I'm wanting to extract a zip file loaded with images into memory in some way. I don't really care what type of stream they go into, as long as I can load them afterwards. I do not have that great of an understanding with streams, and explanations on the subject don't seem to go into much detail.
Essentially, what I am doing now is extracting the files to (getcurrentdir + '\temp\'). This works, but isn't quite what I am wanting to do. I would be more happy to have the jpg's end up in memory and then be able to read from memory into a TImage.bitmap.
I am currently using jclcompresion to handle zips and rars, but was considering moving back to system.zip because I really only need to be able to handle zip files. If it would be easier to stay with jclcompression though that would work for me.
The read method of the TZipFile class can be used with a stream
procedure Read(FileName: string; out Stream: TStream; out LocalHeader: TZipHeader); overload;
procedure Read(Index: Integer; out Stream: TStream; out LocalHeader: TZipHeader); overload;
from here you can access the compressed file using the index or the filename.
Check this sample which uses a TMemoryStream to hold the uncompressed data.
uses
Vcl.AxCtrls,
System.Zip;
procedure TForm41.Button1Click(Sender: TObject);
var
LStream : TStream;
LZipFile : TZipFile;
LOleGraphic: TOleGraphic;
LocalHeader: TZipHeader;
begin
LZipFile := TZipFile.Create;
try
//open the compressed file
LZipFile.Open('C:\Users\Dexter\Desktop\registry.zip', zmRead);
//create the memory stream
LStream := TMemoryStream.Create;
try
//LZipFile.Read(0, LStream, LocalHeader); you can use the index of the file
LZipFile.Read('SAM_0408.JPG', LStream, LocalHeader); //or use the filename
//do something with the memory stream
//now using the TOleGraphic to detect the image type from the stream
LOleGraphic := TOleGraphic.Create;
try
LStream.Position:=0;
//load the image from the memory stream
LOleGraphic.LoadFromStream(LStream);
//load the image into the TImage component
Image1.Picture.Assign(LOleGraphic);
finally
LOleGraphic.Free;
end;
finally
LStream.Free;
end;
finally
LZipFile.Free;
end;
end;