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