main.pas

《Kylix程序设计》一书中附带的例程源代码

unit Main;

interface

uses
  SysUtils, Types, Classes, Variants, QGraphics, QControls, QForms, QDialogs,
  QExtCtrls, QStdCtrls;

type
  PMyPoint = ^TMyPoint;
  TMyPoint = record
    X: Integer;
    Y: Integer;
  end;

  TFrmMain = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    { Private declarations }
    FList: TList;
    FFirst: Boolean;
  public
    { Public declarations }
  end;

var
  FrmMain: TFrmMain;

implementation

{$R *.xfm}

procedure TFrmMain.FormCreate(Sender: TObject);
begin
  FList := TList.Create();
  FFirst := true;
end;

procedure TFrmMain.FormDestroy(Sender: TObject);
begin
  if Assigned( FList ) then
  begin
    Flist.Free();
    Flist := nil;
  end;
end;

procedure TFrmMain.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  pPoint: PMyPoint;
begin
  if Button = mbLeft then
  begin
    New( pPoint );
    pPoint^.X := X;
    pPoint^.Y := Y;
    FList.Add( pPoint );
//    Canvas.Pen.Color := clBlack;
    if FFirst then
    begin
      Canvas.MoveTo( X, Y );
      FFirst := false;
    end
    else
    begin
      Canvas.LineTo( X, Y );
    end;
  end;
end;

end.