1 /* 2 Copyright (C) 1997 Martin Jones (mjones (at) kde.org) 3 (C) 1998 Waldo Bastian (bastian (at) kde.org) 4 (C) 1998, 1999 Torben Weis (weis (at) kde.org) 5 (C) 1999 Lars Knoll (knoll (at) kde.org) 6 (C) 1999 Antti Koivisto (koivisto (at) kde.org) 7 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved. 8 9 This library is free software; you can redistribute it and/or 10 modify it under the terms of the GNU Library General Public 11 License as published by the Free Software Foundation; either 12 version 2 of the License, or (at your option) any later version. 13 14 This library is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 Library General Public License for more details. 18 19 You should have received a copy of the GNU Library General Public License 20 along with this library; see the file COPYING.LIB. If not, write to 21 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 22 Boston, MA 02110-1301, USA. 23 */ 24 25 #ifndef FrameView_h 26 #define FrameView_h 27 28 #include "core/frame/AdjustViewSizeOrNot.h" 29 #include "core/rendering/Pagination.h" 30 #include "core/rendering/PaintPhase.h" 31 #include "core/rendering/PartialLayoutState.h" 32 #include "platform/geometry/LayoutRect.h" 33 #include "platform/graphics/Color.h" 34 #include "platform/scroll/ScrollView.h" 35 #include "wtf/Forward.h" 36 #include "wtf/OwnPtr.h" 37 #include "wtf/text/WTFString.h" 38 39 namespace WebCore { 40 41 class AXObjectCache; 42 class Element; 43 class FloatSize; 44 class Frame; 45 class KURL; 46 class Node; 47 class Page; 48 class RenderBox; 49 class RenderEmbeddedObject; 50 class RenderObject; 51 class RenderScrollbarPart; 52 class RenderStyle; 53 54 Pagination::Mode paginationModeForRenderStyle(RenderStyle*); 55 56 typedef unsigned long long DOMTimeStamp; 57 58 class FrameView : public ScrollView { 59 public: 60 friend class RenderView; 61 friend class Internals; 62 63 static PassRefPtr<FrameView> create(Frame*); 64 static PassRefPtr<FrameView> create(Frame*, const IntSize& initialSize); 65 66 virtual ~FrameView(); 67 68 virtual HostWindow* hostWindow() const; 69 70 virtual void invalidateRect(const IntRect&); 71 virtual void setFrameRect(const IntRect&); 72 73 virtual bool scheduleAnimation(); 74 75 Frame& frame() const { return *m_frame; } 76 77 RenderView* renderView() const; 78 79 LayoutUnit marginWidth() const { return m_margins.width(); } // -1 means default 80 LayoutUnit marginHeight() const { return m_margins.height(); } // -1 means default 81 void setMarginWidth(LayoutUnit); 82 void setMarginHeight(LayoutUnit); 83 84 virtual void setCanHaveScrollbars(bool); 85 void updateCanHaveScrollbars(); 86 87 virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation); 88 89 virtual void setContentsSize(const IntSize&); 90 91 void layout(bool allowSubtree = true); 92 bool didFirstLayout() const; 93 void layoutTimerFired(Timer<FrameView>*); 94 void scheduleRelayout(); 95 void scheduleRelayoutOfSubtree(RenderObject*); 96 void unscheduleRelayout(); 97 bool layoutPending() const; 98 bool isInLayout() const { return m_inLayout; } 99 100 RenderObject* layoutRoot(bool onlyDuringLayout = false) const; 101 void clearLayoutRoot() { m_layoutRoot = 0; } 102 int layoutCount() const { return m_layoutCount; } 103 104 bool needsLayout() const; 105 void setNeedsLayout(); 106 void setViewportConstrainedObjectsNeedLayout(); 107 108 // Methods for getting/setting the size Blink should use to layout the contents. 109 IntSize layoutSize(IncludeScrollbarsInRect = ExcludeScrollbars) const; 110 void setLayoutSize(const IntSize&); 111 112 // If this is set to false, the layout size will need to be explicitly set by the owner. 113 // E.g. WebViewImpl sets its mainFrame's layout size manually 114 void setLayoutSizeFixedToFrameSize(bool isFixed) { m_layoutSizeFixedToFrameSize = isFixed; } 115 bool layoutSizeFixedToFrameSize() { return m_layoutSizeFixedToFrameSize; } 116 117 bool needsFullRepaint() const { return m_doFullRepaint; } 118 119 void serviceScriptedAnimations(double monotonicAnimationStartTime); 120 121 void updateCompositingLayersAfterStyleChange(); 122 void updateCompositingLayersAfterLayout(); 123 124 bool hasCompositedContent() const; 125 bool isEnclosedInCompositingLayer() const; 126 127 // Returns true when a paint with the PaintBehaviorFlattenCompositingLayers flag set gives 128 // a faithful representation of the content. 129 bool isSoftwareRenderable() const; 130 131 void resetScrollbars(); 132 void prepareForDetach(); 133 void detachCustomScrollbars(); 134 virtual void recalculateScrollbarOverlayStyle(); 135 136 void clear(); 137 138 bool isTransparent() const; 139 void setTransparent(bool isTransparent); 140 141 // True if the FrameView is not transparent, and the base background color is opaque. 142 bool hasOpaqueBackground() const; 143 144 Color baseBackgroundColor() const; 145 void setBaseBackgroundColor(const Color&); 146 void updateBackgroundRecursively(const Color&, bool); 147 148 bool shouldUpdateWhileOffscreen() const; 149 void setShouldUpdateWhileOffscreen(bool); 150 bool shouldUpdate() const; 151 152 void adjustViewSize(); 153 154 virtual IntRect windowClipRect(bool clipToContents = true) const; 155 IntRect windowClipRectForFrameOwner(const HTMLFrameOwnerElement*, bool clipToLayerContents) const; 156 157 virtual IntRect windowResizerRect() const; 158 159 virtual float visibleContentScaleFactor() const OVERRIDE { return m_visibleContentScaleFactor; } 160 void setVisibleContentScaleFactor(float); 161 162 virtual float inputEventsScaleFactor() const OVERRIDE; 163 virtual IntSize inputEventsOffsetForEmulation() const OVERRIDE; 164 void setInputEventsTransformForEmulation(const IntSize&, float); 165 166 virtual void setScrollPosition(const IntPoint&) OVERRIDE; 167 virtual void repaintFixedElementsAfterScrolling(); 168 virtual void updateFixedElementsAfterScrolling(); 169 virtual bool shouldRubberBandInDirection(ScrollDirection) const; 170 virtual bool isRubberBandInProgress() const OVERRIDE; 171 void setScrollPositionNonProgrammatically(const IntPoint&); 172 173 // This is different than visibleContentRect() in that it ignores negative (or overly positive) 174 // offsets from rubber-banding, and it takes zooming into account. 175 LayoutRect viewportConstrainedVisibleContentRect() const; 176 177 AtomicString mediaType() const; 178 void setMediaType(const AtomicString&); 179 void adjustMediaTypeForPrinting(bool printing); 180 181 void setCannotBlitToWindow(); 182 void setIsOverlapped(bool); 183 bool isOverlapped() const { return m_isOverlapped; } 184 bool isOverlappedIncludingAncestors() const; 185 void setContentIsOpaque(bool); 186 187 void addSlowRepaintObject(); 188 void removeSlowRepaintObject(); 189 bool hasSlowRepaintObjects() const { return m_slowRepaintObjectCount; } 190 191 // Includes fixed- and sticky-position objects. 192 typedef HashSet<RenderObject*> ViewportConstrainedObjectSet; 193 void addViewportConstrainedObject(RenderObject*); 194 void removeViewportConstrainedObject(RenderObject*); 195 const ViewportConstrainedObjectSet* viewportConstrainedObjects() const { return m_viewportConstrainedObjects.get(); } 196 bool hasViewportConstrainedObjects() const { return m_viewportConstrainedObjects && m_viewportConstrainedObjects->size() > 0; } 197 198 void handleLoadCompleted(); 199 void resetDeferredRepaintDelay(); 200 201 void updateAnnotatedRegions(); 202 void updateControlTints(); 203 204 void restoreScrollbar(); 205 206 void postLayoutTimerFired(Timer<FrameView>*); 207 208 bool wasScrolledByUser() const; 209 void setWasScrolledByUser(bool); 210 211 bool safeToPropagateScrollToParent() const { return m_safeToPropagateScrollToParent; } 212 void setSafeToPropagateScrollToParent(bool isSafe) { m_safeToPropagateScrollToParent = isSafe; } 213 214 void addWidgetToUpdate(RenderEmbeddedObject&); 215 216 virtual void paintContents(GraphicsContext*, const IntRect& damageRect); 217 void setPaintBehavior(PaintBehavior); 218 PaintBehavior paintBehavior() const; 219 bool isPainting() const; 220 bool hasEverPainted() const { return m_lastPaintTime; } 221 void setLastPaintTime(double lastPaintTime) { m_lastPaintTime = lastPaintTime; } 222 void setNodeToDraw(Node*); 223 224 virtual void paintOverhangAreas(GraphicsContext*, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect); 225 virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect); 226 virtual void paintScrollbar(GraphicsContext*, Scrollbar*, const IntRect&) OVERRIDE; 227 228 Color documentBackgroundColor() const; 229 230 static double currentFrameTimeStamp() { return s_currentFrameTimeStamp; } 231 232 void updateLayoutAndStyleIfNeededRecursive(); 233 234 void incrementVisuallyNonEmptyCharacterCount(unsigned); 235 void incrementVisuallyNonEmptyPixelCount(const IntSize&); 236 void setIsVisuallyNonEmpty() { m_isVisuallyNonEmpty = true; } 237 bool isVisuallyNonEmpty() const { return m_isVisuallyNonEmpty; } 238 void enableAutoSizeMode(bool enable, const IntSize& minSize, const IntSize& maxSize); 239 240 void forceLayout(bool allowSubtree = false); 241 void forceLayoutForPagination(const FloatSize& pageSize, const FloatSize& originalPageSize, float maximumShrinkFactor, AdjustViewSizeOrNot); 242 243 bool scrollToFragment(const KURL&); 244 bool scrollToAnchor(const String&); 245 void maintainScrollPositionAtAnchor(Node*); 246 void scrollElementToRect(Element*, const IntRect&); 247 248 // Methods to convert points and rects between the coordinate space of the renderer, and this view. 249 virtual IntRect convertFromRenderer(const RenderObject*, const IntRect&) const; 250 virtual IntRect convertToRenderer(const RenderObject*, const IntRect&) const; 251 virtual IntPoint convertFromRenderer(const RenderObject*, const IntPoint&) const; 252 virtual IntPoint convertToRenderer(const RenderObject*, const IntPoint&) const; 253 254 bool isFrameViewScrollCorner(RenderScrollbarPart* scrollCorner) const { return m_scrollCorner == scrollCorner; } 255 256 bool isScrollable(); 257 258 enum ScrollbarModesCalculationStrategy { RulesFromWebContentOnly, AnyRule }; 259 void calculateScrollbarModesForLayout(ScrollbarMode& hMode, ScrollbarMode& vMode, ScrollbarModesCalculationStrategy = AnyRule); 260 261 // Normal delay 262 static void setRepaintThrottlingDeferredRepaintDelay(double); 263 // Negative value would mean that first few repaints happen without a delay 264 static void setRepaintThrottlingnInitialDeferredRepaintDelayDuringLoading(double); 265 // The delay grows on each repaint to this maximum value 266 static void setRepaintThrottlingMaxDeferredRepaintDelayDuringLoading(double); 267 // On each repaint the delay increses by this amount 268 static void setRepaintThrottlingDeferredRepaintDelayIncrementDuringLoading(double); 269 270 virtual IntPoint lastKnownMousePosition() const; 271 bool shouldSetCursor() const; 272 273 void setCursor(const Cursor&); 274 275 virtual bool scrollbarsCanBeActive() const OVERRIDE; 276 277 // FIXME: Remove this method once plugin loading is decoupled from layout. 278 void flushAnyPendingPostLayoutTasks(); 279 280 virtual bool shouldSuspendScrollAnimations() const; 281 virtual void scrollbarStyleChanged(int newStyle, bool forceUpdate); 282 283 void setAnimatorsAreActive(); 284 285 RenderBox* embeddedContentBox() const; 286 287 void setTracksRepaints(bool); 288 bool isTrackingRepaints() const { return m_isTrackingRepaints; } 289 void resetTrackedRepaints(); 290 const Vector<IntRect>& trackedRepaintRects() const { return m_trackedRepaintRects; } 291 String trackedRepaintRectsAsText() const; 292 293 typedef HashSet<ScrollableArea*> ScrollableAreaSet; 294 // Returns whether the scrollable area has just been newly added. 295 bool addScrollableArea(ScrollableArea*); 296 // Returns whether the scrollable area has just been removed. 297 bool removeScrollableArea(ScrollableArea*); 298 bool containsScrollableArea(const ScrollableArea*) const; 299 const ScrollableAreaSet* scrollableAreas() const { return m_scrollableAreas.get(); } 300 301 // With CSS style "resize:" enabled, a little resizer handle will appear at the bottom 302 // right of the object. We keep track of these resizer areas for checking if touches 303 // (implemented using Scroll gesture) are targeting the resizer. 304 typedef HashSet<RenderBox*> ResizerAreaSet; 305 void addResizerArea(RenderBox*); 306 void removeResizerArea(RenderBox*); 307 const ResizerAreaSet* resizerAreas() const { return m_resizerAreas.get(); } 308 309 virtual void removeChild(Widget*) OVERRIDE; 310 311 // This function exists for ports that need to handle wheel events manually. 312 // On Mac WebKit1 the underlying NSScrollView just does the scrolling, but on most other platforms 313 // we need this function in order to do the scroll ourselves. 314 bool wheelEvent(const PlatformWheelEvent&); 315 316 // Page and FrameView both store a Pagination value. Page::pagination() is set only by API, 317 // and FrameView::pagination() is set only by CSS. Page::pagination() will affect all 318 // FrameViews in the page cache, but FrameView::pagination() only affects the current 319 // FrameView. FrameView::pagination() will return m_pagination if it has been set. Otherwise, 320 // it will return Page::pagination() since currently there are no callers that need to 321 // distinguish between the two. 322 const Pagination& pagination() const; 323 void setPagination(const Pagination&); 324 325 bool inProgrammaticScroll() const { return m_inProgrammaticScroll; } 326 void setInProgrammaticScroll(bool programmaticScroll) { m_inProgrammaticScroll = programmaticScroll; } 327 328 void setHasSoftwareFilters(bool hasSoftwareFilters) { m_hasSoftwareFilters = hasSoftwareFilters; } 329 bool hasSoftwareFilters() const { return m_hasSoftwareFilters; } 330 331 virtual bool isActive() const OVERRIDE; 332 333 // DEPRECATED: Use viewportConstrainedVisibleContentRect() instead. 334 IntSize scrollOffsetForFixedPosition() const; 335 336 PartialLayoutState& partialLayout() { return m_partialLayout; } 337 338 // Override scrollbar notifications to update the AXObject cache. 339 virtual void didAddScrollbar(Scrollbar*, ScrollbarOrientation) OVERRIDE; 340 virtual void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation) OVERRIDE; 341 342 class DeferredRepaintScope { 343 public: 344 DeferredRepaintScope(FrameView&); 345 ~DeferredRepaintScope(); 346 private: 347 RefPtr<FrameView> m_view; 348 }; 349 350 protected: 351 virtual bool scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect); 352 virtual void scrollContentsSlowPath(const IntRect& updateRect); 353 354 virtual bool isVerticalDocument() const; 355 virtual bool isFlippedDocument() const; 356 357 private: 358 explicit FrameView(Frame*); 359 360 void beginDeferredRepaints(); 361 void endDeferredRepaints(); 362 void flushDeferredRepaints(); 363 void startDeferredRepaintTimer(double delay); 364 365 void reset(); 366 void init(); 367 368 virtual void frameRectsChanged(); 369 virtual bool isFrameView() const OVERRIDE { return true; } 370 371 friend class RenderWidget; 372 bool useSlowRepaints(bool considerOverlap = true) const; 373 bool useSlowRepaintsIfNotOverlapped() const; 374 void updateCanBlitOnScrollRecursively(); 375 bool contentsInCompositedLayer() const; 376 377 void applyOverflowToViewport(RenderObject*, ScrollbarMode& hMode, ScrollbarMode& vMode); 378 void applyPaginationToViewport(); 379 380 void updateOverflowStatus(bool horizontalOverflow, bool verticalOverflow); 381 382 void paintControlTints(); 383 384 void updateCounters(); 385 void autoSizeIfEnabled(); 386 void forceLayoutParentViewIfNeeded(); 387 void performPreLayoutTasks(); 388 void performLayout(RenderObject* rootForThisLayout, bool inSubtreeLayout); 389 void scheduleOrPerformPostLayoutTasks(); 390 void performPostLayoutTasks(); 391 392 void repaintTree(RenderObject* root); 393 394 virtual void gatherDebugLayoutRects(RenderObject* layoutRoot); 395 396 virtual void repaintContentRectangle(const IntRect&); 397 virtual void contentsResized() OVERRIDE; 398 virtual void scrollbarExistenceDidChange(); 399 400 // Override ScrollView methods to do point conversion via renderers, in order to 401 // take transforms into account. 402 virtual IntRect convertToContainingView(const IntRect&) const OVERRIDE; 403 virtual IntRect convertFromContainingView(const IntRect&) const OVERRIDE; 404 virtual IntPoint convertToContainingView(const IntPoint&) const OVERRIDE; 405 virtual IntPoint convertFromContainingView(const IntPoint&) const OVERRIDE; 406 407 // ScrollableArea interface 408 virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) OVERRIDE; 409 virtual void getTickmarks(Vector<IntRect>&) const OVERRIDE; 410 virtual void scrollTo(const IntSize&) OVERRIDE; 411 virtual ScrollableArea* enclosingScrollableArea() const OVERRIDE; 412 virtual IntRect scrollableAreaBoundingBox() const OVERRIDE; 413 virtual bool scrollAnimatorEnabled() const OVERRIDE; 414 virtual bool usesCompositedScrolling() const OVERRIDE; 415 virtual GraphicsLayer* layerForScrolling() const OVERRIDE; 416 virtual GraphicsLayer* layerForHorizontalScrollbar() const OVERRIDE; 417 virtual GraphicsLayer* layerForVerticalScrollbar() const OVERRIDE; 418 virtual GraphicsLayer* layerForScrollCorner() const OVERRIDE; 419 420 void sendResizeEventIfNeeded(); 421 422 void updateScrollableAreaSet(); 423 424 virtual void notifyPageThatContentAreaWillPaint() const; 425 426 bool shouldUseLoadTimeDeferredRepaintDelay() const; 427 void deferredRepaintTimerFired(Timer<FrameView>*); 428 void doDeferredRepaints(); 429 void updateDeferredRepaintDelayAfterRepaint(); 430 double adjustedDeferredRepaintDelay() const; 431 432 void updateWidgetsTimerFired(Timer<FrameView>*); 433 bool updateWidgets(); 434 435 void scrollToAnchor(); 436 void scrollPositionChanged(); 437 438 bool hasCustomScrollbars() const; 439 bool shouldUseCustomScrollbars(Element*& customScrollbarElement, Frame*& customScrollbarFrame); 440 441 virtual void updateScrollCorner(); 442 443 FrameView* parentFrameView() const; 444 445 virtual AXObjectCache* axObjectCache() const; 446 void removeFromAXObjectCache(); 447 448 bool isMainFrame() const; 449 450 void setLayoutSizeInternal(const IntSize&); 451 452 static double s_currentFrameTimeStamp; // used for detecting decoded resource thrash in the cache 453 static bool s_inPaintContents; 454 455 LayoutSize m_size; 456 LayoutSize m_margins; 457 458 typedef HashSet<RefPtr<RenderEmbeddedObject> > EmbeddedObjectSet; 459 EmbeddedObjectSet m_widgetUpdateSet; 460 461 RefPtr<Frame> m_frame; 462 463 bool m_doFullRepaint; 464 465 bool m_canHaveScrollbars; 466 bool m_cannotBlitToWindow; 467 bool m_isOverlapped; 468 bool m_contentIsOpaque; 469 unsigned m_slowRepaintObjectCount; 470 int m_borderX; 471 int m_borderY; 472 473 Timer<FrameView> m_layoutTimer; 474 bool m_delayedLayout; 475 RenderObject* m_layoutRoot; 476 477 bool m_layoutSchedulingEnabled; 478 bool m_inLayout; 479 bool m_doingPreLayoutStyleUpdate; 480 bool m_inSynchronousPostLayout; 481 int m_layoutCount; 482 unsigned m_nestedLayoutCount; 483 Timer<FrameView> m_postLayoutTasksTimer; 484 Timer<FrameView> m_updateWidgetsTimer; 485 bool m_firstLayoutCallbackPending; 486 487 bool m_firstLayout; 488 bool m_isTransparent; 489 Color m_baseBackgroundColor; 490 IntSize m_lastViewportSize; 491 float m_lastZoomFactor; 492 493 AtomicString m_mediaType; 494 AtomicString m_mediaTypeWhenNotPrinting; 495 496 bool m_overflowStatusDirty; 497 bool m_horizontalOverflow; 498 bool m_verticalOverflow; 499 RenderObject* m_viewportRenderer; 500 501 Pagination m_pagination; 502 503 bool m_wasScrolledByUser; 504 bool m_inProgrammaticScroll; 505 bool m_safeToPropagateScrollToParent; 506 507 unsigned m_deferringRepaints; 508 unsigned m_repaintCount; 509 Vector<LayoutRect> m_repaintRects; 510 Timer<FrameView> m_deferredRepaintTimer; 511 double m_deferredRepaintDelay; 512 double m_lastPaintTime; 513 514 bool m_isTrackingRepaints; // Used for testing. 515 Vector<IntRect> m_trackedRepaintRects; 516 517 bool m_shouldUpdateWhileOffscreen; 518 519 RefPtr<Node> m_nodeToDraw; 520 PaintBehavior m_paintBehavior; 521 bool m_isPainting; 522 523 unsigned m_visuallyNonEmptyCharacterCount; 524 unsigned m_visuallyNonEmptyPixelCount; 525 bool m_isVisuallyNonEmpty; 526 bool m_firstVisuallyNonEmptyLayoutCallbackPending; 527 528 RefPtr<Node> m_maintainScrollPositionAnchor; 529 530 // Renderer to hold our custom scroll corner. 531 RenderScrollbarPart* m_scrollCorner; 532 533 // If true, automatically resize the frame view around its content. 534 bool m_shouldAutoSize; 535 bool m_inAutoSize; 536 // True if autosize has been run since m_shouldAutoSize was set. 537 bool m_didRunAutosize; 538 // The lower bound on the size when autosizing. 539 IntSize m_minAutoSize; 540 // The upper bound on the size when autosizing. 541 IntSize m_maxAutoSize; 542 543 OwnPtr<ScrollableAreaSet> m_scrollableAreas; 544 OwnPtr<ResizerAreaSet> m_resizerAreas; 545 OwnPtr<ViewportConstrainedObjectSet> m_viewportConstrainedObjects; 546 547 static double s_normalDeferredRepaintDelay; 548 static double s_initialDeferredRepaintDelayDuringLoading; 549 static double s_maxDeferredRepaintDelayDuringLoading; 550 static double s_deferredRepaintDelayIncrementDuringLoading; 551 552 bool m_hasSoftwareFilters; 553 554 float m_visibleContentScaleFactor; 555 IntSize m_inputEventsOffsetForEmulation; 556 float m_inputEventsScaleFactorForEmulation; 557 558 PartialLayoutState m_partialLayout; 559 IntSize m_layoutSize; 560 bool m_layoutSizeFixedToFrameSize; 561 }; 562 563 inline void FrameView::incrementVisuallyNonEmptyCharacterCount(unsigned count) 564 { 565 if (m_isVisuallyNonEmpty) 566 return; 567 m_visuallyNonEmptyCharacterCount += count; 568 // Use a threshold value to prevent very small amounts of visible content from triggering didFirstVisuallyNonEmptyLayout. 569 // The first few hundred characters rarely contain the interesting content of the page. 570 static const unsigned visualCharacterThreshold = 200; 571 if (m_visuallyNonEmptyCharacterCount > visualCharacterThreshold) 572 setIsVisuallyNonEmpty(); 573 } 574 575 inline void FrameView::incrementVisuallyNonEmptyPixelCount(const IntSize& size) 576 { 577 if (m_isVisuallyNonEmpty) 578 return; 579 m_visuallyNonEmptyPixelCount += size.width() * size.height(); 580 // Use a threshold value to prevent very small amounts of visible content from triggering didFirstVisuallyNonEmptyLayout 581 static const unsigned visualPixelThreshold = 32 * 32; 582 if (m_visuallyNonEmptyPixelCount > visualPixelThreshold) 583 setIsVisuallyNonEmpty(); 584 } 585 586 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView()); 587 588 } // namespace WebCore 589 590 #endif // FrameView_h 591
