unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs;type  TForm1 = class(TForm)    procedure FormPaint(Sender: TObject);    procedure FormCreate(Sender: TObject);    procedure FormDestroy(Sender: TObject);    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;      Shift: TShiftState; X, Y: Integer);    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);    procedure FormMouseUp(Sender: TObject; Button: TMouseButton;      Shift: TShiftState; X, Y: Integer);  end;var  Form1: TForm1;implementation{$R *.dfm}uses GDIPOBJ, GDIPAPI;var  x: Integer = 20;  y: Integer = 20;  w: Integer = 100;  h: Integer = 50;  f: Byte;  a,b: Integer;  p: TGPPen;procedure TForm1.FormCreate(Sender: TObject);begin  p := TGPPen.Create(MakeColor(255,0,0), 2);end;procedure TForm1.FormDestroy(Sender: TObject);begin  p.Free;end;procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;  Shift: TShiftState; X, Y: Integer);begin  f := 1;  a := X;  b := Y;end;procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,  Y: Integer);begin  if (f = 0) then Exit;  if ssCtrl in Shift then  begin    f := 2;    Text := 'Ctrl 键被按下, 鼠标可调整大小';  end else Text := '没有按下 Ctrl 键, 鼠标可调整位置';  a := X - a;  b := Y - b;  Repaint;  a := X;  b := Y;end;procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;  Shift: TShiftState; X, Y: Integer);begin  f := 0;end;procedure TForm1.FormPaint(Sender: TObject);var  g: TGPGraphics;begin  g := TGPGraphics.Create(Canvas.Handle);  g.Clear(MakeColor(255,255,255));  case f of    1: begin      Inc(x,a);      Inc(y,b);    end;    2: begin      Inc(w,a);      Inc(h,b);    end;  end;  g.DrawEllipse(p, x, y, w, h);  g.Free;end;end.

object Form1: TForm1  Left = 0  Top = 0  Caption = 'Form1'  ClientHeight = 176  ClientWidth = 337  Color = clBtnFace  Font.Charset = DEFAULT_CHARSET  Font.Color = clWindowText  Font.Height = -11  Font.Name = 'Tahoma'  Font.Style = []  OldCreateOrder = False  Position = poDesktopCenter  OnCreate = FormCreate  OnDestroy = FormDestroy  OnMouseDown = FormMouseDown  OnMouseMove = FormMouseMove  OnMouseUp = FormMouseUp  OnPaint = FormPaint  PixelsPerInch = 96  TextHeight = 13end