Changeset 181510 in webkit

Timestamp:

Mar 15, 2015, 12:13:36 PM (11 years ago)

Author:

Brent Fulgham

Message:

scroll snap points do not properly account for zoomed pages
​https://bugs.webkit.org/show_bug.cgi?id=142706
<rdar://problem/20165771>

Reviewed by Anders Carlsson.

When a WebView is zoomed (such that it has a non-unity pageScaleFactor), we need to account for this
scaling value when selecting our correct scroll snap point target, as well as when specifying the
pixel location for our animation to target.

• page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.h:
• page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm:

(WebCore::ScrollingTreeFrameScrollingNodeMac::pageScaleFactor): Added new delegate method.

• platform/cocoa/ScrollController.h:

(WebCore::ScrollControllerClient::pageScaleFactor): Added new default delegate.

• platform/cocoa/ScrollController.mm:

(WebCore::ScrollController::beginScrollSnapAnimation): Calculate the correct scroll target
based on the page scale factor.

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.h (modified) (1 diff)
• page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm (modified) (1 diff)
• platform/cocoa/ScrollController.h (modified) (1 diff)
• platform/cocoa/ScrollController.mm (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2015-03-15  Brent Fulgham  <bfulgham@apple.com>
+
+        scroll snap points do not properly account for zoomed pages
+        https://bugs.webkit.org/show_bug.cgi?id=142706
+        <rdar://problem/20165771>
+
+        Reviewed by Anders Carlsson.
+
+        When a WebView is zoomed (such that it has a non-unity pageScaleFactor), we need to account for this
+        scaling value when selecting our correct scroll snap point target, as well as when specifying the
+        pixel location for our animation to target.
+
+        * page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.h:
+        * page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm:
+        (WebCore::ScrollingTreeFrameScrollingNodeMac::pageScaleFactor): Added new delegate method.
+        * platform/cocoa/ScrollController.h:
+        (WebCore::ScrollControllerClient::pageScaleFactor): Added new default delegate.
+        * platform/cocoa/ScrollController.mm:
+        (WebCore::ScrollController::beginScrollSnapAnimation): Calculate the correct scroll target
+        based on the page scale factor.
+
 2015-03-15  Csaba Osztrogonác  <ossy@webkit.org>
 

trunk/Source/WebCore/page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.h

@@ -83 +83 @@
     LayoutUnit scrollOffsetOnAxis(ScrollEventAxis) const override;
     void immediateScrollOnAxis(ScrollEventAxis, float delta) override;
+    float pageScaleFactor() const override;
 #endif
 

trunk/Source/WebCore/page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm

@@ -559 +559 @@
     immediateScrollBy(change - currentPosition);
 }
+
+float ScrollingTreeFrameScrollingNodeMac::pageScaleFactor() const
+{
+    return frameScaleFactor();
+}
 #endif
 

trunk/Source/WebCore/platform/cocoa/ScrollController.h

@@ -87 +87 @@
     {
         // Override to perform client-specific scroll snap point end logic
-        
+    }
+
+    virtual float pageScaleFactor() const
+    {
+        return 1.0f;
     }
 #endif

trunk/Source/WebCore/platform/cocoa/ScrollController.mm

@@ -685 +685 @@
         return;
 
-    projectedScrollDestination = std::min(std::max(projectedScrollDestination, snapState.m_snapOffsets.first()), snapState.m_snapOffsets.last());
+    float scaleFactor = m_client->pageScaleFactor();
+    
+    projectedScrollDestination = std::min(std::max(LayoutUnit(projectedScrollDestination / scaleFactor), snapState.m_snapOffsets.first()), snapState.m_snapOffsets.last());
     snapState.m_initialOffset = offset;
-    snapState.m_targetOffset = closestSnapOffset<LayoutUnit, float>(snapState.m_snapOffsets, projectedScrollDestination, initialWheelDelta);
+    snapState.m_targetOffset = scaleFactor * closestSnapOffset<LayoutUnit, float>(snapState.m_snapOffsets, projectedScrollDestination, initialWheelDelta);
     if (snapState.m_initialOffset == snapState.m_targetOffset)
         return;