unit1.pas

画图应用程序

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Panel1: TPanel;
    PaintBox1: TPaintBox;
    Button2: TButton;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Edit1: TEdit;
    UpDown1: TUpDown;
    Label5: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure PaintBox1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure PaintBox1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure PaintBox1MouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure UpDown1Click(Sender: TObject; Button: TUDBtnType);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
//是否应该画图的标志变量
  drawit:boolean=false;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
//清空画图板
  Paintbox1.Repaint;
end;

procedure TForm1.PaintBox1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Paintbox1.Canvas.MoveTo(x,y);
//判断鼠标键以设置画笔颜色
  if (Button = mbRight) then
    Paintbox1.Canvas.Pen.Color:=clBlue
  else
  if (Button = mbLeft) then
    Paintbox1.Canvas.Pen.Color:=clRed;
//设置绘图标志为真
  drawit:=true;
end;

procedure TForm1.PaintBox1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
//判断是否应该进行绘图
  if drawit then
    Paintbox1.Canvas.LineTo(x,y);
end;

procedure TForm1.PaintBox1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
//鼠标键弹起，不再进行绘图
  drawit:=false;
end;

procedure TForm1.UpDown1Click(Sender: TObject; Button: TUDBtnType);
begin
//设置画笔粗细
  PaintBox1.Canvas.Pen.Width:=strtoint(Edit1.Text);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  close;
end;

end.