main.pas

来自「《Kylix程序设计》一书中附带的例程源代码」· PAS 代码 · 共 90 行

unit Main;

interface

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

type
  TFrmMain = class(TForm)
    BtnShow: TButton;
    procedure BtnShowClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  FrmMain: TFrmMain;

implementation

uses Shapes;

{$R *.xfm}

procedure TFrmMain.BtnShowClick(Sender: TObject);
var
  X, Y: Integer;
  str: string;
  Shape: TGeoShape;
  Point: TGeoPoint;
  Line: TGeoLine;
begin
  X := 10;
  Y := 10;

  Shape := TGeoShape.Create();
  str := Shape.Draw();
  Canvas.TextOut( X, Y, '(TGeoShape)Shape:' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( Shape );
  Inc( Y, 25 );

  Point := TGeoPoint.Create();
  str := Point.Draw();
  Canvas.TextOut( X, Y, '(TGeoPoint)Point:' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( Point );
  Inc( Y, 25 );

  Line := TGeoLine.Create();
  str := Line.Draw();
  Canvas.TextOut( X, Y, '(TGeoLine)Line:' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( Line );
  Inc( Y, 25 );

  Shape := TGeoPoint.Create();
  str := Shape.Draw();
  Canvas.TextOut( X, Y, '(TGeoPoint)Shape:' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( Shape );
  Inc( Y, 25 );

  Shape := TGeoPoint.Create();
  str := TGeoPoint( Shape ).Draw();
  Canvas.TextOut( X, Y, '(TGeoPoint)TGeoPoint(Shape):' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( TGeoPoint( Shape ) );
  Inc( Y, 25 );
{
  Shape := TGeoPoint.Create();
  str := Shape.Draw( Canvas ); // Error. Too many parameters
  Canvas.TextOut( X, Y, '(TGeoPoint)Shape:' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( TGeoPoint( Shape ) );
  Inc( Y, 25 );
}
  Shape := TGeoPoint.Create();
  str := TGeoPoint( Shape ).Draw( Canvas );
  Canvas.TextOut( X, Y, '(TGeoPoint)TGeoPoint(Shape):' );
  Canvas.TextOut( X+270, Y, str );
  FreeAndNil( TGeoPoint( Shape ) );
  Inc( Y, 25 );
end;

end.