render_object.h

It is WEB browser core module with source code. Very good!

    // 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 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
    OOM_MODIFIED
    {
        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_mouseInside               : 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

#ifdef __WINSCW__
#pragma enumsalwaysint reset
#endif

#endif