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 "nsContainerFrame.h"
  17 #include "nsIAnonymousContentCreator.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 nsContainerFrame,
  32                                public nsIAnonymousContentCreator {
  33   using Element = mozilla::dom::Element;
  34
  35  public:
  36   explicit nsScrollbarFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
  37       : nsContainerFrame(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   nsresult GetFrameName(nsAString& aResult) const override {
  55     return MakeFrameName(u"ScrollbarFrame"_ns, aResult);
  56   }
  57 #endif
  58
  59   // nsIFrame overrides
  60   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   mozilla::StyleScrollbarWidth ScrollbarWidth() const;
  82   nscoord ScrollbarTrackSize() const;
  83   nsSize ScrollbarMinSize() const;
  84   bool IsHorizontal() const;
  85
  86   void Destroy(DestroyContext&) override;
  87
  88   void Init(nsIContent* aContent, nsContainerFrame* aParent,
  89             nsIFrame* aPrevInFlow) override;
  90
  91   void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
  92               const ReflowInput& aReflowInput,
  93               nsReflowStatus& aStatus) override;
  94
  95   void SetScrollbarMediatorContent(nsIContent* aMediator);
  96   nsIScrollbarMediator* GetScrollbarMediator();
  97
  98   /**
  99    * The following three methods set the value of mIncrement when a
 100    * scrollbar button is pressed.
 101    */
 102   void SetIncrementToLine(int32_t aDirection);
 103   void SetIncrementToPage(int32_t aDirection);
 104   void SetIncrementToWhole(int32_t aDirection);
 105
 106   /**
 107    * If aImplementsScrollByUnit is Yes then this uses mSmoothScroll,
 108    * mScrollUnit, and mDirection and calls ScrollByUnit on the
 109    * nsIScrollbarMediator. The return value is 0. This is better because it is
 110    * more modern and the scroll frame can perform the scroll via apz for
 111    * example. The old way below is still supported for xul trees. If
 112    * aImplementsScrollByUnit is No this adds mIncrement to the current
 113    * position and updates the curpos attribute obeying mSmoothScroll.
 114    * @returns The new position after clamping, in CSS Pixels
 115    * @note This method might destroy the frame, pres shell, and other objects.
 116    */
 117   enum class ImplementsScrollByUnit { Yes, No };
 118   int32_t MoveToNewPosition(ImplementsScrollByUnit aImplementsScrollByUnit);
 119   int32_t GetIncrement() { return mIncrement; }
 120
 121   // nsIAnonymousContentCreator
 122   nsresult CreateAnonymousContent(nsTArray<ContentInfo>& aElements) override;
 123   void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
 124                                 uint32_t aFilter) override;
 125
 126   void UpdateChildrenAttributeValue(nsAtom* aAttribute, bool aNotify);
 127
 128  protected:
 129   bool mSmoothScroll;
 130   mozilla::ScrollUnit mScrollUnit;
 131   // Direction and multiple to scroll
 132   int32_t mDirection;
 133
 134   // Amount to scroll, in CSSPixels
 135   // Ignored in favour of mScrollUnit/mDirection for regular scroll frames.
 136   // Trees use this though.
 137   int32_t mIncrement;
 138
 139  private:
 140   nsCOMPtr<nsIContent> mScrollbarMediator;
 141
 142   nsCOMPtr<Element> mUpTopButton;
 143   nsCOMPtr<Element> mDownTopButton;
 144   nsCOMPtr<Element> mSlider;
 145   nsCOMPtr<Element> mThumb;
 146   nsCOMPtr<Element> mUpBottomButton;
 147   nsCOMPtr<Element> mDownBottomButton;
 148 };  // class nsScrollbarFrame
 149
 150 #endif