unit1.pas

本光盘是《Delphi 7应用教程》一书的配套光盘

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
  Var
     PaintNow:Boolean;
     X1,Y1:integer;

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  Canvas.Pen.Width :=5;
  Canvas.Pen.Color :=ClBlue;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  PaintNow:=True;
  x1:=x;
  y1:=y;
end;

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  PaintNow:=False;
end;

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  If paintNow then
     begin
        Canvas.moveto(x1,y1);
        Canvas.LineTo(x,y);
     end;
     x1:=x;y1:=y;
end;

end.