/*

 * Copyright (C) 2004, 2006, 2007, 2008 Apple Inc. All rights reserved.

 * Copyright (C) 2009 Holger Hans Peter Freyther

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#ifndef ScrollView_h

#define ScrollView_h

#include "IntRect.h"

#include "Scrollbar.h"

#include "ScrollbarClient.h"

#include "ScrollTypes.h"

#include "Widget.h"

#include <wtf/HashSet.h>

#if PLATFORM(MAC) && defined __OBJC__

@protocol WebCoreFrameScrollView;

#endif

#if PLATFORM(GTK)

typedef struct _GtkAdjustment GtkAdjustment;

#endif

#if PLATFORM(WX)

class wxScrollWinEvent;

#endif

namespace WebCore {

class HostWindow;

class PlatformWheelEvent;

class Scrollbar;

class ScrollView : public Widget, public ScrollbarClient {

public:

    ~ScrollView();

    // ScrollbarClient method.  FrameView overrides the other two.

    virtual void valueChanged(Scrollbar*);

    // The window thats hosts the ScrollView.  The ScrollView will communicate scrolls and repaints to the

    // host window in the window's coordinate space.

    virtual HostWindow* hostWindow() const = 0;

    // Returns a clip rect in host window coordinates.  Used to clip the blit on a scroll.

    virtual IntRect windowClipRect(bool clipToContents = true) const = 0;

    // Methods for child manipulation and inspection.

    const HashSet<RefPtr<Widget> >* children() const { return &m_children; }

    void addChild(PassRefPtr<Widget>);

    void removeChild(Widget*);

    // If the scroll view does not use a native widget, then it will have cross-platform Scrollbars.  These methods

    // can be used to obtain those scrollbars.

    Scrollbar* horizontalScrollbar() const { return m_horizontalScrollbar.get(); }

    Scrollbar* verticalScrollbar() const { return m_verticalScrollbar.get(); }

    bool isScrollViewScrollbar(const Widget* child) const { return horizontalScrollbar() == child || verticalScrollbar() == child; }

    // Methods for setting and retrieving the scrolling mode in each axis (horizontal/vertical).  The mode has values of

    // AlwaysOff, AlwaysOn, and Auto.  AlwaysOff means never show a scrollbar, AlwaysOn means always show a scrollbar.

    // Auto means show a scrollbar only when one is needed.

    // Note that for platforms with native widgets, these modes are considered advisory.  In other words the underlying native

    // widget may choose not to honor the requested modes.

    void setScrollbarModes(ScrollbarMode horizontalMode, ScrollbarMode verticalMode);

    void setHorizontalScrollbarMode(ScrollbarMode mode) { setScrollbarModes(mode, verticalScrollbarMode()); }

    void setVerticalScrollbarMode(ScrollbarMode mode) { setScrollbarModes(horizontalScrollbarMode(), mode); }

    void scrollbarModes(ScrollbarMode& horizontalMode, ScrollbarMode& verticalMode) const;

    ScrollbarMode horizontalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return horizontal; }

    ScrollbarMode verticalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return vertical; }

    void setCanHaveScrollbars(bool flag);

    bool canHaveScrollbars() const { return horizontalScrollbarMode() != ScrollbarAlwaysOff || verticalScrollbarMode() != ScrollbarAlwaysOff; }

    // Overridden by FrameView to create custom CSS scrollbars if applicable.

    virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);

    // If the prohibits scrolling flag is set, then all scrolling in the view (even programmatic scrolling) is turned off.

    void setProhibitsScrolling(bool b) { m_prohibitsScrolling = b; }

    bool prohibitsScrolling() const { return m_prohibitsScrolling; }

    // Whether or not a scroll view will blit visible contents when it is scrolled.  Blitting is disabled in situations

    // where it would cause rendering glitches (such as with fixed backgrounds or when the view is partially transparent).

    void setCanBlitOnScroll(bool);

    bool canBlitOnScroll() const;

    // The visible content rect has a location that is the scrolled offset of the document. The width and height are the viewport width

    // and height.  By default the scrollbars themselves are excluded from this rectangle, but an optional boolean argument allows them to be

    // included.

    IntRect visibleContentRect(bool includeScrollbars = false) const;

    int visibleWidth() const { return visibleContentRect().width(); }

    int visibleHeight() const { return visibleContentRect().height(); }

    // Methods for getting/setting the size webkit should use to layout the contents.  By default this is the same as the visible

    // content size.  Explicitly setting a layout size value will cause webkit to layout the contents using this size instead.

    int layoutWidth() const;

    int layoutHeight() const;

    IntSize fixedLayoutSize() const;

    void setFixedLayoutSize(const IntSize&);

    bool useFixedLayout() const;

    void setUseFixedLayout(bool enable);

    // Methods for getting/setting the size of the document contained inside the ScrollView (as an IntSize or as individual width and height

    // values).

    IntSize contentsSize() const; // Always at least as big as the visibleWidth()/visibleHeight().

    int contentsWidth() const { return contentsSize().width(); }

    int contentsHeight() const { return contentsSize().height(); }

    virtual void setContentsSize(const IntSize&);

    // Methods for querying the current scrolled position (both as a point, a size, or as individual X and Y values).

    IntPoint scrollPosition() const { return visibleContentRect().location(); }

    IntSize scrollOffset() const { return visibleContentRect().location() - IntPoint(); } // Gets the scrolled position as an IntSize. Convenient for adding to other sizes.

    IntPoint maximumScrollPosition() const; // The maximum position we can be scrolled to.

    int scrollX() const { return scrollPosition().x(); }

    int scrollY() const { return scrollPosition().y(); }

    // Methods for scrolling the view.  setScrollPosition is the only method that really scrolls the view.  The other two methods are helper functions

    // that ultimately end up calling setScrollPosition.

    void setScrollPosition(const IntPoint&);

    void scrollBy(const IntSize& s) { return setScrollPosition(scrollPosition() + s); }

    void scrollRectIntoViewRecursively(const IntRect&);

    // This method scrolls by lines, pages or pixels.

    bool scroll(ScrollDirection, ScrollGranularity);

    // Scroll the actual contents of the view (either blitting or invalidating as needed).

    void scrollContents(const IntSize& scrollDelta);

    // This gives us a means of blocking painting on our scrollbars until the first layout has occurred.

    void setScrollbarsSuppressed(bool suppressed, bool repaintOnUnsuppress = false);

    bool scrollbarsSuppressed() const { return m_scrollbarsSuppressed; }

    // Event coordinates are assumed to be in the coordinate space of a window that contains

    // the entire widget hierarchy. It is up to the platform to decide what the precise definition

    // of containing window is. (For example on Mac it is the containing NSWindow.)

    IntPoint windowToContents(const IntPoint&) const;

    IntPoint contentsToWindow(const IntPoint&) const;

    IntRect windowToContents(const IntRect&) const;

    IntRect contentsToWindow(const IntRect&) const;

    // Methods for converting to and from screen coordinates.

    IntRect contentsToScreen(const IntRect&) const;

    IntPoint screenToContents(const IntPoint&) const;

    // 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

    // we know that we are either not in a window right now or if that window is not visible.

    bool isOffscreen() const;

    // These methods are used to enable scrollbars to avoid window resizer controls that overlap the scroll view.  This happens on Mac

    // for example.

    virtual IntRect windowResizerRect() const { return IntRect(); }

    bool containsScrollbarsAvoidingResizer() const;

    void adjustScrollbarsAvoidingResizerCount(int overlapDelta);

    virtual void setParent(ScrollView*); // Overridden to update the overlapping scrollbar count.

    // Called when our frame rect changes (or the rect/scroll position of an ancestor changes).

    virtual void frameRectsChanged();

    // Widget override to update our scrollbars and notify our contents of the resize.

    virtual void setFrameRect(const IntRect&);

    // For platforms that need to hit test scrollbars from within the engine's event handlers (like Win32).

    Scrollbar* scrollbarAtPoint(const IntPoint& windowPoint);

    // This method exists for scrollviews that need to handle wheel events manually.

    // On Mac the underlying NSScrollView just does the scrolling, but on other platforms

    // (like Windows), we need this method in order to do the scroll ourselves.

    void wheelEvent(PlatformWheelEvent&);

    IntPoint convertChildToSelf(const Widget* child, const IntPoint& point) const

    {

        IntPoint newPoint = point;

        if (!isScrollViewScrollbar(child))

            newPoint = point - scrollOffset();

        newPoint.move(child->x(), child->y());

        return newPoint;

    }

    IntPoint convertSelfToChild(const Widget* child, const IntPoint& point) const

    {

        IntPoint newPoint = point;

        if (!isScrollViewScrollbar(child))

            newPoint = point + scrollOffset();

        newPoint.move(-child->x(), -child->y());

        return newPoint;

    }

    // Widget override.  Handles painting of the contents of the view as well as the scrollbars.

    virtual void paint(GraphicsContext*, const IntRect&);

    void paintScrollbars(GraphicsContext*, const IntRect&);

    // Widget overrides to ensure that our children's visibility status is kept up to date when we get shown and hidden.

    virtual void show();

    virtual void hide();

    virtual void setParentVisible(bool);

    // Pan scrolling.

    static const int noPanScrollRadius = 15;

    void addPanScrollIcon(const IntPoint&);

    void removePanScrollIcon();

    void paintPanScrollIcon(GraphicsContext*);

    virtual bool isPointInScrollbarCorner(const IntPoint&);

    virtual bool scrollbarCornerPresent() const;

    virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const;

    virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const;

    virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const;

    virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const;

protected:

    ScrollView();

    virtual void repaintContentRectangle(const IntRect&, bool now = false);

    virtual void paintContents(GraphicsContext*, const IntRect& damageRect) = 0;

    virtual void contentsResized() = 0;

    virtual void visibleContentsResized() = 0;

    // These methods are used to create/destroy scrollbars.

    void setHasHorizontalScrollbar(bool);

    void setHasVerticalScrollbar(bool);

    IntRect scrollCornerRect() const;

    virtual void updateScrollCorner();

    virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);

private:

    RefPtr<Scrollbar> m_horizontalScrollbar;

    RefPtr<Scrollbar> m_verticalScrollbar;

    ScrollbarMode m_horizontalScrollbarMode;

    ScrollbarMode m_verticalScrollbarMode;

    bool m_prohibitsScrolling;

    HashSet<RefPtr<Widget> > m_children;

    // This bool is unused on Mac OS because we directly ask the platform widget

    // whether it is safe to blit on scroll.

    bool m_canBlitOnScroll;

    IntSize m_scrollOffset; // FIXME: Would rather store this as a position, but we will wait to make this change until more code is shared.

    IntSize m_fixedLayoutSize;

    IntSize m_contentsSize;

    int m_scrollbarsAvoidingResizer;

    bool m_scrollbarsSuppressed;

    bool m_inUpdateScrollbars;

    unsigned m_updateScrollbarsPass;

    IntPoint m_panScrollIconPoint;

    bool m_drawPanScrollIcon;

    bool m_useFixedLayout;

    void init();

    void destroy();

    // Called to update the scrollbars to accurately reflect the state of the view.

    void updateScrollbars(const IntSize& desiredOffset);

    void platformInit();

    void platformDestroy();

    void platformAddChild(Widget*);

    void platformRemoveChild(Widget*);

    void platformSetScrollbarModes();

    void platformScrollbarModes(ScrollbarMode& horizontal, ScrollbarMode& vertical) const;

    void platformSetCanBlitOnScroll(bool);

    bool platformCanBlitOnScroll() const;

    IntRect platformVisibleContentRect(bool includeScrollbars) const;

    IntSize platformContentsSize() const;

    void platformSetContentsSize();

    IntRect platformContentsToScreen(const IntRect&) const;

    IntPoint platformScreenToContents(const IntPoint&) const;

    void platformSetScrollPosition(const IntPoint&);

    bool platformScroll(ScrollDirection, ScrollGranularity);

    void platformSetScrollbarsSuppressed(bool repaintOnUnsuppress);

    void platformRepaintContentRectangle(const IntRect&, bool now);

    bool platformIsOffscreen() const;

#if PLATFORM(MAC) && defined __OBJC__

public:

    NSView* documentView() const;

private:

    NSScrollView<WebCoreFrameScrollView>* scrollView() const;

#endif

#if PLATFORM(GTK)

public:

    void setGtkAdjustments(GtkAdjustment* hadj, GtkAdjustment* vadj);

    GtkAdjustment* m_horizontalAdjustment;

    GtkAdjustment* m_verticalAdjustment;

    void setScrollOffset(const IntSize& offset) { m_scrollOffset = offset; }

#endif

#if PLATFORM(WX)

public:

    virtual void setPlatformWidget(wxWindow*);

    void adjustScrollbars(int x = -1, int y = -1, bool refresh = true);

private:

    class ScrollViewPrivate;

    ScrollViewPrivate* m_data;

#endif

}; // class ScrollView

} // namespace WebCore

#endif // ScrollView_h