unit1.pas

Delphi7应用编程150例 附书源码

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Image1: TImage;
    btnOpen: TButton;
    btnSave: TButton;
    OpenPictureDialog1: TOpenPictureDialog;
    SavePictureDialog1: TSavePictureDialog;
    procedure BmpToJpg(SrcFileName,DestFileName:AnsiString);
    procedure JpgToBmp(SrcFileName,DestFileName:AnsiString);
    procedure btnOpenClick(Sender: TObject);
    procedure btnSaveClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  ImageFile:AnsiString;
  BitFile:TBitmap;
  JpgFile:TJPEGImage;

implementation

{$R *.dfm}

procedure TForm1.BmpToJpg(SrcFileName,DestFileName:AnsiString);
begin
    //把Bmp格式的文件转换成为jpg格式
    JpgFile:=TJPEGImage.Create();
    BitFile:=TBitmap.Create();
    try
        BitFile.LoadFromFile(SrcFileName);
        JpgFile.Width:=BitFile.Width;
        JpgFile.Height:=BitFile.Height;
        JpgFile.Assign(BitFile);
        JpgFile.SaveToFile(DestFileName);
     finally
        BitFile.Free;
        JpgFile.Free;
     end;
end;

procedure TForm1.JpgToBmp(SrcFileName,DestFileName:AnsiString);
begin
    //把jpg格式的文件转换成为Bmp格式
    JpgFile:=TJPEGImage.Create();
    BitFile:=TBitmap.Create();
    try
        JpgFile.LoadFromFile(SrcFileName);
        BitFile.Width:=JpgFile.Width;
        BitFile.Height:=JpgFile.Height;
        BitFile.Assign(JpgFile);
        BitFile.SaveToFile(DestFileName);
     finally
        BitFile.Free;
        JpgFile.Free;
     end;
end;
procedure TForm1.btnOpenClick(Sender: TObject);
begin
    if self.OpenPictureDialog1.Execute then
    begin
        ImageFile:=self.OpenPictureDialog1.FileName;
        Image1.Picture.LoadFromFile(ImageFile);
    end;
end;

procedure TForm1.btnSaveClick(Sender: TObject);
begin
    if self.SavePictureDialog1.Execute then
    begin
        if LowerCase(ExtractFileExt(ImageFile))='bmp' then
        begin
            BmpToJpg(ImageFile,self.SavePictureDialog1.FileName);
        end
        else if LowerCase(ExtractFileExt(ImageFile))='jpg' then
        begin
            JpgToBmp(ImageFile,self.SavePictureDialog1.FileName);
        end;
    end;
end;

end.