[sane-devel] OT: scanimage output format

[m. allan noah]

not possible to use png's progressive loading, cause it uses Adam7, which 
needs a low-resolution version of the image at the beginning of the file, 
followed by multiple (effectively) higher res versions.

if your client is timing out, you could try sending them a redirect to 
keep the page refreshed. but then you will need to store your output on 
the fs or in a db for retrieval...

allan

On Mon, 27 Oct 2003, Wolfgang Pichler wrote:

> hi all,
> 
> for a webapplication i am calling scanimage the scan a contract in the
> client scanner - i am calling it with
> $fd = popen('SANE_DEFAULT_DEVICE="net:'.$client_ip.':plustek" scanimage
> -l 0 -t 0 -x 210 -y 288 --mode Gray | pnmtopng','r');
> $output = "";
> while(!feof($fd)) {
> 	$output .= fread($fd, 1024);
> }
> pclose ($fd);
> echo $output;
> 
> (the correct headers also get set before)
> 
> this already works.
> 
> But with that call the hole image gets scanned and that converted into
> png format (so that the browser can read it). What I'd like is to get
> scanimage to output the scan directly in png format (or a program which
> can directly process the the data and convert it to png on the fly -
> while the scan still runs) - so that while the scan runs the scan get
> directly outputed on the client (so that the user can see the progress).
> Is this possible ? And if its possible, how ?
> 
> mfG
> Wolfi
> 
> 
> 
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