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Date Posted: 06:49:30 10/17/01 Wed
Author: Petko Penev
Subject: Invalid offset into the BLOB - AGAIN

Dear Sirs,
I have a problem with writing Tiff-files in Blob-fields. On the site - www.voy.com - I saw that other peoples have the same problem: (Date Posted: 11:05:04 08/05/01 Sun Author: Ruy Subject: Invalid offset into the BLOB), but from your answers it is not clearly how to resolve the problem. Those’s why I will ask you again and send you detailed examples of the problem code:
procedure TMain.aLoadShemaExecute(Sender: TObject);
var
Stream: TBlobStream;
begin
with OpenPictureDialog1 do
if Execute then
begin
ImageShema.Picture.LoadFromFile(FileName); // Only tiff files (ImageShema: TImage)

with DataModule1.tblTree do
begin
Edit;
Stream:=TBlobStream.Create(FieldByName('Picture') as TBlobField, bmWrite);
(ImageShema.Picture.Graphic as TTiffGraphic).SaveToStream(Stream); // Here raise the error

Post;
Stream.Free;
end;
end;
end;

In the code above, the following error is raised:
"Invalid offset into the Blob".The error is raised due the executing of TIFFClose(TiffHandle) in the procedure - EnTifGr.WriteDibToTiffStream.
That’s why I was forced to use the lower code, ho is working correctly.

procedure TMain.aLoadShemaExecute(Sender: TObject);
var
Stream: TBlobStream;
iFileHandle: Integer;
iFileLength: Integer;
iBytesRead: Integer;
Buffer: ^Byte;
begin
with OpenPictureDialog1 do
if Execute then
begin
ImageShema.Picture.LoadFromFile(FileName); // Only tiff files (ImageShema: TImage)

with DataModule1.tblTree do
begin
Edit;
Stream:=TBlobStream.Create(FieldByName('Picture') as TBlobField, bmWrite);

iFileHandle := FileOpen(FName, fmOpenRead);
iFileLength := FileSeek(iFileHandle,0,2);
FileSeek(iFileHandle,0,0);
Buffer := AllocMem(iFileLength);
iBytesRead := FileRead(iFileHandle, Buffer^, iFileLength);
FileClose(iFileHandle);

Stream.Write(Buffer^,iBytesRead);
end;
finally
FreeMem(Buffer,iFileLength);
Stream.Free;
end;
end;

Another one code, which raises the same error is:

procedure TMain.aLoadShemaExecute(Sender: TObject);
var
Stream: TBlobStream;
begin
with OpenPictureDialog1 do
if Execute then
begin
ImageScrollBox1.FileName:=FileName; // (ImageScrellBox1: TImageScrollBox)

with DataModule1.tblTree do
begin
Edit;
Stream:=TBlobStream.Create(FieldByName('Picture') as TBlobField, bmWrite);
ImageScrollBox1.SaveToStream(Stream,'TIF'); // Here raise the error
Post;
Stream.Free;
end;
end;
end;

My opinion is, that the method TTiffGraphic.SaveToStream doesn’t work correctly.
How you will comment all that?

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