How do I magnify a small area around around the pointer?

I have looked at the default GNOME magnifier, and it either magnifies the whole screen, or half of it. The full screen magnification means I can see only a quarter of the screen at once, and the half screen magnification stops following my pointer and jumps away when stop moving the mouse, making it useless. Even if it did not do that it still hides too much of the screen. I just sometimes need a little help seeing text when it's in a hard to read color or a bit too small, without affecting any of the screen beyond a small around around the pointer.

I have seen magnus, but it appears to put the magnified part of the screen in a totally different part of the screen, meaning I have to look away from where I'm trying to concentrate, as well as having to move the magnification window whenever I need to see what's actually under it - well, at least if I want to see it unmagnified.

I'm picturing something that looks like an actual (or really virtual) rectangular magnifying lens floating over the screen centered on the pointer. Something like this except that that shows the mouse and lets you continue to work as if it's not there. How can I magnify the screen like this? Am I missing a knob to control the built-in GNOME magnifier? Is there a different magnifier I can use?