Bug 907243 - Move SetDPI to APZCTreeManager. r=kats

browser/metro/profile/metro.js

@@ -36,6 +36,7 @@ pref("prompts.tab_modal.enabled", true);
 pref("layers.offmainthreadcomposition.enabled", true);
 pref("layers.async-pan-zoom.enabled", false);
 pref("layers.componentalpha.enabled", false);
+pref("gfx.azpc.touch_start_tolerance", "0.1"); // dpi * tolerance = pixel threshold
 pref("gfx.axis.fling_friction", "0.002");
 
 // Enable Microsoft TSF support by default for imes.

gfx/layers/composite/APZCTreeManager.cpp

@@ -25,6 +25,8 @@
 namespace mozilla {
 namespace layers {
 
+float APZCTreeManager::sDPI = 72.0;
+
 APZCTreeManager::APZCTreeManager()
     : mTreeLock("APZCTreeLock")
 {

gfx/layers/composite/APZCTreeManager.h

@@ -235,6 +235,17 @@ public:
    */
   void ClearTree();
 
+  /**
+   * Set the dpi value used by all AsyncPanZoomControllers.
+   * DPI defaults to 72 if not set using SetDPI() at any point.
+   */
+  static void SetDPI(float aDpiValue) { sDPI = aDpiValue; }
+
+  /**
+   * Returns the current dpi value in use.
+   */
+  static float GetDPI() { return sDPI; }
+
 protected:
   /**
    * Debug-build assertion that can be called to ensure code is running on the
@@ -292,6 +303,8 @@ private:
    * input delivery thread, and so does not require locking.
    */
   nsRefPtr<AsyncPanZoomController> mApzcForInputBlock;
+
+  static float sDPI;
 };
 
 }

gfx/layers/ipc/AsyncPanZoomController.cpp

@@ -212,7 +212,6 @@ AsyncPanZoomController::AsyncPanZoomController(uint64_t aLayersId,
      mLastAsyncScrollOffset(0, 0),
      mCurrentAsyncScrollOffset(0, 0),
      mAsyncScrollTimeoutTask(nullptr),
-     mDPI(72),
      mDisableNextTouchBatch(false),
      mHandlingTouchQueue(false),
      mDelayPanning(false)
@@ -222,8 +221,6 @@ AsyncPanZoomController::AsyncPanZoomController(uint64_t aLayersId,
   if (aGestures == USE_GESTURE_DETECTOR) {
     mGestureEventListener = new GestureEventListener(this);
   }
-
-  SetDPI(mDPI);
 }
 
 AsyncPanZoomController::~AsyncPanZoomController() {
@@ -432,7 +429,7 @@ nsEventStatus AsyncPanZoomController::OnTouchMove(const MultiTouchInput& aEvent)
       return nsEventStatus_eIgnore;
 
     case TOUCHING: {
-      float panThreshold = gTouchStartTolerance * mDPI;
+      float panThreshold = gTouchStartTolerance * APZCTreeManager::GetDPI();
       UpdateWithTouchAtDevicePoint(aEvent);
 
       if (PanDistance() < panThreshold) {
@@ -950,14 +947,6 @@ const CSSRect AsyncPanZoomController::CalculatePendingDisplayPort(
   return scrollableRect.ClampRect(shiftedDisplayPort) - scrollOffset;
 }
 
-void AsyncPanZoomController::SetDPI(int aDPI) {
-  mDPI = aDPI;
-}
-
-int AsyncPanZoomController::GetDPI() {
-  return mDPI;
-}
-
 void AsyncPanZoomController::ScheduleComposite() {
   if (mCompositorParent) {
     mCompositorParent->ScheduleRenderOnCompositorThread();

gfx/layers/ipc/AsyncPanZoomController.h

@@ -207,19 +207,6 @@ public:
    */
   ViewTransform GetCurrentAsyncTransform();
 
-  /**
-   * Sets the DPI of the device for use within panning and zooming logic. It is
-   * a platform responsibility to set this on initialization of this class and
-   * whenever it changes.
-   */
-  void SetDPI(int aDPI);
-
-  /**
-   * Gets the DPI of the device for use outside the panning and zooming logic.
-   * It defaults to 72 if not set using SetDPI() at any point.
-   */
-  int GetDPI();
-
   /**
    * Recalculates the displayport. Ideally, this should paint an area bigger
    * than the composite-to dimensions so that when you scroll down, you don't
@@ -590,8 +577,6 @@ private:
   // ensures the last mozbrowserasyncscroll event is always been fired.
   CancelableTask* mAsyncScrollTimeoutTask;
 
-  int mDPI;
-
   // Flag used to determine whether or not we should disable handling of the
   // next batch of touch events. This is used for sync scrolling of subframes.
   bool mDisableNextTouchBatch;

gfx/layers/ipc/GestureEventListener.cpp

@@ -108,7 +108,7 @@ nsEventStatus GestureEventListener::HandleInputEvent(const InputData& aEvent)
     ScreenIntPoint delta = event.mTouches[0].mScreenPoint - mTouchStartPosition;
     if (mTouches.Length() == 1 &&
         NS_hypot(delta.x, delta.y) >
-          mAsyncPanZoomController->GetDPI() * mAsyncPanZoomController->GetTouchStartTolerance())
+          APZCTreeManager::GetDPI() * mAsyncPanZoomController->GetTouchStartTolerance())
     {
       HandleTapCancel(event);
     }

widget/windows/winrt/MetroWidget.cpp

@@ -836,9 +836,11 @@ CompositorParent* MetroWidget::NewCompositorParent(int aSurfaceWidth, int aSurfa
   CompositorParent *compositor = nsBaseWidget::NewCompositorParent(aSurfaceWidth, aSurfaceHeight);
 
   if (ShouldUseAPZC()) {
-    CompositorParent::SetControllerForLayerTree(compositor->RootLayerTreeId(), this);
-    MetroWidget::sAPZC = CompositorParent::GetAPZCTreeManager(compositor->RootLayerTreeId());
     mRootLayerTreeId = compositor->RootLayerTreeId();
+    CompositorParent::SetControllerForLayerTree(mRootLayerTreeId, this);
+
+    MetroWidget::sAPZC = CompositorParent::GetAPZCTreeManager(compositor->RootLayerTreeId());
+    MetroWidget::sAPZC->SetDPI(GetDPI());
 
     nsresult rv;
     nsCOMPtr<nsIObserverService> observerService = do_GetService("@mozilla.org/observer-service;1", &rv);