use smooth scrolling on Mac only by default

platform/core-api/src/com/intellij/ui/ComponentSettings.java

@@ -16,6 +16,7 @@
 package com.intellij.ui;
 
 import com.intellij.openapi.application.ApplicationManager;
+import com.intellij.openapi.util.SystemInfo;
 import com.intellij.openapi.util.registry.Registry;
 import com.intellij.openapi.util.registry.RegistryValue;
 import com.intellij.util.SystemProperties;
@@ -27,6 +28,9 @@ import java.awt.*;
  * IDE-agnostic component settings.
  */
 public class ComponentSettings {
+  private static final boolean SUPPORTED_JAVA = SystemInfo.isJetbrainsJvm || SystemInfo.isJavaVersionAtLeast("1.9");
+  private static final RegistryValue SUPPORTED = Registry.get("ide.scroll.precise");
+
   private static final RegistryValue HIGH_PRECISION_SCROLLING = Registry.get("idea.true.smooth.scrolling.high.precision");
 
   private static final RegistryValue PIXEL_PERFECT_SCROLLING = Registry.get("idea.true.smooth.scrolling.pixel.perfect");
@@ -57,7 +61,8 @@ public class ComponentSettings {
 
   // Returns whether "true smooth scrolling" is applicable to the particular component
   public boolean isTrueSmoothScrollingEligibleFor(Component component) {
-    return !ApplicationManager.getApplication().isUnitTestMode() &&
+    return isSmoothScrollingSupported() &&
+           !ApplicationManager.getApplication().isUnitTestMode() &&
            mySmoothScrollingEnabled &&
            !myRemoteDesktopConnected &&
            !myPowerSaveModeEnabled &&
@@ -65,6 +70,11 @@ public class ComponentSettings {
            component.isShowing();
   }
 
+  // Returns whether smooth scrolling supported
+  public boolean isSmoothScrollingSupported() {
+    return SUPPORTED.asBoolean() || (SUPPORTED_JAVA && SystemInfo.isMac);
+  }
+
   // Returns whether high-precision scrolling events are enabled
   public boolean isHighPrecisionScrollingEnabled() {
     return HIGH_PRECISION_SCROLLING.asBoolean();

platform/platform-api/src/com/intellij/ui/components/JBScrollBar.java

@@ -17,7 +17,6 @@ package com.intellij.ui.components;
 
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.SystemInfo;
-import com.intellij.openapi.util.registry.Registry;
 import com.intellij.openapi.wm.IdeGlassPane.TopComponent;
 import com.intellij.ui.ComponentSettings;
 import com.intellij.ui.InputSource;
@@ -54,7 +53,6 @@ public class JBScrollBar extends JScrollBar implements TopComponent, Interpolabl
   public static final Key<RegionPainter<Object>> TRACK = Key.create("JB_SCROLL_BAR_TRACK");
 
   private static final double THRESHOLD = 1D + 1E-5D;
-  private static final boolean SUPPORTED_JAVA = SystemInfo.isJetbrainsJvm || SystemInfo.isJavaVersionAtLeast("1.9");
   private final Interpolator myInterpolator = new Interpolator(this::getValue, this::setCurrentValue);
   private final Adjuster myAdjuster = new Adjuster(delta -> setValue(getTargetValue() + delta));
   private boolean isUnitIncrementSet;
@@ -245,44 +243,26 @@ public class JBScrollBar extends JScrollBar implements TopComponent, Interpolabl
     return Math.max(minDelta, Math.min(maxDelta, delta));
   }
 
-  /**
-   * Indicates whether MouseWheelEvent#getPreciseWheelRotation can be used to calculate an absolute scrolling delta.
-   *
-   * @return {@code true} if an absolute scrolling delta is supported, {@code false} otherwise
-   * @see #getPreciseDelta(MouseWheelEvent)
-   */
-  static boolean isAbsoluteDeltaSupported() {
-    ComponentSettings settings = ComponentSettings.getInstance();
-    if (SUPPORTED_JAVA && settings.isPixelPerfectScrollingEnabled()) {
-      if (SystemInfo.isMac && Registry.is("ide.scroll.precise.rotation.mac")) return true;
-      if (SystemInfo.isWindows && Registry.is("ide.scroll.precise.rotation.windows")) return true;
-    }
-    return false;
-  }
-
   /**
    * Calculates a scrolling delta from the specified event.
    *
    * @param event the mouse wheel event
    * @return a scrolling delta for this scrollbar
-   * @see #isAbsoluteDeltaSupported
    */
   private double getPreciseDelta(MouseWheelEvent event) {
     double rotation = event.getPreciseWheelRotation();
     ComponentSettings settings = ComponentSettings.getInstance();
-    if (SUPPORTED_JAVA && settings.isPixelPerfectScrollingEnabled()) {
+    if (settings.isPixelPerfectScrollingEnabled()) {
       // calculate an absolute delta if possible
-      if (SystemInfo.isMac && Registry.is("ide.scroll.precise.rotation.mac")) {
+      if (SystemInfo.isMac) {
         // Native code in our JDK for Mac uses 0.1 to convert pixels to units,
         // so we use 10 to restore amount of pixels to scroll.
         return 10 * rotation;
       }
-      if (SystemInfo.isWindows && Registry.is("ide.scroll.precise.rotation.windows")) {
-        JViewport viewport = getViewport();
-        Font font = viewport == null ? null : getViewFont(viewport);
-        int size = font == null ? JBUI.scale(10) : font.getSize(); // assume an unit size
-        return size * rotation * event.getScrollAmount();
-      }
+      JViewport viewport = getViewport();
+      Font font = viewport == null ? null : getViewFont(viewport);
+      int size = font == null ? JBUI.scale(10) : font.getSize(); // assume an unit size
+      return size * rotation * event.getScrollAmount();
     }
     if (settings.isHighPrecisionScrollingEnabled()) {
       // calculate a relative delta if possible

platform/platform-api/src/com/intellij/ui/components/JBScrollPane.java

@@ -713,36 +713,18 @@ public class JBScrollPane extends JScrollPane {
     if (event.isConsumed()) return false;
     // any rotation expected (forward or backward)
     boolean ignore = event.getWheelRotation() == 0;
-    if (ignore && (JBScrollBar.isAbsoluteDeltaSupported() || ComponentSettings.getInstance().isHighPrecisionScrollingEnabled())) {
-      double rotation = event.getPreciseWheelRotation();
-      ignore = rotation == 0.0D || !Double.isFinite(rotation);
+    if (ignore) {
+      ComponentSettings settings = ComponentSettings.getInstance();
+      if (settings.isSmoothScrollingSupported()) {
+        if (settings.isPixelPerfectScrollingEnabled() || settings.isHighPrecisionScrollingEnabled()) {
+          double rotation = event.getPreciseWheelRotation();
+          ignore = rotation == 0.0D || !Double.isFinite(rotation);
+        }
+      }
     }
     return !ignore && 0 == (SCROLL_MODIFIERS & event.getModifiers());
   }
 
-  /**
-   * Indicates whether we can use MouseWheelEvent#getPreciseWheelRotation to scroll.
-   *
-   * @deprecated will be removed after fixing a blit-scrolling
-   */
-  @Deprecated
-  @SuppressWarnings("DeprecatedIsStillUsed")
-  public static boolean isPreciseRotationSupported() {
-    if (PRECISE_ROTATION_SUPPORTED) {
-      if (SystemInfo.isMac) return Registry.is("ide.scroll.precise.rotation.mac");
-      if (SystemInfo.isWindows) return Registry.is("ide.scroll.precise.rotation.windows");
-    }
-    return false;
-  }
-
-  /**
-   * Indicates whether the system property "idea.true.smooth.scrolling" is not set to "true"
-   * (it is needed to avoid possible conflicts with another scrolling implementation)
-   * and the current JVM contains our fixes for MouseWheelEvent#getPreciseWheelRotation.
-   */
-  private static final boolean PRECISE_ROTATION_SUPPORTED = !isTrueSmoothScrollingEnabled() &&
-                                                            (SystemInfo.isJetbrainsJvm || SystemInfo.isJavaVersionAtLeast("1.9"));
-
   private static final int SCROLL_MODIFIERS = // event modifiers allowed during scrolling
     ~InputEvent.SHIFT_MASK & ~InputEvent.SHIFT_DOWN_MASK & // for horizontal scrolling
     ~InputEvent.BUTTON1_MASK & ~InputEvent.BUTTON1_DOWN_MASK; // for selection

platform/util/resources/misc/registry.properties

@@ -118,11 +118,8 @@ ide.splitter.mouseZone=6
 ide.autoscroll.from.source.delay=100
 ide.autoscroll.from.source.delay.description=Delay before performing the AutoscrollFromSource action
 
-ide.scroll.precise.rotation.mac=true
-ide.scroll.precise.rotation.mac.description=Use precise wheel rotation on Mac (may decrease scrolling performance).
-
-ide.scroll.precise.rotation.windows=false
-ide.scroll.precise.rotation.windows.description=Use precise wheel rotation on Windows (may decrease scrolling performance).
+ide.scroll.precise=false
+ide.scroll.precise.description=Use precise wheel rotation (may decrease scrolling performance).
 
 ide.scroll.default.unit.increment=false
 ide.scroll.default.unit.increment.description=Use default unit increment from Java (may decrease scrolling performance).