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    * Takes a point aPt that is in the coordinate system of |this|'s parent view
 223    * and converts it to be in the coordinate system of |this| taking into
 224    * account the offset and any app unit per dev pixel ratio differences.
 225    */
 226   nsPoint ConvertFromParentCoords(nsPoint aPt) const;
 227
 228   /**
 229    * Called to query the visibility state of a view.
 230    * @result current visibility state
 231    */
 232   ViewVisibility GetVisibility() const { return mVis; }
 233
 234   /**
 235    * Get whether the view "floats" above all other views,
 236    * which tells the compositor not to consider higher views in
 237    * the view hierarchy that would geometrically intersect with
 238    * this view. This is a hack, but it fixes some problems with
 239    * views that need to be drawn in front of all other views.
 240    * @result true if the view floats, false otherwise.
 241    */
 242   bool GetFloating() const { return (mVFlags & NS_VIEW_FLAG_FLOATING) != 0; }
 243
 244   /**
 245    * Called to query the parent of the view.
 246    * @result view's parent
 247    */
 248   nsView* GetParent() const { return mParent; }
 249
 250   /**
 251    * The view's first child is the child which is earliest in document order.
 252    * @result first child
 253    */
 254   nsView* GetFirstChild() const { return mFirstChild; }
 255
 256   /**
 257    * Called to query the next sibling of the view.
 258    * @result view's next sibling
 259    */
 260   nsView* GetNextSibling() const { return mNextSibling; }
 261
 262   /**
 263    * Set the view's frame.
 264    */
 265   void SetFrame(nsIFrame* aRootFrame) { mFrame = aRootFrame; }
 266
 267   /**
 268    * Retrieve the view's frame.
 269    */
 270   nsIFrame* GetFrame() const { return mFrame; }
 271
 272   /**
 273    * Get the nearest widget in this view or a parent of this view and
 274    * the offset from the widget's origin to this view's origin
 275    * @param aOffset - if non-null the offset from this view's origin to the
 276    * widget's origin (usually positive) expressed in appunits of this will be
 277    * returned in aOffset.
 278    * @return the widget closest to this view; can be null because some view
 279    * trees don't have widgets at all (e.g., printing), but if any view in the
 280    * view tree has a widget, then it's safe to assume this will not return null
 281    */
 282   nsIWidget* GetNearestWidget(nsPoint* aOffset) const;
 283
 284   /**
 285    * Create a widget to associate with this view.  This variant of
 286    * CreateWidget*() will look around in the view hierarchy for an
 287    * appropriate parent widget for the view.
 288    *
 289    * @param aWidgetInitData data used to initialize this view's widget before
 290    *        its create is called.
 291    * @return error status
 292    */
 293   nsresult CreateWidget(mozilla::widget::InitData* aWidgetInitData = nullptr,
 294                         bool aEnableDragDrop = true,
 295                         bool aResetVisibility = true);
 296
 297   /**
 298    * Create a widget for this view with an explicit parent widget.
 299    * |aParentWidget| must be nonnull.  The other params are the same
 300    * as for |CreateWidget()|.
 301    */
 302   nsresult CreateWidgetForParent(nsIWidget* aParentWidget,
 303                                  mozilla::widget::InitData* = nullptr,
 304                                  bool aEnableDragDrop = true,
 305                                  bool aResetVisibility = true);
 306
 307   /**
 308    * Create a popup widget for this view.  Pass |aParentWidget| to
 309    * explicitly set the popup's parent.  If it's not passed, the view
 310    * hierarchy will be searched for an appropriate parent widget.  The
 311    * other params are the same as for |CreateWidget()|, except that
 312    * |aWidgetInitData| must be nonnull.
 313    */
 314   nsresult CreateWidgetForPopup(mozilla::widget::InitData*,
 315                                 nsIWidget* aParentWidget = nullptr);
 316
 317   /**
 318    * Destroys the associated widget for this view.  If this method is
 319    * not called explicitly, the widget when be destroyed when its
 320    * view gets destroyed.
 321    */
 322   void DestroyWidget();
 323
 324   /**
 325    * Attach/detach a top level widget from this view. When attached, the view
 326    * updates the widget's device context and allows the view to begin receiving
 327    * gecko events. The underlying base window associated with the widget will
 328    * continues to receive events it expects.
 329    *
 330    * An attached widget will not be destroyed when the view is destroyed,
 331    * allowing the recycling of a single top level widget over multiple views.
 332    *
 333    * @param aWidget The widget to attach to / detach from.
 334    */
 335   nsresult AttachToTopLevelWidget(nsIWidget* aWidget);
 336   nsresult DetachFromTopLevelWidget();
 337
 338   /**
 339    * Returns a flag indicating whether the view owns it's widget
 340    * or is attached to an existing top level widget.
 341    */
 342   bool IsAttachedToTopLevel() const { return mWidgetIsTopLevel; }
 343
 344   /**
 345    * In 4.0, the "cutout" nature of a view is queryable.
 346    * If we believe that all cutout view have a native widget, this
 347    * could be a replacement.
 348    * @param aWidget out parameter for widget that this view contains,
 349    *        or nullptr if there is none.
 350    */
 351   nsIWidget* GetWidget() const { return mWindow; }
 352
 353   /**
 354    * The widget which we have attached a listener to can also have a "previous"
 355    * listener set on it. This is to keep track of the last nsView when
 356    * navigating to a new one so that we can continue to paint that if the new
 357    * one isn't ready yet.
 358    */
 359   void SetPreviousWidget(nsIWidget* aWidget) { mPreviousWindow = aWidget; }
 360
 361   /**
 362    * Returns true if the view has a widget associated with it.
 363    */
 364   bool HasWidget() const { return mWindow != nullptr; }
 365
 366   void SetForcedRepaint(bool aForceRepaint) { mForcedRepaint = aForceRepaint; }
 367
 368   void SetNeedsWindowPropertiesSync();
 369
 370   /**
 371    * Make aWidget direct its events to this view.
 372    * The caller must call DetachWidgetEventHandler before this view
 373    * is destroyed.
 374    */
 375   void AttachWidgetEventHandler(nsIWidget* aWidget);
 376   /**
 377    * Stop aWidget directing its events to this view.
 378    */
 379   void DetachWidgetEventHandler(nsIWidget* aWidget);
 380
 381 #ifdef DEBUG
 382   /**
 383    * Output debug info to FILE
 384    * @param out output file handle
 385    * @param aIndent indentation depth
 386    * NOTE: virtual so that debugging tools not linked into gklayout can access
 387    * it
 388    */
 389   virtual void List(FILE* out, int32_t aIndent = 0) const;
 390 #endif  // DEBUG
 391
 392   /**
 393    * @result true iff this is the root view for its view manager
 394    */
 395   bool IsRoot() const;
 396
 397   LayoutDeviceIntRect CalcWidgetBounds(mozilla::widget::WindowType,
 398                                        mozilla::widget::TransparencyMode);
 399
 400   LayoutDeviceIntRect RecalcWidgetBounds();
 401
 402   // This is an app unit offset to add when converting view coordinates to
 403   // widget coordinates.  It is the offset in view coordinates from widget
 404   // origin (unlike views, widgets can't extend above or to the left of their
 405   // origin) to view origin expressed in appunits of this.
 406   nsPoint ViewToWidgetOffset() const { return mViewToWidgetOffset; }
 407
 408   /**
 409    * Called to indicate that the position of the view has been changed.
 410    * The specified coordinates are in the parent view's coordinate space.
 411    * @param x new x position
 412    * @param y new y position
 413    */
 414   void SetPosition(nscoord aX, nscoord aY);
 415
 416   /**
 417    * Called to indicate that the z-index of a view has been changed.
 418    * The z-index is relative to all siblings of the view.
 419    * @param aAuto Indicate that the z-index of a view is "auto". An "auto"
 420    *              z-index means that the view does not define a new stacking
 421    *              context, which means that the z-indicies of the view's
 422    *              children are relative to the view's siblings.
 423    * @param zindex new z depth
 424    */
 425   void SetZIndex(bool aAuto, int32_t aZIndex);
 426   bool GetZIndexIsAuto() const {
 427     return (mVFlags & NS_VIEW_FLAG_AUTO_ZINDEX) != 0;
 428   }
 429   int32_t GetZIndex() const { return mZIndex; }
 430
 431   void SetParent(nsView* aParent) { mParent = aParent; }
 432   void SetNextSibling(nsView* aSibling) {
 433     NS_ASSERTION(aSibling != this, "Can't be our own sibling!");
 434     mNextSibling = aSibling;
 435   }
 436
 437   nsRegion& GetDirtyRegion() {
 438     if (!mDirtyRegion) {
 439       NS_ASSERTION(!mParent || GetFloating(),
 440                    "Only display roots should have dirty regions");
 441       mDirtyRegion = mozilla::MakeUnique<nsRegion>();
 442     }
 443     return *mDirtyRegion;
 444   }
 445
 446   // nsIWidgetListener
 447   virtual mozilla::PresShell* GetPresShell() override;
 448   virtual nsView* GetView() override { return this; }
 449   virtual bool WindowMoved(nsIWidget* aWidget, int32_t x, int32_t y,
 450                            ByMoveToRect) override;
 451   virtual bool WindowResized(nsIWidget* aWidget, int32_t aWidth,
 452                              int32_t aHeight) override;
 453 #if defined(MOZ_WIDGET_ANDROID)
 454   virtual void DynamicToolbarMaxHeightChanged(
 455       mozilla::ScreenIntCoord aHeight) override;
 456   virtual void DynamicToolbarOffsetChanged(
 457       mozilla::ScreenIntCoord aOffset) override;
 458 #endif
 459   virtual bool RequestWindowClose(nsIWidget* aWidget) override;
 460   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 461   virtual void WillPaintWindow(nsIWidget* aWidget) override;
 462   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 463   virtual bool PaintWindow(nsIWidget* aWidget,
 464                            LayoutDeviceIntRegion aRegion) override;
 465   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 466   virtual void DidPaintWindow() override;
 467   virtual void DidCompositeWindow(
 468       mozilla::layers::TransactionId aTransactionId,
 469       const mozilla::TimeStamp& aCompositeStart,
 470       const mozilla::TimeStamp& aCompositeEnd) override;
 471   virtual void RequestRepaint() override;
 472   virtual bool ShouldNotBeVisible() override;
 473   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 474   virtual nsEventStatus HandleEvent(mozilla::WidgetGUIEvent* aEvent,
 475                                     bool aUseAttachedEvents) override;
 476   virtual void SafeAreaInsetsChanged(const mozilla::ScreenIntMargin&) override;
 477
 478   virtual ~nsView();
 479
 480   nsPoint GetOffsetTo(const nsView* aOther, const int32_t aAPD) const;
 481   nsIWidget* GetNearestWidget(nsPoint* aOffset, const int32_t aAPD) const;
 482
 483   bool IsPrimaryFramePaintSuppressed();
 484
 485  private:
 486   explicit nsView(nsViewManager* = nullptr,
 487                   ViewVisibility = ViewVisibility::Show);
 488
 489   bool ForcedRepaint() { return mForcedRepaint; }
 490
 491   // Do the actual work of ResetWidgetBounds, unconditionally.  Don't
 492   // call this method if we have no widget.
 493   void DoResetWidgetBounds(bool aMoveOnly, bool aInvalidateChangedSize);
 494   void InitializeWindow(bool aEnableDragDrop, bool aResetVisibility);
 495
 496   bool IsEffectivelyVisible();
 497
 498   /**
 499    * Called to indicate that the dimensions of the view have been changed.
 500    * The x and y coordinates may be < 0, indicating that the view extends above
 501    * or to the left of its origin position. The term 'dimensions' indicates it
 502    * is relative to this view.
 503    */
 504   void SetDimensions(const nsRect& aRect, bool aPaint = true,
 505                      bool aResizeWidget = true);
 506
 507   /**
 508    * Called to indicate that the visibility of a view has been
 509    * changed.
 510    * @param visibility new visibility state
 511    */
 512   void SetVisibility(ViewVisibility visibility);
 513
 514   /**
 515    * Set/Get whether the view "floats" above all other views,
 516    * which tells the compositor not to consider higher views in
 517    * the view hierarchy that would geometrically intersect with
 518    * this view. This is a hack, but it fixes some problems with
 519    * views that need to be drawn in front of all other views.
 520    * @result true if the view floats, false otherwise.
 521    */
 522   void SetFloating(bool aFloatingView);
 523
 524   // Helper function to get mouse grabbing off this view (by moving it to the
 525   // parent, if we can)
 526   void DropMouseGrabbing();
 527
 528   // Same as GetBounds but converts to parent appunits if they are different.
 529   nsRect GetBoundsInParentUnits() const;
 530
 531   bool HasNonEmptyDirtyRegion() {
 532     return mDirtyRegion && !mDirtyRegion->IsEmpty();
 533   }
 534
 535   void InsertChild(nsView* aChild, nsView* aSibling);
 536   void RemoveChild(nsView* aChild);
 537
 538   void ResetWidgetBounds(bool aRecurse, bool aForceSync);
 539   void AssertNoWindow();
 540
 541   void NotifyEffectiveVisibilityChanged(bool aEffectivelyVisible);
 542
 543   // Update the cached RootViewManager for all view manager descendents.
 544   void InvalidateHierarchy();
 545
 546   nsViewManager* mViewManager;
 547   nsView* mParent;
 548   nsCOMPtr<nsIWidget> mWindow;
 549   nsCOMPtr<nsIWidget> mPreviousWindow;
 550   nsView* mNextSibling;
 551   nsView* mFirstChild;
 552   nsIFrame* mFrame;
 553   mozilla::UniquePtr<nsRegion> mDirtyRegion;
 554   int32_t mZIndex;
 555   ViewVisibility mVis;
 556   // position relative our parent view origin but in our appunits
 557   nscoord mPosX, mPosY;
 558   // relative to parent, but in our appunits
 559   nsRect mDimBounds;
 560   // in our appunits
 561   nsPoint mViewToWidgetOffset;
 562   uint32_t mVFlags;
 563   bool mWidgetIsTopLevel;
 564   bool mForcedRepaint;
 565   bool mNeedsWindowPropertiesSync;
 566 };
 567
 568 #endif