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unit JButton;

interface

uses
  Classes, Graphics, StdCtrls, Controls, Forms, Messages, Windows;

 type
  TJButton = class(TButtonControl)
  private
    FDefault: Boolean;
    FCancel: Boolean;
    FActive: Boolean;
    FModalResult: TModalResult;
    procedure SetDefault(Value: Boolean);
    procedure CMDialogKey(var Message: TCMDialogKey); message CM_DIALOGKEY;
    procedure CMDialogChar(var Message: TCMDialogChar); message CM_DIALOGCHAR;
    procedure CMFocusChanged(var Message: TCMFocusChanged); message CM_FOCUSCHANGED;
    procedure CNCommand(var Message: TWMCommand); message CN_COMMAND;
    procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure CreateWnd; override;
    procedure SetButtonStyle(ADefault: Boolean); virtual;
  public
    constructor Create(AOwner: TComponent); override;
    procedure Click; override;
    function UseRightToLeftAlignment: Boolean; override;
  published
    property Action;
    property Anchors;
    property BiDiMode;
    property Caption;
    property Constraints;
    property DragCursor;
    property DragKind;
    property DragMode;
    property Enabled;
    property Font;
    property ParentBiDiMode;
    property ParentFont;
    property ParentShowHint;
    property PopupMenu;
    property ShowHint;
    property TabOrder;
    property TabStop default True;
    property Visible;
    property OnClick;
    property OnContextPopup;
    property OnDragDrop;
    property OnDragOver;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnStartDock;
    property OnStartDrag;
    property Cancel: Boolean read FCancel write FCancel default False;
    property Default: Boolean read FDefault write SetDefault default False;
    property ModalResult: TModalResult read FModalResult write FModalResult default 0;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Jakane', [TJButton]);
end;

constructor TJButton.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := [csSetCaption, csOpaque, csDoubleClicks];
  Width := 75;
  Height := 25;
  TabStop := True;
end;

procedure TJButton.Click;
var
  Form: TCustomForm;
begin
  Form := GetParentForm(Self);
  if Form <> nil then Form.ModalResult := ModalResult;
  inherited Click;
end;

function TJButton.UseRightToLeftAlignment: Boolean;
begin
  Result := False;
end;

procedure TJButton.SetButtonStyle(ADefault: Boolean);
const
  BS_MASK = $000F;
var
  Style: Word;
begin
  if HandleAllocated then
  begin
    if ADefault then Style := BS_DEFPUSHBUTTON else Style := BS_PUSHBUTTON;
    if GetWindowLong(Handle, GWL_STYLE) and BS_MASK <> Style then
      SendMessage(Handle, BM_SETSTYLE, Style, 1);
  end;
end;

procedure TJButton.SetDefault(Value: Boolean);
var
  Form: TCustomForm;
begin
  FDefault := Value;
  if HandleAllocated then
  begin
    Form := GetParentForm(Self);
    if Form <> nil then
      Form.Perform(CM_FOCUSCHANGED, 0, Longint(Form.ActiveControl));
  end;
end;

procedure TJButton.CreateParams(var Params: TCreateParams);
const
  ButtonStyles: array[Boolean] of DWORD = (BS_PUSHBUTTON, BS_DEFPUSHBUTTON);
begin
  inherited CreateParams(Params);
  CreateSubClass(Params, 'BUTTON');                                                     //   <============
  Params.Style := Params.Style or ButtonStyles[FDefault];
end;

procedure TJButton.CreateWnd;
begin
  inherited CreateWnd;
  FActive := FDefault;
end;

procedure TJButton.CNCommand(var Message: TWMCommand);
begin
  if Message.NotifyCode = BN_CLICKED then Click;
end;

procedure TJButton.CMDialogKey(var Message: TCMDialogKey);
begin
  with Message do
    if  (((CharCode = VK_RETURN) and FActive) or
      ((CharCode = VK_ESCAPE) and FCancel)) and
      (KeyDataToShiftState(Message.KeyData) = []) and CanFocus then
    begin
      Click;
      Result := 1;
    end else
      inherited;
end;

procedure TJButton.CMDialogChar(var Message: TCMDialogChar);
begin
  with Message do
    if IsAccel(CharCode, Caption) and CanFocus then
    begin
      Click;
      Result := 1;
    end else
      inherited;
end;

procedure TJButton.CMFocusChanged(var Message: TCMFocusChanged);
begin
  with Message do
    if Sender is TButton then
      FActive := Sender = Self
    else
      FActive := FDefault;
  SetButtonStyle(FActive);
  inherited;
end;

procedure TJButton.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
  DefaultHandler(Message);
end;

end.