layout/generic/nsIScrollableFrame.h

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  37
  38 /*
  39  * interface for rendering objects that wrap rendering objects that should
  40  * be scrollable
  41  */
  42
  43 #ifndef nsIScrollFrame_h___
  44 #define nsIScrollFrame_h___
  45
  46 #include "nsISupports.h"
  47 #include "nsCoord.h"
  48 #include "nsIViewManager.h"
  49 #include "nsIScrollableViewProvider.h"
  50 #include "nsPresContext.h"
  51 #include "nsIFrame.h" // to get nsIBox, which is a typedef
  52
  53 class nsBoxLayoutState;
  54
  55 // IID for the nsIScrollableFrame interface
  56 #define NS_ISCROLLABLE_FRAME_IID    \
  57 { 0xf285c180, 0x8492, 0x48d5, \
  58 { 0xb1, 0xb5, 0x03, 0x28, 0x21, 0xc9, 0x72, 0x02 } }
  59
  60 class nsIScrollableFrame : public nsIScrollableViewProvider {
  61 public:
  62
  63   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ISCROLLABLE_FRAME_IID)
  64
  65   /**
  66    * Get the frame that we are scrolling within the scrollable frame.
  67    * @result child frame
  68    */
  69   virtual nsIFrame* GetScrolledFrame() const = 0;
  70
  71   typedef nsPresContext::ScrollbarStyles ScrollbarStyles;
  72
  73   virtual ScrollbarStyles GetScrollbarStyles() const = 0;
  74
  75   /**
  76    * Return the actual sizes of all possible scrollbars. Returns 0 for scrollbar
  77    * positions that don't have a scrollbar or where the scrollbar is not visible.
  78    * Do not call this while this frame's descendants are being reflowed, it won't be
  79    * accurate.
  80    */
  81   virtual nsMargin GetActualScrollbarSizes() const = 0;
  82
  83   /**
  84    * Return the sizes of all scrollbars assuming that any scrollbars that could
  85    * be visible due to overflowing content, are.
  86    */
  87   virtual nsMargin GetDesiredScrollbarSizes(nsBoxLayoutState* aState) = 0;
  88   virtual nsMargin GetDesiredScrollbarSizes(nsPresContext* aPresContext,
  89                                             nsIRenderingContext* aRC) = 0;
  90
  91   /**
  92    * Get the position of the scrolled view.
  93    */
  94   virtual nsPoint GetScrollPosition() const = 0;
  95
  96   /**
  97    * Scroll the view to the given x,y, update's the scrollbar's thumb
  98    * positions and the view's offset. Clamps the values to be
  99    * legal. Updates the display based on aUpdateFlags.
 100    * @param aX left edge to scroll to
 101    * @param aY top edge to scroll to
 102    * @param aUpdateFlags passed onto nsIViewManager->UpdateView()
 103    * @return error status
 104    */
 105   virtual void ScrollTo(nsPoint aScrollPosition, PRUint32 aFlags = NS_VMREFRESH_NO_SYNC)=0;
 106
 107   virtual nsIScrollableView* GetScrollableView() = 0;
 108
 109   /**
 110    * Set information about whether the vertical and horizontal scrollbars
 111    * are currently visible
 112    */
 113   virtual void SetScrollbarVisibility(PRBool aVerticalVisible, PRBool aHorizontalVisible) = 0;
 114
 115   virtual nsIBox* GetScrollbarBox(PRBool aVertical) = 0;
 116
 117   virtual void CurPosAttributeChanged(nsIContent* aChild, PRInt32 aModType) = 0;
 118
 119   /**
 120    * This tells the scroll frame to try scrolling to the scroll
 121    * position that was restored from the history. This must be called
 122    * at least once after state has been restored. It is called by the
 123    * scrolled frame itself during reflow, but sometimes state can be
 124    * restored after reflows are done...
 125    */
 126   virtual void ScrollToRestoredPosition() = 0;
 127 };
 128
 129 NS_DEFINE_STATIC_IID_ACCESSOR(nsIScrollableFrame, NS_ISCROLLABLE_FRAME_IID)
 130
 131 #endif