Displaying TIFF with ASP.NET/C# - MemoryStream throws GDI+ Generic Error

[T. Davis]

In C#, I am able to successfully stream a TIFF image that comes from a
BLOB field in a database, save it to file, then convert the pages
within TIFF file into jpegs (using GDI+) and display on the web (using
ASP.NET).

However, when I generate the Image object using FromStream (passing in
the MemoryStream containing image bytes), an exception of "A generic
error occurred in GDI+" is thrown when performing the conversion/save
for display. I cannot find info on why this occurs?

Again, using FromFile works fine, and the image streamed from the DB
is fine.

-- start code snippet --

/* bytedata is a byte array holding the returned image (BLOB) */

Response.Conten tType = "image/jpeg";

// get byte array's length
int ArraySize = new int();
ArraySize = byteData.GetUpp erBound(0);

// put into memorystream and instantiate Image object
MemoryStream memStream = new MemoryStream();
memStream.Write (byteData,0,Arr aySize);
System.Drawing. Image myImg =
System.Drawing. Image.FromStrea m(memStream);
memStream.Close ();
memStream = null;

// prepare for display - debug showed correct FrameDimension used
System.Drawing. Imaging.FrameDi mension fDimension;
fDimension = new System.Drawing. Imaging.FrameDi mension(myImg.F rameDimensionsL ist[0]);

// just display the first page in TIFF, or display single-page TIFF
try {
myImg.SelectAct iveFrame(fDimen sion,0);
myImg.Save(Resp onse.OutputStre am,
System.Drawing. Imaging.ImageFo rmat.Jpeg); // EXCEPTION IS THROWN HERE
catch (Exception err)
{
throw err;
}
finally
{
myImg.Dispose() ;
}

-- end code snippet --
Help, please. Thanks in advance...

TD

[Eric Newton]

I believe bitmaps need to save to seekable streams

Write to a memory stream first, then byte copy out to Response.Output Stream

HTH

--
Eric Newton
C#/ASP Application Developer
http://ensoft-software.com/
er**@cc.ensoft-software.com [remove the first "CC."]

"T. Davis" <co*****@escmag .com> wrote in message
news:6f******** *************** ***@posting.goo gle.com...

In C#, I am able to successfully stream a TIFF image that comes from a
BLOB field in a database, save it to file, then convert the pages
within TIFF file into jpegs (using GDI+) and display on the web (using
ASP.NET).

However, when I generate the Image object using FromStream (passing in
the MemoryStream containing image bytes), an exception of "A generic
error occurred in GDI+" is thrown when performing the conversion/save
for display. I cannot find info on why this occurs?

Again, using FromFile works fine, and the image streamed from the DB
is fine.

-- start code snippet --

/* bytedata is a byte array holding the returned image (BLOB) */

Response.Conten tType = "image/jpeg";

// get byte array's length
int ArraySize = new int();
ArraySize = byteData.GetUpp erBound(0);

// put into memorystream and instantiate Image object
MemoryStream memStream = new MemoryStream();
memStream.Write (byteData,0,Arr aySize);
System.Drawing. Image myImg =
System.Drawing. Image.FromStrea m(memStream);
memStream.Close ();
memStream = null;

// prepare for display - debug showed correct FrameDimension used
System.Drawing. Imaging.FrameDi mension fDimension;
fDimension = new System.Drawing. Imaging.FrameDi mension(myImg.F rameDimensionsL ist[0]);
// just display the first page in TIFF, or display single-page TIFF
try {
myImg.SelectAct iveFrame(fDimen sion,0);
myImg.Save(Resp onse.OutputStre am,
System.Drawing. Imaging.ImageFo rmat.Jpeg); // EXCEPTION IS THROWN HERE
catch (Exception err)
{
throw err;
}
finally
{
myImg.Dispose() ;
}

-- end code snippet --
Help, please. Thanks in advance...

TD

[T. Davis]

Eric -

Is MemoryStream not a seekable stream?

Also, could you elaborate on your suggestion... you suggest byte copy
out of the memory stream into an outputstream? I'm not sure I can
pass that outputstream then into the Image object, if I understand
correctly...

Thanks,
TD
"Eric Newton" <er**@cc.enso ft-software.com> wrote in message news:<Oh******* *******@TK2MSFT NGP10.phx.gbl>. ..

I believe bitmaps need to save to seekable streams

Write to a memory stream first, then byte copy out to Response.Output Stream

HTH

--
Eric Newton
C#/ASP Application Developer
http://ensoft-software.com/
er**@cc.ensoft-software.com [remove the first "CC."]

"T. Davis" <co*****@escmag .com> wrote in message
news:6f******** *************** ***@posting.goo gle.com...

In C#, I am able to successfully stream a TIFF image that comes from a
BLOB field in a database, save it to file, then convert the pages
within TIFF file into jpegs (using GDI+) and display on the web (using
ASP.NET).

However, when I generate the Image object using FromStream (passing in
the MemoryStream containing image bytes), an exception of "A generic
error occurred in GDI+" is thrown when performing the conversion/save
for display. I cannot find info on why this occurs?

Again, using FromFile works fine, and the image streamed from the DB
is fine.

-- start code snippet --

/* bytedata is a byte array holding the returned image (BLOB) */

Response.Conten tType = "image/jpeg";

// get byte array's length
int ArraySize = new int();
ArraySize = byteData.GetUpp erBound(0);

// put into memorystream and instantiate Image object
MemoryStream memStream = new MemoryStream();
memStream.Write (byteData,0,Arr aySize);
System.Drawing. Image myImg =
System.Drawing. Image.FromStrea m(memStream);
memStream.Close ();
memStream = null;

// prepare for display - debug showed correct FrameDimension used
System.Drawing. Imaging.FrameDi mension fDimension;
fDimension = new

System.Drawing. Imaging.FrameDi mension(myImg.F rameDimensionsL ist[0]);

// just display the first page in TIFF, or display single-page TIFF
try {
myImg.SelectAct iveFrame(fDimen sion,0);
myImg.Save(Resp onse.OutputStre am,
System.Drawing. Imaging.ImageFo rmat.Jpeg); // EXCEPTION IS THROWN HERE
catch (Exception err)
{
throw err;
}
finally
{
myImg.Dispose() ;
}

-- end code snippet --
Help, please. Thanks in advance...

TD

[Eric Newton]

MemoryStreams are seekable, unless a constructor variant is called that
forces no seeking... but in essense a MemoryStream is just a dynamically
sizing byte array.

Incidentally a Bitmap constructor can take a memory stream as a parameter

you could do a memStream.ToByt eArray() then throw that at
Response.Output Stream.WriteByt es()
--
Eric Newton
C#/ASP Application Developer
http://ensoft-software.com/
er**@cc.ensoft-software.com [remove the first "CC."]

"T. Davis" <co*****@escmag .com> wrote in message
news:6f******** *************** ***@posting.goo gle.com...

Eric -

Is MemoryStream not a seekable stream?

Also, could you elaborate on your suggestion... you suggest byte copy
out of the memory stream into an outputstream? I'm not sure I can
pass that outputstream then into the Image object, if I understand
correctly...

Thanks,
TD
"Eric Newton" <er**@cc.enso ft-software.com> wrote in message

news:<Oh******* *******@TK2MSFT NGP10.phx.gbl>. ..

I believe bitmaps need to save to seekable streams

Write to a memory stream first, then byte copy out to Response.Output Stream
HTH

--
Eric Newton
C#/ASP Application Developer
http://ensoft-software.com/
er**@cc.ensoft-software.com [remove the first "CC."]

"T. Davis" <co*****@escmag .com> wrote in message
news:6f******** *************** ***@posting.goo gle.com...

In C#, I am able to successfully stream a TIFF image that comes from a
BLOB field in a database, save it to file, then convert the pages
within TIFF file into jpegs (using GDI+) and display on the web (using
ASP.NET).

However, when I generate the Image object using FromStream (passing in
the MemoryStream containing image bytes), an exception of "A generic
error occurred in GDI+" is thrown when performing the conversion/save
for display. I cannot find info on why this occurs?

Again, using FromFile works fine, and the image streamed from the DB
is fine.

-- start code snippet --

/* bytedata is a byte array holding the returned image (BLOB) */

Response.Conten tType = "image/jpeg";

// get byte array's length
int ArraySize = new int();
ArraySize = byteData.GetUpp erBound(0);

// put into memorystream and instantiate Image object
MemoryStream memStream = new MemoryStream();
memStream.Write (byteData,0,Arr aySize);
System.Drawing. Image myImg =
System.Drawing. Image.FromStrea m(memStream);
memStream.Close ();
memStream = null;

// prepare for display - debug showed correct FrameDimension used
System.Drawing. Imaging.FrameDi mension fDimension;
fDimension = new

System.Drawing. Imaging.FrameDi mension(myImg.F rameDimensionsL ist[0]);

// just display the first page in TIFF, or display single-page TIFF
try {
myImg.SelectAct iveFrame(fDimen sion,0);
myImg.Save(Resp onse.OutputStre am,
System.Drawing. Imaging.ImageFo rmat.Jpeg); // EXCEPTION IS THROWN HERE
catch (Exception err)
{
throw err;
}
finally
{
myImg.Dispose() ;
}

-- end code snippet --
Help, please. Thanks in advance...

TD