8173876: Fast precise scrolling and DeltaAccumulator fix for macOS Sierra 10.12.2

Reviewed-by: serb, alexsch

jdk/src/java.desktop/macosx/classes/sun/lwawt/macosx/CPlatformResponder.java

@@ -265,9 +265,8 @@ final class CPlatformResponder {
 
     static class DeltaAccumulator {
 
-        static final double MIN_THRESHOLD = 0.1;
-        static final double MAX_THRESHOLD = 0.5;
         double accumulatedDelta;
+        boolean accumulate;
 
         int getRoundedDelta(double delta, int scrollPhase) {
 
@@ -278,25 +277,23 @@ final class CPlatformResponder {
                     roundDelta = delta > 0 ? 1 : -1;
                 }
             } else { // trackpad
-                boolean begin = scrollPhase == NSEvent.SCROLL_PHASE_BEGAN;
+                if (scrollPhase == NSEvent.SCROLL_PHASE_BEGAN) {
-                boolean end = scrollPhase == NSEvent.SCROLL_MASK_PHASE_ENDED
-                        || scrollPhase == NSEvent.SCROLL_MASK_PHASE_CANCELLED;
-
-                if (begin) {
                     accumulatedDelta = 0;
+                    accumulate = true;
                 }
+                else if (scrollPhase == NSEvent.SCROLL_PHASE_MOMENTUM_BEGAN) {
+                    accumulate = true;
+                }
+                if (accumulate) {
 
                     accumulatedDelta += delta;
 
-                double absAccumulatedDelta = Math.abs(accumulatedDelta);
-                if (absAccumulatedDelta > MAX_THRESHOLD) {
                     roundDelta = (int) Math.round(accumulatedDelta);
-                    accumulatedDelta -= roundDelta;
-                }
 
-                if (end) {
+                    accumulatedDelta -= roundDelta;
-                    if (roundDelta == 0 && absAccumulatedDelta > MIN_THRESHOLD) {
+
-                        roundDelta = accumulatedDelta > 0 ? 1 : -1;
+                    if (scrollPhase == NSEvent.SCROLL_PHASE_ENDED) {
+                        accumulate = false;
                     }
                 }
             }

jdk/src/java.desktop/macosx/classes/sun/lwawt/macosx/NSEvent.java

@@ -36,8 +36,8 @@ final class NSEvent {
     static final int SCROLL_PHASE_UNSUPPORTED = 1;
     static final int SCROLL_PHASE_BEGAN = 2;
     static final int SCROLL_PHASE_CONTINUED = 3;
-    static final int SCROLL_MASK_PHASE_CANCELLED = 4;
+    static final int SCROLL_PHASE_MOMENTUM_BEGAN = 4;
-    static final int SCROLL_MASK_PHASE_ENDED = 5;
+    static final int SCROLL_PHASE_ENDED = 5;
 
     private int type;
     private int modifierFlags;

jdk/src/java.desktop/macosx/native/libawt_lwawt/awt/AWTView.m

@@ -382,6 +382,13 @@ static BOOL shouldUsePressAndHold() {
         clickCount = [event clickCount];
     }
 
+    jdouble deltaX = [event deltaX];
+    jdouble deltaY = [event deltaY];
+    if ([AWTToolkit hasPreciseScrollingDeltas: event]) {
+        deltaX = [event scrollingDeltaX] * 0.1;
+        deltaY = [event scrollingDeltaY] * 0.1;
+    }
+    
     static JNF_CLASS_CACHE(jc_NSEvent, "sun/lwawt/macosx/NSEvent");
     static JNF_CTOR_CACHE(jctor_NSEvent, jc_NSEvent, "(IIIIIIIIDDI)V");
     jobject jEvent = JNFNewObject(env, jctor_NSEvent,
@@ -391,8 +398,8 @@ static BOOL shouldUsePressAndHold() {
                                   [event buttonNumber],
                                   (jint)localPoint.x, (jint)localPoint.y,
                                   (jint)absP.x, (jint)absP.y,
-                                  [event deltaY],
+                                  deltaY,
-                                  [event deltaX],
+                                  deltaX,
                                   [AWTToolkit scrollStateWithEvent: event]);
     CHECK_NULL(jEvent);
     

jdk/src/java.desktop/macosx/native/libawt_lwawt/awt/CTrayIcon.m

@@ -140,6 +140,13 @@ static NSSize ScaledImageSizeForStatusBar(NSSize imageSize, BOOL autosize) {
 
     clickCount = [event clickCount];
 
+    jdouble deltaX = [event deltaX];
+    jdouble deltaY = [event deltaY];
+    if ([AWTToolkit hasPreciseScrollingDeltas: event]) {
+        deltaX = [event scrollingDeltaX] * 0.1;
+        deltaY = [event scrollingDeltaY] * 0.1;
+    }
+
     static JNF_CLASS_CACHE(jc_NSEvent, "sun/lwawt/macosx/NSEvent");
     static JNF_CTOR_CACHE(jctor_NSEvent, jc_NSEvent, "(IIIIIIIIDDI)V");
     jobject jEvent = JNFNewObject(env, jctor_NSEvent,
@@ -149,8 +156,8 @@ static NSSize ScaledImageSizeForStatusBar(NSSize imageSize, BOOL autosize) {
                                   [event buttonNumber],
                                   (jint)localPoint.x, (jint)localPoint.y,
                                   (jint)absP.x, (jint)absP.y,
-                                  [event deltaY],
+                                  deltaY,
-                                  [event deltaX],
+                                  deltaX,
                                   [AWTToolkit scrollStateWithEvent: event]);
     CHECK_NULL(jEvent);
 

jdk/src/java.desktop/macosx/native/libawt_lwawt/awt/LWCToolkit.h

@@ -42,6 +42,7 @@ extern jint* gButtonDownMasks;
 + (long) getEventCount;
 + (void) eventCountPlusPlus;
 + (jint) scrollStateWithEvent: (NSEvent*) event;
++ (BOOL) hasPreciseScrollingDeltas: (NSEvent*) event;
 @end
 
 /*

jdk/src/java.desktop/macosx/native/libawt_lwawt/awt/LWCToolkit.m

@@ -47,7 +47,7 @@
 #define SCROLL_PHASE_UNSUPPORTED 1
 #define SCROLL_PHASE_BEGAN 2
 #define SCROLL_PHASE_CONTINUED 3
-#define SCROLL_PHASE_CANCELLED 4
+#define SCROLL_PHASE_MOMENTUM_BEGAN 4
 #define SCROLL_PHASE_ENDED 5
 
 int gNumberOfButtons;
@@ -85,16 +85,33 @@ static long eventCount;
         return 0;
     }
     
-    NSEventPhase phase = [event phase];
+    if ([event phase]) {
-    NSEventPhase momentumPhase = [event momentumPhase];
+        // process a phase of manual scrolling
-    
+        switch ([event phase]) {
-    if (!phase && !momentumPhase) return SCROLL_PHASE_UNSUPPORTED;
-    switch (phase) {
             case NSEventPhaseBegan: return SCROLL_PHASE_BEGAN;
-        case NSEventPhaseCancelled: return SCROLL_PHASE_CANCELLED;
+            case NSEventPhaseCancelled: return SCROLL_PHASE_ENDED;
             case NSEventPhaseEnded: return SCROLL_PHASE_ENDED;
             default: return SCROLL_PHASE_CONTINUED;
         }
+    }
+
+    if ([event momentumPhase]) {
+        // process a phase of automatic scrolling
+        switch ([event momentumPhase]) {
+            case NSEventPhaseBegan: return SCROLL_PHASE_MOMENTUM_BEGAN;
+            case NSEventPhaseCancelled: return SCROLL_PHASE_ENDED;
+            case NSEventPhaseEnded: return SCROLL_PHASE_ENDED;
+            default: return SCROLL_PHASE_CONTINUED;
+        }
+    }
+    // phase and momentum phase both are not set
+    return SCROLL_PHASE_UNSUPPORTED;
+}
+
++ (BOOL) hasPreciseScrollingDeltas: (NSEvent*) event {
+    return [event type] == NSScrollWheel
+        && [event respondsToSelector:@selector(hasPreciseScrollingDeltas)]
+        && [event hasPreciseScrollingDeltas];
 }
 @end
 

jdk/test/javax/swing/plaf/basic/BasicScrollPaneUI/8166591/TooMuchWheelRotationEventsTest.java

@@ -40,7 +40,7 @@ import javax.swing.SwingUtilities;
 
 /*
  * @test
- * @bug 8166591
+ * @bug 8166591 8173876
  * @key headful
  * @summary [macos 10.12] Trackpad scrolling of text on OS X 10.12 Sierra
  *    is very fast (Trackpad, Retina only)