render_object.h   [plain text]

/*
 * This file is part of the html renderer for KDE.
 *
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2003 Apple Computer, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 */
#ifndef render_object_h
#define render_object_h

#include <qcolor.h>
#include <qrect.h>
#include <assert.h>

#include "editing/text_affinity.h"
#include "misc/khtmllayout.h"
#include "misc/loader_client.h"
#include "misc/helper.h"
#include "rendering/render_style.h"
#include "khtml_events.h"
#include "xml/dom_docimpl.h"
#include "visible_position.h"

#include "KWQScrollBar.h"

class QPainter;
class QTextStream;
class CSSStyle;
class KHTMLView;
class RenderArena;

#ifndef NDEBUG
#define KHTMLAssert( x ) if( !(x) ) { \
    const RenderObject *o = this; while( o->parent() ) o = o->parent(); \
    o->printTree(); \
    qDebug(" this object = %p", this ); \
    assert( false ); \
}
#else
#define KHTMLAssert( x )
#endif

/*
 *	The painting of a layer occurs in three distinct phases.  Each phase involves
 *	a recursive descent into the layer's render objects. The first phase is the background phase.
 *	The backgrounds and borders of all blocks are painted.  Inlines are not painted at all.
 *	Floats must paint above block backgrounds but entirely below inline content that can overlap them.
 *	In the foreground phase, all inlines are fully painted.  Inline replaced elements will get all
 *	three phases invoked on them during this phase.
 */

typedef enum {
    PaintActionBlockBackground,
    PaintActionChildBlockBackground,
    PaintActionChildBlockBackgrounds,
    PaintActionFloat,
    PaintActionForeground,
    PaintActionOutline,
    PaintActionSelection,
    PaintActionCollapsedTableBorders
} PaintAction;

typedef enum {
    HitTestAll,
    HitTestSelf,
    HitTestDescendants
} HitTestFilter;

typedef enum {
    HitTestBlockBackground,
    HitTestChildBlockBackground,
    HitTestChildBlockBackgrounds,
    HitTestFloat,
    HitTestForeground
} HitTestAction;

namespace DOM {
    class HTMLAreaElementImpl;
    class DOMString;
    class DocumentImpl;
    class ElementImpl;
    class EventImpl;
    class Position;
};

namespace khtml {
    class RenderFlow;
    class RenderBlock;
    class RenderStyle;
    class RenderTable;
    class CachedObject;
    class RenderCanvas;
    class RenderText;
    class RenderFrameSet;
    class RenderLayer;
    class InlineBox;
    class InlineFlowBox;
    class CollapsedBorderValue;

#if APPLE_CHANGES
struct DashboardRegionValue
{
    QString label;
    QRect bounds;
    QRect clip;
    int type;

    bool operator==(const DashboardRegionValue& o) const
    {
        return type == o.type && bounds == o.bounds && label == o.label;
    }
};
#endif


/**
 * Base Class for all rendering tree objects.
 */
class RenderObject : public CachedObjectClient
{
public:
    // Anonymous objects should pass the document as their node, and they will then automatically be
    // marked as anonymous in the constructor.
    RenderObject(DOM::NodeImpl* node);
    virtual ~RenderObject();

    RenderObject *parent() const { return m_parent; }
    bool hasAncestor(const RenderObject *obj) const;

    RenderObject *previousSibling() const { return m_previous; }
    RenderObject *nextSibling() const { return m_next; }

    virtual RenderObject *firstChild() const { return 0; }
    virtual RenderObject *lastChild() const { return 0; }

    RenderObject *nextRenderer() const; 
    RenderObject *previousRenderer() const; 

    RenderObject *nextEditable() const; 
    RenderObject *previousEditable() const; 

    RenderObject *firstLeafChild() const;
    RenderObject *lastLeafChild() const;
    
    virtual RenderLayer* layer() const { return 0; }
    RenderLayer* enclosingLayer();
    void addLayers(RenderLayer* parentLayer, RenderObject* newObject);
    void removeLayers(RenderLayer* parentLayer);
    void moveLayers(RenderLayer* oldParent, RenderLayer* newParent);
    RenderLayer* findNextLayer(RenderLayer* parentLayer, RenderObject* startPoint,
                               bool checkParent=true);
    virtual void positionChildLayers() { }
    virtual bool requiresLayer();
    
    virtual QRect getOverflowClipRect(int tx, int ty) { return QRect(0,0,0,0); }
    virtual QRect getClipRect(int tx, int ty) { return QRect(0,0,0,0); }
    bool hasClip() { return isPositioned() &&  style()->hasClip(); }
    
    virtual int getBaselineOfFirstLineBox() const { return -1; } 
    
    // Obtains the nearest enclosing block (including this block) that contributes a first-line style to our inline
    // children.
    virtual RenderBlock* firstLineBlock() const;
    virtual void updateFirstLetter();
    
    // Called when an object that was floating or positioned becomes a normal flow object
    // again.  We have to make sure the render tree updates as needed to accommodate the new
    // normal flow object.
    void handleDynamicFloatPositionChange();

    // This function is a convenience helper for creating an anonymous block that inherits its
    // style from this RenderObject.
    RenderBlock* createAnonymousBlock();
    
    // Whether or not a positioned element requires normal flow x/y to be computed
    // to determine its position.
    bool hasStaticX() const;
    bool hasStaticY() const;
    virtual void setStaticX(int staticX) {};
    virtual void setStaticY(int staticY) {};
    virtual int staticX() const { return 0; }
    virtual int staticY() const { return 0; }
    
    // RenderObject tree manipulation
    //////////////////////////////////////////
    virtual bool canHaveChildren() const;
    virtual void addChild(RenderObject *newChild, RenderObject *beforeChild = 0);
    virtual void removeChild(RenderObject *oldChild);

    // raw tree manipulation
    virtual RenderObject* removeChildNode(RenderObject* child);
    virtual void appendChildNode(RenderObject* child);
    virtual void insertChildNode(RenderObject* child, RenderObject* before);
    //////////////////////////////////////////

private:
    //////////////////////////////////////////
    // Helper functions. Dangerous to use!
    void setPreviousSibling(RenderObject *previous) { m_previous = previous; }
    void setNextSibling(RenderObject *next) { m_next = next; }
    void setParent(RenderObject *parent) { m_parent = parent; }
    //////////////////////////////////////////
    
    void addAbsoluteRectForLayer(QRect& result);

public:
    virtual const char *renderName() const { return "RenderObject"; }
#ifndef NDEBUG
    QString information() const;
    virtual void printTree(int indent=0) const;
    virtual void dump(QTextStream *stream, QString ind = "") const;
#endif

    static RenderObject *createObject(DOM::NodeImpl* node, RenderStyle* style);

    // Overloaded new operator.  Derived classes must override operator new
    // in order to allocate out of the RenderArena.
    void* operator new(size_t sz, RenderArena* renderArena) throw();    

    // Overridden to prevent the normal delete from being called.
    void operator delete(void* ptr, size_t sz);
        
private:
    // The normal operator new is disallowed on all render objects.
    void* operator new(size_t sz) throw();
    
public:
    RenderArena* renderArena() const;
    
    // some helper functions...
    virtual bool isRenderBlock() const { return false; }
    virtual bool isRenderInline() const { return false; }
    virtual bool isInlineFlow() const { return false; }
    virtual bool isBlockFlow() const { return false; }
    virtual bool isInlineBlockOrInlineTable() const { return false; }
    virtual bool childrenInline() const { return false; }
    virtual void setChildrenInline(bool b) { };

    virtual RenderFlow* continuation() const;
    virtual bool isInlineContinuation() const;
    
    virtual bool isListItem() const { return false; }
    virtual bool isListMarker() const { return false; }
    virtual bool isCanvas() const { return false; }
    bool isRoot() const;
    bool isBody() const;
    bool isHR() const;
    virtual bool isBR() const { return false; }
    virtual bool isTableCell() const { return false; }
    virtual bool isTableRow() const { return false; }
    virtual bool isTableSection() const { return false; }
    virtual bool isTableCol() const { return false; }
    virtual bool isTable() const { return false; }
    virtual bool isWidget() const { return false; }
    virtual bool isFormElement() const { return false; }
    virtual bool isImage() const { return false; }
    virtual bool isTextArea() const { return false; }
    virtual bool isFrameSet() const { return false; }
    virtual bool isApplet() const { return false; }
    
    virtual bool isEditable() const;

    bool isHTMLMarquee() const;
    
    bool isAnonymous() const { return m_isAnonymous; }
    void setIsAnonymous(bool b) { m_isAnonymous = b; }
    bool isAnonymousBlock() const { return m_isAnonymous && 
                                           style()->display() == BLOCK && 
                                           style()->styleType() == RenderStyle::NOPSEUDO &&
                                           !isListMarker(); }
    
    bool isFloating() const { return m_floating; }
    bool isPositioned() const { return m_positioned; } // absolute or fixed positioning
    bool isRelPositioned() const { return m_relPositioned; } // relative positioning
    bool isText() const  { return m_isText; }
    bool isInline() const { return m_inline; }  // inline object
    bool isCompact() const { return style()->display() == COMPACT; } // compact object
    bool isRunIn() const { return style()->display() == RUN_IN; } // run-in object
    bool isDragging() const;
    bool isReplaced() const { return m_replaced; } // a "replaced" element (see CSS)
    bool shouldPaintBackgroundOrBorder() const { return m_paintBackground; }
    bool needsLayout() const   { return m_needsLayout || m_normalChildNeedsLayout || m_posChildNeedsLayout; }
    bool selfNeedsLayout() const { return m_needsLayout; }
    bool posChildNeedsLayout() const { return m_posChildNeedsLayout; }
    bool normalChildNeedsLayout() const { return m_normalChildNeedsLayout; }
    bool minMaxKnown() const{ return m_minMaxKnown; }
    bool recalcMinMax() const { return m_recalcMinMax; }
    bool isSelectionBorder() const;
    
    bool hasOverflowClip() const { return m_hasOverflowClip; }
    bool hasAutoScrollbars() const { return hasOverflowClip() && 
        (style()->overflow() == OAUTO || style()->overflow() == OOVERLAY); }
    bool scrollsOverflow() const { return hasOverflowClip() &&
        (style()->overflow() == OSCROLL || hasAutoScrollbars()); }
    bool includeScrollbarSize() const { return hasOverflowClip() &&
        (style()->overflow() == OSCROLL || style()->overflow() == OAUTO); }

    RenderStyle* getPseudoStyle(RenderStyle::PseudoId pseudo, RenderStyle* parentStyle = 0) const;
    
    void updateDragState(bool dragOn);

    RenderCanvas* canvas() const;

    // don't even think about making this method virtual!
    DOM::NodeImpl* element() const { return m_isAnonymous ? 0 : m_node; }
    DOM::DocumentImpl* document() const { return m_node->getDocument(); }
    void setNode(DOM::NodeImpl* node) { m_node = node; }
    DOM::NodeImpl* node() const { return m_node; }
    
   /**
     * returns the object containing this one. can be different from parent for
     * positioned elements
     */
    RenderObject *container() const;

    virtual void markAllDescendantsWithFloatsForLayout(RenderObject* floatToRemove = 0);
    void markContainingBlocksForLayout();
    void setNeedsLayout(bool b, bool markParents = true);
    void setChildNeedsLayout(bool b, bool markParents = true);
    void setMinMaxKnown(bool b=true) {
	m_minMaxKnown = b;
	if ( !b ) {
	    RenderObject *o = this;
	    RenderObject *root = this;
	    while( o ) { // ### && !o->m_recalcMinMax ) {
		o->m_recalcMinMax = true;
		root = o;
		o = o->m_parent;
	    }
	}
    }

    void setNeedsLayoutAndMinMaxRecalc() {
        setMinMaxKnown(false);
        setNeedsLayout(true);
    }
    
    void setPositioned(bool b=true)  { m_positioned = b;  }
    void setRelPositioned(bool b=true) { m_relPositioned = b; }
    void setFloating(bool b=true) { m_floating = b; }
    void setInline(bool b=true) { m_inline = b; }
    void setShouldPaintBackgroundOrBorder(bool b=true) { m_paintBackground = b; }
    void setRenderText() { m_isText = true; }
    void setReplaced(bool b=true) { m_replaced = b; }
    void setHasOverflowClip(bool b = true) { m_hasOverflowClip = b; }

    void scheduleRelayout();
    
    void updateBackgroundImages(RenderStyle* oldStyle);

    virtual InlineBox* createInlineBox(bool makePlaceHolderBox, bool isRootLineBox, bool isOnlyRun=false);
    virtual void dirtyLineBoxes(bool fullLayout, bool isRootLineBox=false);
    
    // For inline replaced elements, this function returns the inline box that owns us.  Enables
    // the replaced RenderObject to quickly determine what line it is contained on and to easily
    // iterate over structures on the line.
    virtual InlineBox* inlineBoxWrapper() const;
    virtual void setInlineBoxWrapper(InlineBox* b);
    void deleteLineBoxWrapper();

    virtual InlineBox *inlineBox(long offset=0, EAffinity affinity = UPSTREAM);
    
    // for discussion of lineHeight see CSS2 spec
    virtual short lineHeight( bool firstLine, bool isRootLineBox=false ) const;
    // for the vertical-align property of inline elements
    // the difference between this objects baseline position and the lines baseline position.
    virtual short verticalPositionHint( bool firstLine ) const;
    // the offset of baseline from the top of the object.
    virtual short baselinePosition( bool firstLine, bool isRootLineBox=false ) const;
    // width of tab character
    int tabWidth() const;

    /*
     * Paint the object and its children, clipped by (x|y|w|h).
     * (tx|ty) is the calculated position of the parent
     */
    struct PaintInfo {
        PaintInfo(QPainter* _p, const QRect& _r, PaintAction _phase, RenderObject *_paintingRoot)
        : p(_p), r(_r), phase(_phase), paintingRoot(_paintingRoot), outlineObjects(0) {}
        ~PaintInfo() { delete outlineObjects; }
        QPainter* p;
        QRect     r;
        PaintAction phase;
        RenderObject *paintingRoot;      // used to draw just one element and its visual kids
        QPtrDict<RenderFlow>* outlineObjects; // used to list which outlines should be painted by a block with inline children
    };
    virtual void paint(PaintInfo& i, int tx, int ty);
    void paintBorder(QPainter *p, int _tx, int _ty, int w, int h, const RenderStyle* style, bool begin=true, bool end=true);
    void paintOutline(QPainter *p, int _tx, int _ty, int w, int h, const RenderStyle* style);

    // RenderBox implements this.
    virtual void paintBoxDecorations(PaintInfo& i, int _tx, int _ty) {};

    virtual void paintBackgroundExtended(QPainter *p, const QColor& c, const BackgroundLayer* bgLayer, int clipy, int cliph,
                                         int _tx, int _ty, int w, int height,
                                         int bleft, int bright) {};

    /*
     * This function calculates the minimum & maximum width that the object
     * can be set to.
     *
     * when the Element calls setMinMaxKnown(true), calcMinMaxWidth() will
     * be no longer called.
     *
     * when a element has a fixed size, m_minWidth and m_maxWidth should be
     * set to the same value. This has the special meaning that m_width,
     * contains the actual value.
     *
     * assumes calcMinMaxWidth has already been called for all children.
     */
    virtual void calcMinMaxWidth() { }

    /*
     * Does the min max width recalculations after changes.
     */
    void recalcMinMaxWidths();

    /*
     * Calculates the actual width of the object (only for non inline
     * objects)
     */
    virtual void calcWidth() {}

    /*
     * This function should cause the Element to calculate its
     * width and height and the layout of its content
     *
     * when the Element calls setNeedsLayout(false), layout() is no
     * longer called during relayouts, as long as there is no
     * style sheet change. When that occurs, m_needsLayout will be
     * set to true and the Element receives layout() calls
     * again.
     */
    virtual void layout() = 0;

    /* This function performs a layout only if one is needed. */
    void layoutIfNeeded() { if (needsLayout()) layout(); }

    // used for element state updates that can not be fixed with a
    // repaint and do not need a relayout
    virtual void updateFromElement() {};

    virtual int availableHeight() const { return 0; }

    // Whether or not the element shrinks to its max width (rather than filling the width
    // of a containing block).  HTML4 buttons, legends, and floating/compact elements do this.
    bool sizesToMaxWidth() const;

#if APPLE_CHANGES
    // Called recursively to update the absolute positions of all widgets.
    virtual void updateWidgetPositions();
    
    QValueList<DashboardRegionValue> RenderObject::computeDashboardRegions();
    void addDashboardRegions (QValueList<DashboardRegionValue>& regions);
    void collectDashboardRegions (QValueList<DashboardRegionValue>& regions);
#endif

    // does a query on the rendertree and finds the innernode
    // and overURL for the given position
    // if readonly == false, it will recalc hover styles accordingly
    class NodeInfo
    {
        friend class RenderLayer;
        friend class RenderImage;
        friend class RenderText;
        friend class RenderInline;
        friend class RenderObject;
        friend class RenderFrameSet;
        friend class DOM::HTMLAreaElementImpl;
    public:
        NodeInfo(bool readonly, bool active, bool mouseMove = false)
            : m_innerNode(0), m_innerNonSharedNode(0), m_innerURLElement(0), m_readonly(readonly), m_active(active), m_mouseMove(mouseMove)
            { }

        DOM::NodeImpl* innerNode() const { return m_innerNode; }
        DOM::NodeImpl* innerNonSharedNode() const { return m_innerNonSharedNode; }
        DOM::NodeImpl* URLElement() const { return m_innerURLElement; }
        bool readonly() const { return m_readonly; }
        bool active() const { return m_active; }
        bool mouseMove() const { return m_mouseMove; }

    private:
        void setInnerNode(DOM::NodeImpl* n) { m_innerNode = n; }
        void setInnerNonSharedNode(DOM::NodeImpl* n) { m_innerNonSharedNode = n; }
        void setURLElement(DOM::NodeImpl* n) { m_innerURLElement = n; }

        DOM::NodeImpl* m_innerNode;
        DOM::NodeImpl* m_innerNonSharedNode;
        DOM::NodeImpl* m_innerURLElement;
        bool m_readonly;
        bool m_active;
        bool m_mouseMove;
    };

    // Used to signal a specific subrect within an object that must be repainted after
    // layout is complete.
    struct RepaintInfo {
        RenderObject* m_object;
        QRect m_repaintRect;
    
        RepaintInfo(RenderObject* o, const QRect& r) :m_object(o), m_repaintRect(r) {}
    };
    
    bool hitTest(NodeInfo& info, int x, int y, int tx, int ty, HitTestFilter hitTestFilter = HitTestAll);
    virtual bool nodeAtPoint(NodeInfo& info, int x, int y, int tx, int ty,
                             HitTestAction hitTestAction);
    void setInnerNode(NodeInfo& info);

    virtual VisiblePosition positionForCoordinates(int x, int y);
    
    virtual void dirtyLinesFromChangedChild(RenderObject* child, bool adding = true);
    
    // Set the style of the object and update the state of the object accordingly.
    virtual void setStyle(RenderStyle* style);

    // Updates only the local style ptr of the object.  Does not update the state of the object,
    // and so only should be called when the style is known not to have changed (or from setStyle).
    void setStyleInternal(RenderStyle* style);

    // returns the containing block level element for this element.
    RenderBlock *containingBlock() const;

    // return just the width of the containing block
    virtual int containingBlockWidth() const;
    // return just the height of the containing block
    virtual int containingBlockHeight() const;

    // size of the content area (box size minus padding/border)
    virtual int contentWidth() const { return 0; }
    virtual int contentHeight() const { return 0; }

    // intrinsic extend of replaced elements. undefined otherwise
    virtual int intrinsicWidth() const { return 0; }
    virtual int intrinsicHeight() const { return 0; }

    // used by flexible boxes to impose a flexed width/height override
    virtual int overrideSize() const { return 0; }
    virtual int overrideWidth() const { return 0; }
    virtual int overrideHeight() const { return 0; }
    virtual void setOverrideSize(int s) {}

    // relative to parent node
    virtual void setPos( int /*xPos*/, int /*yPos*/ ) { }
    virtual void setWidth( int /*width*/ ) { }
    virtual void setHeight( int /*height*/ ) { }

    virtual int xPos() const { return 0; }
    virtual int yPos() const { return 0; }

    // calculate client position of box
    virtual bool absolutePosition(int &/*xPos*/, int &/*yPos*/, bool fixed = false);

    // width and height are without margins but include paddings and borders
    virtual int width() const { return 0; }
    virtual int height() const { return 0; }

    virtual QRect borderBox() const { return QRect(0, 0, width(), height()); }

    // The height of a block when you include normal flow overflow spillage out of the bottom
    // of the block (e.g., a <div style="height:25px"> that has a 100px tall image inside
    // it would have an overflow height of borderTop() + paddingTop() + 100px.
    virtual int overflowHeight(bool includeInterior=true) const { return height(); }
    virtual int overflowWidth(bool includeInterior=true) const { return width(); }
    virtual void setOverflowHeight(int) {}
    virtual void setOverflowWidth(int) {}
    virtual int overflowLeft(bool includeInterior=true) const { return 0; }
    virtual int overflowTop(bool includeInterior=true) const { return 0; }
    virtual QRect overflowRect(bool includeInterior=true) const { return borderBox(); }

    // IE extensions. Used to calculate offsetWidth/Height.  Overridden by inlines (render_flow) 
    // to return the remaining width on a given line (and the height of a single line). -dwh
    virtual int offsetWidth() const { return width(); }
    virtual int offsetHeight() const { return height(); }
    
    // IE exxtensions.  Also supported by Gecko.  We override in render flow to get the
    // left and top correct. -dwh
    virtual int offsetLeft() const;
    virtual int offsetTop() const;
    virtual RenderObject* offsetParent() const;

    // More IE extensions.  clientWidth and clientHeight represent the interior of an object
    // excluding border and scrollbar.
    int clientWidth() const;
    int clientHeight() const;

    // scrollWidth/scrollHeight will be the same as clientWidth/clientHeight unless the
    // object has overflow:hidden/scroll/auto specified and also has overflow.
    int scrollWidth() const;
    int scrollHeight() const;
    
    virtual bool scroll(KWQScrollDirection direction, KWQScrollGranularity granularity, float multiplier=1.0);

    // The following seven functions are used to implement collapsing margins.
    // All objects know their maximal positive and negative margins.  The
    // formula for computing a collapsed margin is |maxPosMargin|-|maxNegmargin|.
    // For a non-collapsing, e.g., a leaf element, this formula will simply return
    // the margin of the element.  Blocks override the maxTopMargin and maxBottomMargin
    // methods.
    virtual bool isSelfCollapsingBlock() const { return false; }
    virtual int collapsedMarginTop() const 
        { return maxTopMargin(true)-maxTopMargin(false); }
    virtual int collapsedMarginBottom() const 
        { return maxBottomMargin(true)-maxBottomMargin(false); }
    virtual bool isTopMarginQuirk() const { return false; }
    virtual bool isBottomMarginQuirk() const { return false; }
    virtual int maxTopMargin(bool positive) const {
        if (positive)
            if (marginTop() > 0)
                return marginTop();
            else
                return 0;
        else
            if (marginTop() < 0)
                return 0 - marginTop();
            else
                return 0;
    }
    virtual int maxBottomMargin(bool positive) const {
        if (positive)
            if (marginBottom() > 0)
                return marginBottom();
            else
                return 0;
        else
            if (marginBottom() < 0)
                return 0 - marginBottom();
            else
                return 0;
    }

    virtual int marginTop() const { return 0; }
    virtual int marginBottom() const { return 0; }
    virtual int marginLeft() const { return 0; }
    virtual int marginRight() const { return 0; }

    // Virtual since table cells override 
    virtual int paddingTop() const;
    virtual int paddingBottom() const;
    virtual int paddingLeft() const;
    virtual int paddingRight() const;
    
    virtual int borderTop() const { return style()->borderTopWidth(); }
    virtual int borderBottom() const { return style()->borderBottomWidth(); }
    virtual int borderTopExtra() const { return 0; }
    virtual int borderBottomExtra() const { return 0; }
    virtual int borderLeft() const { return style()->borderLeftWidth(); }
    virtual int borderRight() const { return style()->borderRightWidth(); }

    virtual void absoluteRects(QValueList<QRect>& rects, int _tx, int _ty);
    QRect absoluteBoundingBoxRect();
    
    // the rect that will be painted if this object is passed as the paintingRoot
    QRect paintingRootRect(QRect& topLevelRect);

#if APPLE_CHANGES
    virtual void addFocusRingRects(QPainter *painter, int _tx, int _ty);
#endif

    virtual int minWidth() const { return 0; }
    virtual int maxWidth() const { return 0; }

    RenderStyle* style() const { return m_style; }
    RenderStyle* style( bool firstLine ) const;

    void getTextDecorationColors(int decorations, QColor& underline, QColor& overline,
                                 QColor& linethrough, bool quirksMode=false);

    enum BorderSide {
        BSTop, BSBottom, BSLeft, BSRight
    };
    void drawBorder(QPainter *p, int x1, int y1, int x2, int y2, BorderSide s,
                    QColor c, const QColor& textcolor, EBorderStyle style,
                    int adjbw1, int adjbw2, bool invalidisInvert = false);

    virtual void setTable(RenderTable*) {};

    // Used by collapsed border tables.
    virtual void collectBorders(QValueList<CollapsedBorderValue>& borderStyles);

    // Repaint the entire object.  Called when, e.g., the color of a border changes, or when a border
    // style changes.
    void repaint(bool immediate = false);

    // Repaint a specific subrectangle within a given object.  The rect |r| is in the object's coordinate space.
    void repaintRectangle(const QRect& r, bool immediate = false);
    
    // Repaint only if our old bounds and new bounds are different.
    bool repaintAfterLayoutIfNeeded(const QRect& oldBounds, const QRect& oldFullBounds);

    // Repaint only if the object moved.
    virtual void repaintDuringLayoutIfMoved(int oldX, int oldY);

    // Called to repaint a block's floats.
    virtual void repaintFloatingDescendants();

    // Called before layout to repaint all dirty children (with selfNeedsLayout() set).
    virtual void repaintObjectsBeforeLayout();

    bool checkForRepaintDuringLayout() const;

    // Returns the rect that should be repainted whenever this object changes.  The rect is in the view's
    // coordinate space.  This method deals with outlines and overflow.
    virtual QRect getAbsoluteRepaintRect();

    QRect getAbsoluteRepaintRectWithOutline(int ow);

    virtual void getAbsoluteRepaintRectIncludingFloats(QRect& bounds, QRect& boundsWithChildren);

    // Given a rect in the object's coordinate space, this method converts the rectangle to the view's
    // coordinate space.
    virtual void computeAbsoluteRepaintRect(QRect& r, bool f=false);
    
    virtual unsigned int length() const { return 1; }

    bool isFloatingOrPositioned() const { return (isFloating() || isPositioned()); };
    virtual bool containsFloats() { return false; }
    virtual bool containsFloat(RenderObject* o) { return false; }
    virtual bool hasOverhangingFloats() { return false; }
    virtual QRect floatRect() const { return borderBox(); }

    bool avoidsFloats() const;
    bool usesLineWidth() const;

    // positioning of inline children (bidi)
    virtual void position(InlineBox*, int, int, bool) {}

    // Applied as a "slop" to dirty rect checks during the outline painting phase's dirty-rect checks.
    int maximalOutlineSize(PaintAction p) const;

    enum SelectionState {
        SelectionNone, // The object is not selected.
        SelectionStart, // The object either contains the start of a selection run or is the start of a run
        SelectionInside, // The object is fully encompassed by a selection run
        SelectionEnd, // The object either contains the end of a selection run or is the end of a run
        SelectionBoth // The object contains an entire run or is the sole selected object in that run
    };

    // The current selection state for an object.  For blocks, the state refers to the state of the leaf
    // descendants (as described above in the SelectionState enum declaration).
    virtual SelectionState selectionState() const { return SelectionNone; }
    
    // Sets the selection state for an object.
    virtual void setSelectionState(SelectionState s) { if (parent()) parent()->setSelectionState(s); }

    // A single rectangle that encompasses all of the selected objects within this object.  Used to determine the tightest
    // possible bounding box for the selection.
    virtual QRect selectionRect() { return QRect(); }
    
    // Whether or not an object can be part of the leaf elements of the selection.
    virtual bool canBeSelectionLeaf() const { return false; }

    // Whether or not a block has selected children.
    virtual bool hasSelectedChildren() const { return false; }

    // Whether or not a selection can be attempted on this object.
    bool canSelect() const;

    // Whether or not a selection can be attempted on this object.  Should only be called right before actually beginning a selection,
    // since it fires the selectstart DOM event.
    bool shouldSelect() const;
    
    // Obtains the selection background color that should be used when painting a selection.
    virtual QColor selectionColor(QPainter *p) const;
    
    // Whether or not a given block needs to paint selection gaps.
    virtual bool shouldPaintSelectionGaps() const { return false; }

    // This struct is used when the selection changes to cache the old and new state of the selection for each RenderObject.
    struct SelectionInfo {
        RenderObject* m_object;
        QRect m_rect;
        RenderObject::SelectionState m_state;

        RenderObject* object() const { return m_object; }
        QRect rect() const { return m_rect; }
        SelectionState state() const { return m_state; }
        
        SelectionInfo() { m_object = 0; m_state = SelectionNone; }
        SelectionInfo(RenderObject* o) :m_object(o), m_rect(o->selectionRect()), m_state(o->selectionState()) {}
    };

    DOM::NodeImpl* draggableNode(bool dhtmlOK, bool uaOK, int x, int y, bool& dhtmlWillDrag) const;

    /**
     * Returns the content coordinates of the caret within this render object.
     * @param offset zero-based offset determining position within the render object.
     * @param override @p true if input overrides existing characters,
     * @p false if it inserts them. The width of the caret depends on this one.
     * @param extraWidthToEndOfLine optional out arg to give extra width to end of line -
     * useful for character range rect computations
     */
    virtual QRect caretRect(int offset, EAffinity affinity = UPSTREAM, int *extraWidthToEndOfLine = 0);

    virtual int lowestPosition(bool includeOverflowInterior=true, bool includeSelf=true) const { return 0; }
    virtual int rightmostPosition(bool includeOverflowInterior=true, bool includeSelf=true) const { return 0; }
    virtual int leftmostPosition(bool includeOverflowInterior=true, bool includeSelf=true) const { return 0; }
    
    virtual void calcVerticalMargins() {}
    void removeFromObjectLists();

    // When performing a global document tear-down, the renderer of the document is cleared.  We use this
    // as a hook to detect the case of document destruction and don't waste time doing unnecessary work.
    bool documentBeingDestroyed() const { return !document()->renderer(); }

    virtual void detach();

    const QFont &font(bool firstLine) const {
	return style( firstLine )->font();
    }

    const QFontMetrics &fontMetrics(bool firstLine) const {
	return style( firstLine )->fontMetrics();
    }

    // Virtual function helpers for CSS3 Flexible Box Layout
    virtual bool isFlexibleBox() const { return false; }
    virtual bool isFlexingChildren() const { return false; }
    virtual bool isStretchingChildren() const { return false; }

    // Convenience, to avoid repeating the code to dig down to get this.
    QChar backslashAsCurrencySymbol() const;

    virtual long caretMinOffset() const;
    virtual long caretMaxOffset() const;
    virtual unsigned long caretMaxRenderedOffset() const;

    virtual long previousOffset (long current) const;
    virtual long nextOffset (long current) const;

    virtual void setPixmap(const QPixmap&, const QRect&, CachedImage *);

    virtual void selectionStartEnd(int& spos, int& epos);

    RenderObject* paintingRootForChildren(PaintInfo &i) const {
        // if we're the painting root, kids draw normally, and see root of 0
        return (!i.paintingRoot || i.paintingRoot == this) ? 0 : i.paintingRoot;
    }

    bool shouldPaintWithinRoot(PaintInfo &i) const {
        return !i.paintingRoot || i.paintingRoot == this;
    }
    
protected:

    virtual void printBoxDecorations(QPainter* /*p*/, int /*_x*/, int /*_y*/,
                                     int /*_w*/, int /*_h*/, int /*_tx*/, int /*_ty*/) {}

    virtual QRect viewRect() const;

    void remove();

    void invalidateVerticalPositions();
    short getVerticalPosition( bool firstLine ) const;

    virtual void removeLeftoverAnonymousBoxes();
    
    void arenaDelete(RenderArena *arena, void *objectBase);

private:
    RenderStyle* m_style;

    DOM::NodeImpl* m_node;

    RenderObject *m_parent;
    RenderObject *m_previous;
    RenderObject *m_next;

    mutable short m_verticalPosition;

    bool m_needsLayout               : 1;
    bool m_normalChildNeedsLayout    : 1;
    bool m_posChildNeedsLayout       : 1;
    bool m_minMaxKnown               : 1;
    bool m_floating                  : 1;

    bool m_positioned                : 1;
    bool m_relPositioned             : 1;
    bool m_paintBackground           : 1; // if the box has something to paint in the
                                          // background painting phase (background, border, etc)

    bool m_isAnonymous               : 1;
    bool m_recalcMinMax 	     : 1;
    bool m_isText                    : 1;
    bool m_inline                    : 1;
    bool m_replaced                  : 1;
    bool m_isDragging                : 1;
    
    bool m_hasOverflowClip           : 1;

    // note: do not add unnecessary bitflags, we have 32 bit already!
    friend class RenderListItem;
    friend class RenderContainer;
    friend class RenderCanvas;
};


enum VerticalPositionHint {
    PositionTop = -0x4000,
    PositionBottom = 0x4000,
    PositionUndefined = 0x3fff
};

}; //namespace
#endif