Create a convenient way to set font size

[Renkai]

The font size setting of Pillow is quite complex, and it's part of the font setting, not an independent setting.

https://stackoverflow.com/questions/4902198/pil-how-to-scale-text-size-in-relation-to-the-size-of-the-image

I guess most of our community members are not so picky about the font. We just want the font big enough to see it clearly.

[Renkai]

might be helpful links: https://www.geeksforgeeks.org/python-pil-imagefont-load_default/