gecko-dev/layout/generic/nsHTMLContainerFrame.h

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/* base class #2 for rendering objects that have child lists */

#ifndef nsHTMLContainerFrame_h___
#define nsHTMLContainerFrame_h___

#include "nsContainerFrame.h"
#include "gfxPoint.h"
#include "nsIDeviceContext.h"

class nsString;
class nsAbsoluteFrame;
class nsPlaceholderFrame;
struct nsStyleDisplay;
struct nsStylePosition;
struct nsHTMLReflowMetrics;
struct nsHTMLReflowState;
class nsLineBox;

// Some macros for container classes to do sanity checking on
// width/height/x/y values computed during reflow.
#ifdef DEBUG
#define CRAZY_W (1000000*nsIDeviceContext::AppUnitsPerCSSPixel())
#define CRAZY_H CRAZY_W

#define CRAZY_WIDTH(_x) (((_x) < -CRAZY_W) || ((_x) > CRAZY_W))
#define CRAZY_HEIGHT(_y) (((_y) < -CRAZY_H) || ((_y) > CRAZY_H))
#endif

class nsDisplayTextDecoration;

// Base class for html container frames that provides common
// functionality.
class nsHTMLContainerFrame : public nsContainerFrame {
public:
  NS_DECL_FRAMEARENA_HELPERS

  /**
   * Helper method to wrap views around frames. Used by containers
   * under special circumstances (can be used by leaf frames as well)
   */
  static nsresult CreateViewForFrame(nsIFrame* aFrame,
                                     PRBool aForce);

  static nsresult ReparentFrameView(nsPresContext* aPresContext,
                                    nsIFrame*       aChildFrame,
                                    nsIFrame*       aOldParentFrame,
                                    nsIFrame*       aNewParentFrame);

  static nsresult ReparentFrameViewList(nsPresContext*     aPresContext,
                                        const nsFrameList& aChildFrameList,
                                        nsIFrame*          aOldParentFrame,
                                        nsIFrame*          aNewParentFrame);

  /**
   * Helper method to create next-in-flows if necessary. If aFrame
   * already has a next-in-flow then this method does
   * nothing. Otherwise, a new continuation frame is created and
   * linked into the flow. In addition, the new frame is inserted
   * into the principal child list after aFrame.
   * @note calling this method on a block frame is illegal. Use
   * nsBlockFrame::CreateContinuationFor() instead.
   * @param aNextInFlowResult will contain the next-in-flow
   *        <b>if and only if</b> one is created. If a next-in-flow already
   *        exists aNextInFlowResult is set to nsnull.
   * @return NS_OK if a next-in-flow already exists or is successfully created.
   */
  nsresult CreateNextInFlow(nsPresContext* aPresContext,
                            nsIFrame*       aFrame,
                            nsIFrame*&      aNextInFlowResult);

  /**
   * Displays the standard border, background and outline for the frame
   * and calls DisplayTextDecorationsAndChildren. This is suitable for
   * inline frames or frames that behave like inlines.
   */
  NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                              const nsRect&           aDirtyRect,
                              const nsDisplayListSet& aLists);
                              
  nsresult DisplayTextDecorations(nsDisplayListBuilder* aBuilder,
                                  nsDisplayList* aBelowTextDecorations,
                                  nsDisplayList* aAboveTextDecorations,
                                  nsLineBox* aLine);

protected:
  nsHTMLContainerFrame(nsStyleContext *aContext) : nsContainerFrame(aContext) {}

  /**
   * Displays the below-children decorations, then the children, then
   * the above-children decorations, with the decorations going in the
   * Content() list. This is suitable for inline elements and elements
   * that behave like inline elements (e.g. MathML containers).
   */
  nsresult DisplayTextDecorationsAndChildren(nsDisplayListBuilder* aBuilder, 
                                             const nsRect& aDirtyRect,
                                             const nsDisplayListSet& aLists);

  /**
   * Fetch the text decorations for this frame. 
   *  @param aIsBlock      whether |this| is a block frame or no.
   *  @param aDecorations  mask with all decorations. 
   *                         See bug 1777 and 20163 to understand how a
   *                         frame can end up with several decorations.
   *  @param aUnderColor   The color of underline if the appropriate bit 
   *                         in aDecoration is set. It is undefined otherwise.
   *  @param aOverColor    The color of overline if the appropriate bit 
   *                         in aDecoration is set. It is undefined otherwise.
   *  @param aStrikeColor  The color of strike-through if the appropriate bit 
   *                         in aDecoration is set. It is undefined otherwise.
   *  NOTE: This function assigns NS_STYLE_TEXT_DECORATION_NONE to
   *        aDecorations for text-less frames.  See bug 20163 for
   *        details.
   */
  void GetTextDecorations(nsPresContext* aPresContext, 
                          PRBool aIsBlock,
                          PRUint8& aDecorations, 
                          nscolor& aUnderColor, 
                          nscolor& aOverColor, 
                          nscolor& aStrikeColor);

  /** 
   * Function that does the actual drawing of the textdecoration. 
   *   input:
   *    @param aCtx               the Thebes graphics context to draw on
   *    @param aLine              the line, or nsnull if this is an inline frame
   *    @param aColor             the color of the text-decoration
   *    @param aAscent            ascent of the font from which the
   *                                text-decoration was derived. 
   *    @param aOffset            distance *above* baseline where the
   *                                text-decoration should be drawn,
   *                                i.e. negative offsets draws *below*
   *                                the baseline.
   *    @param aSize              the thickness of the line
   *    @param aDecoration        which line will be painted
   *                                i.e., NS_STYLE_TEXT_DECORATION_UNDERLINE or
   *                                      NS_STYLE_TEXT_DECORATION_OVERLINE or
   *                                      NS_STYLE_TEXT_DECORATION_LINE_THROUGH.
   */
  virtual void PaintTextDecorationLine(gfxContext* aCtx,
                                       const nsPoint& aPt,
                                       nsLineBox* aLine,
                                       nscolor aColor,
                                       gfxFloat aOffset,
                                       gfxFloat aAscent,
                                       gfxFloat aSize,
                                       const PRUint8 aDecoration);

  virtual void AdjustForTextIndent(const nsLineBox* aLine,
                                   nscoord& start,
                                   nscoord& width);

  friend class nsDisplayTextDecoration;
  friend class nsDisplayTextShadow;
};

#endif /* nsHTMLContainerFrame_h___ */