layout/xul/nsScrollbarFrame.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 //
   8 // nsScrollbarFrame
   9 //
  10
  11 #ifndef nsScrollbarFrame_h__
  12 #define nsScrollbarFrame_h__
  13
  14 #include "mozilla/Attributes.h"
  15 #include "mozilla/ScrollTypes.h"
  16 #include "nsIAnonymousContentCreator.h"
  17 #include "nsBoxFrame.h"
  18
  19 class nsIScrollbarMediator;
  20
  21 namespace mozilla {
  22 class PresShell;
  23 namespace dom {
  24 class Element;
  25 }
  26 }  // namespace mozilla
  27
  28 nsIFrame* NS_NewScrollbarFrame(mozilla::PresShell* aPresShell,
  29                                mozilla::ComputedStyle* aStyle);
  30
  31 class nsScrollbarFrame final : public nsBoxFrame,
  32                                public nsIAnonymousContentCreator {
  33   using Element = mozilla::dom::Element;
  34
  35  public:
  36   explicit nsScrollbarFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
  37       : nsBoxFrame(aStyle, aPresContext, kClassID),
  38         mSmoothScroll(false),
  39         mScrollUnit(mozilla::ScrollUnit::DEVICE_PIXELS),
  40         mDirection(0),
  41         mIncrement(0),
  42         mScrollbarMediator(nullptr),
  43         mUpTopButton(nullptr),
  44         mDownTopButton(nullptr),
  45         mSlider(nullptr),
  46         mThumb(nullptr),
  47         mUpBottomButton(nullptr),
  48         mDownBottomButton(nullptr) {}
  49
  50   NS_DECL_QUERYFRAME
  51   NS_DECL_FRAMEARENA_HELPERS(nsScrollbarFrame)
  52
  53 #ifdef DEBUG_FRAME_DUMP
  54   virtual nsresult GetFrameName(nsAString& aResult) const override {
  55     return MakeFrameName(u"ScrollbarFrame"_ns, aResult);
  56   }
  57 #endif
  58
  59   // nsIFrame overrides
  60   virtual nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
  61                                     int32_t aModType) override;
  62
  63   NS_IMETHOD HandlePress(nsPresContext* aPresContext,
  64                          mozilla::WidgetGUIEvent* aEvent,
  65                          nsEventStatus* aEventStatus) override;
  66
  67   NS_IMETHOD HandleMultiplePress(nsPresContext* aPresContext,
  68                                  mozilla::WidgetGUIEvent* aEvent,
  69                                  nsEventStatus* aEventStatus,
  70                                  bool aControlHeld) override;
  71
  72   MOZ_CAN_RUN_SCRIPT
  73   NS_IMETHOD HandleDrag(nsPresContext* aPresContext,
  74                         mozilla::WidgetGUIEvent* aEvent,
  75                         nsEventStatus* aEventStatus) override;
  76
  77   NS_IMETHOD HandleRelease(nsPresContext* aPresContext,
  78                            mozilla::WidgetGUIEvent* aEvent,
  79                            nsEventStatus* aEventStatus) override;
  80
  81   virtual void DestroyFrom(nsIFrame* aDestructRoot,
  82                            PostDestroyData& aPostDestroyData) override;
  83
  84   virtual void Init(nsIContent* aContent, nsContainerFrame* aParent,
  85                     nsIFrame* aPrevInFlow) override;
  86
  87   virtual void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
  88                       const ReflowInput& aReflowInput,
  89                       nsReflowStatus& aStatus) override;
  90
  91   void SetScrollbarMediatorContent(nsIContent* aMediator);
  92   nsIScrollbarMediator* GetScrollbarMediator();
  93
  94   // nsBox methods
  95
  96   /**
  97    * Treat scrollbars as clipping their children; overflowing children
  98    * will not be allowed to set an overflow rect on this
  99    * frame. This means that when the scroll code decides to hide a
 100    * scrollframe by setting its height or width to zero, that will
 101    * hide the children too.
 102    */
 103   virtual bool DoesClipChildrenInBothAxes() override { return true; }
 104
 105   virtual nsresult GetXULMargin(nsMargin& aMargin) override;
 106
 107   /**
 108    * The following three methods set the value of mIncrement when a
 109    * scrollbar button is pressed.
 110    */
 111   void SetIncrementToLine(int32_t aDirection);
 112   void SetIncrementToPage(int32_t aDirection);
 113   void SetIncrementToWhole(int32_t aDirection);
 114   /**
 115    * If aImplementsScrollByUnit is Yes then this uses mSmoothScroll,
 116    * mScrollUnit, and mDirection and calls ScrollByUnit on the
 117    * nsIScrollbarMediator. The return value is 0. This is better because it is
 118    * more modern and the scroll frame can perform the scroll via apz for
 119    * example. The old way below is still supported for xul trees. If
 120    * aImplementsScrollByUnit is No this adds mIncrement to the current
 121    * position and updates the curpos attribute obeying mSmoothScroll.
 122    * @returns The new position after clamping, in CSS Pixels
 123    * @note This method might destroy the frame, pres shell, and other objects.
 124    */
 125   enum class ImplementsScrollByUnit { Yes, No };
 126   int32_t MoveToNewPosition(ImplementsScrollByUnit aImplementsScrollByUnit);
 127   int32_t GetIncrement() { return mIncrement; }
 128
 129   // nsIAnonymousContentCreator
 130   virtual nsresult CreateAnonymousContent(
 131       nsTArray<ContentInfo>& aElements) override;
 132   virtual void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
 133                                         uint32_t aFilter) override;
 134
 135   void UpdateChildrenAttributeValue(nsAtom* aAttribute, bool aNotify);
 136
 137  protected:
 138   bool mSmoothScroll;
 139   mozilla::ScrollUnit mScrollUnit;
 140   // Direction and multiple to scroll
 141   int32_t mDirection;
 142
 143   // Amount to scroll, in CSSPixels
 144   // Ignored in favour of mScrollUnit/mDirection for regular scroll frames.
 145   // Trees use this though.
 146   int32_t mIncrement;
 147
 148  private:
 149   nsCOMPtr<nsIContent> mScrollbarMediator;
 150
 151   nsCOMPtr<Element> mUpTopButton;
 152   nsCOMPtr<Element> mDownTopButton;
 153   nsCOMPtr<Element> mSlider;
 154   nsCOMPtr<Element> mThumb;
 155   nsCOMPtr<Element> mUpBottomButton;
 156   nsCOMPtr<Element> mDownBottomButton;
 157 };  // class nsScrollbarFrame
 158
 159 #endif