectly. You can do it manually, image on the right, but without locking the initial angle/direction of the stroke, it will look off.