UserInterface.Control

Unit
Source
Symbols

Symbol	Description
TChildControlList
TControl	Visual user interface element that can react to user input.
TControlChildIteratorFactory
TControlFactory	Abstract base class for a facility that creates a `TControl` for a `TValuePath`
TControlPurpose
TDragSite	Base class for source or target handlers for drag-and-drop operations.
TFocusability
TKeyboardFocusManager
TListEndPoint
TMouseManager
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///////////////////////////////////////////////////////////////////////////
//                                                                       //
//  Copyright (c) 2015 by Charta Software B.V.                           //
//  All rights reserved                                                  //
//                                                                       //
//  Version:  1.7.0.83525                                                //
//  Web site: https://pascal.chartasoftware.com/                         //
//                                                                       //
//  This code and information are provided "as is" without warranty of   //
//  any kind. Dissemination of this information or reproduction of       //
//  this material is strictly forbidden unless prior written permission  //
//  is obtained from Charta Software B.V..                               //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

unit UserInterface.Control;

interface

{$SCOPEDENUMS ON}

uses
  Boolean,
  Collection.List,
  Comparator,
  Condition,
  Condition.Projecting,
  Drawing.Canvas,
  Drawing.Resource,
  Event,
  Geometry._2d.Integer32.Point,
  Geometry._2d.Integer32.Rectangle,
  Geometry._2d.Integer32.Size,
  Geometry._2d.Side,
  Integer._32,
  Iterator,
  Iterator.Tree,
  Listeners,
  Mathematics.Sign,
  Object_.Base,
  Object_.List,
  Text,
  TypedValue,
  UserInterface.ClipBoard,
  UserInterface.Control.Caret,
  UserInterface.Control.Mode,
  UserInterface.Control.Style,
  UserInterface.Control.Window.Hint,
  UserInterface.Device.Monitor,
  UserInterface.DragAndDrop.Action,
  UserInterface.Keyboard,
  UserInterface.Keyboard.Event,
  UserInterface.Keyboard.Key,
  UserInterface.Keyboard.Modifiers,
  UserInterface.Mouse,
  UserInterface.Mouse.Event,
  UserInterface.Navigation,
  UserInterface.Object_.Selection,
  UserInterface.User.Level,
  Value,
  Value.Path,
  Windows.Gdi.Cursor;

type
  TControl = class;
  TControlFactory = class;

  TFocusability = (None, Focusable, FocusOnMouse);
  TListEndPoint = (Head, Tail);

  TMouseManager = class(TBaseObject)
  private
    FMouse:              TMouse;
    FOverControl:        TControl;
    FControlWithCapture: TControl;

    procedure   SetOverControl(const Value: TControl);
    procedure   SetControlWithCapture(const Value: TControl);

    procedure   DetachFromControl(Control: TControl);
    procedure   AttachToControl(Control: TControl);

  protected
    procedure   CaptureChanged(); virtual;
    function    LastChanceHandleEvent(RootControl: TControl; Event: TEvent): TBoolean; virtual;

    procedure   DistributeMouseLeave(RootControl: TControl; Control: TControl; const Position: TInteger32Point);

  public
    constructor Create(); override;
    destructor  Destroy(); override;

    function    HandleEvent(Event: TEvent): TBoolean; override;

    function    GetCursorPosition(): TInteger32Point; virtual; abstract;
    procedure   SetCursor(Cursor: TCursor); virtual; abstract;

    function    ControlForEvent(TopLevelControl: TControl; Event: TMouseEvent): TControl;

    function    SendEventToControl(TopLevelControl: TControl; Event: TMouseEvent): TBoolean;

    property    Mouse: TMouse read FMouse;
    property    OverControl: TControl read FOverControl write SetOverControl;
    property    ControlWithCapture: TControl read FControlWithCapture write SetControlWithCapture;
  end;

  TKeyboardFocusManager = class(TBaseObject)
  protected
    function    GetFocusedControl(): TControl; virtual; abstract;
    procedure   SetFocusedControl(const Value: TControl); virtual; abstract;

    function    GetListeners(): TListeners; virtual; abstract;

  public
    Keyboard: TKeyboard;

    constructor Create(); override;
    destructor  Destroy(); override;

    function    ReceivesKeyboardInput(Control: TControl): TBoolean; virtual; abstract;

    property    FocusedControl: TControl read GetFocusedControl write SetFocusedControl;
    property    Listeners: TListeners read GetListeners; 
  end;

  TDragSite = class(TObject)
  public
    Container: TControl;
    Control:   TControl;
    Actions:   TDragDropActions;
    
    constructor Create(Container: TControl; Control: TControl); virtual;

    procedure   Attach(Control: TControl); virtual; 
    procedure   Detach(); virtual;
  end;

  TControlPurpose = (Standalone, Cell, Preview, Form);

  TControl = class(TBaseObject)
  private
    FChildControls:  TList<TControl>;
    FParentControl:  TControl;
    FListeners:      TListeners;
    FCaret:          TCaret;
    FCaptionVisible: TBoolean;
    FIsEditor:       TBoolean;
    FMode:           TControlMode;
    FAllowedModes:   TControlModes;
    FFocusability:   TFocusability;
    FPath:           TValuePath;
    FStyle:          TControlStyle;

    procedure   SetParentControl(const Value: TControl);
    function    GetLeft(): TInteger32;
    procedure   SetLeft(const Value: TInteger32);
    function    GetWidth(): TInteger32;
    procedure   SetWidth(const Value: TInteger32);
    function    GetTop(): TInteger32;
    procedure   SetTop(const Value: TInteger32);
    function    GetSide(Side: TSide): TInteger32;
    function    GetHeight(): TInteger32;
    procedure   SetHeight(const Value: TInteger32);
    procedure   SetMode(const Value: TControlMode);
    function    GetSize(): TInteger32Size;
    procedure   SetSize(const Value: TInteger32Size);
    procedure   SetBounds(const Value: TInteger32Rectangle);
    function    GetScreenBounds(): TInteger32Rectangle;
    function    GetPosition(): TInteger32Point;
    procedure   SetPosition(const Value: TInteger32Point);
    procedure   SetIsEditor(const Value: TBoolean);
    procedure   SetAllowedModes(const Value: TControlModes);
    procedure   SetCaret(const Value: TCaret);
    procedure   SetPath(const Value: TValuePath);

  protected
    FCaption: TText;
    FBounds:  TInteger32Rectangle;

    function    GetActiveChildControl(): TControl; virtual;
    procedure   SetActiveChildControl(const Value: TControl); virtual;
    function    TopLevelWindow(): TControl;
    function    GetFocusability(): TFocusability; virtual;

    procedure   UpdateBounds(const OldBounds: TInteger32Rectangle; const NewBounds: TInteger32Rectangle); virtual;
    procedure   BoundsChanged(const OldBounds: TInteger32Rectangle; const NewBounds: TInteger32Rectangle); virtual;
    procedure   SizeChanged(); virtual; deprecated; // Please use BoundsChanged()

    function    GetClippingBoundsForChild(Control: TControl): TInteger32Rectangle; virtual;
    function    GetContextMenuTargetBounds(): TInteger32Rectangle; virtual;

    procedure   PaintChildControl(Canvas: TCanvas; Control: TControl);
    procedure   PaintFocusRectangle(Canvas: TCanvas; const Rectangle: TInteger32Rectangle);
    procedure   RepaintOnFocusChange(); virtual;

    procedure   RethinkScrollBars(); virtual;
    procedure   ChildRethinksScrollBars(Child: TControl); virtual;

    function    Navigate(Direction: TNavigationDirection; KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoUp(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoDown(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoLeft(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoRight(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoForward: TBoolean; virtual;
    function    GoBackward: TBoolean; virtual;
    function    GoPageUp(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoPageDown(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoPageLeft(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoPageRight(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoVerticalHome(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoVerticalEnd(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoHorizontalHome(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoHorizontalEnd(KeyModifiers: TKeyModifiers): TBoolean; virtual;
    function    GoParent(KeyModifiers: TKeyModifiers): TBoolean; virtual;

    function    GetEditor(): TControl; virtual;
    function    IsInlineEditing(): TBoolean;
    procedure   StopInlineEditing(Successful: TBoolean); virtual;
    function    GetEditorBounds(): TInteger32Rectangle; virtual;
    procedure   SetEditorValue(Value: TValue); virtual;
    procedure   ResetEditorValue(); virtual;
    procedure   ScrollEditorIntoView(); virtual;

    function    EditingCanBeStopped(Successful: TBoolean): TBoolean; virtual;
    function    StartEditing(): TBoolean; virtual;
    function    StopEditing(Successful: TBoolean): TBoolean; virtual;
    procedure   QuitEditingMode(Successful: TBoolean);

    function    GetCaption(): TText; virtual;
    function    GetCaptionVisible(): TBoolean; virtual;
    procedure   CaptionChanged(); virtual;
    procedure   SetCaption(const Value: TText); virtual;
    procedure   SetCaptionVisible(const Value: TBoolean); virtual;

    procedure   ChildControlAdded(Control: TControl); virtual;
    procedure   ChildControlRemoved(Control: TControl); virtual;

    procedure   SetChildControlVisible(Control: TControl; Visible: TBoolean; ListEndPoint: TListEndPoint = TListEndPoint.Tail);

    function    GetValue(): TValue; virtual;
    procedure   SetValue(const Value: TValue); virtual;

    function    HandleClipboardKey(Key: TKey; KeyModifiers: TKeyModifiers): TBoolean;
    function    HandleContextMenuKey(Event: TKeyDownEvent): TBoolean;

    procedure   FireValueChanged();
    procedure   FireDefaultActionExecuted(); virtual;
    procedure   FireEvent(Event: TEvent);

    procedure   DescendantRequestsFocus(Descendant: TControl); virtual;
    procedure   DescendantRequestsFocusInComposition(Descendant: TControl); virtual;
    procedure   DescendantFiresEvent(Descendant: TControl; Event: TEvent); virtual;

    procedure   DescendantOpensControl(Descendant: TControl; Control: TControl; TransferFocus: TBoolean);
    procedure   DescendantOpensControlForValue(Descendant: TControl; Value: TValuePath; TransferFocus: TBoolean);

    procedure   HasBeenBoundToLayout(); virtual;
    procedure   CopyCaretFromDescendant(Descendant: TControl); deprecated;

    procedure   StyleChanged(Property_: TControlStyleProperty); virtual;
    procedure   DetermineStyle();

    function    ChildForMouseEvent(Event: TMouseEvent): TControl; virtual;

    procedure   AllowedModesChanged(); virtual;

    procedure   DistributeEventDownHierarchy(Event: TEvent; Order: TTreeVerticalOrder; FreeEvent: TBoolean = True);

  public
    Purpose:            TControlPurpose;
    SuppressInvalidate: TBoolean; // TODO: This should not be necessary any more one refactor away the "painters" in TTableControl and TTreeControl

    constructor Create(); override;
    destructor  Destroy(); override;

    function    HandleEvent(Event: TEvent): TBoolean; override;

    procedure   Paint(Canvas: TCanvas); virtual;
    procedure   PaintChildren(Canvas: TCanvas); virtual;
    procedure   PaintAll(Canvas: TCanvas); virtual;

    function    IsBoundToLayout(): TBoolean; virtual;

    function    CreateToolbar(): TControl; virtual;

    function    Embellish(): TControl; virtual;
    function    IsEmbellishment(): TBoolean; virtual;
    function    IsComposition(): TBoolean; virtual;
    function    GetEmbellishedControl(): TControl; virtual;
    function    GetRootEmbellishment(): TControl;
    function    RootComposition(): TControl;
    function    CompositeControlHasFocus(): TBoolean; virtual;
    function    ControlInCompositionHasFocus(): TBoolean; virtual;
    function    CompositionReceivesKeyboardInput(): TBoolean;

    function    RootControl(): TControl;
    function    RootOverlappedControl(): TControl;
    function    IsDynamicContainer(): TBoolean; virtual;
    function    GetChildOfDynamicContainer(): TControl;

    function    GetDrawingResources(): TDrawingResources; virtual;
    function    GetClipBoard(): TClipBoard; virtual;
    function    GetFocusManager(): TKeyboardFocusManager; virtual;
    function    GetMouseManager(): TMouseManager; virtual;
    function    IsMouseLeftDown(): TBoolean;
    function    ShouldCancelMouseCaptureAutomatically(): TBoolean; virtual; deprecated; // TODO: Mouse capture should never be captured automatically

    procedure   LayoutControls(); virtual;

    function    RelativeToScreen(Point: TInteger32Point): TInteger32Point;
    function    ScreenToRelative(Point: TInteger32Point): TInteger32Point;

    function    CreateNearestMonitor(const Reference: TInteger32Point): TMonitor; virtual;
    function    GetHintWindow(): THintWindow; virtual;

    function    GetPreferredSize(AvailableSize: TInteger32Size): TInteger32Size; virtual;
    function    GetScrollSize(AvailableSize: TInteger32Size): TInteger32Size; virtual;

    function    ResolveStyleSize(const AvailableSize: TInteger32Size): TInteger32Size;

    procedure   MakeRectangleVisible(Rectangle: TInteger32Rectangle);
    procedure   MakeRectangleVisibleForControl(Control: TControl; Rectangle: TInteger32Rectangle); virtual;
    function    GetVisibleRectangle(): TInteger32Rectangle;
    procedure   VisibleRectangleChanged(); virtual;
    function    GetVisibleRectangleForControl(Control: TControl): TInteger32Rectangle; virtual;
    function    HandlesNavigationDimension(NavigationDimension: TValidNavigationDimension): TBoolean; virtual;

    function    HandleMouseEvent(Event: TMouseEvent): TBoolean; virtual;
    function    DistributeMouseEventDownHierarchy(Event: TMouseEvent): TBoolean; virtual;
    function    DistributeMouseEventUpHierarchy(Event: TMouseEvent): TBoolean;

    function    MouseLeftDown(Event: TMouseButtonEvent): TBoolean; virtual;
    function    MouseLeftUp(Event: TMouseButtonEvent): TBoolean; virtual;
    function    MouseRightDown(Event: TMouseButtonEvent): TBoolean; virtual;
    function    MouseRightUp(Event: TMouseButtonEvent): TBoolean; virtual;

    function    MouseButton(Event: TMouseButtonEvent): TBoolean; virtual;
    function    MouseWheel(Event: TMouseWheelEvent): TBoolean; virtual;
    function    MouseMove(Event: TMouseMoveEvent): TBoolean; virtual;
    function    MouseLeave(Event: TMouseLeaveEvent): TBoolean; virtual;
    
    function    GetCursorForPosition(const Position: TInteger32Point): TCursor; virtual;

    function    HandleKeyboardEvent(Event: TKeyboardEvent): TBoolean; virtual;
    function    ShouldForwardKeyboardEventDownChain(Event: TKeyboardEvent): TBoolean; virtual;
    function    DistributeKeyboardEventThroughChain(Event: TKeyboardEvent): TBoolean;
    function    DistributeKeyboardEventUpCompositionHierarchy(Event: TKeyboardEvent): TBoolean;

    function    KeyDown(Event: TKeyDownEvent): TBoolean; virtual;
    function    KeyUp(Event: TKeyUpEvent): TBoolean; virtual;
    function    KeyPress(Event: TKeyPressEvent): TBoolean; virtual;
    function    ShouldForwardKeyDownDownChain(Event: TKeyDownEvent): TBoolean; virtual;
    function    ShouldForwardKeyUpDownChain(Event: TKeyUpEvent): TBoolean; virtual;
    function    ShouldForwardKeyPressDownChain(Event: TKeyPressEvent): TBoolean; virtual;

    // TODO: We should probably introduce a TControlFocusManager which provides much of the following functionality (including composition focus)
    procedure   GainedFocus(); virtual;
    procedure   LostFocus(); virtual;
    procedure   RequestFocus();
    procedure   RequestFocusInComposition();
    procedure   GainedFocusInComposition(); virtual;
    procedure   LostFocusInComposition(); virtual;
    function    HasFocus(): TBoolean;
    function    HasFocusInComposition(): TBoolean;
    function    ControlWithCompositionFocus(): TControl;
    function    ChildWithCompositionFocus(): TControl; virtual;
    function    ChildHasCompositionFocus(ChildControl: TControl): TBoolean; virtual;
    function    CanReceiveFocus(): TBoolean;
    function    ControlInHierarchyCanReceiveFocus(): TBoolean;
    function    DefaultControlToFocus(): TControl; virtual;
    function    DefaultControlToNavigate(): TControl; virtual;
    function    ReceivesKeyboardInput(): TBoolean;
    function    NextInKeyboardInputChain(): TControl; virtual;
    function    HasAncestor(Control: TControl): TBoolean;

    function    IsVisible(): TBoolean; virtual;
    function    IsChildVisible(Control: TControl): TBoolean; virtual;
    procedure   MakeVisible();

    procedure   Enter(); virtual; 
    procedure   EnterFromTop(Fast: TBoolean); virtual;
    procedure   EnterFromBottom(Fast: TBoolean); virtual;
    procedure   EnterFromLeft(Fast: TBoolean); virtual;
    procedure   EnterFromRight(Fast: TBoolean); virtual;

    function    ChildWithPosition(Position: TInteger32Point): TControl; virtual;
    function    DescendantWithPosition(const Position: TInteger32Point): TControl;

    function    ConvertPositionToChildPosition(Position: TInteger32Point; Child: TControl): TInteger32Point; virtual;
    function    ConvertPositionFromChildPosition(Position: TInteger32Point; Child: TControl): TInteger32Point; virtual;

    function    ConvertPositionToDescendantPosition(const Position: TInteger32Point; Descendant: TControl): TInteger32Point; 
    function    Old_PositionRelativeTo(Ancestor: TControl): TInteger32Point; deprecated; // TODO: The calculated result is wrong
    function    PositionRelativeTo(Ancestor: TControl): TInteger32Point;

    procedure   Invalidate();
    procedure   InvalidateRectangle(const Rectangle: TInteger32Rectangle);

    function    GetDragControl(const Position: TInteger32Point): TControl; virtual;
    function    CreateDragSource(Control: TControl): TDragSite; virtual;
    function    CreateDragTarget(Source: TDragSite; const Position: TInteger32Point): TDragSite; virtual;

    function    GetControlFactory(): TControlFactory;
    procedure   OpenControl(Control: TControl; TransferFocus: TBoolean);
    procedure   Old_OpenControlForValue(Value: TValue; TransferFocus: TBoolean); deprecated 'Use OpenControlForValue() with an entire TValuePath';
    procedure   OpenControlForValue(Path: TValuePath; TransferFocus: TBoolean);
    procedure   CloseControl(Control: TControl); virtual;
    function    IsOverlapped(): TBoolean; virtual;
    procedure   CloseAllShowing(Object_: TObject);

    function    HierarchyContainsControl(Control: TControl): TBoolean;

    function    CopyToClipboard(): TBoolean; virtual;
    function    CutToClipboard(): TBoolean; virtual;
    function    PasteFromClipboard(): TBoolean; virtual;
    function    Undo(): TBoolean; virtual;
    function    Redo(): TBoolean; virtual;

    function    GetFocusedObject(): TValuePath; virtual;
    function    GetObjectSelection(): TObjectSelection; virtual;

    function    FindFirstDescendant(Condition: TCondition<TControl>): TControl; virtual;
    function    FindFirstSibling(Condition: TCondition<TControl>): TControl; virtual;

    function    ControlIsAtSide(Control: TControl; Side: TSide): TBoolean;
    function    ControlOverlapsAtSide(Control: TControl; Side: TSide): TBoolean;

    function    FilterFocusableControlsAtSide(Controls: TList<TControl>; Side: TSide): TList<TControl>;
    function    FilterOverlappingControlsAtSide(Controls: TList<TControl>; Side: TSide): TList<TControl>;
    function    FilterClosestControlsAtSide(Controls: TList<TControl>; Side: TSide): TList<TControl>;

    function    AncestorControlWithControlsAtSide(Side: TSide): TControl;
    function    ControlAtSide(Controls: TList<TControl>; Side: TSide): TControl;
    function    LeafControlAtSide(Control: TControl; Side: TSide): TControl;

    function    CreateChildIterator(): TIterator<TControl>; virtual;
    function    CreateSubtreeIterator(Order: TTreeVerticalOrder): TIterator<TControl>;

    property    ParentControl: TControl read FParentControl write SetParentControl;
    property    Listeners: TListeners read FListeners;
    property    ActiveChildControl: TControl read GetActiveChildControl write SetActiveChildControl;
    property    Caret: TCaret read FCaret write SetCaret;
    property    Left: TInteger32 read GetLeft write SetLeft;
    property    Top: TInteger32 read GetTop write SetTop;
    property    Width: TInteger32 read GetWidth write SetWidth;
    property    Height: TInteger32 read GetHeight write SetHeight;
    property    Side[Side: TSide]: TInteger32 read GetSide;
    property    Position: TInteger32Point read GetPosition write SetPosition;
    property    Size: TInteger32Size read GetSize write SetSize;
    property    Bounds: TInteger32Rectangle read FBounds write SetBounds;
    property    ScreenBounds: TInteger32Rectangle read GetScreenBounds;
    property    Focusability: TFocusability read GetFocusability write FFocusability;
    property    Mode: TControlMode read FMode write SetMode;
    property    Editor: TControl read GetEditor;
    property    Caption: TText read GetCaption write SetCaption;
    property    CaptionVisible: TBoolean read GetCaptionVisible write SetCaptionVisible;
    property    Value: TValue read GetValue write SetValue;
    property    Path: TValuePath read FPath write SetPath;
    property    ChildControls: TList<TControl> read FChildControls;
    property    IsEditor: TBoolean read FIsEditor write SetIsEditor;
    property    AllowedModes: TControlModes read FAllowedModes write SetAllowedModes;
    property    Style: TControlStyle read FStyle;

  public
    type
      TSideComparator = class(TComparator<TControl>)
      public
        Side: TSide;

        constructor Create(Side: TSide); reintroduce; virtual;
      
        function    Compare(const Left: TControl; const Right: TControl): TSign; override;
      end;

    type
      TShows = class(TProjectingCondition<TControl, TObject>)
      public
        function    Matches(const Control: TControl): TBoolean; override;
      end;
  end;

  TChildControlList = class(TObjectList<TControl>)
  private
    ParentControl: TControl;

  protected
    procedure   AcquireElement(Control: TControl); override;
    procedure   ReleaseElement(Control: TControl); override;
    
  public
    constructor Create(ParentControl: TControl); reintroduce; virtual;
    destructor  Destroy(); override;
  end;

  TControlFactory = class(TObject)
  protected
    function    GetUserLevel(): TUserLevel; virtual; abstract;
    procedure   SetUserLevel(const Value: TUserLevel); virtual; abstract;

  public
    function    CreateControl(OuterFactory: TControlFactory; Purpose: TControlPurpose; Path: TValuePath; Value: TTypedValue = nil): TControl; virtual; abstract;

    property    UserLevel: TUserLevel read GetUserLevel write SetUserLevel; 
  end;

  TControlChildIteratorFactory = class(TChildIteratorFactory<TControl>)
  public
    function    CreateChildIterator(Parent: TControl): TIterator<TControl>; override;
  end;

implementation

uses
  Application,
  Color.Constants,
  Drawing.Fill,
  Drawing.Stroke,
  Drawing.Stroke.Pattern,
  Event.DistributionCenter,
  Exception,
  Exception.NotImplemented,
  Font.Purpose,
  Integer,
  Mathematics,
  Reference.User,
  UserInterface.Control.Event,
  Windows.Control;

{ TControl }

constructor TControl.Create();
begin
  inherited Create();

  FChildControls  := TChildControlList.Create(Self);
  FCaption        := '';
  FCaptionVisible := True;
  FFocusability   := TFocusability.FocusOnMouse;
  FAllowedModes   := [TControlMode.Display, TControlMode.Edit];
  FStyle          := TControlStyle.Create(Self);
  FBounds         := TInteger32Size.New(0, 0);

  FListeners := TListeners.Create();
  FListeners.AddReference();

  Path := TValuePath.Create([]);
end;

function TControl.CreateChildIterator(): TIterator<TControl>;
begin
  Result := ChildControls.CreateIterator();
end;

function TControl.CreateDragSource(Control: TControl): TDragSite;
begin
  Result := nil;
end;

function TControl.CreateDragTarget(Source: TDragSite; const Position: TInteger32Point): TDragSite;
begin
  Result := nil;
end;

function TControl.GetFocusedObject(): TValuePath;
begin
  Result := TValuePath.Create([]);
end;

function TControl.CreateNearestMonitor(const Reference: TInteger32Point): TMonitor;
begin
  if ParentControl <> nil then
    Result := ParentControl.CreateNearestMonitor(Reference)
  else
    Result := nil;
end;

function TControl.CreateSubtreeIterator(Order: TTreeVerticalOrder): TIterator<TControl>;
begin
  Result := TTreeIterator<TControl>.Create(Self, Order, TControlChildIteratorFactory.Create());
end;

function TControl.CreateToolbar(): TControl;
begin
  Result := nil;
end;

function TControl.GetHeight(): TInteger32;
begin
  Result := Bounds.Height;
end;

function TControl.GetHintWindow(): THintWindow;
begin
  if ParentControl <> nil then
    Result := ParentControl.GetHintWindow()
  else
    Result := nil;
end;

function TControl.GetLeft(): TInteger32;
begin
  Result := Bounds.Left;
end;

procedure TControl.DescendantFiresEvent(Descendant: TControl; Event: TEvent);
var
  Listeners: TListeners;
begin
  if not SuppressInvalidate or not (Event is TControlInvalidatedEvent) then
  begin
    if ParentControl <> nil then
      ParentControl.DescendantFiresEvent(Descendant, Event)
    else
    begin
      Listeners := Descendant.Listeners;
      Listeners.AddReference();

      try
        TEventDistributionCenter.Instance.PostEvent(Event);
        Listeners.DistributeEvent(Event, False);
      finally
        Listeners.ReleaseReference();
      end;
    end;
  end;
end;

procedure TControl.DescendantRequestsFocus(Descendant: TControl);
begin
  if ParentControl <> nil then
    ParentControl.DescendantRequestsFocus(Descendant)
  else
    Descendant.GetFocusManager().FocusedControl := Descendant;
end;

procedure TControl.DescendantRequestsFocusInComposition(Descendant: TControl);
begin
  if ParentControl <> nil then
    ParentControl.DescendantRequestsFocusInComposition(Descendant);
end;

procedure TControl.DescendantOpensControl(Descendant, Control: TControl; TransferFocus: TBoolean);
begin
  if ParentControl <> nil then
    ParentControl.DescendantOpensControl(Descendant, Control, TransferFocus)
  else
    TApplication.Instance.OpenControl(Control, TransferFocus);
end;

procedure TControl.DescendantOpensControlForValue(Descendant: TControl; Value: TValuePath; TransferFocus: TBoolean);
begin
  if ParentControl <> nil then
    ParentControl.DescendantOpensControlForValue(Descendant, Value, TransferFocus)
  else
    TApplication.Instance.OpenControlForValue(Value, TransferFocus);
end;

function TControl.DescendantWithPosition(const Position: TInteger32Point): TControl;
begin
  Result := ChildWithPosition(Position);

  if Result <> nil then
    Result := Result.DescendantWithPosition(ConvertPositionToChildPosition(Position, Result))
  else
    Result := Self;
end;

destructor TControl.Destroy();
begin
  FireEvent(TWillBeFreedEvent.Create(Self));

  if ParentControl <> nil then
    ParentControl.ChildControls.Remove(Self);

  Path.ReleaseReference();
  Editor.Free();
  ChildControls.Free();
  Listeners.ReleaseReference();
  Style.Free();

  Caret.ReleaseReference();

  inherited Destroy();
end;

procedure TControl.DetermineStyle();
var
  Iterator: TIterator<TControl>;
  Control:  TControl;
begin
  Iterator := CreateSubtreeIterator(TTreeVerticalOrder.TopDown);

  while Iterator.IsValid() do
  begin
    Control := Iterator.Current;
    Control.Style.Background.Fill := ParentControl.Style.Background.Fill;
    Control.Style.PanelBackground.Fill := ParentControl.Style.PanelBackground.Fill;

    Iterator.GotoNext();
  end;

  Iterator.Free();
end;

procedure TControl.DistributeEventDownHierarchy(Event: TEvent; Order: TTreeVerticalOrder; FreeEvent: TBoolean = True);
var
  Iterator: TIterator<TControl>;
begin
  try
    Iterator := CreateSubtreeIterator(Order);

    try
      while Iterator.IsValid() do
      begin
        Iterator.Current.HandleEvent(Event);
        Iterator.GotoNext();
      end;
    finally
      Iterator.Free();
    end;
  finally
    if FreeEvent then
      Event.Free();
  end;
end;

function TControl.DistributeKeyboardEventThroughChain(Event: TKeyboardEvent): TBoolean;
var
  NextInChain: TControl;
begin
  NextInChain := NextInKeyboardInputChain();

  Result :=
    (
      (NextInChain <> nil)
      and ShouldForwardKeyboardEventDownChain(Event)
      and NextInChain.DistributeKeyboardEventThroughChain(Event)
    )
    or HandleKeyboardEvent(Event);
end;

function TControl.DistributeKeyboardEventUpCompositionHierarchy(Event: TKeyboardEvent): TBoolean;
var
  Control: TControl;
begin
  Control := Self;

  repeat
    Result  := Control.DistributeKeyboardEventThroughChain(Event);
    Control := Control.ParentControl;
  until Result or (Control = nil) or not Control.IsComposition();
end;

function TControl.DistributeMouseEventDownHierarchy(Event: TMouseEvent): TBoolean;
var
  Child: TControl;
begin
  Child := ChildForMouseEvent(Event);

  if Child <> nil then
  begin
    Event.Position := ConvertPositionToChildPosition(Event.Position, Child);
    Result := Child.DistributeMouseEventDownHierarchy(Event);
  end  
  else
    Result := DistributeMouseEventUpHierarchy(Event);
end;

function TControl.DistributeMouseEventUpHierarchy(Event: TMouseEvent): TBoolean;
var
  Control:       TControl;
  ParentControl: TControl;
begin
  Control := Self;
  Result  := False;

  while not Result and (Control <> nil) do
  begin
    Result := Control.HandleMouseEvent(Event);

    if not Result then
    begin
      ParentControl := Control.ParentControl;

      if ParentControl <> nil then
        Event.Position := ParentControl.ConvertPositionFromChildPosition(Event.Position, Control);

      Control := ParentControl;
    end;
  end;
end;

procedure TControl.GainedFocus();
begin
  Invalidate();
  FireEvent(TControlGotFocusEvent.Create(Self));
end;

procedure TControl.GainedFocusInComposition();
begin
end;

procedure TControl.Invalidate();
begin
  InvalidateRectangle(GetVisibleRectangle());
end;

procedure TControl.InvalidateRectangle(const Rectangle: TInteger32Rectangle);
begin
  FireEvent(TControlInvalidatedEvent.Create(Self, Rectangle));
end;

function TControl.HasFocus(): TBoolean;
var
  FocusManager: TKeyboardFocusManager;
begin
  FocusManager := GetFocusManager();
  Result       := (FocusManager <> nil) and (Self = FocusManager.FocusedControl);
end;

function TControl.HasFocusInComposition(): TBoolean;
var
  Embellishment: TControl;
  Composition:   TControl;
begin
  Result        := False;
  Embellishment := GetRootEmbellishment();

  if Embellishment <> nil then
  begin
    Composition := Embellishment.ParentControl;
    Result      := (Composition <> nil) and Composition.ChildHasCompositionFocus(Self);
  end;
end;

procedure TControl.LostFocus();
begin
  StopInlineEditing(True);
  Invalidate();
  FireEvent(TControlLostFocusEvent.Create(Self));
end;

procedure TControl.LostFocusInComposition();
begin
end;

function TControl.MouseLeftDown(Event: TMouseButtonEvent): TBoolean;
begin
  Result := False;
end;

function TControl.MouseLeftUp(Event: TMouseButtonEvent): TBoolean;
begin
  Result := False;
end;

function TControl.MouseMove(Event: TMouseMoveEvent): TBoolean;
begin
  Result := False;
end;

procedure TControl.Paint(Canvas: TCanvas);
begin
end;

procedure TControl.RequestFocus();
begin
  DescendantRequestsFocus(Self);
end;

procedure TControl.RequestFocusInComposition();
begin
  DescendantRequestsFocusInComposition(Self);
end;

procedure TControl.SetHeight(const Value: TInteger32);
begin
  Bounds := TInteger32Rectangle.New(Bounds.TopLeft, TInteger32Size.New(Bounds.Width, Value));
end;

procedure TControl.SetLeft(const Value: TInteger32);
begin
  Bounds := TInteger32Rectangle.New(TInteger32Point.New(Value, Bounds.Top), Bounds.Size);
end;

procedure TControl.SetSize(const Value: TInteger32Size);
begin
  Bounds := TInteger32Rectangle.New(Bounds.TopLeft, Value);
end;

procedure TControl.SetTop(const Value: TInteger32);
begin
  Bounds := TInteger32Rectangle.New(TInteger32Point.New(Bounds.Left, Value), Bounds.Size);
end;

procedure TControl.SetWidth(const Value: TInteger32);
begin
  Bounds := TInteger32Rectangle.New(Bounds.TopLeft, TInteger32Size.New(Value, Bounds.Height));
end;

procedure TControl.SizeChanged();
begin
  FireEvent(TControlSizeChangedEvent.Create(Self));
end;

function TControl.RelativeToScreen(Point: TInteger32Point): TInteger32Point;
var
  VisibleRectangle: TInteger32Rectangle;
  ScreenBounds:     TInteger32Rectangle;
begin
  VisibleRectangle := GetVisibleRectangle();
  ScreenBounds     := Self.ScreenBounds;
  Result           := ScreenBounds.TopLeft + Point - VisibleRectangle.TopLeft;
end;

function TControl.ScreenToRelative(Point: TInteger32Point): TInteger32Point;
var
  VisibleRectangle: TInteger32Rectangle;
  ScreenBounds:     TInteger32Rectangle;
begin
  VisibleRectangle := GetVisibleRectangle();
  ScreenBounds     := Self.ScreenBounds;
  Result           := Point - ScreenBounds.TopLeft + VisibleRectangle.TopLeft;
end;

procedure TControl.ResetEditorValue();
begin
end;

function TControl.ResolveStyleSize(const AvailableSize: TInteger32Size): TInteger32Size;
begin
  Result := GetPreferredSize(AvailableSize);

  if Style.Width.Value is TControlSizeFixed then
    Result.Width := (Style.Width.Value as TControlSizeFixed).Value
  else if Style.Width.Value is TControlSizeAvailable then
    Result.Width := AvailableSize.Width;

  if Style.Height.Value is TControlSizeFixed then
    Result.Height := (Style.Height.Value as TControlSizeFixed).Value
  else if Style.Height.Value is TControlSizeAvailable then
    Result.Height := AvailableSize.Height;
end;

function TControl.MouseRightDown(Event: TMouseButtonEvent): TBoolean;
begin
  Result := False;
end;

function TControl.MouseRightUp(Event: TMouseButtonEvent): TBoolean;
begin
  Result := False;
end;

function TControl.MouseWheel(Event: TMouseWheelEvent): TBoolean;
begin
  Result := False;
end;

function TControl.KeyDown(Event: TKeyDownEvent): TBoolean;
begin
  Result := HandleClipboardKey(Event.Key, Event.Modifiers);

  if not Result and IsNavigationKey(Event.Key) then
    Result := Navigate(KeyToNavigation(Event.Key, Event.Modifiers), Event.Modifiers);

  if not Result then
    Result := HandleContextMenuKey(Event);
end;

function TControl.KeyPress(Event: TKeyPressEvent): TBoolean;
begin
  Result := False;
end;

function TControl.KeyUp(Event: TKeyUpEvent): TBoolean;
begin
  Result := False;
end;

function TControl.GetEditor(): TControl;
begin
  Result := nil;
end;

function TControl.GetEditorBounds(): TInteger32Rectangle;
begin
  Result := TInteger32Rectangle.New(0, 0, 0, 0);
end;

function TControl.GetFocusability(): TFocusability;
begin
  Result := FFocusability;
end;

function TControl.GetFocusManager(): TKeyboardFocusManager;
begin
  if ParentControl <> nil then
    Result := ParentControl.GetFocusManager()
  else
    Result := nil;
end;

function TControl.GetContextMenuTargetBounds(): TInteger32Rectangle;
begin
  Result := TInteger32Rectangle.New(0, 0, 0, 0);
end;

function TControl.IsInlineEditing(): TBoolean;
begin
  Result := (Editor <> nil) and (Editor.Mode = TControlMode.Edit);
end;

function TControl.IsMouseLeftDown(): TBoolean;
var
  MouseManager: TMouseManager;
begin
  MouseManager := GetMouseManager();
  Result       := (MouseManager.ControlWithCapture = Self) and (MouseManager.Mouse.Left.State = MouseManager.Mouse.Left.Down);
end;

function TControl.IsOverlapped(): TBoolean;
begin
  Result := False;
end;

function TControl.IsVisible(): TBoolean;
begin
  Result := (ParentControl = nil) or ParentControl.IsChildVisible(Self);
end;

procedure TControl.Enter();
begin
  DefaultControlToFocus.RequestFocus();
end;

procedure TControl.EnterFromBottom(Fast: TBoolean);
begin
  Enter();
end;

procedure TControl.EnterFromLeft(Fast: TBoolean);
begin
  Enter();
end;

procedure TControl.EnterFromRight(Fast: TBoolean);
begin
  Enter();
end;

procedure TControl.EnterFromTop(Fast: TBoolean);
begin
  Enter();
end;

procedure TControl.ScrollEditorIntoView();
begin
end;

procedure TControl.SetEditorValue(Value: TValue);
begin
end;

procedure TControl.StopInlineEditing(Successful: TBoolean);
begin
  if IsInlineEditing then
    Editor.StopEditing(Successful);
end;

procedure TControl.StyleChanged(Property_: TControlStyleProperty);
begin
  FireEvent(TControlStyleChanged.Create(Self, Property_));
end;

function TControl.GetCaption(): TText;
begin
  Result := FCaption;
end;

function TControl.GetCaptionVisible(): TBoolean;
begin
  Result := FCaptionVisible;
end;

function TControl.GetClipBoard(): TClipBoard;
begin
  if ParentControl <> nil then
    Result := ParentControl.GetClipBoard()
  else
    Result := nil;
end;

function TControl.GetClippingBoundsForChild(Control: TControl): TInteger32Rectangle;
begin
  Result := Control.Bounds;
end;

function TControl.GetControlFactory(): TControlFactory;
begin
  Result := TApplication.Instance.ControlFactory;
end;

procedure TControl.SetCaption(const Value: TText);
begin
  if Value <> Caption then
  begin
    FCaption := Value;
    CaptionChanged();
  end;
end;

procedure TControl.SetCaptionVisible(const Value: TBoolean);
begin
  FCaptionVisible := Value;
end;

procedure TControl.SetCaret(const Value: TCaret);
begin
  Value.AddReference();

  try
    if (Value <> Caret) and ((Value = nil) or (Caret = nil) or (Value.Bounds <> Caret.Bounds)) then
    begin
      Value.AddReference();
      Caret.ReleaseReference();

      FCaret := Value;
      FireEvent(TControlCaretChangedEvent.Create(Self));
    end;
  finally
    Value.ReleaseReference();
  end;
end;

procedure TControl.SetChildControlVisible(Control: TControl; Visible: TBoolean; ListEndPoint: TListEndPoint = TListEndPoint.Tail);
begin
  // TODO: Do we need the ListEndPoint variable? Isn't this a sign that something is wrong if we depend on the
  //       order of child controls? Currently the TTreeControl cheats by refreshing during the paint operation
  //       which might cause child controls (the scroll bars) to be added or removed during a paint.
  if ChildControls.Contains(Control) then
  begin
    if not Visible then
      ChildControls.Remove(Control);
  end
  else if Visible then
  begin
    if ListEndPoint = TListEndPoint.Tail then
      ChildControls.Add(Control)
    else
      ChildControls.AddAt(0, Control);
  end;
end;

function TControl.Navigate(Direction: TNavigationDirection; KeyModifiers: TKeyModifiers): TBoolean;
begin
  case Direction of
    TNavigationDirection.Forward:
      Result := GoForward();
    TNavigationDirection.Backward:
      Result := GoBackward();
    TNavigationDirection.Up:
      Result := GoUp(KeyModifiers);
    TNavigationDirection.Down:
      Result := GoDown(KeyModifiers);
    TNavigationDirection.Left:
      Result := GoLeft(KeyModifiers);
    TNavigationDirection.Right:
      Result := GoRight(KeyModifiers);
    TNavigationDirection.PageUp:
      Result := GoPageUp(KeyModifiers);
    TNavigationDirection.PageDown:
      Result := GoPageDown(KeyModifiers);
    TNavigationDirection.PageLeft:
      Result := GoPageLeft(KeyModifiers);
    TNavigationDirection.PageRight:
      Result := GoPageRight(KeyModifiers);
    TNavigationDirection.VerticalHome:
      Result := GoVerticalHome(KeyModifiers);
    TNavigationDirection.VerticalEnd:
      Result := GoVerticalEnd(KeyModifiers);
    TNavigationDirection.HorizontalHome:
      Result := GoHorizontalHome(KeyModifiers);
    TNavigationDirection.HorizontalEnd:
      Result := GoHorizontalEnd(KeyModifiers);
    TNavigationDirection.Parent:
      Result := GoParent(KeyModifiers);
    else
      Result := False;
  end;
end;

function TControl.GoBackward: TBoolean;
begin
  Result := False;
end;

function TControl.GoDown(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoVerticalEnd(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoForward: TBoolean;
begin
  Result := False;
end;

function TControl.GoVerticalHome(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoLeft(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoPageDown(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoPageLeft(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoPageRight(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoPageUp(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoRight(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoUp(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GetPreferredSize(AvailableSize: TInteger32Size): TInteger32Size;
begin
  Result := TInteger32Size.New(0, 0);
end;

procedure TControl.QuitEditingMode(Successful: TBoolean);
begin
  Mode := TControlMode.Display;
  Listeners.DistributeEvent(TControlStoppedEditing.Create(Self, Successful));
end;

procedure TControl.RethinkScrollBars();
begin
  if ParentControl <> nil then
    ParentControl.ChildRethinksScrollBars(Self);
end;

function TControl.GetScrollSize(AvailableSize: TInteger32Size): TInteger32Size;
begin
  Result := GetPreferredSize(AvailableSize);
end;

procedure TControl.RepaintOnFocusChange();
begin
  Invalidate();
end;

procedure TControl.ChildControlAdded(Control: TControl);
begin
  Control.ParentControl := Self;
end;

procedure TControl.ChildControlRemoved(Control: TControl);
begin
  Control.ParentControl := nil;
end;

function TControl.ChildForMouseEvent(Event: TMouseEvent): TControl;
begin
  Result := ChildWithPosition(Event.Position);
end;

function TControl.ChildHasCompositionFocus(ChildControl: TControl): TBoolean;
begin
  Result := False;
end;

function TControl.Undo(): TBoolean;
begin
  Result := False;
end;

procedure TControl.UpdateBounds(const OldBounds: TInteger32Rectangle; const NewBounds: TInteger32Rectangle);
begin
  FBounds := NewBounds;
  BoundsChanged(OldBounds, NewBounds);
end;

function TControl.ShouldCancelMouseCaptureAutomatically(): TBoolean;
begin
  Result := True;
end;

function TControl.ShouldForwardKeyboardEventDownChain(Event: TKeyboardEvent): TBoolean;
begin
  if Event is TKeyDownEvent then
    Result := ShouldForwardKeyDownDownChain(Event as TKeyDownEvent)
  else if Event is TKeyUpEvent then
    Result := ShouldForwardKeyUpDownChain(Event as TKeyUpEvent)
  else if Event is TKeyPressEvent then
    Result := ShouldForwardKeyPressDownChain(Event as TKeyPressEvent)
  else
    Result := False;
end;

function TControl.ShouldForwardKeyDownDownChain(Event: TKeyDownEvent): TBoolean;
begin
  Result := True;
end;

function TControl.GetDragControl(const Position: TInteger32Point): TControl;
begin
  Result := nil;
end;

function TControl.GetDrawingResources(): TDrawingResources;
begin
  if ParentControl <> nil then
    Result := ParentControl.GetDrawingResources()
  else
    Result := nil;
end;

function TControl.GetChildOfDynamicContainer(): TControl;
begin
  Result := RootComposition;

  while (Result <> nil) and (Result.ParentControl <> nil) and not Result.ParentControl.IsDynamicContainer() do
    Result := Result.ParentControl.RootComposition;
end;

function TControl.HierarchyContainsControl(Control: TControl): TBoolean;
begin
  Result := Control = Self;

  while not Result and (Control <> nil) do
  begin
    Control := Control.ParentControl;
    Result  := Control = Self;
  end;
end;

function TControl.GetMouseManager(): TMouseManager;
begin
  if ParentControl <> nil then
    Result := ParentControl.GetMouseManager()
  else
    Result := nil;
end;

function TControl.GetObjectSelection(): TObjectSelection;
begin
  Result := nil;
end;

procedure TControl.AllowedModesChanged();
begin
end;

function TControl.AncestorControlWithControlsAtSide(Side: TSide): TControl;
var
  Controls:        TList<TControl>;
  AncestorControl: TControl;
begin
  Result          := nil;
  AncestorControl := ParentControl;

  while (Result = nil) and (AncestorControl <> nil) do
  begin
    Controls := FilterFocusableControlsAtSide(AncestorControl.ChildControls, Side);

    if Controls.Count > 0 then
      Result := AncestorControl;

    Controls.Free();
    AncestorControl := AncestorControl.ParentControl;
  end;
end;

procedure TControl.BoundsChanged(const OldBounds: TInteger32Rectangle; const NewBounds: TInteger32Rectangle);
begin
  if NewBounds.Size <> OldBounds.Size then
    SizeChanged();

  FireEvent(TControlBoundsChangedEvent.Create(Self, OldBounds, NewBounds));
  Invalidate();  
end;

function TControl.GetValue(): TValue;
begin
  Result := nil;
end;

procedure TControl.SetValue(const Value: TValue);
begin
  Value.Discard(); // TODO: We probably should raise an exception here
end;

procedure TControl.SetBounds(const Value: TInteger32Rectangle);
var
  OldBounds: TInteger32Rectangle;
  NewBounds: TInteger32Rectangle;
begin
  OldBounds := Bounds;
  NewBounds := TInteger32Rectangle.New(Value.TopLeft, TInteger32Size.New(Maximum(Value.Width, 0), Maximum(Value.Height, 0)));

  if NewBounds <> OldBounds then
    UpdateBounds(OldBounds, NewBounds);
end;

procedure TControl.PaintChildControl(Canvas: TCanvas; Control: TControl);
begin
  Canvas.ClippingWindow.Push(GetClippingBoundsForChild(Control));
  Canvas.Transformation.AppendTranslation(Control.Position);

  try
    Control.PaintAll(Canvas);
  except
    on Exception: EException do
    begin
      Canvas.Fill := TFill.Create(TNamedColor.Red);
      Canvas.Font := TPurposeFont.WindowText;
      Canvas.FillText(TInteger32Point.New(0, TPurposeFont.WindowText.Ascent), Exception.ClassName + ': ' + Exception.Message);
    end;
  end;

  Canvas.Transformation.RemoveLast();
  Canvas.ClippingWindow.Pop();
end;

procedure TControl.SetMode(const Value: TControlMode);
begin
  if Value <> Mode then
  begin
    FMode := Value;
    FireEvent(TControlModeChangedEvent.Create(Self));
    Invalidate();
  end;
end;

function TControl.StartEditing(): TBoolean;
begin
  Result := TControlMode.Edit in AllowedModes;

  if Result then
  begin
    Mode := TControlMode.Edit;
    Listeners.DistributeEvent(TControlStartedEditing.Create(Self));
  end;
end;

function TControl.StopEditing(Successful: TBoolean): TBoolean;
begin
  Result := EditingCanBeStopped(Successful);

  if Result then
    QuitEditingMode(Successful);
end;

function TControl.DefaultControlToFocus(): TControl;
var
  i:  TInteger32;
begin
  if Focusability <> TFocusability.None then
    Result := Self
  else
  begin
    Result := nil;
    i      := 0;

    while (Result = nil) and (i < ChildControls.Count) do
    begin
      Result := ChildControls[i].DefaultControlToFocus;
      Inc(i);
    end;
  end;
end;

procedure TControl.PaintFocusRectangle(Canvas: TCanvas; const Rectangle: TInteger32Rectangle);
begin
  Canvas.Stroke := TStroke.Create(TNamedColor.Black, 1, TStrokePattern.Create([1, 1]));
  Canvas.DrawRectangle(Rectangle);
end;

function TControl.CompositeControlHasFocus(): TBoolean;
begin
  Result := HasFocus;
end;

function TControl.CompositionReceivesKeyboardInput(): TBoolean;
var
  Composition: TControl;
begin
  Composition := GetRootEmbellishment().ParentControl;
  Result      := (Composition <> nil) and Composition.ReceivesKeyboardInput();
end;

function TControl.ControlAtSide(Controls: TList<TControl>; Side: TSide): TControl;
var
  FocusableControls:   TList<TControl>;
  ClosestControls:     TList<TControl>;
  OverlappingControls: TList<TControl>;
  SideToCompare:       TSide;
begin
  FocusableControls   := FilterFocusableControlsAtSide(Controls, Side);
  OverlappingControls := FilterOverlappingControlsAtSide(FocusableControls, Side);

  if OverlappingControls.Count > 0 then
    ClosestControls := FilterClosestControlsAtSide(OverlappingControls, Side)
  else
    ClosestControls := FilterClosestControlsAtSide(FocusableControls, Side);

  if Side in [sdLeft, sdRight] then
    SideToCompare := sdTop
  else
    SideToCompare := sdLeft;

  Result := ClosestControls.GetMinimum(TSideComparator.Create(SideToCompare));

  FocusableControls.Free();
  ClosestControls.Free();
  OverlappingControls.Free();
end;

function TControl.ControlInCompositionHasFocus(): TBoolean;
var
  Embellishment: TControl;
begin
  Embellishment := GetRootEmbellishment();
  Result        := (Embellishment.ParentControl <> nil) and Embellishment.ParentControl.CompositeControlHasFocus;
end;

function TControl.ControlInHierarchyCanReceiveFocus(): TBoolean;
var
  i:  TInteger32;
begin
  Result := CanReceiveFocus;
  i      := 0;

  while not Result and (i < ChildControls.Count) do
  begin
    Result := ChildControls[i].ControlInHierarchyCanReceiveFocus;
    Inc(i);
  end;
end;

function TControl.ControlIsAtSide(Control: TControl; Side: TSide): TBoolean;
var
  ScreenBounds:          TInteger32Rectangle;
  ReferenceScreenBounds: TInteger32Rectangle;
begin
  ScreenBounds          := Control.ScreenBounds;
  ReferenceScreenBounds := Self.ScreenBounds;

  case Side of
    sdLeft:   Result := ScreenBounds.Right < ReferenceScreenBounds.Left;
    sdRight:  Result := ScreenBounds.Left > ReferenceScreenBounds.Right;
    sdTop:    Result := ScreenBounds.Bottom < ReferenceScreenBounds.Top;
    sdBottom: Result := ScreenBounds.Top > ReferenceScreenBounds.Bottom;
  else
    raise EException.Create('Unknown side');
  end;
end;

function TControl.ControlOverlapsAtSide(Control: TControl; Side: TSide): TBoolean;
var
  ScreenBounds:          TInteger32Rectangle;
  ReferenceScreenBounds: TInteger32Rectangle;
begin
  ScreenBounds          := Control.ScreenBounds;
  ReferenceScreenBounds := Self.ScreenBounds;

  Result :=
    ((Side in [sdLeft, sdRight]) and (ScreenBounds.Top <= ReferenceScreenBounds.Bottom) and (ScreenBounds.Bottom >= ReferenceScreenBounds.Top)) or
    ((Side in [sdTop, sdBottom]) and (ScreenBounds.Left <= ReferenceScreenBounds.Right) and (ScreenBounds.Right >= ReferenceScreenBounds.Left));
end;

function TControl.ControlWithCompositionFocus(): TControl;
var
  Embellishment: TControl;
  Composition:   TControl;
begin
  Result        := nil;
  Embellishment := GetRootEmbellishment();

  if Embellishment <> nil then
  begin
    Composition := Embellishment.ParentControl;

    if Composition <> nil then
      Result := Composition.ChildWithCompositionFocus();
  end;
end;

function TControl.GetScreenBounds(): TInteger32Rectangle;
var
  Control:        TControl;
  TopLevelWindow: TWindowsControl;
begin
  Control := Self;
  Result  := Control.GetVisibleRectangle();

  while not Control.IsOverlapped and (Control.ParentControl <> nil) do
  begin
    Result.TopLeft     := Control.ParentControl.ConvertPositionFromChildPosition(Result.TopLeft, Control);
    Result.BottomRight := Control.ParentControl.ConvertPositionFromChildPosition(Result.BottomRight, Control);
    
    Control := Control.ParentControl;
  end;

  if Control is TWindowsControl then
  begin
    TopLevelWindow := Control as TWindowsControl;

    Result.TopLeft     := Result.TopLeft + TopLevelWindow.Control.Position + TopLevelWindow.Position;
    Result.BottomRight := Result.BottomRight + TopLevelWindow.Control.Position + TopLevelWindow.Position;
  end;
end;

function TControl.GetCursorForPosition(const Position: TInteger32Point): TCursor;
begin
  Result := CursorManager.Arrow;
end;

function TControl.GetActiveChildControl(): TControl;
begin
  Result := nil;
end;

procedure TControl.SetActiveChildControl(const Value: TControl);
begin
end;

procedure TControl.SetAllowedModes(const Value: TControlModes);
begin
  if Value <> AllowedModes then
  begin
    FAllowedModes := Value;

    if not (Mode in AllowedModes) then
    begin
      if Mode = TControlMode.Edit then
        StopEditing(True)
      else if Mode = TControlMode.Display then
        StartEditing();
    end;

    AllowedModesChanged();
  end;
end;

function TControl.TopLevelWindow(): TControl;
begin
  Result := Self;

  while Result.ParentControl <> nil do
    Result := Result.ParentControl; 
end;

function TControl.GetPosition(): TInteger32Point;
begin
  Result := Bounds.TopLeft;
end;

procedure TControl.SetParentControl(const Value: TControl);
var
  OldBoundToLayout: TBoolean;
  Changes:          TControlHierarchyChanges;
begin
  if Value <> ParentControl then
  begin
    OldBoundToLayout := IsBoundToLayout;

    FParentControl := Value;
    Changes := [TControlHierarchyChange.Parent];

    if OldBoundToLayout <> IsBoundToLayout then
      Changes := Changes + [TControlHierarchyChange.BoundToLayout];

    // TODO: Probably we should not only fire an event when ParentControl is assigned
    if ParentControl <> nil then
      DistributeEventDownHierarchy(TControlHierarchyEvent.Create(Self, Changes), TTreeVerticalOrder.BottomUp);
  end;
end;

procedure TControl.SetPath(const Value: TValuePath);
begin
  if Value <> Path then
  begin 
    Value.AddReference();
    Path.ReleaseReference();

    FPath := Value;
  end;
end;

procedure TControl.SetPosition(const Value: TInteger32Point);
begin
  Bounds := TInteger32Rectangle.New(Value, Bounds.Size);
end;

procedure TControl.CopyCaretFromDescendant(Descendant: TControl);
var
  CaretBounds: TInteger32Rectangle;
begin
  if Descendant.Caret <> nil then
  begin
    CaretBounds := Descendant.Caret.Bounds;
    CaretBounds := CaretBounds.Offset(Descendant.Position);
    Caret       := TCaret.Create(CaretBounds);
  end
  else
    Caret := nil;
end;

function TControl.CopyToClipboard(): TBoolean;
begin
  Result := False;
end;

function TControl.CutToClipboard(): TBoolean;
begin
  Result := False;
end;

function TControl.PasteFromClipboard(): TBoolean;
begin
  Result := False;
end;

function TControl.PositionRelativeTo(Ancestor: TControl): TInteger32Point;
var
  Control: TControl;
begin
  Result  := TInteger32Point.New(0, 0);
  Control := Self;

  while Control <> Ancestor do
  begin
    Result  := Control.ParentControl.ConvertPositionFromChildPosition(Result, Control);
    Control := Control.ParentControl;
  end;
end;

function TControl.Old_PositionRelativeTo(Ancestor: TControl): TInteger32Point;
var
  Control: TControl;
begin
  Result := TInteger32Point.New(0, 0);

  if Ancestor <> Self then
  begin
    Control := Self;

    while Control.ParentControl <> Ancestor do
    begin
      Result  := Control.ParentControl.ConvertPositionFromChildPosition(Result, Control);
      Control := Control.ParentControl;
    end;
  end;
end;

function TControl.HandleClipboardKey(Key: TKey; KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;

  if KeyModifiers = [TKeyModifier.Control] then
  begin
    case Key of
      TKey.C:
        Result := CopyToClipboard();
      TKey.X:
        Result := CutToClipboard();
      TKey.V:
        Result := PasteFromClipboard();
      TKey.Y:
        Result := Redo();
      TKey.Z:
        Result := Undo();
    end;
  end;
end;

function TControl.HandleContextMenuKey(Event: TKeyDownEvent): TBoolean;
var
  TargetRectangle: TInteger32Rectangle;
begin
  Result := (Event.Key = TKey.ContextMenu) or ((Event.Key = TKey.F10) and (Event.Modifiers = [TKeyModifier.Shift]));

  if Result then
  begin
    TargetRectangle := GetContextMenuTargetBounds();
    FireEvent(TControlContextMenuEvent.Create(Self, TargetRectangle.BottomRight));
  end;
end;

function TControl.HandleEvent(Event: TEvent): TBoolean;
var
  Control:        TControl;
  ControlEvent:   TControlEvent;
  HierarchyEvent: TControlHierarchyEvent;
begin
  Result := False;

  if Event is TControlEvent then
  begin
    ControlEvent := Event as TControlEvent;
    Control      := ControlEvent.GetControl();   
  
    if ControlEvent is TControlCaretChangedEvent then
    begin
      // TODO: We really should not copy Carets from editor to containing control
      if Control = Editor then
      begin
        Result := True;
        CopyCaretFromDescendant(Control);
      end;
    end
    else if Event is TControlEditingEvent then
    begin
      if Control = Editor then
      begin
        if Event is TControlStartedEditing then
        begin
          Result := True;
          ScrollEditorIntoView();
        end
        else if Event is TControlStoppedEditing then
        begin
          Result := True;

          if (Event as TControlStoppedEditing).Successful then
            SetEditorValue(Editor.Value)
          else
            ResetEditorValue();
        end;
      end;
    end
    else if Event is TControlValueChanged then
    begin
      if Control = Editor then
      begin
        Result := True;
      
        if Editor.Mode <> TControlMode.Edit then
          SetEditorValue(Editor.Value);

        ScrollEditorIntoView();
      end;
    end
    else if Event is TControlHierarchyEvent then
    begin
      HierarchyEvent := Event as TControlHierarchyEvent;

      if (TControlHierarchyChange.BoundToLayout in HierarchyEvent.Changes) and IsBoundToLayout() then
        HasBeenBoundToLayout();

      if (HierarchyEvent.GetControl() = Self) and (TControlHierarchyChange.Parent in HierarchyEvent.Changes) and (ParentControl <> nil) then
        DetermineStyle();
    end
  end
  else if Event is TControlStylePropertyChanged then
    StyleChanged((Event as TControlStylePropertyChanged).Property_);
end;

function TControl.HandleKeyboardEvent(Event: TKeyboardEvent): TBoolean;
begin
  if Event is TKeyDownEvent then
    Result := KeyDown(Event as TKeyDownEvent)
  else if Event is TKeyUpEvent then
    Result := KeyUp(Event as TKeyUpEvent)
  else if Event is TKeyPressEvent then
    Result := KeyPress(Event as TKeyPressEvent)
  else
    Result := False;
end;

function TControl.HandleMouseEvent(Event: TMouseEvent): TBoolean;
begin
  if Event is TMouseButtonEvent then
    Result := MouseButton(Event as TMouseButtonEvent)
  else if Event is TMouseMoveEvent then
    Result := MouseMove(Event as TMouseMoveEvent)
  else if Event is TMouseWheelEvent then
    Result := MouseWheel(Event as TMouseWheelEvent)
  else if Event is TMouseLeaveEvent then
    Result := MouseLeave(Event as TMouseLeaveEvent)
  else
    Result := False;
end;

function TControl.HandlesNavigationDimension(NavigationDimension: TValidNavigationDimension): TBoolean;
begin
  Result := False;
end;

function TControl.MouseButton(Event: TMouseButtonEvent): TBoolean;
begin
  Result := False;

  if Event is TMouseButtonDownEvent then
  begin
    if Event.Button = Event.Mouse.Left then
    begin
      // TODO: Should we really generically request the focus here? It might be better to leave it up to individual implementations of MouseLeftDown()
      //       Currently this means that when a mouse event bubbles up the hierarchy each parent control requests the focus which seems like a waste
      if FocusAbility = TFocusability.FocusOnMouse then
        RequestFocus();

      Result := MouseLeftDown(Event);
    end
    else if Event.Button = Event.Mouse.Right then
      Result := MouseRightDown(Event);
  end
  else if Event is TMouseButtonUpEvent then
  begin
    if Event.Button = Event.Mouse.Left then
      Result := MouseLeftUp(Event)
    else if Event.Button = Event.Mouse.Right then
      Result := MouseRightUp(Event);
  end;
end;

function TControl.MouseLeave(Event: TMouseLeaveEvent): TBoolean;
begin
  Result := False;
end;

function TControl.EditingCanBeStopped(Successful: TBoolean): TBoolean;
begin
  Result := TControlMode.Display in AllowedModes;
end;

function TControl.Embellish(): TControl;
begin
  Result := Self;
end;

function TControl.GetEmbellishedControl(): TControl;
begin
  Result := Self;
end;

function TControl.GetRootEmbellishment(): TControl;
begin
  Result := Self;

  while (Result.ParentControl <> nil) and Result.ParentControl.IsEmbellishment do
    Result := Result.ParentControl;
end;

function TControl.RootOverlappedControl: TControl;
begin
  Result := Self;

  while not Result.IsOverlapped and (Result.ParentControl <> nil) do
    Result := Result.ParentControl;
end;

function TControl.IsBoundToLayout(): TBoolean;
begin
  Result := (ParentControl <> nil) and ParentControl.IsBoundToLayout();
end;

function TControl.IsChildVisible(Control: TControl): TBoolean;
begin
  Result := IsVisible;
end;

function TControl.IsComposition(): TBoolean;
begin
  Result := False;
end;

function TControl.IsDynamicContainer(): TBoolean;
begin
  Result := False;
end;

function TControl.IsEmbellishment(): TBoolean;
begin
  Result := False;
end;

procedure TControl.ChildRethinksScrollBars(Child: TControl);
begin
end;

function TControl.GetTop(): TInteger32;
begin
  Result := Bounds.Top;
end;

function TControl.ReceivesKeyboardInput(): TBoolean;
var
  FocusManager: TKeyboardFocusManager;
begin
  FocusManager := GetFocusManager();
  Result       := (FocusManager <> nil) and FocusManager.ReceivesKeyboardInput(Self);
end;

function TControl.Redo(): TBoolean;
begin
  Result := False;
end;

function TControl.NextInKeyboardInputChain(): TControl;
begin
  Result := Editor;
end;

procedure TControl.OpenControl(Control: TControl; TransferFocus: TBoolean);
begin
  DescendantOpensControl(Self, Control, TransferFocus);
end;

procedure TControl.OpenControlForValue(Path: TValuePath; TransferFocus: TBoolean);
begin
  Path.AddReference();

  try
    DescendantOpensControlForValue(Self, Path, TransferFocus);
  finally
    Path.ReleaseReference();
  end;
end;

procedure TControl.Old_OpenControlForValue(Value: TValue; TransferFocus: TBoolean);
begin
  OpenControlForValue(TValuePath.Create([Value]), TransferFocus);
end;

procedure TControl.SetIsEditor(const Value: TBoolean);
begin
  if Value <> IsEditor then
  begin
    FIsEditor := Value;
    Invalidate();
  end;
end;

function TControl.FilterClosestControlsAtSide(Controls: TList<TControl>; Side: TSide): TList<TControl>;
var
  i:       TInteger32;
  Closest: TInteger32;
  Value:   TInteger32;
  Control: TControl;
begin
  Result  := TObjectList<TControl>.Create();
  Result.ElementManager := TReferenceUser<TControl>.Create();

  if Side in [sdRight, sdBottom] then
    Closest := High(TInteger32)
  else
    Closest := Low(TInteger32);

  for i := 0 to Controls.Count - 1 do
  begin
    Control := Controls[i];

    case Side of
      sdLeft:   Value := Control.Bounds.Right;
      sdRight:  Value := Control.Left;
      sdTop:    Value := Control.Bounds.Bottom;
      sdBottom: Value := Control.Top;
      else
        raise EException.Create('Unknown side');
    end;

    if Value = Closest then
      Result.Add(Control)
    else if ((Side in [sdLeft, sdTop]) and (Value > Closest)) or ((Side in [sdRight, sdBottom]) and (Value < Closest)) then
    begin
      Result.Clear();
      Result.Add(Control);
      
      Closest := Value;
    end;
  end;
end;

function TControl.FilterFocusableControlsAtSide(Controls: TList<TControl>; Side: TSide): TList<TControl>;
var
  i:       TInteger32;
  Control: TControl;
begin
  Result := TObjectList<TControl>.Create();
  Result.ElementManager := TReferenceUser<TControl>.Create();

  for i := 0 to Controls.Count - 1 do
  begin
    Control := Controls[i];

    if ControlIsAtSide(Control, Side) and Control.ControlInHierarchyCanReceiveFocus() then
      Result.Add(Control);
  end;
end;

function TControl.FilterOverlappingControlsAtSide(Controls: TList<TControl>; Side: TSide): TList<TControl>;
var
  i:       TInteger32;
  Control: TControl;
begin
  Result := TObjectList<TControl>.Create();
  Result.ElementManager := TReferenceUser<TControl>.Create();

  for i := 0 to Controls.Count - 1 do
  begin
    Control := Controls[i];

    if ControlOverlapsAtSide(Control, Side) then
      Result.Add(Control);
  end;
end;

function TControl.FindFirstDescendant(Condition: TCondition<TControl>): TControl;
var
  i: TInteger32;
begin
  Condition.AddReference();

  try
    if Condition.Matches(Self) then
      Result := Self
    else
    begin
      Result := nil;
      i      := 0;

      while (Result = nil) and (i < ChildControls.Count) do
      begin
        Result := ChildControls[i].FindFirstDescendant(Condition);
        Inc(i);
      end;
    end;
  finally
    Condition.ReleaseReference();
  end;
end;

function TControl.FindFirstSibling(Condition: TCondition<TControl>): TControl;
var
  Control: TControl;
begin
  Condition.AddReference();

  try
    Control := Self;
    Result  := nil;

    while (Result = nil) and (Control <> nil) do
    begin
      Result  := Control.FindFirstDescendant(Condition);
      Control := Control.ParentControl;
    end;
  finally
    Condition.ReleaseReference();
  end;
end;

procedure TControl.FireDefaultActionExecuted();
begin
  FireEvent(TControlDefaultActionExecutedEvent.Create(Self));
end;

procedure TControl.FireEvent(Event: TEvent);
begin
  DescendantFiresEvent(Self, Event);
  Event.Free();
end;

procedure TControl.FireValueChanged();
begin
  Listeners.DistributeEvent(TControlValueChanged.Create(Self));
end;

function TControl.ShouldForwardKeyPressDownChain(Event: TKeyPressEvent): TBoolean;
begin
  Result := True;
end;

function TControl.ShouldForwardKeyUpDownChain(Event: TKeyUpEvent): TBoolean;
begin
  Result := True;
end;

function TControl.RootComposition(): TControl;
begin
  Result := Self;

  while (Result.ParentControl <> nil) and Result.ParentControl.IsComposition do
    Result := Result.ParentControl;
end;

function TControl.RootControl(): TControl;
begin
  Result := Self;

  while Result.ParentControl <> nil do
    Result := Result.ParentControl; 
end;

function TControl.CanReceiveFocus(): TBoolean;
begin
  Result := Focusability <> TFocusability.None;
end;

procedure TControl.CaptionChanged();
begin
end;

function TControl.HasAncestor(Control: TControl): TBoolean;
var
  CurrentControl: TControl;
begin
  CurrentControl := Self;

  while (Control <> CurrentControl) and (CurrentControl <> nil) do
    CurrentControl := CurrentControl.ParentControl;

  Result := Control = CurrentControl;
end;

procedure TControl.HasBeenBoundToLayout();
begin
end;

function TControl.GetSide(Side: TSide): TInteger32;
begin
  case Side of
    sdLeft:   
      Result := Bounds.Left;
    sdRight:  
      Result := Bounds.Right;
    sdTop:    
      Result := Bounds.Top;
    sdBottom: 
      Result := Bounds.Bottom;
    else
      raise EException.Create('Unsupported side');
  end;
end;

function TControl.GetSize(): TInteger32Size;
begin
  Result := Bounds.Size;
end;

procedure TControl.CloseAllShowing(Object_: TObject);
var
  Root:             TControl;
  Control:          TControl;
  ChildOfContainer: TControl;
begin
  Root := TopLevelWindow();

  repeat
    Control := Root.FindFirstDescendant(TControl.TShows.Create(Object_));

    if Control <> nil then
    begin
      ChildOfContainer := Control.GetChildOfDynamicContainer();

      if (ChildOfContainer <> nil) and ChildOfContainer.ParentControl.IsDynamicContainer() then
        ChildOfContainer.ParentControl.CloseControl(ChildOfContainer)
      else
        raise EException.Create('Cannot close control: ' + Control.ClassName);
    end;
  until Control = nil;
end;

procedure TControl.CloseControl(Control: TControl);
begin
end;

function TControl.GoHorizontalEnd(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoHorizontalHome(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.GoParent(KeyModifiers: TKeyModifiers): TBoolean;
begin
  Result := False;
end;

function TControl.DefaultControlToNavigate(): TControl;
begin
  if ChildControls.Count > 0 then
    Result := ChildControls[0]
  else
    Result := Self;
end;

procedure TControl.MakeVisible();
var
  Embellishment: TControl;
begin
  Embellishment := GetRootEmbellishment();
  Embellishment.MakeRectangleVisible(Embellishment.Bounds.Size);
end;

procedure TControl.PaintAll(Canvas: TCanvas);
var
  Bounds: TInteger32Rectangle;
begin
  Bounds := Size;

  if Bounds.OverlapsWith(Canvas.ClippingWindow.Current) then
  begin
    Paint(Canvas);
    PaintChildren(Canvas);
  end;
end;

procedure TControl.LayoutControls();
begin
end;

function TControl.LeafControlAtSide(Control: TControl; Side: TSide): TControl;
var
  Controls: TList<TControl>;
begin
  Controls := Control.ChildControls;

  while (Control.FocusAbility = TFocusability.None) and (Controls.Count > 0) do
  begin
    Control  := ControlAtSide(Controls, Side);
    Controls := Control.ChildControls;
  end;

  if Control.FocusAbility <> TFocusability.None then
    Result := Control
  else
    Result := nil;
end;

procedure TControl.PaintChildren(Canvas: TCanvas);
var
  i: TInteger32;
begin
  for i := 0 to ChildControls.Count - 1 do
    PaintChildControl(Canvas, ChildControls[i]);
end;

procedure TControl.MakeRectangleVisible(Rectangle: TInteger32Rectangle);
begin
  if ParentControl <> nil then
    ParentControl.MakeRectangleVisibleForControl(Self, Rectangle.Offset(Position));
end;

procedure TControl.MakeRectangleVisibleForControl(Control: TControl; Rectangle: TInteger32Rectangle);
begin
  if ParentControl <> nil then
    ParentControl.MakeRectangleVisibleForControl(Self, Rectangle.Offset(Position));
end;

function TControl.ChildWithCompositionFocus(): TControl;
begin
  Result := nil;
end;

function TControl.ChildWithPosition(Position: TInteger32Point): TControl;
var
  i:       TInteger32;
  Control: TControl;
begin
  Result  := nil;
  i       := 0;

  while (Result = nil) and (i < ChildControls.Count) do
  begin
    Control := ChildControls[i];

    if Control.Bounds.Contains(Position) then
      Result := Control
    else
      Inc(i);
  end;
end;

function TControl.ConvertPositionToChildPosition(Position: TInteger32Point; Child: TControl): TInteger32Point;
begin
  Result := Position - Child.Position;
end;

function TControl.ConvertPositionToDescendantPosition(const Position: TInteger32Point; Descendant: TControl): TInteger32Point;
begin
  Result := Position;

  while (Descendant <> Self) and (Descendant.ParentControl <> nil) do
  begin
    Result     := Descendant.ParentControl.ConvertPositionToChildPosition(Result, Descendant);
    Descendant := Descendant.ParentControl;
  end;
end;

function TControl.ConvertPositionFromChildPosition(Position: TInteger32Point; Child: TControl): TInteger32Point;
begin
  Result := Position + Child.Position;
end;

function TControl.GetVisibleRectangle(): TInteger32Rectangle;
begin
  if ParentControl <> nil then
    Result := ParentControl.GetVisibleRectangleForControl(Self)
  else
    Result := Bounds.Size;
end;

function TControl.GetVisibleRectangleForControl(Control: TControl): TInteger32Rectangle;
begin
  Result := Control.Bounds.Size;
end;

function TControl.GetWidth(): TInteger32;
begin
  Result := Bounds.Width;
end;

procedure TControl.VisibleRectangleChanged();
begin
  FireEvent(TControlVisibleRectangleChangedEvent.Create(Self));
end;

{ TChildControlList }

procedure TChildControlList.AcquireElement(Control: TControl);
begin
  ParentControl.ChildControlAdded(Control);
end;

constructor TChildControlList.Create(ParentControl: TControl);
begin
  inherited Create();

  Self.ParentControl := ParentControl;
end;

destructor TChildControlList.Destroy();
var
  i: TInteger32;
begin
  for i := 0 to Count - 1 do
    Self[i].Free();

  inherited Destroy();
end;

procedure TChildControlList.ReleaseElement(Control: TControl);
begin
  ParentControl.ChildControlRemoved(Control);
end;

{ TMouseManager }

procedure TMouseManager.AttachToControl(Control: TControl);
begin
  if Control <> nil then
    Control.Listeners.Add(Self);
end;

procedure TMouseManager.CaptureChanged();
begin
end;

function TMouseManager.ControlForEvent(TopLevelControl: TControl; Event: TMouseEvent): TControl;
begin
  if ControlWithCapture <> nil then
    Result := ControlWithCapture
  else if TopLevelControl <> nil then
    Result := TopLevelControl.DescendantWithPosition(Event.Position)
  else
    Result := nil;
end;

constructor TMouseManager.Create();
begin
  inherited Create();

  FMouse := TMouse.Create();
end;

destructor TMouseManager.Destroy();
begin
  Mouse.Free();
  DetachFromControl(OverControl);

  inherited Destroy();
end;

procedure TMouseManager.DetachFromControl(Control: TControl);
begin
  if Control <> nil then
    Control.Listeners.Remove(Self);
end;

procedure TMouseManager.DistributeMouseLeave(RootControl: TControl; Control: TControl; const Position: TInteger32Point);
var
  Event: TMouseLeaveEvent;
begin
  if (Control <> nil) and Control.HasAncestor(RootControl) then
  begin
    Event := TMouseLeaveEvent.Create(Mouse);
    Event.Position := RootControl.ConvertPositionToDescendantPosition(Position, Control);

    try
      while (Control <> RootControl) and not TInteger32Rectangle(Control.Size).Contains(Event.Position) do
      begin
        Control.HandleMouseEvent(Event);
        Event.Position := Control.ParentControl.ConvertPositionFromChildPosition(Event.Position, Control);
        Control := Control.ParentControl;
      end;

      if (Control = RootControl) and not TInteger32Rectangle(Control.Size).Contains(Event.Position) then
        Control.HandleMouseEvent(Event);
    finally
      Event.Free();
    end;
  end;
end;

function TMouseManager.HandleEvent(Event: TEvent): TBoolean;
var
  WillBeFreed: TWillBeFreedEvent;
begin
  Result := False;

  if Event is TWillBeFreedEvent then
  begin
    WillBeFreed := Event as TWillBeFreedEvent;

    if WillBeFreed.Object_ = OverControl then
      OverControl := nil;

    if WillBeFreed.Object_ = ControlWithCapture then
      ControlWithCapture := nil;
  end;
end;

function TMouseManager.LastChanceHandleEvent(RootControl: TControl; Event: TEvent): TBoolean;
var
  MouseMoveEvent: TMouseMoveEvent;
  LeaveControl:   TControl;
begin
  Result       := False;
  LeaveControl := OverControl;

  if Event is TMouseLeaveEvent then
  begin
    OverControl := nil;
    Result      := True;

    DistributeMouseLeave(RootControl, LeaveControl, (Event as TMouseLeaveEvent).Position);
  end
  else if (Event is TMouseMoveEvent) and (ControlWithCapture = nil) then
  begin
    MouseMoveEvent := Event as TMouseMoveEvent;
    OverControl    := RootControl.DescendantWithPosition(MouseMoveEvent.Position);

    DistributeMouseLeave(RootControl, LeaveControl, MouseMoveEvent.Position);
    SetCursor(OverControl.GetCursorForPosition(RootControl.ConvertPositionToDescendantPosition(MouseMoveEvent.Position, OverControl)));
  end;
end;

function TMouseManager.SendEventToControl(TopLevelControl: TControl; Event: TMouseEvent): TBoolean;
var
  Control: TControl;
begin
  Result := LastChanceHandleEvent(TopLevelControl, Event);

  if not Result then
  begin
    if ControlWithCapture <> nil then
    begin
      Control := ControlWithCapture;
      Event.Position := TopLevelControl.ConvertPositionToDescendantPosition(Event.Position, Control);
    end
    else
      Control := TopLevelControl;

    if (Event is TMouseButtonUpEvent) and (ControlWithCapture <> nil) and ControlWithCapture.ShouldCancelMouseCaptureAutomatically() then
      ControlWithCapture := nil;

    if Control = TopLevelControl then
      Result := Control.DistributeMouseEventDownHierarchy(Event)
    else
      Result := Control.DistributeMouseEventUpHierarchy(Event);
  end;
end;

procedure TMouseManager.SetControlWithCapture(const Value: TControl);
begin
  if Value <> ControlWithCapture then
  begin
    DetachFromControl(ControlWithCapture);
    FControlWithCapture := Value;
    
    AttachToControl(ControlWithCapture);
    CaptureChanged();
  end;
end;

procedure TMouseManager.SetOverControl(const Value: TControl);
begin
  if Value <> OverControl then
  begin
    DetachFromControl(OverControl);
    FOverControl := Value;
    AttachToControl(OverControl);
  end;
end;

{ TKeyboardFocusManager }

constructor TKeyboardFocusManager.Create();
begin
  inherited Create();

  Keyboard := TKeyboard.Create();
end;

destructor TKeyboardFocusManager.Destroy();
begin
  Keyboard.Free();

  inherited Destroy();
end;

{ TControl.TSideComparator }

function TControl.TSideComparator.Compare(const Left: TControl; const Right: TControl): TSign;
begin
  Result := TInteger.Compare(Left.Side[Side], Right.Side[Side]);
end;

constructor TControl.TSideComparator.Create(Side: TSide);
begin
  inherited Create();

  Self.Side := Side;
end;

{ TControlChildIteratorFactory }

function TControlChildIteratorFactory.CreateChildIterator(Parent: TControl): TIterator<TControl>;
begin
  Result := Parent.CreateChildIterator();
end;

{ TDragSite }

procedure TDragSite.Attach(Control: TControl);
begin
  raise ENotSupported.Create(ClassType, 'Attach');
end;

constructor TDragSite.Create(Container: TControl; Control: TControl);
begin
  inherited Create();

  Self.Container := Container;
  Self.Control   := Control;
end;

procedure TDragSite.Detach();
begin
  raise ENotSupported.Create(ClassType, 'Detach');
end;

{ TControl.TShows }

function TControl.TShows.Matches(const Control: TControl): TBoolean;
begin
  Result := Control.Path.Contains(ComparisonValue);
end;

end.