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 "nsIWidgetListener.h"
  16 #include "Units.h"
  17 #include "mozilla/Attributes.h"
  18 #include "mozilla/EventForwards.h"
  19 #include "mozilla/UniquePtr.h"
  20
  21 class nsViewManager;
  22 class nsIWidget;
  23 class nsIFrame;
  24
  25 namespace mozilla {
  26 class PresShell;
  27 namespace widget {
  28 struct InitData;
  29 enum class TransparencyMode : uint8_t;
  30 enum class WindowType : uint8_t;
  31 }  // namespace widget
  32 }  // namespace mozilla
  33
  34 /**
  35  * nsView's serve two main purposes: 1) a bridge between nsIFrame's and
  36  * nsIWidget's, 2) linking the frame tree of a(n) (in-process) subdocument with
  37  * its parent document frame tree. Historically views were used for more things,
  38  * but their role has been reduced, and could be reduced to nothing in the
  39  * future (bug 337801 tracks removing views). Views are generally associated
  40  * with a frame. A view that does not have a frame is called an anonymous view.
  41  * Some frames also have associated widgets (think os level windows). If a frame
  42  * has a widget it must also have a view, but not all frames with views will
  43  * have widgets.
  44  *
  45  * Only four types of frames can have a view: root frames (ViewportFrame),
  46  * subdocument frames (nsSubDocumentFrame),
  47  * menu popup frames (nsMenuPopupFrame), and list control frames
  48  * (nsListControlFrame). Root frames and subdocument frames have views to link
  49  * the two documents together (the frame trees do not link up otherwise).
  50  * Menu popup frames, and list control frames have views because
  51  * they (sometimes) need to create widgets.
  52  * Menu popup frames handles xul popups, which is anything
  53  * where we need content to go over top the main window at an os level. List
  54  * control frames handle select popups/dropdowns in non-e10s mode.
  55  *
  56  * The term "root view" refers to the root view of a document. Just like root
  57  * frames, root views can have parent views. Only the root view of the root
  58  * document in the process will not have a parent.
  59  *
  60  * All views are created by their frames except root views. Root views are
  61  * special. Root views are created in nsDocumentViewer::MakeWindow before the
  62  * root frame is created, so the root view will not have a frame very early in
  63  * document creation.
  64  *
  65  * Subdocument frames have an anonymous (no frame associated
  66  * with it) inner view that is a child of their "outer" view.
  67  *
  68  * On a subdocument frame the inner view serves as the parent of the
  69  * root view of the subdocument. The outer and inner view of the subdocument
  70  * frame belong to the subdocument frame and hence to the parent document. The
  71  * root view of the subdocument belongs to the subdocument.
  72  * nsLayoutUtils::GetCrossDocParentFrame and nsPresContext::GetParentPresContext
  73  * depend on this view structure and are the main way that we traverse across
  74  * the document boundary in layout.
  75  *
  76  * When the load of a new document is started in the subdocument, the creation
  77  * of the new subdocument and destruction of the old subdocument are not
  78  * linked. (This creation and destruction is handled in nsDocumentViewer.cpp.)
  79  * This means that the old and new document will both exist at the same time
  80  * during the loading of the new document. During this period the inner view of
  81  * the subdocument parent will be the parent of two root views. This means that
  82  * during this period there is a choice for which subdocument we draw,
  83  * nsSubDocumentFrame::GetSubdocumentPresShellForPainting is what makes that
  84  * choice. Note that this might not be a totally free choice, ie there might be
  85  * hidden dependencies and bugs if the way we choose is changed.
  86  *
  87  * One thing that is special about the root view of a chrome window is that
  88  * instead of creating a widget for the view, they can "attach" to the
  89  * existing widget that was created by appshell code or something else. (see
  90  * nsDocumentViewer::ShouldAttachToTopLevel)
  91  */
  92
  93 // Enumerated type to indicate the visibility of a layer.
  94 // hide - the layer is not shown.
  95 // show - the layer is shown irrespective of the visibility of
  96 //        the layer's parent.
  97 enum class ViewVisibility : uint8_t { Hide = 0, Show = 1 };
  98
  99 // Public view flags
 100
 101 // Indicates that the view is using auto z-indexing
 102 #define NS_VIEW_FLAG_AUTO_ZINDEX 0x0004
 103
 104 // Indicates that the view is a floating view.
 105 #define NS_VIEW_FLAG_FLOATING 0x0008
 106
 107 //----------------------------------------------------------------------
 108
 109 /**
 110  * View interface
 111  *
 112  * Views are NOT reference counted. Use the Destroy() member function to
 113  * destroy a view.
 114  *
 115  * The lifetime of the view hierarchy is bounded by the lifetime of the
 116  * view manager that owns the views.
 117  *
 118  * Most of the methods here are read-only. To set the corresponding properties
 119  * of a view, go through nsViewManager.
 120  */
 121
 122 class nsView final : public nsIWidgetListener {
 123  public:
 124   friend class nsViewManager;
 125
 126   typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
 127   typedef mozilla::LayoutDeviceIntRegion LayoutDeviceIntRegion;
 128
 129   void operator delete(void* ptr) { ::operator delete(ptr); }
 130
 131   /**
 132    * Get the view manager which "owns" the view.
 133    * This method might require some expensive traversal work in the future. If
 134    * you can get the view manager from somewhere else, do that instead.
 135    * @result the view manager
 136    */
 137   nsViewManager* GetViewManager() const { return mViewManager; }
 138
 139   /**
 140    * Find the view for the given widget, if there is one.
 141    * @return the view the widget belongs to, or null if the widget doesn't
 142    * belong to any view.
 143    */
 144   static nsView* GetViewFor(const nsIWidget* aWidget);
 145
 146   /**
 147    * Destroy the view.
 148    *
 149    * The view destroys its child views, and destroys and releases its
 150    * widget (if it has one).
 151    *
 152    * Also informs the view manager that the view is destroyed by calling
 153    * SetRootView(NULL) if the view is the root view and calling RemoveChild()
 154    * otherwise.
 155    */
 156   void Destroy();
 157
 158   /**
 159    * Called to get the position of a view.
 160    * The specified coordinates are relative to the parent view's origin, but
 161    * are in appunits of this.
 162    * This is the (0, 0) origin of the coordinate space established by this view.
 163    * @param x out parameter for x position
 164    * @param y out parameter for y position
 165    */
 166   nsPoint GetPosition() const {
 167     NS_ASSERTION(!IsRoot() || (mPosX == 0 && mPosY == 0),
 168                  "root views should always have explicit position of (0,0)");
 169     return nsPoint(mPosX, mPosY);
 170   }
 171
 172   /**
 173    * Called to get the dimensions and position of the view's bounds.
 174    * The view's bounds (x,y) are relative to the origin of the parent view, but
 175    * are in appunits of this.
 176    * The view's bounds (x,y) might not be the same as the view's position,
 177    * if the view has content above or to the left of its origin.
 178    * @param aBounds out parameter for bounds
 179    */
 180   nsRect GetBounds() const { return mDimBounds; }
 181
 182   /**
 183    * The bounds of this view relative to this view. So this is the same as
 184    * GetBounds except this is relative to this view instead of the parent view.
 185    */
 186   nsRect GetDimensions() const {
 187     nsRect r = mDimBounds;
 188     r.MoveBy(-mPosX, -mPosY);
 189     return r;
 190   }
 191
 192   /**
 193    * Get the offset between the coordinate systems of |this| and aOther.
 194    * Adding the return value to a point in the coordinate system of |this|
 195    * will transform the point to the coordinate system of aOther.
 196    *
 197    * The offset is expressed in appunits of |this|. So if you are getting the
 198    * offset between views in different documents that might have different
 199    * appunits per devpixel ratios you need to be careful how you use the
 200    * result.
 201    *
 202    * If aOther is null, this will return the offset of |this| from the
 203    * root of the viewmanager tree.
 204    *
 205    * This function is fastest when aOther is an ancestor of |this|.
 206    *
 207    * NOTE: this actually returns the offset from aOther to |this|, but
 208    * that offset is added to transform _coordinates_ from |this| to aOther.
 209    */
 210   nsPoint GetOffsetTo(const nsView* aOther) const;
 211
 212   /**
 213    * Get the offset between the origin of |this| and the origin of aWidget.
 214    * Adding the return value to a point in the coordinate system of |this|
 215    * will transform the point to the coordinate system of aWidget.
 216    *
 217    * The offset is expressed in appunits of |this|.
 218    */
 219   nsPoint GetOffsetToWidget(nsIWidget* aWidget) const;
 220
 221   /**
 222    * Called to query the visibility state of a view.
 223    * @result current visibility state
 224    */
 225   ViewVisibility GetVisibility() const { return mVis; }
 226
 227   /**
 228    * Get whether the view "floats" above all other views,
 229    * which tells the compositor not to consider higher views in
 230    * the view hierarchy that would geometrically intersect with
 231    * this view. This is a hack, but it fixes some problems with
 232    * views that need to be drawn in front of all other views.
 233    * @result true if the view floats, false otherwise.
 234    */
 235   bool GetFloating() const { return (mVFlags & NS_VIEW_FLAG_FLOATING) != 0; }
 236
 237   /**
 238    * Called to query the parent of the view.
 239    * @result view's parent
 240    */
 241   nsView* GetParent() const { return mParent; }
 242
 243   /**
 244    * The view's first child is the child which is earliest in document order.
 245    * @result first child
 246    */
 247   nsView* GetFirstChild() const { return mFirstChild; }
 248
 249   /**
 250    * Called to query the next sibling of the view.
 251    * @result view's next sibling
 252    */
 253   nsView* GetNextSibling() const { return mNextSibling; }
 254
 255   /**
 256    * Set the view's frame.
 257    */
 258   void SetFrame(nsIFrame* aRootFrame) { mFrame = aRootFrame; }
 259
 260   /**
 261    * Retrieve the view's frame.
 262    */
 263   nsIFrame* GetFrame() const { return mFrame; }
 264
 265   /**
 266    * Get the nearest widget in this view or a parent of this view and
 267    * the offset from the widget's origin to this view's origin
 268    * @param aOffset - if non-null the offset from this view's origin to the
 269    * widget's origin (usually positive) expressed in appunits of this will be
 270    * returned in aOffset.
 271    * @return the widget closest to this view; can be null because some view
 272    * trees don't have widgets at all (e.g., printing), but if any view in the
 273    * view tree has a widget, then it's safe to assume this will not return null
 274    */
 275   nsIWidget* GetNearestWidget(nsPoint* aOffset) const;
 276
 277   /**
 278    * Create a widget to associate with this view.  This variant of
 279    * CreateWidget*() will look around in the view hierarchy for an
 280    * appropriate parent widget for the view.
 281    *
 282    * @param aWidgetInitData data used to initialize this view's widget before
 283    *        its create is called.
 284    * @return error status
 285    */
 286   nsresult CreateWidget(mozilla::widget::InitData* aWidgetInitData = nullptr,
 287                         bool aEnableDragDrop = true,
 288                         bool aResetVisibility = true);
 289
 290   /**
 291    * Create a widget for this view with an explicit parent widget.
 292    * |aParentWidget| must be nonnull.  The other params are the same
 293    * as for |CreateWidget()|.
 294    */
 295   nsresult CreateWidgetForParent(nsIWidget* aParentWidget,
 296                                  mozilla::widget::InitData* = nullptr,
 297                                  bool aEnableDragDrop = true,
 298                                  bool aResetVisibility = true);
 299
 300   /**
 301    * Create a popup widget for this view.  Pass |aParentWidget| to
 302    * explicitly set the popup's parent.  If it's not passed, the view
 303    * hierarchy will be searched for an appropriate parent widget.  The
 304    * other params are the same as for |CreateWidget()|, except that
 305    * |aWidgetInitData| must be nonnull.
 306    */
 307   nsresult CreateWidgetForPopup(mozilla::widget::InitData*,
 308                                 nsIWidget* aParentWidget = nullptr);
 309
 310   /**
 311    * Destroys the associated widget for this view.  If this method is
 312    * not called explicitly, the widget when be destroyed when its
 313    * view gets destroyed.
 314    */
 315   void DestroyWidget();
 316
 317   /**
 318    * Attach/detach a top level widget from this view. When attached, the view
 319    * updates the widget's device context and allows the view to begin receiving
 320    * gecko events. The underlying base window associated with the widget will
 321    * continues to receive events it expects.
 322    *
 323    * An attached widget will not be destroyed when the view is destroyed,
 324    * allowing the recycling of a single top level widget over multiple views.
 325    *
 326    * @param aWidget The widget to attach to / detach from.
 327    */
 328   nsresult AttachToTopLevelWidget(nsIWidget* aWidget);
 329   nsresult DetachFromTopLevelWidget();
 330
 331   /**
 332    * Returns a flag indicating whether the view owns it's widget
 333    * or is attached to an existing top level widget.
 334    */
 335   bool IsAttachedToTopLevel() const { return mWidgetIsTopLevel; }
 336
 337   /**
 338    * In 4.0, the "cutout" nature of a view is queryable.
 339    * If we believe that all cutout view have a native widget, this
 340    * could be a replacement.
 341    * @param aWidget out parameter for widget that this view contains,
 342    *        or nullptr if there is none.
 343    */
 344   nsIWidget* GetWidget() const { return mWindow; }
 345
 346   /**
 347    * The widget which we have attached a listener to can also have a "previous"
 348    * listener set on it. This is to keep track of the last nsView when
 349    * navigating to a new one so that we can continue to paint that if the new
 350    * one isn't ready yet.
 351    */
 352   void SetPreviousWidget(nsIWidget* aWidget) { mPreviousWindow = aWidget; }
 353
 354   /**
 355    * Returns true if the view has a widget associated with it.
 356    */
 357   bool HasWidget() const { return mWindow != nullptr; }
 358
 359   void SetForcedRepaint(bool aForceRepaint) { mForcedRepaint = aForceRepaint; }
 360
 361   void SetNeedsWindowPropertiesSync();
 362
 363   /**
 364    * Make aWidget direct its events to this view.
 365    * The caller must call DetachWidgetEventHandler before this view
 366    * is destroyed.
 367    */
 368   void AttachWidgetEventHandler(nsIWidget* aWidget);
 369   /**
 370    * Stop aWidget directing its events to this view.
 371    */
 372   void DetachWidgetEventHandler(nsIWidget* aWidget);
 373
 374 #ifdef DEBUG
 375   /**
 376    * Output debug info to FILE
 377    * @param out output file handle
 378    * @param aIndent indentation depth
 379    * NOTE: virtual so that debugging tools not linked into gklayout can access
 380    * it
 381    */
 382   virtual void List(FILE* out, int32_t aIndent = 0) const;
 383 #endif  // DEBUG
 384
 385   /**
 386    * @result true iff this is the root view for its view manager
 387    */
 388   bool IsRoot() const;
 389
 390   LayoutDeviceIntRect CalcWidgetBounds(mozilla::widget::WindowType,
 391                                        mozilla::widget::TransparencyMode);
 392
 393   LayoutDeviceIntRect RecalcWidgetBounds();
 394
 395   // This is an app unit offset to add when converting view coordinates to
 396   // widget coordinates.  It is the offset in view coordinates from widget
 397   // origin (unlike views, widgets can't extend above or to the left of their
 398   // origin) to view origin expressed in appunits of this.
 399   nsPoint ViewToWidgetOffset() const { return mViewToWidgetOffset; }
 400
 401   /**
 402    * Called to indicate that the position of the view has been changed.
 403    * The specified coordinates are in the parent view's coordinate space.
 404    * @param x new x position
 405    * @param y new y position
 406    */
 407   void SetPosition(nscoord aX, nscoord aY);
 408
 409   /**
 410    * Called to indicate that the z-index of a view has been changed.
 411    * The z-index is relative to all siblings of the view.
 412    * @param aAuto Indicate that the z-index of a view is "auto". An "auto"
 413    *              z-index means that the view does not define a new stacking
 414    *              context, which means that the z-indicies of the view's
 415    *              children are relative to the view's siblings.
 416    * @param zindex new z depth
 417    */
 418   void SetZIndex(bool aAuto, int32_t aZIndex);
 419   bool GetZIndexIsAuto() const {
 420     return (mVFlags & NS_VIEW_FLAG_AUTO_ZINDEX) != 0;
 421   }
 422   int32_t GetZIndex() const { return mZIndex; }
 423
 424   void SetParent(nsView* aParent) { mParent = aParent; }
 425   void SetNextSibling(nsView* aSibling) {
 426     NS_ASSERTION(aSibling != this, "Can't be our own sibling!");
 427     mNextSibling = aSibling;
 428   }
 429
 430   nsRegion& GetDirtyRegion() {
 431     if (!mDirtyRegion) {
 432       NS_ASSERTION(!mParent || GetFloating(),
 433                    "Only display roots should have dirty regions");
 434       mDirtyRegion = mozilla::MakeUnique<nsRegion>();
 435     }
 436     return *mDirtyRegion;
 437   }
 438
 439   // nsIWidgetListener
 440   virtual mozilla::PresShell* GetPresShell() override;
 441   virtual nsView* GetView() override { return this; }
 442   virtual bool WindowMoved(nsIWidget* aWidget, int32_t x, int32_t y,
 443                            ByMoveToRect) override;
 444   virtual bool WindowResized(nsIWidget* aWidget, int32_t aWidth,
 445                              int32_t aHeight) override;
 446 #if defined(MOZ_WIDGET_ANDROID)
 447   virtual void DynamicToolbarMaxHeightChanged(
 448       mozilla::ScreenIntCoord aHeight) override;
 449   virtual void DynamicToolbarOffsetChanged(
 450       mozilla::ScreenIntCoord aOffset) override;
 451 #endif
 452   virtual bool RequestWindowClose(nsIWidget* aWidget) override;
 453   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 454   virtual void WillPaintWindow(nsIWidget* aWidget) override;
 455   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 456   virtual bool PaintWindow(nsIWidget* aWidget,
 457                            LayoutDeviceIntRegion aRegion) override;
 458   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 459   virtual void DidPaintWindow() override;
 460   virtual void DidCompositeWindow(
 461       mozilla::layers::TransactionId aTransactionId,
 462       const mozilla::TimeStamp& aCompositeStart,
 463       const mozilla::TimeStamp& aCompositeEnd) override;
 464   virtual void RequestRepaint() override;
 465   virtual bool ShouldNotBeVisible() override;
 466   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 467   virtual nsEventStatus HandleEvent(mozilla::WidgetGUIEvent* aEvent,
 468                                     bool aUseAttachedEvents) override;
 469   virtual void SafeAreaInsetsChanged(const mozilla::ScreenIntMargin&) override;
 470
 471   virtual ~nsView();
 472
 473   nsPoint GetOffsetTo(const nsView* aOther, const int32_t aAPD) const;
 474   nsIWidget* GetNearestWidget(nsPoint* aOffset, const int32_t aAPD) const;
 475
 476   bool IsPrimaryFramePaintSuppressed();
 477
 478  private:
 479   explicit nsView(nsViewManager* = nullptr,
 480                   ViewVisibility = ViewVisibility::Show);
 481
 482   bool ForcedRepaint() { return mForcedRepaint; }
 483
 484   // Do the actual work of ResetWidgetBounds, unconditionally.  Don't
 485   // call this method if we have no widget.
 486   void DoResetWidgetBounds(bool aMoveOnly, bool aInvalidateChangedSize);
 487   void InitializeWindow(bool aEnableDragDrop, bool aResetVisibility);
 488
 489   bool IsEffectivelyVisible();
 490
 491   /**
 492    * Called to indicate that the dimensions of the view have been changed.
 493    * The x and y coordinates may be < 0, indicating that the view extends above
 494    * or to the left of its origin position. The term 'dimensions' indicates it
 495    * is relative to this view.
 496    */
 497   void SetDimensions(const nsRect& aRect, bool aPaint = true,
 498                      bool aResizeWidget = true);
 499
 500   /**
 501    * Called to indicate that the visibility of a view has been
 502    * changed.
 503    * @param visibility new visibility state
 504    */
 505   void SetVisibility(ViewVisibility visibility);
 506
 507   /**
 508    * Set/Get whether the view "floats" above all other views,
 509    * which tells the compositor not to consider higher views in
 510    * the view hierarchy that would geometrically intersect with
 511    * this view. This is a hack, but it fixes some problems with
 512    * views that need to be drawn in front of all other views.
 513    * @result true if the view floats, false otherwise.
 514    */
 515   void SetFloating(bool aFloatingView);
 516
 517   // Helper function to get mouse grabbing off this view (by moving it to the
 518   // parent, if we can)
 519   void DropMouseGrabbing();
 520
 521   bool HasNonEmptyDirtyRegion() {
 522     return mDirtyRegion && !mDirtyRegion->IsEmpty();
 523   }
 524
 525   void InsertChild(nsView* aChild, nsView* aSibling);
 526   void RemoveChild(nsView* aChild);
 527
 528   void ResetWidgetBounds(bool aRecurse, bool aForceSync);
 529   void AssertNoWindow();
 530
 531   void NotifyEffectiveVisibilityChanged(bool aEffectivelyVisible);
 532
 533   // Update the cached RootViewManager for all view manager descendents.
 534   void InvalidateHierarchy();
 535
 536   nsViewManager* mViewManager;
 537   nsView* mParent;
 538   nsCOMPtr<nsIWidget> mWindow;
 539   nsCOMPtr<nsIWidget> mPreviousWindow;
 540   nsView* mNextSibling;
 541   nsView* mFirstChild;
 542   nsIFrame* mFrame;
 543   mozilla::UniquePtr<nsRegion> mDirtyRegion;
 544   int32_t mZIndex;
 545   ViewVisibility mVis;
 546   // position relative our parent view origin but in our appunits
 547   nscoord mPosX, mPosY;
 548   // relative to parent, but in our appunits
 549   nsRect mDimBounds;
 550   // in our appunits
 551   nsPoint mViewToWidgetOffset;
 552   uint32_t mVFlags;
 553   bool mWidgetIsTopLevel;
 554   bool mForcedRepaint;
 555   bool mNeedsWindowPropertiesSync;
 556 };
 557
 558 #endif