How to choose the font size for an image?

Question

Java

I have a picture with a known width and height.
There is a text with an unknown number of characters, of course, they can be counted in the program.
You need to put the text on the picture and put it in such a way that the text on the picture looks neat, that is, it is not small or, on the contrary, huge.
The text can be broken into lines.
The text can be any length, so we need to implement a function that decides whether it will be possible to place the text neatly on the picture or not.
Please suggest some algorithm