java: Refactor AltosFlightDisplay units and font update handling

Make AltosFlightDisplay explicitly implement AltosFontListener and
AltosUnitsListener interfaces to make everyone use the same API. Then,
actually go implement units listeners so that changing units updates
all of the active displays immediately

Signed-off-by: Keith Packard <keithp@keithp.com>

9 files changed, 286 insertions, 134 deletions

diff --git a/altosui/AltosAscent.java b/altosui/AltosAscent.java
index f6ccbf0c..fb05fe11 100644
--- a/altosui/AltosAscent.java
+++ b/altosui/AltosAscent.java
@@ -26,10 +26,12 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 	GridBagLayout	layout;
 	JLabel			cur, max;
 
-	public class AscentStatus {
+	public class AscentStatus implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
 		AltosLights	lights;
+		double		v;
+		AltosUnits	units;
 
 		void show() {
 			value.setVisible(true);
@@ -50,7 +52,8 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			value.setText(s);
 		}
 
-		void show(AltosUnits units, double v) {
+		void show(double v) {
+			this.v = v;
 			show(units.show(8, v));
 		}
 
@@ -63,12 +66,18 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			lights.set(false);
 		}
 
-		void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
-		public AscentStatus (GridBagLayout layout, int y, String text) {
+		public void units_changed(boolean imperial_units) {
+			if (units != null)
+				show(v);
+		}
+
+		public AscentStatus (GridBagLayout layout, int y, AltosUnits units, String text) {
+			this.units = units;
 			GridBagConstraints	c = new GridBagConstraints();
 			c.weighty = 1;
 
@@ -105,10 +114,13 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 		}
 	}
 
-	public class AscentValue {
+	public abstract class AscentValue implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
-		void show(AltosState state, AltosListenerState listener_state) {}
+		double		v;
+		AltosUnits	units;
+
+		abstract void show(AltosState state, AltosListenerState listener_state);
 
 		void reset() {
 			value.setText("");
@@ -124,7 +136,8 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			value.setText(s);
 		}
 
-		void show(AltosUnits units, double v) {
+		void show(double v) {
+			this.v = v;
 			show(units.show(8, v));
 		}
 
@@ -136,12 +149,18 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			label.setVisible(false);
 			value.setVisible(false);
 		}
-		void set_font() {
+
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
-		public AscentValue (GridBagLayout layout, int y, String text) {
+		public void units_changed(boolean imperial_units) {
+			if (units != null)
+				show(v);
+		}
+
+		public AscentValue (GridBagLayout layout, int y, AltosUnits units, String text) {
 			GridBagConstraints	c = new GridBagConstraints();
 			c.weighty = 1;
 
@@ -167,13 +186,19 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			layout.setConstraints(value, c);
 			add(value);
 		}
+
+		public AscentValue (GridBagLayout layout, int y, String text) {
+			this(layout, y, null, text);
+		}
 	}
 
-	public class AscentValueHold {
+	public class AscentValueHold implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
 		JTextField	max_value;
 		double		max;
+		AltosUnits	units;
+		double		v;
 
 		void show(AltosState state, AltosListenerState listener_state) {}
 
@@ -183,23 +208,29 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			max = AltosLib.MISSING;
 		}
 
-		void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 			max_value.setFont(Altos.value_font);
 		}
 
-		void show(AltosUnits units, double v) {
+		public void units_changed(boolean imperial_units) {
+			show(v);
+		}
+
+		void show(double v) {
+			this.v = v;
 			if (v == AltosLib.MISSING) {
 				value.setText("Missing");
-				max_value.setText("Missing");
 			} else {
 				value.setText(units.show(8, v));
-				if (v > max || max == AltosLib.MISSING) {
-					max_value.setText(units.show(8, v));
+				if (v > max || max == AltosLib.MISSING)
 					max = v;
-				}
 			}
+			if (max == AltosLib.MISSING)
+				max_value.setText("Missing");
+			else
+				max_value.setText(units.show(8, v));
 		}
 
 		void hide() {
@@ -208,7 +239,8 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			max_value.setVisible(false);
 		}
 
-		public AscentValueHold (GridBagLayout layout, int y, String text) {
+		public AscentValueHold (GridBagLayout layout, int y, AltosUnits units, String text) {
+			this.units = units;
 			GridBagConstraints	c = new GridBagConstraints();
 			c.weighty = 1;
 
@@ -245,13 +277,12 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 		}
 	}
 
-
 	class Height extends AscentValueHold {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.height, state.height());
+			show(state.height());
 		}
 		public Height (GridBagLayout layout, int y) {
-			super (layout, y, "Height");
+			super (layout, y, AltosConvert.height, "Height");
 		}
 	}
 
@@ -259,10 +290,10 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 
 	class Speed extends AscentValueHold {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.speed, state.speed());
+			show(state.speed());
 		}
 		public Speed (GridBagLayout layout, int y) {
-			super (layout, y, "Speed");
+			super (layout, y, AltosConvert.speed, "Speed");
 		}
 	}
 
@@ -270,10 +301,10 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 
 	class Accel extends AscentValueHold {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.accel, state.acceleration());
+			show(state.acceleration());
 		}
 		public Accel (GridBagLayout layout, int y) {
-			super (layout, y, "Acceleration");
+			super (layout, y, AltosConvert.accel, "Acceleration");
 		}
 	}
 
@@ -281,10 +312,10 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 
 	class Orient extends AscentValueHold {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.orient, state.orient());
+			show(state.orient());
 		}
 		public Orient (GridBagLayout layout, int y) {
-			super (layout, y, "Tilt Angle");
+			super (layout, y, AltosConvert.orient, "Tilt Angle");
 		}
 	}
 
@@ -307,7 +338,7 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
  			lights.set(state.apogee_voltage >= AltosLib.ao_igniter_good);
 		}
 		public Apogee (GridBagLayout layout, int y) {
-			super(layout, y, "Apogee Igniter Voltage");
+			super(layout, y, null, "Apogee Igniter Voltage");
 		}
 	}
 
@@ -319,7 +350,7 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 			lights.set(state.main_voltage >= AltosLib.ao_igniter_good);
 		}
 		public Main (GridBagLayout layout, int y) {
-			super(layout, y, "Main Igniter Voltage");
+			super(layout, y, null, "Main Igniter Voltage");
 		}
 	}
 
@@ -364,17 +395,28 @@ public class AltosAscent extends JComponent implements AltosFlightDisplay {
 		orient.reset();
 	}
 
-	public void set_font() {
+	public void font_size_changed(int font_size) {
 		cur.setFont(Altos.label_font);
 		max.setFont(Altos.label_font);
-		lat.set_font();
-		lon.set_font();
-		main.set_font();
-		apogee.set_font();
-		height.set_font();
-		speed.set_font();
-		accel.set_font();
-		orient.set_font();
+		lat.font_size_changed(font_size);
+		lon.font_size_changed(font_size);
+		main.font_size_changed(font_size);
+		apogee.font_size_changed(font_size);
+		height.font_size_changed(font_size);
+		speed.font_size_changed(font_size);
+		accel.font_size_changed(font_size);
+		orient.font_size_changed(font_size);
+	}
+
+	public void units_changed(boolean imperial_units) {
+		lat.units_changed(imperial_units);
+		lon.units_changed(imperial_units);
+		main.units_changed(imperial_units);
+		apogee.units_changed(imperial_units);
+		height.units_changed(imperial_units);
+		speed.units_changed(imperial_units);
+		accel.units_changed(imperial_units);
+		orient.units_changed(imperial_units);
 	}
 
 	public void show(AltosState state, AltosListenerState listener_state) {
diff --git a/altosui/AltosCompanionInfo.java b/altosui/AltosCompanionInfo.java
index f8d033a8..514ce611 100644
--- a/altosui/AltosCompanionInfo.java
+++ b/altosui/AltosCompanionInfo.java
@@ -33,18 +33,21 @@ public class AltosCompanionInfo extends JTable implements AltosFlightDisplay {
 		return (infoValueMetrics.getHeight() + infoValueMetrics.getLeading()) * 18 / 10;
 	}
 
-	public void set_font() {
+	public void font_size_changed(int font_size) {
 		setFont(Altos.table_value_font);
 		setRowHeight(desired_row_height());
 		doLayout();
 	}
 
+	public void units_changed(boolean imperial_units) {
+	}
+
 	public AltosCompanionInfo() {
 		super(new AltosFlightInfoTableModel(info_rows, info_columns));
 		model = (AltosFlightInfoTableModel) getModel();
 		setAutoResizeMode(AUTO_RESIZE_ALL_COLUMNS);
 		setShowGrid(true);
-		set_font();
+		font_size_changed(AltosUIPreferences.font_size());
 	}
 
 	public Dimension getPreferredScrollableViewportSize() {
diff --git a/altosui/AltosDescent.java b/altosui/AltosDescent.java
index 5cb693fe..e6710524 100644
--- a/altosui/AltosDescent.java
+++ b/altosui/AltosDescent.java
@@ -25,7 +25,7 @@ import org.altusmetrum.altosuilib_2.*;
 public class AltosDescent extends JComponent implements AltosFlightDisplay {
 	GridBagLayout	layout;
 
-	public abstract class DescentStatus {
+	public abstract class DescentStatus implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
 		AltosLights	lights;
@@ -58,11 +58,14 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 			lights.set(false);
 		}
 
-		void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
+		public void units_changed(boolean imperial_units) {
+		}
+
 		public DescentStatus (GridBagLayout layout, int y, String text) {
 			GridBagConstraints	c = new GridBagConstraints();
 			c.weighty = 1;
@@ -101,9 +104,11 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 		}
 	}
 
-	public abstract class DescentValue {
+	public abstract class DescentValue implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
+		AltosUnits	units;
+		double		v;
 
 		void reset() {
 			value.setText("");
@@ -126,7 +131,8 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 			value.setText(v);
 		}
 
-		void show(AltosUnits units, double v) {
+		void show(double v) {
+			this.v = v;
 			show(units.show(8, v));
 		}
 
@@ -134,12 +140,18 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 			show(String.format(format, v));
 		}
 
-		void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
-		public DescentValue (GridBagLayout layout, int x, int y, String text) {
+		public void units_changed(boolean imperial_units) {
+			if (units != null)
+				show(v);
+		}
+
+		public DescentValue (GridBagLayout layout, int x, int y, AltosUnits units, String text) {
+			this.units = units;
 			GridBagConstraints	c = new GridBagConstraints();
 			c.weighty = 1;
 
@@ -163,9 +175,13 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 			c.weightx = 1;
 			add(value, c);
 		}
+
+		public DescentValue (GridBagLayout layout, int x, int y, String text) {
+			this(layout, x, y, null, text);
+		}
 	}
 
-	public abstract class DescentDualValue {
+	public abstract class DescentDualValue implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value1;
 		JTextField	value2;
@@ -187,12 +203,15 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 			value2.setVisible(false);
 		}
 
-		void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value1.setFont(Altos.value_font);
 			value2.setFont(Altos.value_font);
 		}
 
+		public void units_changed(boolean imperial_units) {
+		}
+
 		abstract void show(AltosState state, AltosListenerState listener_state);
 
 		void show(String v1, String v2) {
@@ -246,10 +265,10 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 
 	class Height extends DescentValue {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.height, state.height());
+			show(state.height());
 		}
 		public Height (GridBagLayout layout, int x, int y) {
-			super (layout, x, y, "Height");
+			super (layout, x, y, AltosConvert.height, "Height");
 		}
 	}
 
@@ -257,10 +276,10 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 
 	class Speed extends DescentValue {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.speed, state.speed());
+			show(state.speed());
 		}
 		public Speed (GridBagLayout layout, int x, int y) {
-			super (layout, x, y, "Speed");
+			super (layout, x, y, AltosConvert.speed, "Speed");
 		}
 	}
 
@@ -308,13 +327,13 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 	class Distance extends DescentValue {
 		void show(AltosState state, AltosListenerState listener_state) {
 			if (state.from_pad != null)
-				show(AltosConvert.distance, state.from_pad.distance);
+				show(state.from_pad.distance);
 			else
 				show("???");
 		}
 
 		public Distance (GridBagLayout layout, int x, int y) {
-			super(layout, x, y, "Ground Distance");
+			super(layout, x, y, AltosConvert.distance, "Ground Distance");
 		}
 	}
 
@@ -364,10 +383,10 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 
 	class Range extends DescentValue {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.distance, state.range);
+			show(state.range);
 		}
 		public Range (GridBagLayout layout, int x, int y) {
-			super (layout, x, y, "Range");
+			super (layout, x, y, AltosConvert.distance, "Range");
 		}
 	}
 
@@ -397,17 +416,30 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 		apogee.reset();
 	}
 
-	public void set_font() {
-		lat.set_font();
-		lon.set_font();
-		height.set_font();
-		speed.set_font();
-		bearing.set_font();
-		range.set_font();
-		distance.set_font();
-		elevation.set_font();
-		main.set_font();
-		apogee.set_font();
+	public void font_size_changed(int font_size) {
+		lat.font_size_changed(font_size);
+		lon.font_size_changed(font_size);
+		height.font_size_changed(font_size);
+		speed.font_size_changed(font_size);
+		bearing.font_size_changed(font_size);
+		range.font_size_changed(font_size);
+		distance.font_size_changed(font_size);
+		elevation.font_size_changed(font_size);
+		main.font_size_changed(font_size);
+		apogee.font_size_changed(font_size);
+	}
+
+	public void units_changed(boolean imperial_units) {
+		lat.units_changed(imperial_units);
+		lon.units_changed(imperial_units);
+		height.units_changed(imperial_units);
+		speed.units_changed(imperial_units);
+		bearing.units_changed(imperial_units);
+		range.units_changed(imperial_units);
+		distance.units_changed(imperial_units);
+		elevation.units_changed(imperial_units);
+		main.units_changed(imperial_units);
+		apogee.units_changed(imperial_units);
 	}
 
 	public void show(AltosState state, AltosListenerState listener_state) {
diff --git a/altosui/AltosFlightStatus.java b/altosui/AltosFlightStatus.java
index 73b84f8d..459b0495 100644
--- a/altosui/AltosFlightStatus.java
+++ b/altosui/AltosFlightStatus.java
@@ -159,7 +159,7 @@ public class AltosFlightStatus extends JComponent implements AltosFlightDisplay
 		last_packet.reset();
 	}
 
-	public void set_font () {
+	public void font_size_changed(int font_size) {
 		call.set_font();
 		serial.set_font();
 		flight.set_font();
@@ -168,6 +168,9 @@ public class AltosFlightStatus extends JComponent implements AltosFlightDisplay
 		last_packet.set_font();
 	}
 
+	public void units_changed(boolean imperial_units) {
+	}
+
 	public void show (AltosState state, AltosListenerState listener_state) {
 		call.show(state, listener_state);
 		serial.show(state, listener_state);
diff --git a/altosui/AltosFlightUI.java b/altosui/AltosFlightUI.java
index 2bd60d6c..baa18686 100644
--- a/altosui/AltosFlightUI.java
+++ b/altosui/AltosFlightUI.java
@@ -24,7 +24,7 @@ import java.util.concurrent.*;
 import org.altusmetrum.altoslib_4.*;
 import org.altusmetrum.altosuilib_2.*;
 
-public class AltosFlightUI extends AltosUIFrame implements AltosFlightDisplay, AltosFontListener {
+public class AltosFlightUI extends AltosUIFrame implements AltosFlightDisplay {
 	AltosVoice		voice;
 	AltosFlightReader	reader;
 	AltosDisplayThread	thread;
@@ -83,22 +83,29 @@ public class AltosFlightUI extends AltosUIFrame implements AltosFlightDisplay, A
 		sitemap.reset();
 	}
 
-	public void set_font() {
-		pad.set_font();
-		ignitor.set_font();
-		ascent.set_font();
-		descent.set_font();
-		landed.set_font();
-		flightStatus.set_font();
-		flightInfo.set_font();
-		sitemap.set_font();
-		companion.set_font();
-	}
-
 	public void font_size_changed(int font_size) {
-		set_font();
+		pad.font_size_changed(font_size);
+		ignitor.font_size_changed(font_size);
+		ascent.font_size_changed(font_size);
+		descent.font_size_changed(font_size);
+		landed.font_size_changed(font_size);
+		flightStatus.font_size_changed(font_size);
+		flightInfo.font_size_changed(font_size);
+		sitemap.font_size_changed(font_size);
+		companion.font_size_changed(font_size);
 	}
 
+	public void units_changed(boolean imperial_units) {
+		pad.units_changed(imperial_units);
+		ignitor.units_changed(imperial_units);
+		ascent.units_changed(imperial_units);
+		descent.units_changed(imperial_units);
+		landed.units_changed(imperial_units);
+		flightStatus.units_changed(imperial_units);
+		flightInfo.units_changed(imperial_units);
+		sitemap.units_changed(imperial_units);
+		companion.units_changed(imperial_units);
+	}
 
 	AltosFlightStatusUpdate	status_update;
 
@@ -318,6 +325,7 @@ public class AltosFlightUI extends AltosUIFrame implements AltosFlightDisplay, A
 		setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
 
 		AltosUIPreferences.register_font_listener(this);
+		AltosPreferences.register_units_listener(this);
 
 		addWindowListener(new WindowAdapter() {
 				@Override
@@ -326,6 +334,7 @@ public class AltosFlightUI extends AltosUIFrame implements AltosFlightDisplay, A
 					setVisible(false);
 					dispose();
 					AltosUIPreferences.unregister_font_listener(AltosFlightUI.this);
+					AltosPreferences.unregister_units_listener(AltosFlightUI.this);
 					if (exit_on_close)
 						System.exit(0);
 				}
diff --git a/altosui/AltosIdleMonitorUI.java b/altosui/AltosIdleMonitorUI.java
index b5652df3..042111ec 100644
--- a/altosui/AltosIdleMonitorUI.java
+++ b/altosui/AltosIdleMonitorUI.java
@@ -27,7 +27,7 @@ import java.util.Arrays;
 import org.altusmetrum.altoslib_4.*;
 import org.altusmetrum.altosuilib_2.*;
 
-public class AltosIdleMonitorUI extends AltosUIFrame implements AltosFlightDisplay, AltosFontListener, AltosIdleMonitorListener, DocumentListener {
+public class AltosIdleMonitorUI extends AltosUIFrame implements AltosFlightDisplay, AltosIdleMonitorListener, DocumentListener {
 	AltosDevice		device;
 	JTabbedPane		pane;
 	AltosPad		pad;
@@ -56,13 +56,14 @@ public class AltosIdleMonitorUI extends AltosUIFrame implements AltosFlightDispl
 		flightInfo.clear();
 	}
 
-	public void set_font() {
-		pad.set_font();
-		flightInfo.set_font();
+	public void font_size_changed(int font_size) {
+		pad.font_size_changed(font_size);
+		flightInfo.font_size_changed(font_size);
 	}
 
-	public void font_size_changed(int font_size) {
-		set_font();
+	public void units_changed(boolean imperial_units) {
+		pad.units_changed(imperial_units);
+		flightInfo.units_changed(imperial_units);
 	}
 
 	AltosFlightStatusUpdate	status_update;
@@ -235,8 +236,8 @@ public class AltosIdleMonitorUI extends AltosUIFrame implements AltosFlightDispl
 						disconnect();
 					} catch (Exception ex) {
 						System.out.printf("Exception %s\n", ex.toString());
-						for (StackTraceElement e : ex.getStackTrace())
-							System.out.printf("%s\n", e.toString());
+						for (StackTraceElement el : ex.getStackTrace())
+							System.out.printf("%s\n", el.toString());
 					}
 					setVisible(false);
 					dispose();
diff --git a/altosui/AltosIgnitor.java b/altosui/AltosIgnitor.java
index 7f79f42b..27917b30 100644
--- a/altosui/AltosIgnitor.java
+++ b/altosui/AltosIgnitor.java
@@ -25,7 +25,7 @@ import org.altusmetrum.altosuilib_2.*;
 public class AltosIgnitor extends JComponent implements AltosFlightDisplay {
 	GridBagLayout	layout;
 
-	public class LaunchStatus {
+	public class LaunchStatus implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
 		AltosLights	lights;
@@ -66,11 +66,14 @@ public class AltosIgnitor extends JComponent implements AltosFlightDisplay {
 			hide();
 		}
 
-		public void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
+		public void units_changed(boolean imperial_units) {
+		}
+
 		public void set_label(String text) {
 			label.setText(text);
 		}
@@ -142,11 +145,14 @@ public class AltosIgnitor extends JComponent implements AltosFlightDisplay {
 			ignitors[i].reset();
 	}
 
-	public void set_font() {
+	public void font_size_changed(int font_size) {
 		if (ignitors == null)
 			return;
 		for (int i = 0; i < ignitors.length; i++)
-			ignitors[i].set_font();
+			ignitors[i].font_size_changed(font_size);
+	}
+
+	public void units_changed(boolean imperial_units) {
 	}
 
 	public void show(AltosState state, AltosListenerState listener_state) {
diff --git a/altosui/AltosLanded.java b/altosui/AltosLanded.java
index 707d8fcc..bb52fe2b 100644
--- a/altosui/AltosLanded.java
+++ b/altosui/AltosLanded.java
@@ -27,10 +27,13 @@ import org.altusmetrum.altosuilib_2.*;
 public class AltosLanded extends JComponent implements AltosFlightDisplay, ActionListener {
 	GridBagLayout	layout;
 
-	public class LandedValue {
+	public abstract class LandedValue implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
-		void show(AltosState state, AltosListenerState listener_state) {}
+		AltosUnits	units;
+		double		v;
+
+		abstract void show(AltosState state, AltosListenerState listener_state);
 
 		void reset() {
 			value.setText("");
@@ -46,7 +49,8 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 			value.setText(s);
 		}
 
-		void show(AltosUnits units, double v) {
+		void show(double v) {
+			this.v = v;
 			show(units.show(8, v));
 		}
 
@@ -54,17 +58,24 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 			show(String.format(format, v));
 		}
 
-		public void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
+		public void units_changed(boolean imperial_units) {
+			if (units != null)
+				show(v);
+		}
+
 		void hide() {
 			label.setVisible(false);
 			value.setVisible(false);
 		}
 
-		public LandedValue (GridBagLayout layout, int y, String text) {
+		public LandedValue (GridBagLayout layout, int y, AltosUnits units, String text) {
+			this.units = units;
+
 			GridBagConstraints	c = new GridBagConstraints();
 			c.weighty = 1;
 
@@ -89,6 +100,10 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 			layout.setConstraints(value, c);
 			add(value);
 		}
+
+		public LandedValue (GridBagLayout layout, int y, String text) {
+			this(layout, y, null, text);
+		}
 	}
 
 	String pos(double p, String pos, String neg) {
@@ -151,12 +166,12 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 		void show (AltosState state, AltosListenerState listener_state) {
 			show();
 			if (state.from_pad != null)
-				show(AltosConvert.distance, state.from_pad.distance);
+				show(state.from_pad.distance);
 			else
 				show("???");
 		}
 		public Distance (GridBagLayout layout, int y) {
-			super (layout, y, "Distance");
+			super (layout, y, AltosConvert.distance, "Distance");
 		}
 	}
 
@@ -164,10 +179,10 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 
 	class Height extends LandedValue {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.height, state.max_height());
+			show(state.max_height());
 		}
 		public Height (GridBagLayout layout, int y) {
-			super (layout, y, "Maximum Height");
+			super (layout, y, AltosConvert.height, "Maximum Height");
 		}
 	}
 
@@ -175,10 +190,10 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 
 	class Speed extends LandedValue {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.speed, state.max_speed());
+			show(state.max_speed());
 		}
 		public Speed (GridBagLayout layout, int y) {
-			super (layout, y, "Maximum Speed");
+			super (layout, y, AltosConvert.speed, "Maximum Speed");
 		}
 	}
 
@@ -186,10 +201,10 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 
 	class Accel extends LandedValue {
 		void show (AltosState state, AltosListenerState listener_state) {
-			show(AltosConvert.accel, state.max_acceleration());
+			show(state.max_acceleration());
 		}
 		public Accel (GridBagLayout layout, int y) {
-			super (layout, y, "Maximum Acceleration");
+			super (layout, y, AltosConvert.accel, "Maximum Acceleration");
 		}
 	}
 
@@ -205,14 +220,24 @@ public class AltosLanded extends JComponent implements AltosFlightDisplay, Actio
 		accel.reset();
 	}
 
-	public void set_font() {
-		lat.set_font();
-		lon.set_font();
-		bearing.set_font();
-		distance.set_font();
-		height.set_font();
-		speed.set_font();
-		accel.set_font();
+	public void font_size_changed(int font_size) {
+		lat.font_size_changed(font_size);
+		lon.font_size_changed(font_size);
+		bearing.font_size_changed(font_size);
+		distance.font_size_changed(font_size);
+		height.font_size_changed(font_size);
+		speed.font_size_changed(font_size);
+		accel.font_size_changed(font_size);
+	}
+
+	public void units_changed(boolean imperial_units) {
+		lat.units_changed(imperial_units);
+		lon.units_changed(imperial_units);
+		bearing.units_changed(imperial_units);
+		distance.units_changed(imperial_units);
+		height.units_changed(imperial_units);
+		speed.units_changed(imperial_units);
+		accel.units_changed(imperial_units);
 	}
 
 	public void show(AltosState state, AltosListenerState listener_state) {
diff --git a/altosui/AltosPad.java b/altosui/AltosPad.java
index a6ac70db..ce1f2ab7 100644
--- a/altosui/AltosPad.java
+++ b/altosui/AltosPad.java
@@ -25,7 +25,7 @@ import org.altusmetrum.altosuilib_2.*;
 public class AltosPad extends JComponent implements AltosFlightDisplay {
 	GridBagLayout	layout;
 
-	public class LaunchStatus {
+	public class LaunchStatus implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
 		AltosLights	lights;
@@ -62,11 +62,14 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 			lights.setVisible(false);
 		}
 
-		public void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
+		public void units_changed(boolean imperial_units) {
+		}
+
 		public void set_label(String text) {
 			label.setText(text);
 		}
@@ -107,10 +110,13 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 		}
 	}
 
-	public class LaunchValue {
+	public abstract class LaunchValue implements AltosFontListener, AltosUnitsListener {
 		JLabel		label;
 		JTextField	value;
-		void show(AltosState state, AltosListenerState listener_state) {}
+		AltosUnits 	units;
+		double		v;
+
+		abstract void show(AltosState state, AltosListenerState listener_state);
 
 		void show() {
 			label.setVisible(true);
@@ -122,17 +128,23 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 			value.setVisible(false);
 		}
 
-		public void set_font() {
+		public void font_size_changed(int font_size) {
 			label.setFont(Altos.label_font);
 			value.setFont(Altos.value_font);
 		}
 
+		public void units_changed(boolean imperial_units) {
+			if (units != null)
+				show(v);
+		}
+
 		void show(String s) {
 			show();
 			value.setText(s);
 		}
 
-		void show(AltosUnits units, double v) {
+		void show(double v) {
+			this.v = v;
 			show(units.show(8, v));
 		}
 
@@ -148,7 +160,9 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 			value.setText("");
 		}
 
-		public LaunchValue (GridBagLayout layout, int y, String text) {
+		public LaunchValue (GridBagLayout layout, int y, AltosUnits units, String text) {
+			this.units = units;
+
 			GridBagConstraints	c = new GridBagConstraints();
 			c.insets = new Insets(Altos.tab_elt_pad, Altos.tab_elt_pad, Altos.tab_elt_pad, Altos.tab_elt_pad);
 			c.weighty = 1;
@@ -173,6 +187,10 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 			layout.setConstraints(value, c);
 			add(value);
 		}
+
+		public LaunchValue (GridBagLayout layout, int y, String text) {
+			this(layout, y, null, text);
+		}
 	}
 
 	class Battery extends LaunchStatus {
@@ -378,13 +396,13 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 				}
 			}
 			if (alt != AltosLib.MISSING) {
-				show("%4.0f m", state.gps.alt);
+				show(alt);
 				set_label(label);
 			} else
 				hide();
 		}
 		public PadAlt (GridBagLayout layout, int y) {
-			super (layout, y, "Pad Altitude");
+			super (layout, y, AltosConvert.height, "Pad Altitude");
 		}
 	}
 
@@ -403,17 +421,30 @@ public class AltosPad extends JComponent implements AltosFlightDisplay {
 		pad_alt.reset();
 	}
 
-	public void set_font() {
-		battery.set_font();
-		apogee.set_font();
-		main.set_font();
-		logging_ready.set_font();
-		gps_locked.set_font();
-		gps_ready.set_font();
-		receiver_battery.set_font();
-		pad_lat.set_font();
-		pad_lon.set_font();
-		pad_alt.set_font();
+	public void font_size_changed(int font_size) {
+		battery.font_size_changed(font_size);
+		apogee.font_size_changed(font_size);
+		main.font_size_changed(font_size);
+		logging_ready.font_size_changed(font_size);
+		gps_locked.font_size_changed(font_size);
+		gps_ready.font_size_changed(font_size);
+		receiver_battery.font_size_changed(font_size);
+		pad_lat.font_size_changed(font_size);
+		pad_lon.font_size_changed(font_size);
+		pad_alt.font_size_changed(font_size);
+	}
+
+	public void units_changed(boolean imperial_units) {
+		battery.units_changed(imperial_units);
+		apogee.units_changed(imperial_units);
+		main.units_changed(imperial_units);
+		logging_ready.units_changed(imperial_units);
+		gps_locked.units_changed(imperial_units);
+		gps_ready.units_changed(imperial_units);
+		receiver_battery.units_changed(imperial_units);
+		pad_lat.units_changed(imperial_units);
+		pad_lon.units_changed(imperial_units);
+		pad_alt.units_changed(imperial_units);
 	}
 
 	public void show(AltosState state, AltosListenerState listener_state) {