Graphing/plotting with embedded webserver?

That seems to be the approach used by most of the client-side JavaScript approaches. It's a good fit for bar graphs, but for drawing lines it's a bit cumbersome. Still, it may be the simplest option.

--
Grant Edwards                   grante             Yow!  He is the
                                  at               MELBA-BEING... the ANGEL
                               visi.com            CAKE... XEROX him... XEROX
                                                   him --

yup. patent. I shouldn't post at the end of the day.

PNG.

Yes, only a couple dozen lines.

Interesting. I didn't know there was an uncompressed PNG format. Thanks, Bob

I have done this with a java applet and activex control, it works great.

might have some example code for somethingsimilar

something GOOD

today so

live!!

I don't think Java is a viable option.

Nobody I know (myself included) runs their browser with Java enabled. I don't even have a JVM installed on 90% of my machines.

I'm definitely not going to do something MS-Specific like ActiveX.

Thanks, I'll check it out.

--
Grant Edwards                   grante             Yow!  if it GLISTENS,
                                  at               gobble it!!
                               visi.com

I can understand your concern about java. But unless you want to do a lot of pixel-poking with html generation on the fly, you will need some client side programming. It is the only way that I know of to get a good real-time data stream, as well.

Grant Edwards wrote:

your

somethingsimilar.

GLISTENS,

I'm willing to do that, if it's the most portable and straight-forward way to do it. I don't care if it's not efficient.

I know. That's why I was asking about JavaScript. Like I said, Java isn't going to be acceptible, but JavaScript would be.

It's real-time, but it's not fast. An update of once a minute would be more than adequate.

--
Grant Edwards                   grante             Yow!  I'm having a MID-WEEK
                                  at               CRISIS!
                               visi.com

The GIF code I looked at needs a minimum of 12K. If you want decent performance, you also need a hash table, which adds 19K.

GIFSAVE by Sverre H. Huseby is public-domain:

The Unisys patent on LZW has expired.

... snip ...

However LZW requires more resources and is less effective than other means, such as LZ77 and LZSS (which are the basis for ZIP et al). It also requires matching hash mechanisms between compressor and decompressor. So its only real purpose is to implement older standards such as GIF.

The only real effect the Unisys patent has had is to inhibit any further investigation of the LZW algorithms. This is typical of software patents.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
   Available for consulting/temporary embedded and systems.
     USE worldnet address!

MID-WEEK

You can use a graphic JavaScript library from

It is under lgpl license. You should write some code using their function to display your plot. You can pass the values to be plotted from the web server as an array. If you make the page to reload every minute you can change the palues passed at each reload, so, it will be dynamic.

Adrian

SNIP

format

the

point

be

BMP also supports compression by RLE (Run Lenght Encoding). Writing RLE encoded line graphs is probably just as easy as writeng them uncompressed.

Wim

A nice little thing. But isn't it a lot overhead, since you need to send the whole JS when updating the graphic. Or am I missing there something (may I load a JS once, and the browser keeps it ?).

--
42Bastian
Do not email to bastian42@yahoo.com, it's a spam-only account :-)
Use @monlynx.de instead !

[...]

Good question. I'm going to give it a try and see if the browser caches the .js library file.

--
Grant Edwards                   grante             Yow!  This is PLEASANT!
                                  at               
                               visi.com

In that case, you are probably best off generating PostScript. Even if a (Windows) machine cannot render PostScript, that facility is only a download away. Because it is high level you just specify a set of points, then tell PostScript to connect the dots, in red, with a 3 mm width line, or whatever. It is compact and easy. If you need to do scaling or rotation, you can offload that to PostScript too.

As an extra bonus you can easily print your images.

--

--
Albert van der Horst,Oranjestr 8,3511 RA UTRECHT,THE NETHERLANDS
Economic growth -- like all pyramid schemes -- ultimately falters.
albert@spenarnc.xs4all.nl http://home.hccnet.nl/a.w.m.van.der.horst