unit PaintBoxExt;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls,Buttons,CanvasPanel;

type
  TPaintBoxExt = class(TPaintbox)
  private
    { Private declarations }
    FOnMouseLeave: TNotifyEvent;
    FOnMiddleDblClick: TNotifyEvent;
  protected
    { Protected declarations }
    procedure CMMouseLeave(var Message: TMessage); message CM_MOUSELEAVE;
    procedure WMMButtonDblClk(var Message: TWMMButtonDblClk); message WM_MBUTTONDBLCLK;
    procedure MouseWheelHandler(var Message: TMessage); override;
  public
    { Public declarations }
    Wnd: HWND;
    Constructor Create(AOwner:TComponent);override;
    
    property WheelAccumulator;
  published
    { Published declarations }
    (*Property OnMouseMove;
    Property OnClick;
    Property OnDblClick;
    Property OnDragDrop;
    Property OnEndDrag;
    Property OnDragOver;
    Property OnStartDrag;
    Property OnMouseUp;
    Property OnMouseDown;
    *)

    property OnMouseLeave:TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
    property OnMiddleDblClick:TNotifyEvent read FOnMiddleDblClick write FOnMiddleDblClick;
    property OnMouseWheel;

  end;

implementation

Procedure TPaintBoxExt.CMMouseLeave(var Message: TMessage);
begin
  if assigned(FOnMouseLeave) then FOnMouseLeave(self);
end;


constructor TPaintBoxExt.Create(AOwner: TComponent);
begin
  inherited;
  //ControlStyle := ControlStyle - [csOpaque];
end;


procedure TPaintBoxExt.MouseWheelHandler(var Message: TMessage);
begin
  //Form := GetParentForm(Self);
  //if (Form <> nil) and (Form <> Self) then Form.MouseWheelHandler(TMessage(Message))
  //else
  with TMessage(Message) do
    Result := Perform(CM_MOUSEWHEEL, WParam, LParam);
end;

procedure TPaintBoxExt.WMMButtonDblClk(var Message: TWMMButtonDblClk);
begin
  FOnMiddleDblClick(Self);
end;

end.