code: def zoom(self, factor):
          
          editor = self.get_current_editorstack().get_current_editor()
          if factor == 0:
              font = self.get_plugin_font()
              editor.set_font(font)
          else:
              font = editor.font()
              size = font.pointSize() + factor
              if size > 0:
                  font.setPointSize(size)
                  editor.set_font(font)
          editor.update_tab_stop_width_spaces()
docs: Zoom in/out/reset