In method editor, if the code is too small, you can enlarge the font. You can also reduce the font.
You can change it in the toolbar Method->View



You can also use the keyboard shortcuts:

On windows, enlarge font size is (Ctrl Shift +). Reduce font size is (Ctrl -).
On macs, by default, enlarge font size is (Cmd Shift +). Reduce font size is (Cmd -).

You can edit keyboard shortcuts through the shortcuts page.
On windows: Edit->Preferences->Shortcuts.
On mac: 4D->Preferences->Shortcuts