A breathing apparatus includes a control unit configured to control operation of the breathing apparatus based on at least a first input value and a second input value. The breathing apparatus also includes a graphical user interface connected to the control unit. The control unit is configured to display a visual output on the graphical user interface including an area defined by a first axis and a second axis. In addition, the breathing apparatus includes an input unit configured to provide selection of a portion of the area. The control unit is configured to set the first input value in response to the position of the selected portion relative the first axis and to set the second input value in response to the position of the selected portion relative the second axis.