layout/base/SelectionCarets.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 sw=2 et tw=78: */
   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 SelectionCarets_h__
   8 #define SelectionCarets_h__
   9
  10 #include "nsIScrollObserver.h"
  11 #include "nsISelectionListener.h"
  12 #include "nsWeakPtr.h"
  13 #include "nsWeakReference.h"
  14 #include "Units.h"
  15 #include "mozilla/EventForwards.h"
  16
  17 class nsCanvasFrame;
  18 class nsIDocument;
  19 class nsIFrame;
  20 class nsIPresShell;
  21 class nsITimer;
  22 class nsIWidget;
  23 class nsPresContext;
  24
  25 namespace mozilla {
  26
  27 /**
  28  * The SelectionCarets draw a pair of carets when the selection is not
  29  * collapsed, one at each end of the selection.
  30  * SelectionCarets also handle visibility, dragging caret and selecting word
  31  * when long tap event fired.
  32  *
  33  * The DOM structure is 2 div elements for showing start and end caret.
  34  *
  35  * Here is an explanation of the html class names:
  36  *   .moz-selectioncaret-left: Indicates start DIV.
  37  *   .moz-selectioncaret-right: Indicates end DIV.
  38  *   .hidden: This class name is set by SetVisibility,
  39  *            SetStartFrameVisibility and SetEndFrameVisibility. Element
  40  *            with this class name become hidden.
  41  *   .tilt: This class name is set by SetTilted. According to the
  42  *          UX spec, when selection contains only one characters, the image of
  43  *          caret becomes tilt.
  44  */
  45 class SelectionCarets MOZ_FINAL : public nsISelectionListener,
  46                                   public nsIScrollObserver,
  47                                   public nsSupportsWeakReference
  48 {
  49 public:
  50   /**
  51    * Indicate which part of caret we are dragging at.
  52    */
  53   enum DragMode {
  54     NONE,
  55     START_FRAME,
  56     END_FRAME
  57   };
  58
  59   explicit SelectionCarets(nsIPresShell *aPresShell);
  60
  61   NS_DECL_ISUPPORTS
  62   NS_DECL_NSISELECTIONLISTENER
  63
  64   // nsIScrollObserver
  65   virtual void ScrollPositionChanged() MOZ_OVERRIDE;
  66
  67   void Terminate()
  68   {
  69     mPresShell = nullptr;
  70   }
  71
  72   nsEventStatus HandleEvent(WidgetEvent* aEvent);
  73
  74   /**
  75    * Set visibility for selection caret.
  76    */
  77   void SetVisibility(bool aVisible);
  78
  79   bool GetVisibility() const
  80   {
  81     return mVisible;
  82   }
  83
  84   /**
  85    * Get from pref "selectioncaret.inflatesize.threshold". This will inflate size of
  86    * caret frame when we checking if user click on caret or not. In app units.
  87    */
  88   static int32_t SelectionCaretsInflateSize()
  89   {
  90     return sSelectionCaretsInflateSize;
  91   }
  92
  93 private:
  94   virtual ~SelectionCarets();
  95
  96   SelectionCarets() MOZ_DELETE;
  97
  98   /**
  99    * Update selection caret position base on current selection range.
 100    */
 101   void UpdateSelectionCarets();
 102
 103   /**
 104    * Select word base on current position, only active when element
 105    * is focused. Triggered by long tap event.
 106    */
 107   nsresult SelectWord();
 108
 109   /**
 110    * Move selection base on current touch/mouse point
 111    */
 112   nsEventStatus DragSelection(const nsPoint &movePoint);
 113
 114   /**
 115    * Get the vertical center position of selection caret relative to canvas
 116    * frame.
 117    */
 118   nscoord GetCaretYCenterPosition();
 119
 120   /**
 121    * Simulate drag state when we change the selection range.
 122    * Hence, the selection change event will fire normally.
 123    */
 124   void SetSelectionDragState(bool aState);
 125
 126   void SetSelectionDirection(bool aForward);
 127
 128   /**
 129    * Move start frame of selection caret to given position.
 130    * In app units.
 131    */
 132   void SetStartFramePos(const nsPoint& aPosition);
 133
 134   /**
 135    * Move end frame of selection caret to given position.
 136    * In app units.
 137    */
 138   void SetEndFramePos(const nsPoint& aPosition);
 139
 140   /**
 141    * Get rect of selection caret's start frame relative
 142    * to document's canvas frame, in app units.
 143    */
 144   nsRect GetStartFrameRect();
 145
 146   /**
 147    * Get rect of selection caret's end frame relative
 148    * to document's canvas frame, in app units.
 149    */
 150   nsRect GetEndFrameRect();
 151
 152   /**
 153    * Set visibility for start part of selection caret, this function
 154    * only affects css property of start frame. So it doesn't change
 155    * mVisible member. When caret overflows element's box we'll hide
 156    * it by calling this function.
 157    */
 158   void SetStartFrameVisibility(bool aVisible);
 159
 160   /**
 161    * Same as above function but for end frame of selection caret.
 162    */
 163   void SetEndFrameVisibility(bool aVisible);
 164
 165   /**
 166    * Set tilt class name to start and end frame of selection caret.
 167    */
 168   void SetTilted(bool aIsTilt);
 169
 170   // Utility function
 171   nsIFrame* GetCaretFocusFrame();
 172   bool GetCaretVisible();
 173   nsISelection* GetSelection();
 174
 175   /**
 176    * Detecting long tap using timer
 177    */
 178   void LaunchLongTapDetector();
 179   void CancelLongTapDetector();
 180   static void FireLongTap(nsITimer* aTimer, void* aSelectionCarets);
 181
 182   void LaunchScrollEndDetector();
 183   static void FireScrollEnd(nsITimer* aTimer, void* aSelectionCarets);
 184
 185   nsIPresShell* mPresShell;
 186
 187   // This timer is used for detecting long tap fire. If content process
 188   // has APZC, we'll use APZC for long tap detecting. Otherwise, we use this
 189   // timer to detect long tap.
 190   nsCOMPtr<nsITimer> mLongTapDetectorTimer;
 191
 192   // This timer is used for detecting scroll end. We don't have
 193   // scroll end event now, so we will fire this event with a
 194   // const time when we scroll. So when timer triggers, we treat it
 195   // as scroll end event.
 196   nsCOMPtr<nsITimer> mScrollEndDetectorTimer;
 197
 198   // When touch or mouse down, we save the position for detecting
 199   // drag distance
 200   nsPoint mDownPoint;
 201
 202   // For filter multitouch event
 203   int32_t mActiveTouchId;
 204
 205   nscoord mCaretCenterToDownPointOffsetY;
 206   DragMode mDragMode;
 207   bool mVisible;
 208   bool mStartCaretVisible;
 209   bool mEndCaretVisible;
 210
 211   // Preference
 212   static int32_t sSelectionCaretsInflateSize;
 213 };
 214 } // namespace mozilla
 215
 216 #endif //SelectionCarets_h__