Hello,
I am building a LabVIEW (8.2) application that will be
acting as a slave to a web server.
Its
primary function is to send graphics in text format (UTF8) over a socket.
There are lovely functions already that will
read and write PNG, BMP, and JPG.
But
the diagrams are locked and they do not expose the binary stream that is being
read or written to file.
I would very much
like access to that binary stream directly.
I have a workaround (see example program), in that I can
write my image to a file, in this case a PNG file, and then immediately read
that file as a binary stream. But this
is inefficient--notice how the example program takes a half-second to run on
just a tiny amount of data. And I understand
that you don't want to expose your PNG encoding scheme to the world; But you
wouldn't have to unlock the diagram, nor expose your algorithm, in order to
output that binary stream.
So I know better than to ask for some function that I've
just dreamed up, as if NI is there to accommodate my fancies. But in this case, I suspect the functionality
is already there, it's just encapsulated in a locked diagram. I suspect that the full binary stream is
there underneath that 'write to png file' function.
You wouldn’t have to build it into a revised version of
LabVIEW (although as a hardcore LV
lover that is being dunked underwater to near suffocation in the internet pool,
I highly advise it). If someone could
please, please, send me a function that exposes that data, I would be eternally
grateful for at least a day. I am after
all about to drop $4200 or so of my own cash into this environment (although I’m
going to anyway, even if you disregard my comment/question).
I'm just surprised that it is not already a
function. If you're wanting to nudge
LabVIEW in the direction of being able to accommodate web serving functionality
(which from a few recent whitepapers, I've gotten this feeling from NI), this
would be a fundamental requirement; i.e., being able to serve up little
graphics via binary (whatever encoding, UTF8, UTF7, doesn’t actually matter)
over a socket (really just a string control, that’s what goes into the TCP and
networking functions anyway). LabVIEW's
2D and 3D graphs, as well as the picture control along with its sundry helper
functions, are hugely powerful. Why not
let us use them to make the best interactive technical websites out there?
Unless of course you point out something obvious that I'm
missing, in which case I'll be both delighted and embarrassed.
Example program
explanation: This shows the workaround that I mentioned. You’ll want to look at the file in the root
C:\ directory “Through_the_binary_blender.png”.
This will show that the binary stream I’ve extracted does indeed contain
the right data. You can open the new PNG file with your choice of image viewers.
Message Edited by Ben Phillips on 11-08-2006 05:36 PM
Message Edited by Ben Phillips on 11-08-2006 05:37 PM
