altosui/telegps: Reduce CPU time needed for flight displays

Don't update displays which aren't shown; track hierarchy changes to
trigger display from most recent state data.

Don't update values which haven't changed; remember previous values
and compare with new before updating widget contents.

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

1 files changed, 1 insertions, 2 deletions

diff --git a/altosuilib/AltosUIMapView.java b/altosuilib/AltosUIMapView.java
index 70198682..efae3767 100644
--- a/altosuilib/AltosUIMapView.java
+++ b/altosuilib/AltosUIMapView.java
@@ -28,7 +28,7 @@ import java.util.*;
 import java.util.concurrent.*;
 import org.altusmetrum.altoslib_4.*;
 
-public class AltosUIMapView extends Canvas implements MouseMotionListener, MouseListener, MouseWheelListener, ComponentListener, AltosUIMapTileListener, AltosUIMapStoreListener {
+public class AltosUIMapView extends Component implements MouseMotionListener, MouseListener, MouseWheelListener, ComponentListener, AltosUIMapTileListener, AltosUIMapStoreListener {
 
 	AltosUIMapPath	path = new AltosUIMapPath();
 
@@ -422,7 +422,6 @@ public class AltosUIMapView extends Canvas implements MouseMotionListener, Mouse
 	}
 
 	public void paint(Graphics g) {
-
 		VolatileImage	back_buffer = create_back_buffer();
 		do {
 			GraphicsConfiguration gc = getGraphicsConfiguration();