Text Size
The text size plugin allows you to temporarily change the text size for better readability in gedit without changing the program's default text size.
Enable Text Size Plugin
To enable the plugin:
Press the menu button in the top-right corner of the window and select Preferences ▸ Plugins.
Select Text Size to enable the plugin.
Use the Text Size plugin
Once you have enabled the plugin, do any of the following to change the text size in gedit:
To increase the text size, press Ctrl++.
To decrease the text size, press Ctrl+-.
To reset the text size to the default size, press Ctrl+0.