layout/generic/nsBlockBandData.h

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  37
  38 /* code for management of floats that implements space manager interfaces */
  39
  40 #ifndef nsBlockBandData_h___
  41 #define nsBlockBandData_h___
  42
  43 #include "nsSpaceManager.h"
  44
  45 class nsPresContext;
  46
  47 // Number of builtin nsBandTrapezoid's
  48 #define NS_BLOCK_BAND_DATA_TRAPS 6
  49
  50 /**
  51  * Class used to manage processing of the space-manager band data.
  52  * Provides HTML/CSS specific behavior to the raw data.
  53  */
  54 class nsBlockBandData : public nsBandData {
  55 public:
  56   nsBlockBandData();
  57   ~nsBlockBandData();
  58
  59   // Initialize. This must be called before any of the other methods.
  60   nsresult Init(nsSpaceManager* aSpaceManager, const nsSize& aSpace);
  61
  62   // Get some available space. Note that aY is relative to the current
  63   // space manager translation.
  64   nsresult GetAvailableSpace(nscoord aY, PRBool aRelaxHeightConstraint,
  65                              nsRect& aResult);
  66
  67   // Get the raw trapezoid count for this band.
  68   PRInt32 GetTrapezoidCount() const {
  69     return mCount;
  70   }
  71
  72   const nsBandTrapezoid* GetTrapezoid(PRInt32 aIndex) const {
  73     return &mTrapezoids[aIndex];
  74   }
  75
  76   // Get the number of floats that are impacting the current
  77   // band. Note that this value is relative to the current translation
  78   // in the space manager which means that some floats may be hidden
  79   // by the translation and therefore won't be in the count.
  80   PRInt32 GetFloatCount() const {
  81     return mLeftFloats + mRightFloats;
  82   }
  83   PRInt32 GetLeftFloatCount() const {
  84     return mLeftFloats;
  85   }
  86   PRInt32 GetRightFloatCount() const {
  87     return mRightFloats;
  88   }
  89
  90 #ifdef DEBUG
  91   void List();
  92 #endif
  93
  94 protected:
  95
  96   /** utility method to calculate the band data at aY.
  97     * nsBlockBandData methods should never call
  98     * mSpaceManager->GetBandData directly.
  99     * They should always call this method instead so data members
 100     * mTrapezoid, mCount, and mSize all get managed properly.
 101     */
 102   nsresult GetBandData(nscoord aY, PRBool aRelaxHeightConstraint);
 103
 104   // The spacemanager we are getting space from
 105   nsSpaceManager* mSpaceManager;
 106   nscoord mSpaceManagerX, mSpaceManagerY;
 107
 108   // Limit to the available space (set by Init)
 109   nsSize mSpace;
 110
 111   // Trapezoids used during band processing
 112   nsBandTrapezoid mData[NS_BLOCK_BAND_DATA_TRAPS];
 113
 114   // Bounding rect of available space between any left and right floats
 115   nsRect mAvailSpace;
 116
 117   // Number of left/right floats in the current band. Note that this
 118   // number may be less than the total number of floats present in
 119   // the band, if our translation in the space manager "hides" some
 120   // floats.
 121   PRInt32 mLeftFloats, mRightFloats;
 122
 123   void ComputeAvailSpaceRect();
 124 };
 125
 126 #endif /* nsBlockBandData_h___ */