Создание фигур в dll

library risunok;
uses
  SysUtils,
  Classes,
  Graphics;
 
{$R *.res}
procedure rect(x:integer;cv:TCanvas);
begin
if x*x>20 then
 begin
  cv.Pen.Color:=clRed;
  cv.Pen.Width:=3;
  cv.Rectangle(100,100,250,200);
 end;
end;
exports rect;
begin
end.

library risunok;
 
uses
  Windows, SysUtils, Classes, Graphics, Dialogs;
 
{$R *.res}
 
procedure rect1(x: integer; DC: THandle);
var
  pent, pen1: THandle;
begin
  if x*x > 20 then begin
    pen1 := CreatePen(PS_SOLID, 3, clRed);
    pent := SelectObject(DC, pen1);
    Rectangle(DC, 100, 100, 250, 200);
    SelectObject(DC, pent);
    DeleteObject(pen1);
  end else
    ShowMessage('Значение x^2 не больше 20');
end;{}
 
exports
  rect1;
 
begin
 
end.

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    PaintBox1: TPaintBox;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
procedure rect1(x: integer; DC: THandle); external 'risunok.dll';
 
procedure TForm1.Button1Click(Sender: TObject);
var
  x: integer;
begin
  x := StrToInt(Edit1.Text);
  rect1(x, PaintBox1.Canvas.Handle);
end;
 
end.