Bug 1174532 - Even if the APZC is not pannable, have a small slop area to consume touchmove events. r=botond

b2g/app/b2g.js

@@ -1028,6 +1028,10 @@ pref("apz.fling_friction", "0.0019");
 pref("apz.max_velocity_inches_per_ms", "0.07");
 pref("apz.touch_start_tolerance", "0.1");
 
+#ifdef MOZ_WIDGET_GONK
+pref("apz.touch_move_tolerance", "0.03");
+#endif
+
 // Tweak default displayport values to reduce the risk of running out of
 // memory when zooming in
 pref("apz.x_skate_size_multiplier", "1.25");

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -290,11 +290,19 @@ using mozilla::gfx::PointTyped;
  * \li\b apz.test.logging_enabled
  * Enable logging of APZ test data (see bug 961289).
  *
+ * \li\b apz.touch_move_tolerance
+ * See the description for apz.touch_start_tolerance below. This is a similar
+ * threshold, except it is used to suppress touchmove events from being delivered
+ * to content for NON-scrollable frames (or more precisely, for APZCs where
+ * ArePointerEventsConsumable returns false).\n
+ * Units: (real-world, i.e. screen) inches
+ *
  * \li\b apz.touch_start_tolerance
  * Constant describing the tolerance in distance we use, multiplied by the
  * device DPI, before we start panning the screen. This is to prevent us from
  * accidentally processing taps as touch moves, and from very short/accidental
- * touches moving the screen.\n
+ * touches moving the screen. touchmove events are also not delivered to content
+ * within this distance on scrollable frames.\n
  * Units: (real-world, i.e. screen) inches
  *
  * \li\b apz.use_paint_duration

gfx/layers/apz/src/InputBlockState.cpp

@@ -831,7 +831,8 @@ TouchBlockState::TouchActionAllowsPanningXY() const
 }
 
 bool
-TouchBlockState::UpdateSlopState(const MultiTouchInput& aInput)
+TouchBlockState::UpdateSlopState(const MultiTouchInput& aInput,
+                                 bool aApzcCanConsumeEvents)
 {
   if (aInput.mType == MultiTouchInput::MULTITOUCH_START) {
     // this is by definition the first event in this block. If it's the first
@@ -844,10 +845,12 @@ TouchBlockState::UpdateSlopState(const MultiTouchInput& aInput)
     return false;
   }
   if (mInSlop) {
+    ScreenCoord threshold = aApzcCanConsumeEvents
+        ? AsyncPanZoomController::GetTouchStartTolerance()
+        : ScreenCoord(gfxPrefs::APZTouchMoveTolerance() * APZCTreeManager::GetDPI());
     bool stayInSlop = (aInput.mType == MultiTouchInput::MULTITOUCH_MOVE) &&
         (aInput.mTouches.Length() == 1) &&
-        ((aInput.mTouches[0].mScreenPoint - mSlopOrigin).Length() <
-            AsyncPanZoomController::GetTouchStartTolerance());
+        ((aInput.mTouches[0].mScreenPoint - mSlopOrigin).Length() < threshold);
     if (!stayInSlop) {
       // we're out of the slop zone, and will stay out for the remainder of
       // this block

gfx/layers/apz/src/InputBlockState.h

@@ -434,11 +434,13 @@ public:
    * Notifies the input block of an incoming touch event so that the block can
    * update its internal slop state. "Slop" refers to the area around the
    * initial touchstart where we drop touchmove events so that content doesn't
-   * see them.
+   * see them. The |aApzcCanConsumeEvents| parameter is factored into how large
+   * the slop area is - if this is true the slop area is larger.
    * @return true iff the provided event is a touchmove in the slop area and
    *         so should not be sent to content.
    */
-  bool UpdateSlopState(const MultiTouchInput& aInput);
+  bool UpdateSlopState(const MultiTouchInput& aInput,
+                       bool aApzcCanConsumeEvents);
 
   bool HasEvents() const override;
   void DropEvents() override;

gfx/layers/apz/src/InputQueue.cpp

@@ -160,12 +160,15 @@ InputQueue::ReceiveTouchInput(const RefPtr<AsyncPanZoomController>& aTarget,
     INPQ_LOG("dropping event due to block %p being in fast motion\n", block);
     result = nsEventStatus_eConsumeNoDefault;
   } else if (target && target->ArePointerEventsConsumable(block, aEvent.AsMultiTouchInput().mTouches.Length())) {
-    if (block->UpdateSlopState(aEvent.AsMultiTouchInput())) {
+    if (block->UpdateSlopState(aEvent.AsMultiTouchInput(), true)) {
       INPQ_LOG("dropping event due to block %p being in slop\n", block);
       result = nsEventStatus_eConsumeNoDefault;
     } else {
       result = nsEventStatus_eConsumeDoDefault;
     }
+  } else if (block->UpdateSlopState(aEvent.AsMultiTouchInput(), false)) {
+    INPQ_LOG("dropping event due to block %p being in mini-slop\n", block);
+    result = nsEventStatus_eConsumeNoDefault;
   }
   if (!MaybeHandleCurrentBlock(block, aEvent)) {
     block->AddEvent(aEvent.AsMultiTouchInput());

gfx/thebes/gfxPrefs.h

@@ -181,6 +181,7 @@ private:
   DECL_GFX_PREF(Live, "apz.printtree",                         APZPrintTree, bool, false);
   DECL_GFX_PREF(Live, "apz.smooth_scroll_repaint_interval",    APZSmoothScrollRepaintInterval, int32_t, 75);
   DECL_GFX_PREF(Live, "apz.test.logging_enabled",              APZTestLoggingEnabled, bool, false);
+  DECL_GFX_PREF(Live, "apz.touch_move_tolerance",              APZTouchMoveTolerance, float, 0.0);
   DECL_GFX_PREF(Live, "apz.touch_start_tolerance",             APZTouchStartTolerance, float, 1.0f/4.5f);
   DECL_GFX_PREF(Live, "apz.use_paint_duration",                APZUsePaintDuration, bool, true);
   DECL_GFX_PREF(Live, "apz.velocity_bias",                     APZVelocityBias, float, 1.0f);

modules/libpref/init/all.js

@@ -588,6 +588,7 @@ pref("apz.printtree", false);
 
 pref("apz.test.logging_enabled", false);
 pref("apz.touch_start_tolerance", "0.2222222");  // 0.2222222 came from 1.0/4.5
+pref("apz.touch_move_tolerance", "0.0");
 pref("apz.use_paint_duration", true);
 pref("apz.velocity_bias", "1.0");
 pref("apz.velocity_relevance_time_ms", 150);