I would like to create a fork of gnome terminal that has font size escape codes.

Instead of rendering text in a grid I would like to render text as follows:

Height of a row is determined by font size. The position of the left of a character in a row is the sum of the sizes of all preceding characters.

How much work would this be? Specifically; In your estimation how many functions would be affected, and how many loops/if branches would need to be modified, rounded to the nearest exponent of 2