Bug 657648 Don't use high resolution scrolling when acceleration is e…

…nabled r=smaug
leto · May 18, 2011 · 2412735 · 2412735
1 parent 423502f
commit 2412735
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/content/events/src/nsEventStateManager.cpp b/content/events/src/nsEventStateManager.cpp
@@ -391,6 +391,7 @@ class nsMouseWheelTransaction {
   static PRInt32 AccelerateWheelDelta(PRInt32 aScrollLines,
                    PRBool aIsHorizontal, PRBool aAllowScrollSpeedOverride,
                    nsIScrollableFrame::ScrollUnit *aScrollQuantity);
+  static PRBool IsAccelerationEnabled();
 
   enum {
     kScrollSeriesTimeout = 80
@@ -651,6 +652,12 @@ nsMouseWheelTransaction::GetIgnoreMoveDelayTime()
     nsContentUtils::GetIntPref("mousewheel.transaction.ignoremovedelay", 100);
 }
 
+PRBool
+nsMouseWheelTransaction::IsAccelerationEnabled()
+{
+  return GetAccelerationStart() >= 0 && GetAccelerationFactor() > 0;
+}
+
 PRInt32
 nsMouseWheelTransaction::AccelerateWheelDelta(PRInt32 aScrollLines,
                            PRBool aIsHorizontal,
@@ -2651,6 +2658,12 @@ nsEventStateManager::DoScrollText(nsIFrame* aTargetFrame,
 
   if (!passToParent && frameToScroll) {
     if (aQueryEvent) {
+      // If acceleration is enabled, pixel scroll shouldn't be used for
+      // high resolution scrolling.
+      if (nsMouseWheelTransaction::IsAccelerationEnabled()) {
+        return NS_OK;
+      }
+
       nscoord appUnitsPerDevPixel =
         aTargetFrame->PresContext()->AppUnitsPerDevPixel();
       aQueryEvent->mReply.mLineHeight =