GIF 图片大小信息

type

 TImageSize = record

   Width: Integer;

   Height: Integer;

 end;

function ReadGIFSize(Stream: TStream): TImageSize;

type

 TGifHeader = record

   Signature: array [0..5] of Char;

   Width, Height: Word;

 end;

var

 Header: TGifHeader;

begin

 FillChar(Header, SizeOf(TGifHeader), #0);

 Result.Width := -1;

 Result.Height := -1;

 with Stream do

 begin

   Seek(0, soFromBeginning);

   ReadBuffer(Header, SizeOf(TGifHeader));

 end;

 if (AnsiUpperCase(Header.Signature) = 'GIF89A') or

   (AnsiUpperCase(Header.Signature) = 'GIF87A') then

 begin

   Result.Width  := Header.Width;

   Result.Height := Header.Height;

 end;

end;

procedure TForm1.Button1Click(Sender: TObject);

const

 FileName = 'D:\test.gif';

var

 fs: TFileStream;

 gifsize: TImageSize;

begin

 fs := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite);

 try

   gifsize := ReadGIFSize(fs);

   ShowMessage(Format('Breite %d H%d', [gifsize.Width, gifsize.Height]));

 finally

   fs.Free;

 end;

end;