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      1 /*
      2  * Copyright (C) 2004, 2006, 2007, 2008 Apple Inc. All rights reserved.
      3  * Copyright (C) 2009 Holger Hans Peter Freyther
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #ifndef ScrollView_h
     28 #define ScrollView_h
     29 
     30 #include "platform/PlatformExport.h"
     31 #include "platform/Widget.h"
     32 #include "platform/geometry/IntRect.h"
     33 #include "platform/scroll/ScrollTypes.h"
     34 #include "platform/scroll/ScrollableArea.h"
     35 #include "platform/scroll/Scrollbar.h"
     36 
     37 #include "wtf/HashSet.h"
     38 #include "wtf/TemporaryChange.h"
     39 
     40 namespace WebCore {
     41 
     42 class HostWindow;
     43 class Scrollbar;
     44 
     45 class PLATFORM_EXPORT ScrollView : public Widget, public ScrollableArea {
     46 public:
     47     virtual ~ScrollView();
     48 
     49     // ScrollableArea functions.
     50     virtual int scrollSize(ScrollbarOrientation) const OVERRIDE;
     51     virtual void setScrollOffset(const IntPoint&) OVERRIDE;
     52     virtual bool isScrollCornerVisible() const OVERRIDE;
     53     virtual void scrollbarStyleChanged() OVERRIDE;
     54     virtual bool userInputScrollable(ScrollbarOrientation) const OVERRIDE;
     55     virtual bool shouldPlaceVerticalScrollbarOnLeft() const OVERRIDE;
     56 
     57     virtual void notifyPageThatContentAreaWillPaint() const;
     58 
     59     // NOTE: This should only be called by the overriden setScrollOffset from ScrollableArea.
     60     virtual void scrollTo(const IntSize& newOffset);
     61 
     62     // The window thats hosts the ScrollView. The ScrollView will communicate scrolls and repaints to the
     63     // host window in the window's coordinate space.
     64     virtual HostWindow* hostWindow() const = 0;
     65 
     66     // Returns a clip rect in host window coordinates. Used to clip the blit on a scroll.
     67     virtual IntRect windowClipRect(IncludeScrollbarsInRect = ExcludeScrollbars) const = 0;
     68 
     69     // Functions for child manipulation and inspection.
     70     const HashSet<RefPtr<Widget> >* children() const { return &m_children; }
     71     virtual void addChild(PassRefPtr<Widget>);
     72     virtual void removeChild(Widget*);
     73 
     74     // If the scroll view does not use a native widget, then it will have cross-platform Scrollbars. These functions
     75     // can be used to obtain those scrollbars.
     76     virtual Scrollbar* horizontalScrollbar() const OVERRIDE { return m_horizontalScrollbar.get(); }
     77     virtual Scrollbar* verticalScrollbar() const OVERRIDE { return m_verticalScrollbar.get(); }
     78     bool isScrollViewScrollbar(const Widget* child) const { return horizontalScrollbar() == child || verticalScrollbar() == child; }
     79 
     80     void positionScrollbarLayers();
     81 
     82     // Functions for setting and retrieving the scrolling mode in each axis (horizontal/vertical). The mode has values of
     83     // AlwaysOff, AlwaysOn, and Auto. AlwaysOff means never show a scrollbar, AlwaysOn means always show a scrollbar.
     84     // Auto means show a scrollbar only when one is needed.
     85     // Note that for platforms with native widgets, these modes are considered advisory. In other words the underlying native
     86     // widget may choose not to honor the requested modes.
     87     void setScrollbarModes(ScrollbarMode horizontalMode, ScrollbarMode verticalMode, bool horizontalLock = false, bool verticalLock = false);
     88     void setHorizontalScrollbarMode(ScrollbarMode mode, bool lock = false) { setScrollbarModes(mode, verticalScrollbarMode(), lock, verticalScrollbarLock()); }
     89     void setVerticalScrollbarMode(ScrollbarMode mode, bool lock = false) { setScrollbarModes(horizontalScrollbarMode(), mode, horizontalScrollbarLock(), lock); };
     90     void scrollbarModes(ScrollbarMode& horizontalMode, ScrollbarMode& verticalMode) const;
     91     ScrollbarMode horizontalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return horizontal; }
     92     ScrollbarMode verticalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return vertical; }
     93 
     94     void setHorizontalScrollbarLock(bool lock = true) { m_horizontalScrollbarLock = lock; }
     95     bool horizontalScrollbarLock() const { return m_horizontalScrollbarLock; }
     96     void setVerticalScrollbarLock(bool lock = true) { m_verticalScrollbarLock = lock; }
     97     bool verticalScrollbarLock() const { return m_verticalScrollbarLock; }
     98 
     99     void setScrollingModesLock(bool lock = true) { m_horizontalScrollbarLock = m_verticalScrollbarLock = lock; }
    100 
    101     virtual void setCanHaveScrollbars(bool);
    102     bool canHaveScrollbars() const { return horizontalScrollbarMode() != ScrollbarAlwaysOff || verticalScrollbarMode() != ScrollbarAlwaysOff; }
    103 
    104     // By default you only receive paint events for the area that is visible. In the case of using a
    105     // tiled backing store, this function can be set, so that the view paints the entire contents.
    106     bool paintsEntireContents() const { return m_paintsEntireContents; }
    107     void setPaintsEntireContents(bool);
    108 
    109     // By default, paint events are clipped to the visible area.  If set to
    110     // false, paint events are no longer clipped.  paintsEntireContents() implies !clipsRepaints().
    111     bool clipsPaintInvalidations() const { return m_clipsRepaints; }
    112     void setClipsRepaints(bool);
    113 
    114     // Overridden by FrameView to create custom CSS scrollbars if applicable.
    115     virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
    116 
    117     virtual bool shouldAttemptToScrollUsingFastPath() const;
    118 
    119     // The visible content rect has a location that is the scrolled offset of the document. The width and height are the viewport width
    120     // and height. By default the scrollbars themselves are excluded from this rectangle, but an optional boolean argument allows them to be
    121     // included.
    122     virtual IntRect visibleContentRect(IncludeScrollbarsInRect = ExcludeScrollbars) const OVERRIDE;
    123     IntSize visibleSize() const { return visibleContentRect().size(); }
    124     virtual int visibleWidth() const OVERRIDE FINAL { return visibleContentRect().width(); }
    125     virtual int visibleHeight() const OVERRIDE FINAL { return visibleContentRect().height(); }
    126 
    127     // visibleContentRect().size() is computed from unscaledVisibleContentSize() divided by the value of visibleContentScaleFactor.
    128     // For the main frame, visibleContentScaleFactor is equal to the page's pageScaleFactor; it's 1 otherwise.
    129     IntSize unscaledVisibleContentSize(IncludeScrollbarsInRect = ExcludeScrollbars) const;
    130     virtual float visibleContentScaleFactor() const { return 1; }
    131 
    132     // Offset used to convert incoming input events while emulating device metics.
    133     virtual IntSize inputEventsOffsetForEmulation() const { return IntSize(); }
    134 
    135     // Scale used to convert incoming input events. Usually the same as visibleContentScaleFactor(), unless specifically changed.
    136     virtual float inputEventsScaleFactor() const { return visibleContentScaleFactor(); }
    137 
    138     // Functions for getting/setting the size of the document contained inside the ScrollView (as an IntSize or as individual width and height
    139     // values).
    140     virtual IntSize contentsSize() const OVERRIDE; // Always at least as big as the visibleWidth()/visibleHeight().
    141     int contentsWidth() const { return contentsSize().width(); }
    142     int contentsHeight() const { return contentsSize().height(); }
    143     virtual void setContentsSize(const IntSize&);
    144 
    145     // Functions for querying the current scrolled position (both as a point, a size, or as individual X and Y values).
    146     virtual IntPoint scrollPosition() const OVERRIDE { return visibleContentRect().location(); }
    147     IntSize scrollOffset() const { return toIntSize(visibleContentRect().location()); } // Gets the scrolled position as an IntSize. Convenient for adding to other sizes.
    148     IntSize pendingScrollDelta() const { return m_pendingScrollDelta; }
    149     virtual IntPoint maximumScrollPosition() const OVERRIDE; // The maximum position we can be scrolled to.
    150     virtual IntPoint minimumScrollPosition() const OVERRIDE; // The minimum position we can be scrolled to.
    151     // Adjust the passed in scroll position to keep it between the minimum and maximum positions.
    152     IntPoint adjustScrollPositionWithinRange(const IntPoint&) const;
    153     int scrollX() const { return scrollPosition().x(); }
    154     int scrollY() const { return scrollPosition().y(); }
    155 
    156     virtual IntSize overhangAmount() const OVERRIDE;
    157 
    158     void cacheCurrentScrollPosition() { m_cachedScrollPosition = scrollPosition(); }
    159     IntPoint cachedScrollPosition() const { return m_cachedScrollPosition; }
    160 
    161     // Functions for scrolling the view.
    162     virtual void setScrollPosition(const IntPoint&);
    163     void scrollBy(const IntSize& s) { return setScrollPosition(scrollPosition() + s); }
    164 
    165     bool scroll(ScrollDirection, ScrollGranularity);
    166 
    167     // Scroll the actual contents of the view (either blitting or invalidating as needed).
    168     void scrollContents(const IntSize& scrollDelta);
    169 
    170     // This gives us a means of blocking painting on our scrollbars until the first layout has occurred.
    171     void setScrollbarsSuppressed(bool suppressed, bool repaintOnUnsuppress = false);
    172     bool scrollbarsSuppressed() const { return m_scrollbarsSuppressed; }
    173 
    174     IntPoint rootViewToContents(const IntPoint&) const;
    175     IntPoint contentsToRootView(const IntPoint&) const;
    176     IntRect rootViewToContents(const IntRect&) const;
    177     IntRect contentsToRootView(const IntRect&) const;
    178 
    179     // Event coordinates are assumed to be in the coordinate space of a window that contains
    180     // the entire widget hierarchy. It is up to the platform to decide what the precise definition
    181     // of containing window is. (For example on Mac it is the containing NSWindow.)
    182     IntPoint windowToContents(const IntPoint&) const;
    183     FloatPoint windowToContents(const FloatPoint&) const;
    184     IntPoint contentsToWindow(const IntPoint&) const;
    185     IntRect windowToContents(const IntRect&) const;
    186     IntRect contentsToWindow(const IntRect&) const;
    187 
    188     // Functions for converting to screen coordinates.
    189     IntRect contentsToScreen(const IntRect&) const;
    190 
    191     // These functions are used to enable scrollbars to avoid window resizer controls that overlap the scroll view. This happens on Mac
    192     // for example.
    193     virtual IntRect windowResizerRect() const { return IntRect(); }
    194     bool containsScrollbarsAvoidingResizer() const;
    195     void adjustScrollbarsAvoidingResizerCount(int overlapDelta);
    196     void windowResizerRectChanged();
    197 
    198     virtual void setParent(Widget*) OVERRIDE; // Overridden to update the overlapping scrollbar count.
    199 
    200     // Called when our frame rect changes (or the rect/scroll position of an ancestor changes).
    201     virtual void frameRectsChanged() OVERRIDE;
    202 
    203     // Widget override to update our scrollbars and notify our contents of the resize.
    204     virtual void setFrameRect(const IntRect&) OVERRIDE;
    205 
    206     // For platforms that need to hit test scrollbars from within the engine's event handlers (like Win32).
    207     Scrollbar* scrollbarAtPoint(const IntPoint& windowPoint);
    208 
    209     virtual IntPoint convertChildToSelf(const Widget* child, const IntPoint& point) const OVERRIDE
    210     {
    211         IntPoint newPoint = point;
    212         if (!isScrollViewScrollbar(child))
    213             newPoint = point - scrollOffset();
    214         newPoint.moveBy(child->location());
    215         return newPoint;
    216     }
    217 
    218     virtual IntPoint convertSelfToChild(const Widget* child, const IntPoint& point) const OVERRIDE
    219     {
    220         IntPoint newPoint = point;
    221         if (!isScrollViewScrollbar(child))
    222             newPoint = point + scrollOffset();
    223         newPoint.moveBy(-child->location());
    224         return newPoint;
    225     }
    226 
    227     // Widget override. Handles painting of the contents of the view as well as the scrollbars.
    228     virtual void paint(GraphicsContext*, const IntRect&) OVERRIDE;
    229     void paintScrollbars(GraphicsContext*, const IntRect&);
    230 
    231     // Widget overrides to ensure that our children's visibility status is kept up to date when we get shown and hidden.
    232     virtual void show() OVERRIDE;
    233     virtual void hide() OVERRIDE;
    234     virtual void setParentVisible(bool) OVERRIDE;
    235 
    236     // Pan scrolling.
    237     static const int noPanScrollRadius = 15;
    238     void addPanScrollIcon(const IntPoint&);
    239     void removePanScrollIcon();
    240     void paintPanScrollIcon(GraphicsContext*);
    241 
    242     virtual bool isPointInScrollbarCorner(const IntPoint&);
    243     virtual bool scrollbarCornerPresent() const;
    244     virtual IntRect scrollCornerRect() const OVERRIDE;
    245     virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
    246     virtual void paintScrollbar(GraphicsContext*, Scrollbar*, const IntRect&);
    247 
    248     virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const OVERRIDE;
    249     virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const OVERRIDE;
    250     virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const OVERRIDE;
    251     virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const OVERRIDE;
    252 
    253     void calculateAndPaintOverhangAreas(GraphicsContext*, const IntRect& dirtyRect);
    254     void calculateAndPaintOverhangBackground(GraphicsContext*, const IntRect& dirtyRect);
    255 
    256     virtual bool isScrollView() const OVERRIDE FINAL { return true; }
    257 
    258 protected:
    259     ScrollView();
    260 
    261     virtual void contentRectangleForPaintInvalidation(const IntRect&);
    262     virtual void paintContents(GraphicsContext*, const IntRect& damageRect) = 0;
    263 
    264     virtual void paintOverhangAreas(GraphicsContext*, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect);
    265 
    266     virtual void scrollbarExistenceDidChange() = 0;
    267     // These functions are used to create/destroy scrollbars.
    268     void setHasHorizontalScrollbar(bool);
    269     void setHasVerticalScrollbar(bool);
    270 
    271     virtual void updateScrollCorner();
    272     virtual void invalidateScrollCornerRect(const IntRect&) OVERRIDE;
    273 
    274     virtual void scrollContentsIfNeeded();
    275     // Scroll the content by blitting the pixels.
    276     virtual bool scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect);
    277     // Scroll the content by invalidating everything.
    278     virtual void scrollContentsSlowPath(const IntRect& updateRect);
    279 
    280     void setScrollOrigin(const IntPoint&, bool updatePositionAtAll, bool updatePositionSynchronously);
    281 
    282     // Subclassed by FrameView to check the writing-mode of the document.
    283     virtual bool isVerticalDocument() const { return true; }
    284     virtual bool isFlippedDocument() const { return false; }
    285 
    286     enum ComputeScrollbarExistenceOption {
    287         FirstPass,
    288         Incremental
    289     };
    290     void computeScrollbarExistence(bool& newHasHorizontalScrollbar, bool& newHasVerticalScrollbar, ComputeScrollbarExistenceOption = FirstPass) const;
    291     void updateScrollbarGeometry();
    292 
    293     // Called to update the scrollbars to accurately reflect the state of the view.
    294     void updateScrollbars(const IntSize& desiredOffset);
    295 
    296     IntSize excludeScrollbars(const IntSize&) const;
    297 
    298     class InUpdateScrollbarsScope {
    299     public:
    300         explicit InUpdateScrollbarsScope(ScrollView* view)
    301             : m_scope(view->m_inUpdateScrollbars, true)
    302         { }
    303     private:
    304         TemporaryChange<bool> m_scope;
    305     };
    306 
    307 private:
    308     bool adjustScrollbarExistence(ComputeScrollbarExistenceOption = FirstPass);
    309 
    310     RefPtr<Scrollbar> m_horizontalScrollbar;
    311     RefPtr<Scrollbar> m_verticalScrollbar;
    312     ScrollbarMode m_horizontalScrollbarMode;
    313     ScrollbarMode m_verticalScrollbarMode;
    314 
    315     bool m_horizontalScrollbarLock;
    316     bool m_verticalScrollbarLock;
    317 
    318     HashSet<RefPtr<Widget> > m_children;
    319 
    320     IntSize m_pendingScrollDelta;
    321     IntSize m_scrollOffset; // FIXME: Would rather store this as a position, but we will wait to make this change until more code is shared.
    322     IntPoint m_cachedScrollPosition;
    323     IntSize m_contentsSize;
    324 
    325     int m_scrollbarsAvoidingResizer;
    326     bool m_scrollbarsSuppressed;
    327 
    328     bool m_inUpdateScrollbars;
    329 
    330     IntPoint m_panScrollIconPoint;
    331     bool m_drawPanScrollIcon;
    332 
    333     bool m_paintsEntireContents;
    334     bool m_clipsRepaints;
    335 
    336     void init();
    337     void destroy();
    338 
    339     IntRect rectToCopyOnScroll() const;
    340 
    341     void calculateOverhangAreasForPainting(IntRect& horizontalOverhangRect, IntRect& verticalOverhangRect);
    342     void updateOverhangAreas();
    343 }; // class ScrollView
    344 
    345 DEFINE_TYPE_CASTS(ScrollView, Widget, widget, widget->isScrollView(), widget.isScrollView());
    346 
    347 } // namespace WebCore
    348 
    349 #endif // ScrollView_h
    350