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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 "IntRect.h"
     31 #include "Scrollbar.h"
     32 #include "ScrollbarClient.h"
     33 #include "ScrollTypes.h"
     34 #include "Widget.h"
     35 
     36 #include <wtf/HashSet.h>
     37 
     38 #if PLATFORM(MAC) && defined __OBJC__
     39 @protocol WebCoreFrameScrollView;
     40 #endif
     41 
     42 #if PLATFORM(GTK)
     43 typedef struct _GtkAdjustment GtkAdjustment;
     44 #endif
     45 
     46 #if PLATFORM(WX)
     47 class wxScrollWinEvent;
     48 #endif
     49 
     50 namespace WebCore {
     51 
     52 class HostWindow;
     53 class PlatformWheelEvent;
     54 class Scrollbar;
     55 
     56 class ScrollView : public Widget, public ScrollbarClient {
     57 public:
     58     ~ScrollView();
     59 
     60     // ScrollbarClient method.  FrameView overrides the other two.
     61     virtual void valueChanged(Scrollbar*);
     62 
     63     // The window thats hosts the ScrollView.  The ScrollView will communicate scrolls and repaints to the
     64     // host window in the window's coordinate space.
     65     virtual HostWindow* hostWindow() const = 0;
     66 
     67     // Returns a clip rect in host window coordinates.  Used to clip the blit on a scroll.
     68     virtual IntRect windowClipRect(bool clipToContents = true) const = 0;
     69 
     70     // Methods for child manipulation and inspection.
     71     const HashSet<RefPtr<Widget> >* children() const { return &m_children; }
     72     void addChild(PassRefPtr<Widget>);
     73     void removeChild(Widget*);
     74 
     75     // If the scroll view does not use a native widget, then it will have cross-platform Scrollbars.  These methods
     76     // can be used to obtain those scrollbars.
     77     Scrollbar* horizontalScrollbar() const { return m_horizontalScrollbar.get(); }
     78     Scrollbar* verticalScrollbar() const { return m_verticalScrollbar.get(); }
     79     bool isScrollViewScrollbar(const Widget* child) const { return horizontalScrollbar() == child || verticalScrollbar() == child; }
     80 
     81     // Methods for setting and retrieving the scrolling mode in each axis (horizontal/vertical).  The mode has values of
     82     // AlwaysOff, AlwaysOn, and Auto.  AlwaysOff means never show a scrollbar, AlwaysOn means always show a scrollbar.
     83     // Auto means show a scrollbar only when one is needed.
     84     // Note that for platforms with native widgets, these modes are considered advisory.  In other words the underlying native
     85     // widget may choose not to honor the requested modes.
     86     void setScrollbarModes(ScrollbarMode horizontalMode, ScrollbarMode verticalMode);
     87     void setHorizontalScrollbarMode(ScrollbarMode mode) { setScrollbarModes(mode, verticalScrollbarMode()); }
     88     void setVerticalScrollbarMode(ScrollbarMode mode) { setScrollbarModes(horizontalScrollbarMode(), mode); }
     89     void scrollbarModes(ScrollbarMode& horizontalMode, ScrollbarMode& verticalMode) const;
     90     ScrollbarMode horizontalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return horizontal; }
     91     ScrollbarMode verticalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return vertical; }
     92     virtual void setCanHaveScrollbars(bool);
     93     bool canHaveScrollbars() const { return horizontalScrollbarMode() != ScrollbarAlwaysOff || verticalScrollbarMode() != ScrollbarAlwaysOff; }
     94 
     95     // By default you only receive paint events for the area that is visible. In the case of using a
     96     // tiled backing store, this method can be set, so that the view paints the entire contents.
     97     bool paintsEntireContents() const { return m_paintsEntireContents; }
     98     void setPaintsEntireContents(bool);
     99 
    100     // Overridden by FrameView to create custom CSS scrollbars if applicable.
    101     virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
    102 
    103     // If the prohibits scrolling flag is set, then all scrolling in the view (even programmatic scrolling) is turned off.
    104     void setProhibitsScrolling(bool b) { m_prohibitsScrolling = b; }
    105     bool prohibitsScrolling() const { return m_prohibitsScrolling; }
    106 
    107     // Whether or not a scroll view will blit visible contents when it is scrolled.  Blitting is disabled in situations
    108     // where it would cause rendering glitches (such as with fixed backgrounds or when the view is partially transparent).
    109     void setCanBlitOnScroll(bool);
    110     bool canBlitOnScroll() const;
    111 
    112     // The visible content rect has a location that is the scrolled offset of the document. The width and height are the viewport width
    113     // and height.  By default the scrollbars themselves are excluded from this rectangle, but an optional boolean argument allows them to be
    114     // included.
    115     IntRect visibleContentRect(bool includeScrollbars = false) const;
    116     int visibleWidth() const { return visibleContentRect().width(); }
    117     int visibleHeight() const { return visibleContentRect().height(); }
    118 
    119     // Methods for getting/setting the size webkit should use to layout the contents.  By default this is the same as the visible
    120     // content size.  Explicitly setting a layout size value will cause webkit to layout the contents using this size instead.
    121     int layoutWidth() const;
    122     int layoutHeight() const;
    123     IntSize fixedLayoutSize() const;
    124     void setFixedLayoutSize(const IntSize&);
    125     bool useFixedLayout() const;
    126     void setUseFixedLayout(bool enable);
    127 
    128     // Methods for getting/setting the size of the document contained inside the ScrollView (as an IntSize or as individual width and height
    129     // values).
    130     IntSize contentsSize() const; // Always at least as big as the visibleWidth()/visibleHeight().
    131     int contentsWidth() const { return contentsSize().width(); }
    132     int contentsHeight() const { return contentsSize().height(); }
    133     virtual void setContentsSize(const IntSize&);
    134 
    135     // Methods for querying the current scrolled position (both as a point, a size, or as individual X and Y values).
    136     IntPoint scrollPosition() const { return visibleContentRect().location(); }
    137     IntSize scrollOffset() const { return visibleContentRect().location() - IntPoint(); } // Gets the scrolled position as an IntSize. Convenient for adding to other sizes.
    138     IntPoint maximumScrollPosition() const; // The maximum position we can be scrolled to.
    139     int scrollX() const { return scrollPosition().x(); }
    140     int scrollY() const { return scrollPosition().y(); }
    141 
    142     // Methods for scrolling the view.  setScrollPosition is the only method that really scrolls the view.  The other two methods are helper functions
    143     // that ultimately end up calling setScrollPosition.
    144     void setScrollPosition(const IntPoint&);
    145     void scrollBy(const IntSize& s) { return setScrollPosition(scrollPosition() + s); }
    146     void scrollRectIntoViewRecursively(const IntRect&);
    147 
    148     // This method scrolls by lines, pages or pixels.
    149     bool scroll(ScrollDirection, ScrollGranularity);
    150 
    151     // Scroll the actual contents of the view (either blitting or invalidating as needed).
    152     void scrollContents(const IntSize& scrollDelta);
    153 
    154     // This gives us a means of blocking painting on our scrollbars until the first layout has occurred.
    155     void setScrollbarsSuppressed(bool suppressed, bool repaintOnUnsuppress = false);
    156     bool scrollbarsSuppressed() const { return m_scrollbarsSuppressed; }
    157 
    158     // Event coordinates are assumed to be in the coordinate space of a window that contains
    159     // the entire widget hierarchy. It is up to the platform to decide what the precise definition
    160     // of containing window is. (For example on Mac it is the containing NSWindow.)
    161     IntPoint windowToContents(const IntPoint&) const;
    162     IntPoint contentsToWindow(const IntPoint&) const;
    163     IntRect windowToContents(const IntRect&) const;
    164     IntRect contentsToWindow(const IntRect&) const;
    165 
    166     // Methods for converting to and from screen coordinates.
    167     IntRect contentsToScreen(const IntRect&) const;
    168     IntPoint screenToContents(const IntPoint&) const;
    169 
    170     // The purpose of this method is to answer whether or not the scroll view is currently visible.  Animations and painting updates can be suspended if
    171     // we know that we are either not in a window right now or if that window is not visible.
    172     bool isOffscreen() const;
    173 
    174     // These methods are used to enable scrollbars to avoid window resizer controls that overlap the scroll view.  This happens on Mac
    175     // for example.
    176     virtual IntRect windowResizerRect() const { return IntRect(); }
    177     bool containsScrollbarsAvoidingResizer() const;
    178     void adjustScrollbarsAvoidingResizerCount(int overlapDelta);
    179     virtual void setParent(ScrollView*); // Overridden to update the overlapping scrollbar count.
    180 
    181     // Called when our frame rect changes (or the rect/scroll position of an ancestor changes).
    182     virtual void frameRectsChanged();
    183 
    184     // Widget override to update our scrollbars and notify our contents of the resize.
    185     virtual void setFrameRect(const IntRect&);
    186 
    187     // For platforms that need to hit test scrollbars from within the engine's event handlers (like Win32).
    188     Scrollbar* scrollbarAtPoint(const IntPoint& windowPoint);
    189 
    190     // This method exists for scrollviews that need to handle wheel events manually.
    191     // On Mac the underlying NSScrollView just does the scrolling, but on other platforms
    192     // (like Windows), we need this method in order to do the scroll ourselves.
    193     void wheelEvent(PlatformWheelEvent&);
    194 
    195     IntPoint convertChildToSelf(const Widget* child, const IntPoint& point) const
    196     {
    197         IntPoint newPoint = point;
    198         if (!isScrollViewScrollbar(child))
    199             newPoint = point - scrollOffset();
    200         newPoint.move(child->x(), child->y());
    201         return newPoint;
    202     }
    203 
    204     IntPoint convertSelfToChild(const Widget* child, const IntPoint& point) const
    205     {
    206         IntPoint newPoint = point;
    207         if (!isScrollViewScrollbar(child))
    208             newPoint = point + scrollOffset();
    209         newPoint.move(-child->x(), -child->y());
    210         return newPoint;
    211     }
    212 
    213     // Widget override.  Handles painting of the contents of the view as well as the scrollbars.
    214     virtual void paint(GraphicsContext*, const IntRect&);
    215     void paintScrollbars(GraphicsContext*, const IntRect&);
    216 
    217     // Widget overrides to ensure that our children's visibility status is kept up to date when we get shown and hidden.
    218     virtual void show();
    219     virtual void hide();
    220     virtual void setParentVisible(bool);
    221 
    222     // Pan scrolling.
    223     static const int noPanScrollRadius = 15;
    224     void addPanScrollIcon(const IntPoint&);
    225     void removePanScrollIcon();
    226     void paintPanScrollIcon(GraphicsContext*);
    227 
    228     virtual bool isPointInScrollbarCorner(const IntPoint&);
    229     virtual bool scrollbarCornerPresent() const;
    230 
    231     virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const;
    232     virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const;
    233     virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const;
    234     virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const;
    235 
    236 protected:
    237     ScrollView();
    238 
    239     virtual void repaintContentRectangle(const IntRect&, bool now = false);
    240     virtual void paintContents(GraphicsContext*, const IntRect& damageRect) = 0;
    241 
    242     virtual void contentsResized() = 0;
    243     virtual void visibleContentsResized() = 0;
    244 
    245     // These methods are used to create/destroy scrollbars.
    246     void setHasHorizontalScrollbar(bool);
    247     void setHasVerticalScrollbar(bool);
    248 
    249     IntRect scrollCornerRect() const;
    250     virtual void updateScrollCorner();
    251     virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
    252 
    253 private:
    254     RefPtr<Scrollbar> m_horizontalScrollbar;
    255     RefPtr<Scrollbar> m_verticalScrollbar;
    256     ScrollbarMode m_horizontalScrollbarMode;
    257     ScrollbarMode m_verticalScrollbarMode;
    258     bool m_prohibitsScrolling;
    259 
    260     HashSet<RefPtr<Widget> > m_children;
    261 
    262     // This bool is unused on Mac OS because we directly ask the platform widget
    263     // whether it is safe to blit on scroll.
    264     bool m_canBlitOnScroll;
    265 
    266     IntSize m_scrollOffset; // FIXME: Would rather store this as a position, but we will wait to make this change until more code is shared.
    267     IntSize m_fixedLayoutSize;
    268     IntSize m_contentsSize;
    269 
    270     int m_scrollbarsAvoidingResizer;
    271     bool m_scrollbarsSuppressed;
    272 
    273     bool m_inUpdateScrollbars;
    274     unsigned m_updateScrollbarsPass;
    275 
    276     IntPoint m_panScrollIconPoint;
    277     bool m_drawPanScrollIcon;
    278     bool m_useFixedLayout;
    279 
    280     bool m_paintsEntireContents;
    281 
    282     void init();
    283     void destroy();
    284 
    285     // Called to update the scrollbars to accurately reflect the state of the view.
    286     void updateScrollbars(const IntSize& desiredOffset);
    287 
    288     void platformInit();
    289     void platformDestroy();
    290     void platformAddChild(Widget*);
    291     void platformRemoveChild(Widget*);
    292     void platformSetScrollbarModes();
    293     void platformScrollbarModes(ScrollbarMode& horizontal, ScrollbarMode& vertical) const;
    294     void platformSetCanBlitOnScroll(bool);
    295     bool platformCanBlitOnScroll() const;
    296     IntRect platformVisibleContentRect(bool includeScrollbars) const;
    297     IntSize platformContentsSize() const;
    298     void platformSetContentsSize();
    299     IntRect platformContentsToScreen(const IntRect&) const;
    300     IntPoint platformScreenToContents(const IntPoint&) const;
    301     void platformSetScrollPosition(const IntPoint&);
    302     bool platformScroll(ScrollDirection, ScrollGranularity);
    303     void platformSetScrollbarsSuppressed(bool repaintOnUnsuppress);
    304     void platformRepaintContentRectangle(const IntRect&, bool now);
    305     bool platformIsOffscreen() const;
    306 
    307 #if PLATFORM(MAC) && defined __OBJC__
    308 public:
    309     NSView* documentView() const;
    310 
    311 private:
    312     NSScrollView<WebCoreFrameScrollView>* scrollView() const;
    313 #endif
    314 
    315 #if PLATFORM(GTK)
    316 public:
    317     void setGtkAdjustments(GtkAdjustment* hadj, GtkAdjustment* vadj, bool resetValues = true);
    318     GtkAdjustment* m_horizontalAdjustment;
    319     GtkAdjustment* m_verticalAdjustment;
    320     void setScrollOffset(const IntSize& offset) { m_scrollOffset = offset; }
    321 #endif
    322 
    323 #if PLATFORM(WX)
    324 public:
    325     virtual void setPlatformWidget(wxWindow*);
    326     void adjustScrollbars(int x = -1, int y = -1, bool refresh = true);
    327 private:
    328     class ScrollViewPrivate;
    329     ScrollViewPrivate* m_data;
    330 #endif
    331 
    332 #if PLATFORM(ANDROID)
    333 public:
    334     bool platformProhibitsScrolling();
    335 #ifdef ANDROID_CAPTURE_OFFSCREEN_PAINTS
    336     // capture parts of rect not contained by vis
    337     void platformOffscreenContentRectangle(const IntRect& vis,
    338         const IntRect& rect);
    339 #endif
    340 #endif
    341 }; // class ScrollView
    342 
    343 } // namespace WebCore
    344 
    345 #endif // ScrollView_h
    346