layout/mathml/nsMathMLmunderoverFrame.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsMathMLmunderoverFrame_h___
   8 #define nsMathMLmunderoverFrame_h___
   9
  10 #include "mozilla/Attributes.h"
  11 #include "nsIReflowCallback.h"
  12 #include "nsMathMLContainerFrame.h"
  13
  14 namespace mozilla {
  15 class PresShell;
  16 }  // namespace mozilla
  17
  18 //
  19 // <munderover> -- attach an underscript-overscript pair to a base
  20 //
  21
  22 class nsMathMLmunderoverFrame final : public nsMathMLContainerFrame,
  23                                       public nsIReflowCallback {
  24  public:
  25   NS_DECL_FRAMEARENA_HELPERS(nsMathMLmunderoverFrame)
  26
  27   friend nsIFrame* NS_NewMathMLmunderoverFrame(mozilla::PresShell* aPresShell,
  28                                                ComputedStyle* aStyle);
  29
  30   nsresult Place(DrawTarget* aDrawTarget, const PlaceFlags& aFlags,
  31                  ReflowOutput& aDesiredSize) override;
  32
  33   NS_IMETHOD InheritAutomaticData(nsIFrame* aParent) override;
  34
  35   NS_IMETHOD TransmitAutomaticData() override;
  36
  37   NS_IMETHOD UpdatePresentationData(uint32_t aFlagsValues,
  38                                     uint32_t aFlagsToUpdate) override;
  39
  40   void Destroy(DestroyContext&) override;
  41
  42   nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
  43                             int32_t aModType) override;
  44
  45   uint8_t ScriptIncrement(nsIFrame* aFrame) override;
  46
  47   // nsIReflowCallback.
  48   bool ReflowFinished() override;
  49   void ReflowCallbackCanceled() override;
  50
  51  protected:
  52   explicit nsMathMLmunderoverFrame(ComputedStyle* aStyle,
  53                                    nsPresContext* aPresContext)
  54       : nsMathMLContainerFrame(aStyle, aPresContext, kClassID),
  55         mIncrementUnder(false),
  56         mIncrementOver(false) {}
  57
  58   virtual ~nsMathMLmunderoverFrame();
  59
  60  private:
  61   bool IsMathContentBoxHorizontallyCentered() const final;
  62
  63   // Helper to set the "increment script level" flag on the element belonging
  64   // to a child frame given by aChildIndex.
  65   //
  66   // When this flag is set, the style system will increment the scriptlevel for
  67   // the child element. This is needed for situations where the style system
  68   // cannot itself determine the scriptlevel (mfrac, munder, mover, munderover).
  69   //
  70   // This should be called during reflow.
  71   //
  72   // We set the flag and if it changed, we request appropriate restyling and
  73   // also queue a post-reflow callback to ensure that restyle and reflow happens
  74   // immediately after the current reflow.
  75   void SetIncrementScriptLevel(uint32_t aChildIndex, bool aIncrement);
  76   void SetPendingPostReflowIncrementScriptLevel();
  77
  78   bool mIncrementUnder;
  79   bool mIncrementOver;
  80
  81   struct SetIncrementScriptLevelCommand {
  82     uint32_t mChildIndex;
  83     bool mDoIncrement;
  84   };
  85
  86   nsTArray<SetIncrementScriptLevelCommand>
  87       mPostReflowIncrementScriptLevelCommands;
  88 };
  89
  90 #endif /* nsMathMLmunderoverFrame_h___ */