JBR-5274 recreate CGraphicsDevice if it was changed.

- AWT code heavily relies on reference comparison when updating graphics devices & configurations, so we need to actually re-create CGraphicsDevice if it was changed.

- Also do not rely on graphicsConfig.getDefaultTransform() when firing `graphicsContextScaleTransform` property change, as graphics devices are mutable and returned default transform may change over time, e.g. when device is invalidated.

src/java.desktop/macosx/classes/sun/awt/CGraphicsDevice.java

@@ -92,12 +92,14 @@ public final class CGraphicsDevice extends GraphicsDevice
             }
         }
 
-        // initializes default device state, might be redundant step since we
-        // call "displayChanged()" later anyway, but we do not want to leave the
-        // device in an inconsistent state after construction
+        // [JBR] we don't call displayChanged after creating a device, so call it here.
         displayChanged();
     }
 
+    int getDisplayID() {
+        return displayID;
+    }
+
     /**
      * Return a list of all configurations.
      */
@@ -175,6 +177,17 @@ public final class CGraphicsDevice extends GraphicsDevice
         //TODO configs?
     }
 
+    /**
+     * @return false if display parameters were changed, so we need to recreate the device.
+     */
+    boolean updateDevice() {
+        int s = scale;
+        double xr = xResolution, yr = yResolution;
+        var b = bounds;
+        displayChanged();
+        return s == scale && xr == xResolution && yr == yResolution && b.equals(bounds);
+    }
+
     public void displayParametersChanged() {
         Insets newScreenInsets = nativeGetScreenInsets(displayID);
         if (!newScreenInsets.equals(screenInsets)) {

src/java.desktop/macosx/classes/sun/awt/CGraphicsEnvironment.java

@@ -175,7 +175,8 @@ public final class CGraphicsEnvironment extends SunGraphicsEnvironment {
      */
     private void rebuildDevices() {
         initDevices();
-        displayChanged();
+        // Do not notify devices, this was already done in initDevices.
+        displayChanger.notifyListeners();
     }
 
     /**
@@ -232,8 +233,17 @@ public final class CGraphicsEnvironment extends SunGraphicsEnvironment {
             displayIDs = new int[]{mainDisplayID};
         }
         for (int id : displayIDs) {
-            devices.put(id, old.containsKey(id) ? old.remove(id)
-                                                : new CGraphicsDevice(id));
+            old.compute(id, (i, d) -> {
+                if (d != null && d.updateDevice()) {
+                    // Device didn't change -> reuse
+                    devices.put(i, d);
+                    return null;
+                } else {
+                    // Device changed -> create new
+                    devices.put(i, new CGraphicsDevice(i));
+                    return d;
+                }
+            });
         }
         // fetch the main display again, the old value might be outdated
         mainDisplayID = getMainDisplayID();
@@ -269,9 +279,12 @@ public final class CGraphicsEnvironment extends SunGraphicsEnvironment {
     }
 
     private CGraphicsDevice getSimilarDevice(CGraphicsDevice old) {
+        CGraphicsDevice sameId = devices.get(old.getDisplayID());
+        if (sameId != null) {
+            return sameId;
+        }
         for (CGraphicsDevice device : devices.values()) {
             if (device.getBounds().equals(old.getBounds())) {
-                // for now we will use the bounds only
                 return device;
             }
         }

src/java.desktop/share/classes/java/awt/Component.java

@@ -351,6 +351,13 @@ public abstract class Component implements ImageObserver, MenuContainer,
      */
     private transient volatile GraphicsConfiguration graphicsConfig;
 
+    /**
+     * Last observed value of {@code graphicsConfig.getDefaultTransform()}.
+     * Used for firing 'graphicsContextScaleTransform' property change,
+     * as values returned by {@link #graphicsConfig} may change over time.
+     */
+    private transient volatile AffineTransform lastGraphicsConfigTransform;
+
     /**
      * A reference to a {@code BufferStrategy} object
      * used to manipulate the buffers on this component.
@@ -1207,13 +1214,17 @@ public abstract class Component implements ImageObserver, MenuContainer,
             return false;
         }
 
-        AffineTransform tx = graphicsConfig != null ? graphicsConfig.getDefaultTransform() : new AffineTransform();
+        AffineTransform tx = lastGraphicsConfigTransform;
         AffineTransform newTx = gc != null ? gc.getDefaultTransform() : new AffineTransform();
         graphicsConfig = gc;
-        if (tx.getScaleX() != newTx.getScaleX() ||
-            tx.getScaleY() != newTx.getScaleY())
+        // We cannot rely on graphicsConfig.getDefaultTransform(),
+        // because its device might have been invalidated and now
+        // reports different scale than it did before.
+        if (!newTx.equals(lastGraphicsConfigTransform))
         {
-            firePropertyChange("graphicsContextScaleTransform", tx, newTx);
+            lastGraphicsConfigTransform = newTx;
+            firePropertyChange("graphicsContextScaleTransform",
+                    tx != null ? tx : new AffineTransform(), newTx);
         }
 
         ComponentPeer peer = this.peer;