Fontzoom.vim is a project mainly written in Vim Script, it's free.
The fontsize controller in gVim.
This is a mirror of http://www.vim.org/scripts/script.php?script_id=2931
fontzoom is a Vim plugin to control gui fontsize. You can change fontsize with + and - keys(when default setting). You can also use the [count]. This plugin remember 'guifont', 'lines', and 'columns' when you change fontsize first. And tries to keep the size of the window as much as possible.
similar plugins: guifont++.vim vimscript #593 zoom.vim vimscript #2321 fontsize.vim vimscript #2809
Latest Version: https://github.com/thinca/vim-fontzoom