unit Myc.Signals.FMX;

interface

uses
    System.Classes,
    FMX.Controls,
    Myc.Signals;

type
    TFMXSignalLink = class(TComponent, TSignal.ISubscriber)
    private
        [volatile]
        FInvalidated: Integer;
        procedure InvalidateControl;

    protected
        function Notify: Boolean;

    public
        constructor Create(AOwner: TControl); reintroduce;
        destructor Destroy; override;
        function Reset: Boolean;
    end;

implementation

uses
    System.SyncObjs;

{ TFMXSignalLink }

constructor TFMXSignalLink.Create(AOwner: TControl);
begin
    inherited Create(AOwner);
    FInvalidated := 0;
end;

destructor TFMXSignalLink.Destroy;
begin
    TThread.RemoveQueuedEvents(InvalidateControl);
    inherited;
end;

procedure TFMXSignalLink.InvalidateControl;
begin
    with TControl(Owner) do
        InvalidateRect(LocalRect);
end;

function TFMXSignalLink.Notify: Boolean;
begin
    if TInterlocked.Exchange(FInvalidated, 1) = 0 then
        TThread.Queue(nil, InvalidateControl);
    exit( true );
end;

function TFMXSignalLink.Reset: Boolean;
begin
    Result := TInterlocked.Exchange(FInvalidated, 0) > 0;
end;

end.