🚀 go-pugleaf

"Robert G. Hoover" <not.a.real.address@anywhere.sorry> wrote in message
news:46b0f5c4$1@newsgroups.borland.com...

> I've got a timing/performance need... I'm trying to capture
> the screen as BMP, compress to JPG, then send over a
> TCustomWinSocket. I'm afraid it just takes too long... :(

You are sending the entire image in full each time.  If you are trying to
implement some kind of real-time video capture of the screen, then you
should be sending deltas instead.  Capture the full image once, send it,
then send only what has changed since the last transmission.  The receiver
can then overlay the deltas on top of each other when they are received.  If
very little changes, then there will be very few transmissions, and you can
probably do away with the JPG conversion altogether (which isn't a good way
to compress BMP anyway since JPG is a lossy format).

> // send image data to client
> SocketOut->SendBuf(WriteStream->Memory, WriteStream->Size);

You are not sending the stream size to the client, so it won't know how many
bytes it needs to read for each image.

> // reset stream for next use
> WriteStream->Clear();

If you are sending images of the same dimensions each time, then you don't
really need to Clear() the stream each time, since the image data is likely
to be the same size the next time around.  Using Clear() will waste time
allocating and freeing the memory over and over.  You could simply reset the
Position back to 0, leaving the memory intact.  The next time you save an
image to the stream, it will overwrite the contents that are already
present.  Since you would start the Position at 0, you could use the
Position to know how many bytes were actually saved, rather than relying on
the Size property.  This way, smaller images can reuse the same stream
memory, and larger images will grow the memory when needed.


Gambit