JBR-6452 Wayland: measure and improve surface buffer management

Improved rendering performance by
* reducing memory copy and making it more efficient,
* tying the next frame display to the frame event from Wayland,
  which dramatically reduces load for very quick Swing apps,
* limiting the number of buffers to 2.

src/java.desktop/unix/classes/sun/awt/wl/WLComponentPeer.java

@@ -82,6 +82,7 @@ public class WLComponentPeer implements ComponentPeer {
             {"hand"}, // HAND_CURSOR
             {"move"}, // MOVE_CURSOR
     };
+    private static final int WHEEL_SCROLL_AMOUNT = 3;
 
     private long nativePtr;
     private volatile boolean surfaceAssigned = false;
@@ -381,16 +382,17 @@ public Graphics getGraphics() {
      * Commits changes accumulated in the underlying SurfaceData object
      * to the server for displaying on the screen. The request may not be
      * granted immediately as the server may be busy reading data provided
-     * previously. In the latter case, the commit will happen later when
-     * the server notifies us (through an event on EDT) that the displaying
-     * buffer is ready to accept new data.
+     * previously. In the latter case, the commit will automatically happen
+     * later when the server notifies us (through an event on EDT) that
+     * the displaying buffer is ready to accept new data.
      */
     public void commitToServer() {
         performLocked(() -> {
             if (getWLSurface(nativePtr) != 0) {
                 surfaceData.flush();
             }
         });
+        Toolkit.getDefaultToolkit().sync();
     }
 
     public Component getTarget() {
@@ -1068,7 +1070,7 @@ void dispatchPointerEventInContext(WLPointerEvent e, WLInputState oldInputState,
                     isPopupTrigger,
                     MouseWheelEvent.WHEEL_UNIT_SCROLL,
                     1,
-                    e.getAxis0Value());
+                    Integer.signum(e.getAxis0Value()) * WHEEL_SCROLL_AMOUNT);
             postMouseEvent(mouseEvent);
         }
 

src/java.desktop/unix/classes/sun/awt/wl/WLToolkit.java

@@ -151,10 +151,7 @@ public class WLToolkit extends UNIXToolkit implements Runnable {
     @SuppressWarnings("removal")
     public WLToolkit() {
         AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
-            final String extraButtons = "sun.awt.enableExtraMouseButtons";
-            areExtraMouseButtonsEnabled =
-                    Boolean.parseBoolean(System.getProperty(extraButtons, "true"));
-            System.setProperty(extraButtons, String.valueOf(areExtraMouseButtonsEnabled));
+            initSystemProperties();
             return null;
         });
 
@@ -181,6 +178,13 @@ public WLToolkit() {
         }
     }
 
+    private static void initSystemProperties() {
+        final String extraButtons = "sun.awt.enableExtraMouseButtons";
+        areExtraMouseButtonsEnabled =
+                Boolean.parseBoolean(System.getProperty(extraButtons, "true"));
+        System.setProperty(extraButtons, String.valueOf(areExtraMouseButtonsEnabled));
+    }
+
     public static boolean isToolkitThread() {
         return Thread.currentThread() == toolkitThread;
     }
@@ -873,9 +877,9 @@ public boolean isAlwaysOnTopSupported() {
 
     @Override
     public boolean useBufferPerWindow() {
-        if (log.isLoggable(PlatformLogger.Level.FINE)) {
-            log.fine("Not implemented: WLToolkit.useBufferPerWindow()");
-        }
+        // TODO: this may depend on the rendering engine used.
+        // When rendering is performed into memory buffers shared with Wayland,
+        // there's no sense in having additional buffers in AWT/Swing.
         return false;
     }