unit1.pas

学习Delphi最好的教材。通过一个个简单而实用的实例

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Edit2: TEdit;
    Label3: TLabel;
    Edit3: TEdit;
    Label4: TLabel;
    Label5: TLabel;
    Edit4: TEdit;
    Label6: TLabel;
    Edit5: TEdit;
    Label7: TLabel;
    Label8: TLabel;
    Edit6: TEdit;
    Label9: TLabel;
    ListBox1: TListBox;
    Label10: TLabel;
    Image1: TImage;
    Button1: TButton;
    SavePictureDialog1: TSavePictureDialog;
    procedure Image1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure Image1MouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Edit1.Text:=IntToStr(X); //把鼠标的X坐标转化为字符串，并显示在Edit1
  Edit2.Text:=IntToStr(Y); //把鼠标的Y坐标转化为字符串，并显示在Edit2
  Label10.Caption:='鼠标按下';
  Image1.Canvas.MoveTo(X,Y);

end;

procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  Edit3.Text:=IntToStr(X); //把鼠标的X坐标转化为字符串，并显示在Edit1
  Edit4.Text:=IntToStr(Y); //把鼠标的Y坐标转化为字符串，并显示在Edit2
  if (Label10.Caption='鼠标按下')
     and(ListBox1.ItemIndex=3) then
  begin
    Image1.Canvas.LineTo(X,Y);
  end;

end;

procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  X1,Y1,X2,Y2:Integer;
begin
  Edit5.Text:=IntToStr(X); //把鼠标的X坐标转化为字符串，并显示在Edit1
  Edit6.Text:=IntToStr(Y); //把鼠标的Y坐标转化为字符串，并显示在Edit2
  X1:=StrToInt(Edit1.Text);
  Y1:=StrToInt(Edit2.Text);
  X2:=StrToInt(Edit5.Text);
  Y2:=StrToInt(Edit6.Text);
  if ListBox1.ItemIndex=1 then
    Image1.Canvas.Rectangle(X1,Y1,X2,Y2);
  if ListBox1.ItemIndex=2 then
    Image1.Canvas.Ellipse(X1,Y1,X2,Y2);
  if ListBox1.ItemIndex=0 then
  begin
    Image1.Canvas.MoveTo(X1,Y1);  //先把画笔移到点(X1,Y1) ，直线的起点
    Image1.Canvas.LineTo(X2,Y2); //画直线到(X2,Y2)  ，直线的终点
  end;
  Label10.Caption:='鼠标松开';

end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  if SavePictureDialog1.Execute then
  Image1.Picture.SaveToFile(SavePictureDialog1.FileName);
end;

end.