view/nsView.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsView_h__
   7 #define nsView_h__
   8
   9 #include "nsCoord.h"
  10 #include "nsRect.h"
  11 #include "nsPoint.h"
  12 #include "nsRegion.h"
  13 #include "nsCRT.h"
  14 #include "nsCOMPtr.h"
  15 #include "nsWidgetInitData.h"  // for nsWindowType
  16 #include "nsIWidgetListener.h"
  17 #include "Units.h"
  18 #include "mozilla/Attributes.h"
  19 #include "mozilla/EventForwards.h"
  20 #include "mozilla/UniquePtr.h"
  21
  22 class nsViewManager;
  23 class nsIWidget;
  24 class nsIFrame;
  25
  26 namespace mozilla {
  27 class PresShell;
  28 }  // namespace mozilla
  29
  30 /**
  31  * nsView's serve two main purposes: 1) a bridge between nsIFrame's and
  32  * nsIWidget's, 2) linking the frame tree of a(n) (in-process) subdocument with
  33  * its parent document frame tree. Historically views were used for more things,
  34  * but their role has been reduced, and could be reduced to nothing in the
  35  * future (bug 337801 tracks removing views). Views are generally associated
  36  * with a frame. A view that does not have a frame is called an anonymous view.
  37  * Some frames also have associated widgets (think os level windows). If a frame
  38  * has a widget it must also have a view, but not all frames with views will
  39  * have widgets.
  40  *
  41  * Only four types of frames can have a view: root frames (ViewportFrame),
  42  * subdocument frames (nsSubDocumentFrame),
  43  * menu popup frames (nsMenuPopupFrame), and list control frames
  44  * (nsListControlFrame). Root frames and subdocument frames have views to link
  45  * the two documents together (the frame trees do not link up otherwise).
  46  * Menu popup frames, and list control frames have views because
  47  * they (sometimes) need to create widgets.
  48  * Menu popup frames handles xul popups, which is anything
  49  * where we need content to go over top the main window at an os level. List
  50  * control frames handle select popups/dropdowns in non-e10s mode.
  51  *
  52  * The term "root view" refers to the root view of a document. Just like root
  53  * frames, root views can have parent views. Only the root view of the root
  54  * document in the process will not have a parent.
  55  *
  56  * All views are created by their frames except root views. Root views are
  57  * special. Root views are created in nsDocumentViewer::MakeWindow before the
  58  * root frame is created, so the root view will not have a frame very early in
  59  * document creation.
  60  *
  61  * Subdocument frames have an anonymous (no frame associated
  62  * with it) inner view that is a child of their "outer" view.
  63  *
  64  * On a subdocument frame the inner view serves as the parent of the
  65  * root view of the subdocument. The outer and inner view of the subdocument
  66  * frame belong to the subdocument frame and hence to the parent document. The
  67  * root view of the subdocument belongs to the subdocument.
  68  * nsLayoutUtils::GetCrossDocParentFrame and nsPresContext::GetParentPresContext
  69  * depend on this view structure and are the main way that we traverse across
  70  * the document boundary in layout.
  71  *
  72  * When the load of a new document is started in the subdocument, the creation
  73  * of the new subdocument and destruction of the old subdocument are not
  74  * linked. (This creation and destruction is handled in nsDocumentViewer.cpp.)
  75  * This means that the old and new document will both exist at the same time
  76  * during the loading of the new document. During this period the inner view of
  77  * the subdocument parent will be the parent of two root views. This means that
  78  * during this period there is a choice for which subdocument we draw,
  79  * nsSubDocumentFrame::GetSubdocumentPresShellForPainting is what makes that
  80  * choice. Note that this might not be a totally free choice, ie there might be
  81  * hidden dependencies and bugs if the way we choose is changed.
  82  *
  83  * One thing that is special about the root view of a chrome window is that
  84  * instead of creating a widget for the view, they can "attach" to the
  85  * existing widget that was created by appshell code or something else. (see
  86  * nsDocumentViewer::ShouldAttachToTopLevel)
  87  */
  88
  89 // Enumerated type to indicate the visibility of a layer.
  90 // hide - the layer is not shown.
  91 // show - the layer is shown irrespective of the visibility of
  92 //        the layer's parent.
  93 enum nsViewVisibility {
  94   nsViewVisibility_kHide = 0,
  95   nsViewVisibility_kShow = 1
  96 };
  97
  98 // Public view flags
  99
 100 // Indicates that the view is using auto z-indexing
 101 #define NS_VIEW_FLAG_AUTO_ZINDEX 0x0004
 102
 103 // Indicates that the view is a floating view.
 104 #define NS_VIEW_FLAG_FLOATING 0x0008
 105
 106 //----------------------------------------------------------------------
 107
 108 /**
 109  * View interface
 110  *
 111  * Views are NOT reference counted. Use the Destroy() member function to
 112  * destroy a view.
 113  *
 114  * The lifetime of the view hierarchy is bounded by the lifetime of the
 115  * view manager that owns the views.
 116  *
 117  * Most of the methods here are read-only. To set the corresponding properties
 118  * of a view, go through nsViewManager.
 119  */
 120
 121 class nsView final : public nsIWidgetListener {
 122  public:
 123   friend class nsViewManager;
 124
 125   typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
 126   typedef mozilla::LayoutDeviceIntRegion LayoutDeviceIntRegion;
 127
 128   void operator delete(void* ptr) { ::operator delete(ptr); }
 129
 130   /**
 131    * Get the view manager which "owns" the view.
 132    * This method might require some expensive traversal work in the future. If
 133    * you can get the view manager from somewhere else, do that instead.
 134    * @result the view manager
 135    */
 136   nsViewManager* GetViewManager() const { return mViewManager; }
 137
 138   /**
 139    * Find the view for the given widget, if there is one.
 140    * @return the view the widget belongs to, or null if the widget doesn't
 141    * belong to any view.
 142    */
 143   static nsView* GetViewFor(const nsIWidget* aWidget);
 144
 145   /**
 146    * Destroy the view.
 147    *
 148    * The view destroys its child views, and destroys and releases its
 149    * widget (if it has one).
 150    *
 151    * Also informs the view manager that the view is destroyed by calling
 152    * SetRootView(NULL) if the view is the root view and calling RemoveChild()
 153    * otherwise.
 154    */
 155   void Destroy();
 156
 157   /**
 158    * Called to get the position of a view.
 159    * The specified coordinates are relative to the parent view's origin, but
 160    * are in appunits of this.
 161    * This is the (0, 0) origin of the coordinate space established by this view.
 162    * @param x out parameter for x position
 163    * @param y out parameter for y position
 164    */
 165   nsPoint GetPosition() const {
 166     NS_ASSERTION(!IsRoot() || (mPosX == 0 && mPosY == 0),
 167                  "root views should always have explicit position of (0,0)");
 168     return nsPoint(mPosX, mPosY);
 169   }
 170
 171   /**
 172    * Called to get the dimensions and position of the view's bounds.
 173    * The view's bounds (x,y) are relative to the origin of the parent view, but
 174    * are in appunits of this.
 175    * The view's bounds (x,y) might not be the same as the view's position,
 176    * if the view has content above or to the left of its origin.
 177    * @param aBounds out parameter for bounds
 178    */
 179   nsRect GetBounds() const { return mDimBounds; }
 180
 181   /**
 182    * The bounds of this view relative to this view. So this is the same as
 183    * GetBounds except this is relative to this view instead of the parent view.
 184    */
 185   nsRect GetDimensions() const {
 186     nsRect r = mDimBounds;
 187     r.MoveBy(-mPosX, -mPosY);
 188     return r;
 189   }
 190
 191   /**
 192    * Get the offset between the coordinate systems of |this| and aOther.
 193    * Adding the return value to a point in the coordinate system of |this|
 194    * will transform the point to the coordinate system of aOther.
 195    *
 196    * The offset is expressed in appunits of |this|. So if you are getting the
 197    * offset between views in different documents that might have different
 198    * appunits per devpixel ratios you need to be careful how you use the
 199    * result.
 200    *
 201    * If aOther is null, this will return the offset of |this| from the
 202    * root of the viewmanager tree.
 203    *
 204    * This function is fastest when aOther is an ancestor of |this|.
 205    *
 206    * NOTE: this actually returns the offset from aOther to |this|, but
 207    * that offset is added to transform _coordinates_ from |this| to aOther.
 208    */
 209   nsPoint GetOffsetTo(const nsView* aOther) const;
 210
 211   /**
 212    * Get the offset between the origin of |this| and the origin of aWidget.
 213    * Adding the return value to a point in the coordinate system of |this|
 214    * will transform the point to the coordinate system of aWidget.
 215    *
 216    * The offset is expressed in appunits of |this|.
 217    */
 218   nsPoint GetOffsetToWidget(nsIWidget* aWidget) const;
 219
 220   /**
 221    * Takes a point aPt that is in the coordinate system of |this|'s parent view
 222    * and converts it to be in the coordinate system of |this| taking into
 223    * account the offset and any app unit per dev pixel ratio differences.
 224    */
 225   nsPoint ConvertFromParentCoords(nsPoint aPt) const;
 226
 227   /**
 228    * Called to query the visibility state of a view.
 229    * @result current visibility state
 230    */
 231   nsViewVisibility GetVisibility() const { return mVis; }
 232
 233   /**
 234    * Get whether the view "floats" above all other views,
 235    * which tells the compositor not to consider higher views in
 236    * the view hierarchy that would geometrically intersect with
 237    * this view. This is a hack, but it fixes some problems with
 238    * views that need to be drawn in front of all other views.
 239    * @result true if the view floats, false otherwise.
 240    */
 241   bool GetFloating() const { return (mVFlags & NS_VIEW_FLAG_FLOATING) != 0; }
 242
 243   /**
 244    * Called to query the parent of the view.
 245    * @result view's parent
 246    */
 247   nsView* GetParent() const { return mParent; }
 248
 249   /**
 250    * The view's first child is the child which is earliest in document order.
 251    * @result first child
 252    */
 253   nsView* GetFirstChild() const { return mFirstChild; }
 254
 255   /**
 256    * Called to query the next sibling of the view.
 257    * @result view's next sibling
 258    */
 259   nsView* GetNextSibling() const { return mNextSibling; }
 260
 261   /**
 262    * Set the view's frame.
 263    */
 264   void SetFrame(nsIFrame* aRootFrame) { mFrame = aRootFrame; }
 265
 266   /**
 267    * Retrieve the view's frame.
 268    */
 269   nsIFrame* GetFrame() const { return mFrame; }
 270
 271   /**
 272    * Get the nearest widget in this view or a parent of this view and
 273    * the offset from the widget's origin to this view's origin
 274    * @param aOffset - if non-null the offset from this view's origin to the
 275    * widget's origin (usually positive) expressed in appunits of this will be
 276    * returned in aOffset.
 277    * @return the widget closest to this view; can be null because some view
 278    * trees don't have widgets at all (e.g., printing), but if any view in the
 279    * view tree has a widget, then it's safe to assume this will not return null
 280    */
 281   nsIWidget* GetNearestWidget(nsPoint* aOffset) const;
 282
 283   /**
 284    * Create a widget to associate with this view.  This variant of
 285    * CreateWidget*() will look around in the view hierarchy for an
 286    * appropriate parent widget for the view.
 287    *
 288    * @param aWidgetInitData data used to initialize this view's widget before
 289    *        its create is called.
 290    * @return error status
 291    */
 292   nsresult CreateWidget(nsWidgetInitData* aWidgetInitData = nullptr,
 293                         bool aEnableDragDrop = true,
 294                         bool aResetVisibility = true);
 295
 296   /**
 297    * Create a widget for this view with an explicit parent widget.
 298    * |aParentWidget| must be nonnull.  The other params are the same
 299    * as for |CreateWidget()|.
 300    */
 301   nsresult CreateWidgetForParent(nsIWidget* aParentWidget,
 302                                  nsWidgetInitData* aWidgetInitData = nullptr,
 303                                  bool aEnableDragDrop = true,
 304                                  bool aResetVisibility = true);
 305
 306   /**
 307    * Create a popup widget for this view.  Pass |aParentWidget| to
 308    * explicitly set the popup's parent.  If it's not passed, the view
 309    * hierarchy will be searched for an appropriate parent widget.  The
 310    * other params are the same as for |CreateWidget()|, except that
 311    * |aWidgetInitData| must be nonnull.
 312    */
 313   nsresult CreateWidgetForPopup(nsWidgetInitData* aWidgetInitData,
 314                                 nsIWidget* aParentWidget = nullptr,
 315                                 bool aEnableDragDrop = true,
 316                                 bool aResetVisibility = true);
 317
 318   /**
 319    * Destroys the associated widget for this view.  If this method is
 320    * not called explicitly, the widget when be destroyed when its
 321    * view gets destroyed.
 322    */
 323   void DestroyWidget();
 324
 325   /**
 326    * Attach/detach a top level widget from this view. When attached, the view
 327    * updates the widget's device context and allows the view to begin receiving
 328    * gecko events. The underlying base window associated with the widget will
 329    * continues to receive events it expects.
 330    *
 331    * An attached widget will not be destroyed when the view is destroyed,
 332    * allowing the recycling of a single top level widget over multiple views.
 333    *
 334    * @param aWidget The widget to attach to / detach from.
 335    */
 336   nsresult AttachToTopLevelWidget(nsIWidget* aWidget);
 337   nsresult DetachFromTopLevelWidget();
 338
 339   /**
 340    * Returns a flag indicating whether the view owns it's widget
 341    * or is attached to an existing top level widget.
 342    */
 343   bool IsAttachedToTopLevel() const { return mWidgetIsTopLevel; }
 344
 345   /**
 346    * In 4.0, the "cutout" nature of a view is queryable.
 347    * If we believe that all cutout view have a native widget, this
 348    * could be a replacement.
 349    * @param aWidget out parameter for widget that this view contains,
 350    *        or nullptr if there is none.
 351    */
 352   nsIWidget* GetWidget() const { return mWindow; }
 353
 354   /**
 355    * The widget which we have attached a listener to can also have a "previous"
 356    * listener set on it. This is to keep track of the last nsView when
 357    * navigating to a new one so that we can continue to paint that if the new
 358    * one isn't ready yet.
 359    */
 360   void SetPreviousWidget(nsIWidget* aWidget) { mPreviousWindow = aWidget; }
 361
 362   /**
 363    * Returns true if the view has a widget associated with it.
 364    */
 365   bool HasWidget() const { return mWindow != nullptr; }
 366
 367   void SetForcedRepaint(bool aForceRepaint) { mForcedRepaint = aForceRepaint; }
 368
 369   void SetNeedsWindowPropertiesSync();
 370
 371   /**
 372    * Make aWidget direct its events to this view.
 373    * The caller must call DetachWidgetEventHandler before this view
 374    * is destroyed.
 375    */
 376   void AttachWidgetEventHandler(nsIWidget* aWidget);
 377   /**
 378    * Stop aWidget directing its events to this view.
 379    */
 380   void DetachWidgetEventHandler(nsIWidget* aWidget);
 381
 382 #ifdef DEBUG
 383   /**
 384    * Output debug info to FILE
 385    * @param out output file handle
 386    * @param aIndent indentation depth
 387    * NOTE: virtual so that debugging tools not linked into gklayout can access
 388    * it
 389    */
 390   virtual void List(FILE* out, int32_t aIndent = 0) const;
 391 #endif  // DEBUG
 392
 393   /**
 394    * @result true iff this is the root view for its view manager
 395    */
 396   bool IsRoot() const;
 397
 398   LayoutDeviceIntRect CalcWidgetBounds(nsWindowType aType);
 399
 400   // This is an app unit offset to add when converting view coordinates to
 401   // widget coordinates.  It is the offset in view coordinates from widget
 402   // origin (unlike views, widgets can't extend above or to the left of their
 403   // origin) to view origin expressed in appunits of this.
 404   nsPoint ViewToWidgetOffset() const { return mViewToWidgetOffset; }
 405
 406   /**
 407    * Called to indicate that the position of the view has been changed.
 408    * The specified coordinates are in the parent view's coordinate space.
 409    * @param x new x position
 410    * @param y new y position
 411    */
 412   void SetPosition(nscoord aX, nscoord aY);
 413
 414   /**
 415    * Called to indicate that the z-index of a view has been changed.
 416    * The z-index is relative to all siblings of the view.
 417    * @param aAuto Indicate that the z-index of a view is "auto". An "auto"
 418    *              z-index means that the view does not define a new stacking
 419    *              context, which means that the z-indicies of the view's
 420    *              children are relative to the view's siblings.
 421    * @param zindex new z depth
 422    */
 423   void SetZIndex(bool aAuto, int32_t aZIndex);
 424   bool GetZIndexIsAuto() const {
 425     return (mVFlags & NS_VIEW_FLAG_AUTO_ZINDEX) != 0;
 426   }
 427   int32_t GetZIndex() const { return mZIndex; }
 428
 429   void SetParent(nsView* aParent) { mParent = aParent; }
 430   void SetNextSibling(nsView* aSibling) {
 431     NS_ASSERTION(aSibling != this, "Can't be our own sibling!");
 432     mNextSibling = aSibling;
 433   }
 434
 435   nsRegion& GetDirtyRegion() {
 436     if (!mDirtyRegion) {
 437       NS_ASSERTION(!mParent || GetFloating(),
 438                    "Only display roots should have dirty regions");
 439       mDirtyRegion = mozilla::MakeUnique<nsRegion>();
 440     }
 441     return *mDirtyRegion;
 442   }
 443
 444   // nsIWidgetListener
 445   virtual mozilla::PresShell* GetPresShell() override;
 446   virtual nsView* GetView() override { return this; }
 447   virtual bool WindowMoved(nsIWidget* aWidget, int32_t x, int32_t y) override;
 448   virtual bool WindowResized(nsIWidget* aWidget, int32_t aWidth,
 449                              int32_t aHeight) override;
 450 #if defined(MOZ_WIDGET_ANDROID)
 451   virtual void DynamicToolbarMaxHeightChanged(
 452       mozilla::ScreenIntCoord aHeight) override;
 453   virtual void DynamicToolbarOffsetChanged(
 454       mozilla::ScreenIntCoord aOffset) override;
 455 #endif
 456   virtual bool RequestWindowClose(nsIWidget* aWidget) override;
 457   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 458   virtual void WillPaintWindow(nsIWidget* aWidget) override;
 459   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 460   virtual bool PaintWindow(nsIWidget* aWidget,
 461                            LayoutDeviceIntRegion aRegion) override;
 462   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 463   virtual void DidPaintWindow() override;
 464   virtual void DidCompositeWindow(
 465       mozilla::layers::TransactionId aTransactionId,
 466       const mozilla::TimeStamp& aCompositeStart,
 467       const mozilla::TimeStamp& aCompositeEnd) override;
 468   virtual void RequestRepaint() override;
 469   virtual bool ShouldNotBeVisible() override;
 470   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 471   virtual nsEventStatus HandleEvent(mozilla::WidgetGUIEvent* aEvent,
 472                                     bool aUseAttachedEvents) override;
 473   virtual void SafeAreaInsetsChanged(const mozilla::ScreenIntMargin&) override;
 474
 475   virtual ~nsView();
 476
 477   nsPoint GetOffsetTo(const nsView* aOther, const int32_t aAPD) const;
 478   nsIWidget* GetNearestWidget(nsPoint* aOffset, const int32_t aAPD) const;
 479
 480   bool IsPrimaryFramePaintSuppressed();
 481
 482  private:
 483   explicit nsView(nsViewManager* aViewManager = nullptr,
 484                   nsViewVisibility aVisibility = nsViewVisibility_kShow);
 485
 486   bool ForcedRepaint() { return mForcedRepaint; }
 487
 488   // Do the actual work of ResetWidgetBounds, unconditionally.  Don't
 489   // call this method if we have no widget.
 490   void DoResetWidgetBounds(bool aMoveOnly, bool aInvalidateChangedSize);
 491   void InitializeWindow(bool aEnableDragDrop, bool aResetVisibility);
 492
 493   bool IsEffectivelyVisible();
 494
 495   /**
 496    * Called to indicate that the dimensions of the view have been changed.
 497    * The x and y coordinates may be < 0, indicating that the view extends above
 498    * or to the left of its origin position. The term 'dimensions' indicates it
 499    * is relative to this view.
 500    */
 501   void SetDimensions(const nsRect& aRect, bool aPaint = true,
 502                      bool aResizeWidget = true);
 503
 504   /**
 505    * Called to indicate that the visibility of a view has been
 506    * changed.
 507    * @param visibility new visibility state
 508    */
 509   void SetVisibility(nsViewVisibility visibility);
 510
 511   /**
 512    * Set/Get whether the view "floats" above all other views,
 513    * which tells the compositor not to consider higher views in
 514    * the view hierarchy that would geometrically intersect with
 515    * this view. This is a hack, but it fixes some problems with
 516    * views that need to be drawn in front of all other views.
 517    * @result true if the view floats, false otherwise.
 518    */
 519   void SetFloating(bool aFloatingView);
 520
 521   // Helper function to get mouse grabbing off this view (by moving it to the
 522   // parent, if we can)
 523   void DropMouseGrabbing();
 524
 525   // Same as GetBounds but converts to parent appunits if they are different.
 526   nsRect GetBoundsInParentUnits() const;
 527
 528   bool HasNonEmptyDirtyRegion() {
 529     return mDirtyRegion && !mDirtyRegion->IsEmpty();
 530   }
 531
 532   void InsertChild(nsView* aChild, nsView* aSibling);
 533   void RemoveChild(nsView* aChild);
 534
 535   void ResetWidgetBounds(bool aRecurse, bool aForceSync);
 536   void AssertNoWindow();
 537
 538   void NotifyEffectiveVisibilityChanged(bool aEffectivelyVisible);
 539
 540   // Update the cached RootViewManager for all view manager descendents.
 541   void InvalidateHierarchy();
 542
 543   nsViewManager* mViewManager;
 544   nsView* mParent;
 545   nsCOMPtr<nsIWidget> mWindow;
 546   nsCOMPtr<nsIWidget> mPreviousWindow;
 547   nsView* mNextSibling;
 548   nsView* mFirstChild;
 549   nsIFrame* mFrame;
 550   mozilla::UniquePtr<nsRegion> mDirtyRegion;
 551   int32_t mZIndex;
 552   nsViewVisibility mVis;
 553   // position relative our parent view origin but in our appunits
 554   nscoord mPosX, mPosY;
 555   // relative to parent, but in our appunits
 556   nsRect mDimBounds;
 557   // in our appunits
 558   nsPoint mViewToWidgetOffset;
 559   uint32_t mVFlags;
 560   bool mWidgetIsTopLevel;
 561   bool mForcedRepaint;
 562   bool mNeedsWindowPropertiesSync;
 563 };
 564
 565 #endif