layout/generic/nsLeafFrame.h

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  37
  38 /* base class for rendering objects that do not have child lists */
  39
  40 #ifndef nsLeafFrame_h___
  41 #define nsLeafFrame_h___
  42
  43 #include "nsFrame.h"
  44 #include "nsDisplayList.h"
  45
  46 /**
  47  * Abstract class that provides simple fixed-size layout for leaf objects
  48  * (e.g. images, form elements, etc.). Deriviations provide the implementation
  49  * of the GetDesiredSize method. The rendering method knows how to render
  50  * borders and backgrounds.
  51  */
  52 class nsLeafFrame : public nsFrame {
  53 public:
  54   NS_DECL_FRAMEARENA_HELPERS
  55
  56   // nsIFrame replacements
  57   NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
  58                               const nsRect&           aDirtyRect,
  59                               const nsDisplayListSet& aLists) {
  60     DO_GLOBAL_REFLOW_COUNT_DSP("nsLeafFrame");
  61     return DisplayBorderBackgroundOutline(aBuilder, aLists);
  62   }
  63
  64   /**
  65    * Both GetMinWidth and GetPrefWidth will return whatever GetIntrinsicWidth
  66    * returns.
  67    */
  68   virtual nscoord GetMinWidth(nsIRenderingContext *aRenderingContext);
  69   virtual nscoord GetPrefWidth(nsIRenderingContext *aRenderingContext);
  70
  71   /**
  72    * Our auto size is just intrinsic width and intrinsic height.
  73    */
  74   virtual nsSize ComputeAutoSize(nsIRenderingContext *aRenderingContext,
  75                                  nsSize aCBSize, nscoord aAvailableWidth,
  76                                  nsSize aMargin, nsSize aBorder,
  77                                  nsSize aPadding, PRBool aShrinkWrap);
  78
  79   /**
  80    * Reflow our frame.  This will use the computed width plus borderpadding for
  81    * the desired width, and use the return value of GetIntrinsicHeight plus
  82    * borderpadding for the desired height.  Ascent will be set to the height,
  83    * and descent will be set to 0.
  84    */
  85   NS_IMETHOD Reflow(nsPresContext*      aPresContext,
  86                     nsHTMLReflowMetrics& aDesiredSize,
  87                     const nsHTMLReflowState& aReflowState,
  88                     nsReflowStatus&      aStatus);
  89
  90   /**
  91    * This method does most of the work that Reflow() above need done.
  92    */
  93   NS_IMETHOD DoReflow(nsPresContext*      aPresContext,
  94                       nsHTMLReflowMetrics& aDesiredSize,
  95                       const nsHTMLReflowState& aReflowState,
  96                       nsReflowStatus&      aStatus);
  97
  98   virtual PRBool IsFrameOfType(PRUint32 aFlags) const
  99   {
 100     // We don't actually contain a block, but we do always want a
 101     // computed width, so tell a little white lie here.
 102     return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplacedContainsBlock));
 103   }
 104
 105 protected:
 106   nsLeafFrame(nsStyleContext* aContext) : nsFrame(aContext) {}
 107   virtual ~nsLeafFrame();
 108
 109   /**
 110    * Return the intrinsic width of the frame's content area. Note that this
 111    * should not include borders or padding and should not depend on the applied
 112    * styles.
 113    */
 114   virtual nscoord GetIntrinsicWidth() = 0;
 115
 116   /**
 117    * Return the intrinsic height of the frame's content area.  This should not
 118    * include border or padding.  This will only matter if the specified height
 119    * is auto.  Note that subclasses must either implement this or override
 120    * Reflow and ComputeAutoSize; the default Reflow and ComputeAutoSize impls
 121    * call this method.
 122    */
 123   virtual nscoord GetIntrinsicHeight();
 124
 125   /**
 126    * Subroutine to add in borders and padding
 127    */
 128   void AddBordersAndPadding(const nsHTMLReflowState& aReflowState,
 129                             nsHTMLReflowMetrics& aDesiredSize);
 130
 131   /**
 132    * Set aDesiredSize to be the available size
 133    */
 134   void SizeToAvailSize(const nsHTMLReflowState& aReflowState,
 135                        nsHTMLReflowMetrics& aDesiredSize);
 136 };
 137
 138 #endif /* nsLeafFrame_h___ */