android: upgrade gestures and scrolling to newer code

Change-Id: I84b9f66036891f6ad384ee71d078c654511a6e38

3 files changed, 155 insertions, 159 deletions

diff --git a/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/Axis.java b/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/Axis.java
index 521e60a1ecd6..d5e3de87675e 100644
--- a/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/Axis.java
+++ b/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/Axis.java
@@ -1,45 +1,17 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla Android code.
- *
- * The Initial Developer of the Original Code is Mozilla Foundation.
- * Portions created by the Initial Developer are Copyright (C) 2012
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Patrick Walton <pcwalton@mozilla.com>
- *   Kartikaya Gupta <kgupta@mozilla.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko.ui;
 
+import android.util.Log;
+
+import org.json.JSONArray;
 import org.mozilla.gecko.util.FloatUtils;
 
+import java.util.Map;
+
 /**
  * This class represents the physics for one axis of movement (i.e. either
  * horizontal or vertical). It tracks the different properties of movement
@@ -47,25 +19,73 @@ import org.mozilla.gecko.util.FloatUtils;
  * a particular axis.
  */
 abstract class Axis {
+    private static final String LOGTAG = "GeckoAxis";
+
+    private static final String PREF_SCROLLING_FRICTION_SLOW = "ui.scrolling.friction_slow";
+    private static final String PREF_SCROLLING_FRICTION_FAST = "ui.scrolling.friction_fast";
+    private static final String PREF_SCROLLING_VELOCITY_THRESHOLD = "ui.scrolling.velocity_threshold";
+    private static final String PREF_SCROLLING_MAX_EVENT_ACCELERATION = "ui.scrolling.max_event_acceleration";
+    private static final String PREF_SCROLLING_OVERSCROLL_DECEL_RATE = "ui.scrolling.overscroll_decel_rate";
+    private static final String PREF_SCROLLING_OVERSCROLL_SNAP_LIMIT = "ui.scrolling.overscroll_snap_limit";
+    private static final String PREF_SCROLLING_MIN_SCROLLABLE_DISTANCE = "ui.scrolling.min_scrollable_distance";
+
     // This fraction of velocity remains after every animation frame when the velocity is low.
-    private static final float FRICTION_SLOW = 0.85f;
+    private static float FRICTION_SLOW;
     // This fraction of velocity remains after every animation frame when the velocity is high.
-    private static final float FRICTION_FAST = 0.97f;
+    private static float FRICTION_FAST;
     // Below this velocity (in pixels per frame), the friction starts increasing from FRICTION_FAST
     // to FRICTION_SLOW.
-    private static final float VELOCITY_THRESHOLD = 10.0f;
+    private static float VELOCITY_THRESHOLD;
     // The maximum velocity change factor between events, per ms, in %.
     // Direction changes are excluded.
-    private static final float MAX_EVENT_ACCELERATION = 0.012f;
+    private static float MAX_EVENT_ACCELERATION;
 
     // The rate of deceleration when the surface has overscrolled.
-    private static final float OVERSCROLL_DECEL_RATE = 0.04f;
+    private static float OVERSCROLL_DECEL_RATE;
     // The percentage of the surface which can be overscrolled before it must snap back.
-    private static final float SNAP_LIMIT = 0.75f;
+    private static float SNAP_LIMIT;
 
     // The minimum amount of space that must be present for an axis to be considered scrollable,
     // in pixels.
-    private static final float MIN_SCROLLABLE_DISTANCE = 0.5f;
+    private static float MIN_SCROLLABLE_DISTANCE;
+
+    private static float getFloatPref(Map<String, Integer> prefs, String prefName, int defaultValue) {
+        Integer value = (prefs == null ? null : prefs.get(prefName));
+        return (float)(value == null || value < 0 ? defaultValue : value) / 1000f;
+    }
+
+    private static int getIntPref(Map<String, Integer> prefs, String prefName, int defaultValue) {
+        Integer value = (prefs == null ? null : prefs.get(prefName));
+        return (value == null || value < 0 ? defaultValue : value);
+    }
+
+    static void addPrefNames(JSONArray prefs) {
+        prefs.put(PREF_SCROLLING_FRICTION_FAST);
+        prefs.put(PREF_SCROLLING_FRICTION_SLOW);
+        prefs.put(PREF_SCROLLING_VELOCITY_THRESHOLD);
+        prefs.put(PREF_SCROLLING_MAX_EVENT_ACCELERATION);
+        prefs.put(PREF_SCROLLING_OVERSCROLL_DECEL_RATE);
+        prefs.put(PREF_SCROLLING_OVERSCROLL_SNAP_LIMIT);
+        prefs.put(PREF_SCROLLING_MIN_SCROLLABLE_DISTANCE);
+    }
+
+    static void setPrefs(Map<String, Integer> prefs) {
+        FRICTION_SLOW = getFloatPref(prefs, PREF_SCROLLING_FRICTION_SLOW, 850);
+        FRICTION_FAST = getFloatPref(prefs, PREF_SCROLLING_FRICTION_FAST, 970);
+        VELOCITY_THRESHOLD = getIntPref(prefs, PREF_SCROLLING_VELOCITY_THRESHOLD, 10);
+        MAX_EVENT_ACCELERATION = getFloatPref(prefs, PREF_SCROLLING_MAX_EVENT_ACCELERATION, 12);
+        OVERSCROLL_DECEL_RATE = getFloatPref(prefs, PREF_SCROLLING_OVERSCROLL_DECEL_RATE, 40);
+        SNAP_LIMIT = getFloatPref(prefs, PREF_SCROLLING_OVERSCROLL_SNAP_LIMIT, 300);
+        MIN_SCROLLABLE_DISTANCE = getFloatPref(prefs, PREF_SCROLLING_MIN_SCROLLABLE_DISTANCE, 500);
+        Log.i(LOGTAG, "Prefs: " + FRICTION_SLOW + "," + FRICTION_FAST + "," + VELOCITY_THRESHOLD + ","
+                + MAX_EVENT_ACCELERATION + "," + OVERSCROLL_DECEL_RATE + "," + SNAP_LIMIT + "," + MIN_SCROLLABLE_DISTANCE);
+    }
+
+    static {
+        // set the scrolling parameters to default values on startup
+        setPrefs(null);
+    }
+
     // The number of milliseconds per frame assuming 60 fps
     private static final float MS_PER_FRAME = 1000.0f / 60.0f;
 
@@ -147,7 +167,7 @@ abstract class Axis {
     }
 
     private Overscroll getOverscroll() {
-        boolean minus = getOrigin() < 0.0f;
+        boolean minus = (getOrigin() < 0.0f);
         boolean plus = (getViewportEnd() > getPageLength());
         if (minus && plus) {
             return Overscroll.BOTH;
@@ -164,14 +184,10 @@ abstract class Axis {
     // overscrolled on this axis, returns 0.
     private float getExcess() {
         switch (getOverscroll()) {
-            case MINUS:
-                return -getOrigin();
-            case PLUS:
-                return getViewportEnd() - getPageLength();
-            case BOTH:
-                return getViewportEnd() - getPageLength() - getOrigin();
-            default:
-                return 0.0f;
+            case MINUS:     return -getOrigin();
+            case PLUS:      return getViewportEnd() - getPageLength();
+            case BOTH:      return getViewportEnd() - getPageLength() - getOrigin();
+            default:        return 0.0f;
         }
     }
 
@@ -180,7 +196,14 @@ abstract class Axis {
      * possible and this axis has not been scroll locked while panning. Otherwise, returns false.
      */
     private boolean scrollable() {
-        return getViewportLength() <= getPageLength() - MIN_SCROLLABLE_DISTANCE && !mScrollingDisabled;
+        // If we're scrolling a subdocument, ignore the viewport length restrictions (since those
+        // apply to the top-level document) and only take into account axis locking.
+        if (mSubscroller.scrolling()) {
+            return !mScrollingDisabled;
+        } else {
+            return getViewportLength() <= getPageLength() - MIN_SCROLLABLE_DISTANCE &&
+                    !mScrollingDisabled;
+        }
     }
 
     /*
@@ -257,8 +280,9 @@ abstract class Axis {
 
     // Performs displacement of the viewport position according to the current velocity.
     void displace() {
-        if (!mSubscroller.scrolling() && !scrollable())
+        if (!scrollable()) {
             return;
+        }
 
         if (mFlingState == FlingStates.PANNING)
             mDisplacement += (mLastTouchPos - mTouchPos) * getEdgeResistance();
diff --git a/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SimpleScaleGestureDetector.java b/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SimpleScaleGestureDetector.java
index 4f9e39857e81..6f920cafb218 100644
--- a/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SimpleScaleGestureDetector.java
+++ b/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SimpleScaleGestureDetector.java
@@ -1,47 +1,17 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla Android code.
- *
- * The Initial Developer of the Original Code is Mozilla Foundation.
- * Portions created by the Initial Developer are Copyright (C) 2012
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Patrick Walton <pcwalton@mozilla.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko.ui;
 
-import org.mozilla.gecko.gfx.PointUtils;
-import org.json.JSONException;
 import android.graphics.PointF;
 import android.util.Log;
 import android.view.MotionEvent;
+
+import org.json.JSONException;
+import org.mozilla.gecko.gfx.PointUtils;
+
 import java.util.LinkedList;
 import java.util.ListIterator;
 import java.util.Stack;
@@ -82,18 +52,18 @@ public class SimpleScaleGestureDetector {
     /** Forward touch events to this function. */
     public void onTouchEvent(MotionEvent event) {
         switch (event.getAction() & MotionEvent.ACTION_MASK) {
-            case MotionEvent.ACTION_DOWN:
-            case MotionEvent.ACTION_POINTER_DOWN:
-                onTouchStart(event);
-                break;
-            case MotionEvent.ACTION_MOVE:
-                onTouchMove(event);
-                break;
-            case MotionEvent.ACTION_POINTER_UP:
-            case MotionEvent.ACTION_UP:
-            case MotionEvent.ACTION_CANCEL:
-                onTouchEnd(event);
-                break;
+        case MotionEvent.ACTION_DOWN:
+        case MotionEvent.ACTION_POINTER_DOWN:
+            onTouchStart(event);
+            break;
+        case MotionEvent.ACTION_MOVE:
+            onTouchMove(event);
+            break;
+        case MotionEvent.ACTION_POINTER_UP:
+        case MotionEvent.ACTION_UP:
+        case MotionEvent.ACTION_CANCEL:
+            onTouchEnd(event);
+            break;
         }
     }
 
@@ -103,7 +73,7 @@ public class SimpleScaleGestureDetector {
 
     private int getActionIndex(MotionEvent event) {
         return (event.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK)
-                >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
+            >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
     }
 
     private void onTouchStart(MotionEvent event) {
@@ -131,11 +101,12 @@ public class SimpleScaleGestureDetector {
     private void onTouchEnd(MotionEvent event) {
         mLastEventTime = event.getEventTime();
 
+        boolean isCancel = (event.getAction() & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_CANCEL;
         int id = event.getPointerId(getActionIndex(event));
         ListIterator<PointerInfo> iterator = mPointerInfo.listIterator();
         while (iterator.hasNext()) {
             PointerInfo pointerInfo = iterator.next();
-            if (pointerInfo.getId() != id) {
+            if (!(isCancel || pointerInfo.getId() == id)) {
                 continue;
             }
 
@@ -156,11 +127,11 @@ public class SimpleScaleGestureDetector {
      */
     public float getFocusX() {
         switch (getPointersDown()) {
-            case 1:
-                return mPointerInfo.getFirst().getCurrent().x;
-            case 2:
-                PointerInfo pointerA = mPointerInfo.getFirst(), pointerB = mPointerInfo.getLast();
-                return (pointerA.getCurrent().x + pointerB.getCurrent().x) / 2.0f;
+        case 1:
+            return mPointerInfo.getFirst().getCurrent().x;
+        case 2:
+            PointerInfo pointerA = mPointerInfo.getFirst(), pointerB = mPointerInfo.getLast();
+            return (pointerA.getCurrent().x + pointerB.getCurrent().x) / 2.0f;
         }
 
         Log.e(LOGTAG, "No gesture taking place in getFocusX()!");
@@ -173,11 +144,11 @@ public class SimpleScaleGestureDetector {
      */
     public float getFocusY() {
         switch (getPointersDown()) {
-            case 1:
-                return mPointerInfo.getFirst().getCurrent().y;
-            case 2:
-                PointerInfo pointerA = mPointerInfo.getFirst(), pointerB = mPointerInfo.getLast();
-                return (pointerA.getCurrent().y + pointerB.getCurrent().y) / 2.0f;
+        case 1:
+            return mPointerInfo.getFirst().getCurrent().y;
+        case 2:
+            PointerInfo pointerA = mPointerInfo.getFirst(), pointerB = mPointerInfo.getLast();
+            return (pointerA.getCurrent().y + pointerB.getCurrent().y) / 2.0f;
         }
 
         Log.e(LOGTAG, "No gesture taking place in getFocusY()!");
@@ -225,9 +196,9 @@ public class SimpleScaleGestureDetector {
     /* Sends the requested scale gesture notification to the listener. */
     private void sendScaleGesture(EventType eventType) {
         switch (eventType) {
-            case BEGIN:     mListener.onScaleBegin(this);   break;
-            case CONTINUE:  mListener.onScale(this);        break;
-            case END:       mListener.onScaleEnd(this);     break;
+        case BEGIN:     mListener.onScaleBegin(this);   break;
+        case CONTINUE:  mListener.onScale(this);        break;
+        case END:       mListener.onScaleEnd(this);     break;
         }
     }
 
diff --git a/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SubdocumentScrollHelper.java b/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SubdocumentScrollHelper.java
index 30b4b30a5a99..8e7de558e18d 100644
--- a/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SubdocumentScrollHelper.java
+++ b/android/experimental/LOAndroid3/src/java/org/mozilla/gecko/ui/SubdocumentScrollHelper.java
@@ -1,74 +1,76 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla Android code.
- *
- * The Initial Developer of the Original Code is Mozilla Foundation.
- * Portions created by the Initial Developer are Copyright (C) 2012
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Kartikaya Gupta <kgupta@mozilla.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko.ui;
 
-
 import android.graphics.PointF;
 import android.os.Handler;
+import android.util.Log;
+
+import org.json.JSONException;
+import org.json.JSONObject;
 
-class SubdocumentScrollHelper  {
-    private static final String LOGTAG = SubdocumentScrollHelper.class.getSimpleName();
+class SubdocumentScrollHelper {
+    private static final String LOGTAG = "GeckoSubdocumentScrollHelper";
 
     private final PanZoomController mPanZoomController;
     private final Handler mUiHandler;
 
+    /* This is the amount of displacement we have accepted but not yet sent to JS; this is
+     * only valid when mOverrideScrollPending is true. */
+    private final PointF mPendingDisplacement;
+
+    /* When this is true, we're sending scroll events to JS to scroll the active subdocument. */
     private boolean mOverridePanning;
+
+    /* When this is true, we have received an ack for the last scroll event we sent to JS, and
+     * are ready to send the next scroll event. Note we only ever have one scroll event inflight
+     * at a time. */
     private boolean mOverrideScrollAck;
+
+    /* When this is true, we have a pending scroll that we need to send to JS; we were unable
+     * to send it when it was initially requested because mOverrideScrollAck was not true. */
     private boolean mOverrideScrollPending;
+
+    /* When this is true, the last scroll event we sent actually did some amount of scrolling on
+     * the subdocument; we use this to decide when we have reached the end of the subdocument. */
     private boolean mScrollSucceeded;
 
     SubdocumentScrollHelper(PanZoomController controller) {
         mPanZoomController = controller;
+        // mUiHandler will be bound to the UI thread since that's where this constructor runs
         mUiHandler = new Handler();
+        mPendingDisplacement = new PointF();
     }
 
     boolean scrollBy(PointF displacement) {
-        if (!mOverridePanning) {
+        if (! mOverridePanning) {
             return false;
         }
 
-        if (!mOverrideScrollAck) {
+        if (! mOverrideScrollAck) {
             mOverrideScrollPending = true;
+            mPendingDisplacement.x += displacement.x;
+            mPendingDisplacement.y += displacement.y;
             return true;
         }
 
+        JSONObject json = new JSONObject();
+        try {
+            json.put("x", displacement.x);
+            json.put("y", displacement.y);
+        } catch (JSONException e) {
+            Log.e(LOGTAG, "Error forming subwindow scroll message: ", e);
+        }
+
         mOverrideScrollAck = false;
         mOverrideScrollPending = false;
+        // clear the |mPendingDisplacement| after serializing |displacement| to
+        // JSON because they might be the same object
+        mPendingDisplacement.x = 0;
+        mPendingDisplacement.y = 0;
 
         return true;
     }
@@ -84,5 +86,4 @@ class SubdocumentScrollHelper  {
     boolean lastScrollSucceeded() {
         return mScrollSucceeded;
     }
-
 }