I've shrunk one of my apps and I can't fix it

[Drewfus]

Can anyone help?
I was using the ultimate guitar app and I accidently rested my hand on the screen and now it has shrunk.
When I open the app it has a black box around it. In the bottom right corner you see 1X in a circle. If I press that then it changes to 2X and the screen gets smaller.
I've never had this before and I can't find anything on any forums.

Hope you can help.

Thanks.

 

[J. A.]

This seems to be an iPhone app that can also be used on an iPad.
The 1x and 2x buttons are for enlarging/shrinking, as you prefer or need it.
If you press 2x, it will be larger again.