Compute snap offsets according to CSS Scroll Snap Spec Level 1

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 176 matching lines @@
 #include "core/loader/NavigationScheduler.h"
 #include "core/loader/appcache/ApplicationCacheHost.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/EventWithHitTestResults.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/PointerLockController.h"
 #include "core/page/scrolling/RootScroller.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
+#include "core/page/scrolling/SnapCoordinator.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGScriptElement.h"
 #include "core/svg/SVGTitleElement.h"
 #include "core/svg/SVGUseElement.h"
 #include "core/timing/DOMWindowPerformance.h"
 #include "core/timing/Performance.h"
 #include "core/workers/SharedWorkerRepositoryClient.h"
 #include "core/xml/parser/XMLDocumentParser.h"
 #include "platform/DateComponents.h"
 #include "platform/EventDispatchForbiddenScope.h"
@@ skipping 1411 matching lines @@
         // Visible overflow on the viewport is meaningless, and the spec says to treat it as 'auto':
         if (overflowX == OverflowVisible)
             overflowX = OverflowAuto;
         if (overflowY == OverflowVisible)
             overflowY = OverflowAuto;
         // Column-gap is (ab)used by the current paged overflow implementation (in lack of other
         // ways to specify gaps between pages), so we have to propagate it too.
         columnGap = overflowStyle->columnGap();
     }
 
+    ScrollSnapType snapType = overflowStyle->getScrollSnapType();
+    const LengthPoint& snapDestination = overflowStyle->scrollSnapDestination();
+
     RefPtr<ComputedStyle> documentStyle = layoutView()->mutableStyle();
     if (documentStyle->getWritingMode() != rootWritingMode
         || documentStyle->direction() != rootDirection
         || documentStyle->visitedDependentColor(CSSPropertyBackgroundColor) != backgroundColor
         || documentStyle->backgroundLayers() != backgroundLayers
         || documentStyle->imageRendering() != imageRendering
         || documentStyle->overflowX() != overflowX
         || documentStyle->overflowY() != overflowY
-        || documentStyle->columnGap() != columnGap) {
+        || documentStyle->columnGap() != columnGap
+        || documentStyle->getScrollSnapType() != snapType
+        || documentStyle->scrollSnapDestination() != snapDestination) {
         RefPtr<ComputedStyle> newStyle = ComputedStyle::clone(*documentStyle);
         newStyle->setWritingMode(rootWritingMode);
         newStyle->setDirection(rootDirection);
         newStyle->setBackgroundColor(backgroundColor);
         newStyle->accessBackgroundLayers() = backgroundLayers;
         newStyle->setImageRendering(imageRendering);
         newStyle->setOverflowX(overflowX);
         newStyle->setOverflowY(overflowY);
         newStyle->setColumnGap(columnGap);
+        newStyle->setScrollSnapType(snapType);
+        newStyle->setScrollSnapDestination(snapDestination);
         layoutView()->setStyle(newStyle);
         setupFontBuilder(*newStyle);
     }
 
     if (body) {
         if (const ComputedStyle* style = body->computedStyle()) {
             if (style->direction() != rootDirection || style->getWritingMode() != rootWritingMode)
                 body->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::WritingModeChange));
         }
     }
@@ skipping 3857 matching lines @@
 void Document::setThreadedParsingEnabledForTesting(bool enabled)
 {
     s_threadedParsingEnabledForTesting = enabled;
 }
 
 bool Document::threadedParsingEnabledForTesting()
 {
     return s_threadedParsingEnabledForTesting;
 }
 
+SnapCoordinator* Document::snapCoordinator()
+{
+    if (RuntimeEnabledFeatures::cssScrollSnapPointsEnabled() && !m_snapCoordinator)
+        m_snapCoordinator = SnapCoordinator::create();
+
+    return m_snapCoordinator.get();
+}
+
 void Document::setContextFeatures(ContextFeatures& features)
 {
     m_contextFeatures = &features;
 }
 
 static LayoutObject* nearestCommonHoverAncestor(LayoutObject* obj1, LayoutObject* obj2)
 {
     if (!obj1 || !obj2)
         return 0;
 
@@ skipping 420 matching lines @@
     visitor->trace(m_templateDocument);
     visitor->trace(m_templateDocumentHost);
     visitor->trace(m_userActionElements);
     visitor->trace(m_svgExtensions);
     visitor->trace(m_timeline);
     visitor->trace(m_compositorPendingAnimations);
     visitor->trace(m_contextDocument);
     visitor->trace(m_canvasFontCache);
     visitor->trace(m_intersectionObserverController);
     visitor->trace(m_intersectionObserverData);
+    visitor->trace(m_snapCoordinator);
     Supplementable<Document>::trace(visitor);
     TreeScope::trace(visitor);
     ContainerNode::trace(visitor);
     ExecutionContext::trace(visitor);
     SecurityContext::trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(Document)
 {
     visitor->traceWrappers(m_importsController);
     ContainerNode::traceWrappers(visitor);
 }
 
 template class CORE_TEMPLATE_EXPORT Supplement<Document>;
 
 } // namespace blink
 
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().getString().utf8().data());
 }
 #endif