main.pas

一个简易的图片浏览器

unit main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  FileCtrl, StdCtrls, ExtCtrls, Buttons,Jpeg, ImgList;

const MaxNum=6;

type
  ShowDataRecord=Record
   Image:TImage;
   Panel:TPanel;
   FileName:string[15];
  end;


  TMainForm = class(TForm)
    DriveComboBox1: TDriveComboBox;
    FilterComboBox1: TFilterComboBox;
    DirectoryListBox1: TDirectoryListBox;
    FileListBox1: TFileListBox;
    Bevel1: TBevel;
    Panel1: TPanel;
    CloseBitBtn: TBitBtn;
    SmallImage: TImage;
    BigViewBitBtn: TBitBtn;
    procedure CloseBitBtnClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FileListBox1Click(Sender: TObject);
    procedure BigViewBitBtnClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    JpgImage:TJpegImage;
    PictureWidth,PictureHeight:Integer;
  end;

var
  MainForm: TMainForm;

implementation

uses Bigpas;

{$R *.DFM}

procedure TMainForm.CloseBitBtnClick(Sender: TObject);
begin
 Close;
end;


procedure TMainForm.FormCreate(Sender: TObject);//创建窗体
begin
 JpgImage:=TJpegImage.Create;
 PictureWidth:=0;
 PictureHeight:=0;
end;

procedure TMainForm.FormDestroy(Sender: TObject);//窗体消亡
begin
  JpgImage.Free;
end;

procedure TMainForm.FileListBox1Click(Sender: TObject);
var
 FileExt:String;//存放文件扩展名
Begin
 //文件扩展名小写化
 FileExt:=AnsiLowerCase(ExtractFileExt(FileListBox1.FileName));
 if (FileExt='.bmp') or (FileExt='.ico') then  //.bmp和.ico格式文件
  begin
   SmallImage.Picture.LoadFromFile(FileListBox1.FileName);//调入文件
   PictureWidth:=SmallImage.Picture.Width;//保存文件宽高
   PictureHeight:=SmallImage.Picture.Height;
  end
 else
  if FileExt='.jpg' then//是.jpg文件
   begin
     JpgImage.LoadFromFile(FileListBox1.FileName);
     SmallImage.Picture.Graphic:=jpgImage;
     PictureWidth:=JpgImage.Width;
     PictureHeight:=JpgImage.Height;
   end;
end;


procedure TMainForm.BigViewBitBtnClick(Sender: TObject);
begin
 if FileListBox1.FileName<>'' then//文件存在
  begin
   with BigForm do
    begin
      BigImage.Picture:=SmallImage.Picture; //图形
      BigImage.Width:=PictureWidth;//设置宽高
      BigImage.Height:=PictureHeight;
      if (PictureHeight>BigForm.ClientHeight) and
        (PictureWidth>BigForm.ClientWidth) then
       begin//图形宽高大于窗体时
        BigImage.Top:=0;
        BigImage.Left:=0;
       end
      else
       if PictureHeight>BigForm.ClientHeight then
        begin//图形高大于窗体高时
         BigImage.Top:=0;
         BigImage.Left:=(BigForm.ClientWidth-PictureWidth) div 2;
        end
       else
        if PictureWidth>BigForm.ClientWidth then
         begin//图形宽大于窗体宽时
          BigImage.Top:=(BigForm.ClientHeight-PictureHeight) div 2;
          BigImage.Left:=0;
         end
        else
         begin//图形宽高小于等到于窗体宽高时
          BigImage.Top:=(BigForm.ClientHeight-PictureHeight) div 2;
          BigImage.Left:=(BigForm.ClientWidth-PictureWidth) div 2;
         end;
      Color:=clBlack;//设置窗体颜色为黑色
      Caption:=FileListBox1.FileName;//显示文件名
      Show;//显示大图
    end;
  end;
end;

end.