layout/generic/nsFlexContainerFrame.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3
   4 /* This Source Code is subject to the terms of the Mozilla Public License
   5  * version 2.0 (the "License"). You can obtain a copy of the License at
   6  * http://mozilla.org/MPL/2.0/. */
   7
   8 /* rendering object for CSS "display: flex" */
   9
  10 #ifndef nsFlexContainerFrame_h___
  11 #define nsFlexContainerFrame_h___
  12
  13 #include "nsContainerFrame.h"
  14
  15 namespace mozilla {
  16 template <class T> class LinkedList;
  17 }
  18
  19 nsContainerFrame* NS_NewFlexContainerFrame(nsIPresShell* aPresShell,
  20                                            nsStyleContext* aContext);
  21
  22 typedef nsContainerFrame nsFlexContainerFrameSuper;
  23
  24 class nsFlexContainerFrame : public nsFlexContainerFrameSuper {
  25 public:
  26   NS_DECL_FRAMEARENA_HELPERS
  27   NS_DECL_QUERYFRAME_TARGET(nsFlexContainerFrame)
  28   NS_DECL_QUERYFRAME
  29
  30   // Factory method:
  31   friend nsContainerFrame* NS_NewFlexContainerFrame(nsIPresShell* aPresShell,
  32                                                     nsStyleContext* aContext);
  33
  34   // Forward-decls of helper classes
  35   class FlexItem;
  36   class FlexLine;
  37   class FlexboxAxisTracker;
  38   struct StrutInfo;
  39
  40   // nsIFrame overrides
  41   virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
  42                                 const nsRect&           aDirtyRect,
  43                                 const nsDisplayListSet& aLists) MOZ_OVERRIDE;
  44
  45   virtual void Reflow(nsPresContext*           aPresContext,
  46                       nsHTMLReflowMetrics&     aDesiredSize,
  47                       const nsHTMLReflowState& aReflowState,
  48                       nsReflowStatus&          aStatus) MOZ_OVERRIDE;
  49
  50   virtual nscoord
  51     GetMinISize(nsRenderingContext* aRenderingContext) MOZ_OVERRIDE;
  52   virtual nscoord
  53     GetPrefISize(nsRenderingContext* aRenderingContext) MOZ_OVERRIDE;
  54
  55   virtual nsIAtom* GetType() const MOZ_OVERRIDE;
  56 #ifdef DEBUG_FRAME_DUMP
  57   virtual nsresult GetFrameName(nsAString& aResult) const MOZ_OVERRIDE;
  58 #endif
  59   // Flexbox-specific public methods
  60   bool IsHorizontal();
  61
  62 protected:
  63   // Protected constructor & destructor
  64   explicit nsFlexContainerFrame(nsStyleContext* aContext) :
  65     nsFlexContainerFrameSuper(aContext)
  66   {}
  67   virtual ~nsFlexContainerFrame();
  68
  69   /*
  70    * This method does the bulk of the flex layout, implementing the algorithm
  71    * described at:
  72    *   http://dev.w3.org/csswg/css-flexbox/#layout-algorithm
  73    * (with a few initialization pieces happening in the caller, Reflow().
  74    *
  75    * Since this is a helper for Reflow(), this takes all the same parameters
  76    * as Reflow(), plus a few more parameters that Reflow() sets up for us.
  77    *
  78    * (The logic behind the division of work between Reflow and DoFlexLayout is
  79    * as follows: DoFlexLayout() begins at the step that we have to jump back
  80    * to, if we find any visibility:collapse children, and Reflow() does
  81    * everything before that point.)
  82    */
  83   void DoFlexLayout(nsPresContext*           aPresContext,
  84                     nsHTMLReflowMetrics&     aDesiredSize,
  85                     const nsHTMLReflowState& aReflowState,
  86                     nsReflowStatus&          aStatus,
  87                     nscoord aContentBoxMainSize,
  88                     nscoord aAvailableHeightForContent,
  89                     nsTArray<StrutInfo>& aStruts,
  90                     const FlexboxAxisTracker& aAxisTracker);
  91
  92   /**
  93    * Checks whether our child-frame list "mFrames" is sorted, using the given
  94    * IsLessThanOrEqual function, and sorts it if it's not already sorted.
  95    *
  96    * XXXdholbert Once we support pagination, we need to make this function
  97    * check our continuations as well (or wrap it in a function that does).
  98    *
  99    * @return true if we had to sort mFrames, false if it was already sorted.
 100    */
 101   template<bool IsLessThanOrEqual(nsIFrame*, nsIFrame*)>
 102   bool SortChildrenIfNeeded();
 103
 104   // Protected flex-container-specific methods / member-vars
 105 #ifdef DEBUG
 106   void SanityCheckAnonymousFlexItems() const;
 107 #endif // DEBUG
 108
 109   /*
 110    * Returns a new FlexItem for the given child frame, allocated on the heap.
 111    * Guaranteed to return non-null. Caller is responsible for managing the
 112    * FlexItem's lifetime.
 113    *
 114    * Before returning, this method also processes the FlexItem to resolve its
 115    * flex basis (including e.g. auto-height) as well as to resolve
 116    * "min-height:auto", via ResolveAutoFlexBasisAndMinSize(). (Basically, the
 117    * returned FlexItem will be ready to participate in the "Resolve the
 118    * Flexible Lengths" step of the Flex Layout Algorithm.)
 119    */
 120   FlexItem* GenerateFlexItemForChild(nsPresContext* aPresContext,
 121                                      nsIFrame* aChildFrame,
 122                                      const nsHTMLReflowState& aParentReflowState,
 123                                      const FlexboxAxisTracker& aAxisTracker);
 124
 125   /**
 126    * This method performs a "measuring" reflow to get the content height of
 127    * aFlexItem.Frame() (treating it as if it had auto-height), & returns the
 128    * resulting height.
 129    * (Helper for ResolveAutoFlexBasisAndMinSize().)
 130    */
 131   nscoord MeasureFlexItemContentHeight(nsPresContext* aPresContext,
 132                                        FlexItem& aFlexItem,
 133                                        bool aForceVerticalResizeForMeasuringReflow,
 134                                        const nsHTMLReflowState& aParentReflowState);
 135
 136   /**
 137    * This method resolves an "auto" flex-basis and/or min-main-size value
 138    * on aFlexItem, if needed.
 139    * (Helper for GenerateFlexItemForChild().)
 140    */
 141   void ResolveAutoFlexBasisAndMinSize(nsPresContext* aPresContext,
 142                                       FlexItem& aFlexItem,
 143                                       const nsHTMLReflowState& aItemReflowState,
 144                                       const FlexboxAxisTracker& aAxisTracker);
 145
 146   // Creates FlexItems for all of our child frames, arranged in a list of
 147   // FlexLines.  These are returned by reference in |aLines|. Our actual
 148   // return value has to be |nsresult|, in case we have to reflow a child
 149   // to establish its flex base size and that reflow fails.
 150   void GenerateFlexLines(nsPresContext* aPresContext,
 151                          const nsHTMLReflowState& aReflowState,
 152                          nscoord aContentBoxMainSize,
 153                          nscoord aAvailableHeightForContent,
 154                          const nsTArray<StrutInfo>& aStruts,
 155                          const FlexboxAxisTracker& aAxisTracker,
 156                          mozilla::LinkedList<FlexLine>& aLines);
 157
 158   nscoord GetMainSizeFromReflowState(const nsHTMLReflowState& aReflowState,
 159                                      const FlexboxAxisTracker& aAxisTracker);
 160
 161   nscoord ComputeCrossSize(const nsHTMLReflowState& aReflowState,
 162                            const FlexboxAxisTracker& aAxisTracker,
 163                            nscoord aSumLineCrossSizes,
 164                            nscoord aAvailableHeightForContent,
 165                            bool* aIsDefinite,
 166                            nsReflowStatus& aStatus);
 167
 168   void SizeItemInCrossAxis(nsPresContext* aPresContext,
 169                            const FlexboxAxisTracker& aAxisTracker,
 170                            nsHTMLReflowState& aChildReflowState,
 171                            FlexItem& aItem);
 172
 173   bool mChildrenHaveBeenReordered; // Have we ever had to reorder our kids
 174                                    // to satisfy their 'order' values?
 175 };
 176
 177 #endif /* nsFlexContainerFrame_h___ */