waveform display in browser

Don't try to read or follow the standards, because those don't tell you which browsers diverge from the standard or in what way.

Instead, use a Javascript library that papers over the differences. The vast majority of sites now use JQuery for that, and nothing will change in the browsers that stops that working properly.

Clifford Heath.

If you get it right you won't need to update.

Don't guess, follow the standards, it's just like reading a datasheet, except that errors in the description are fixed by updating the product.

Actionscript running in the Flash plugin should be able to do it better than Java or JS. Use the free Flashdevelop editor and compiler. I've done some neat stuff with it. The learning curve is horrendous. A PHP or Perl script on the server end formats and sends off data blocks on request. Or have it streaming continously.

- YD.

I heard that Flash is on the way out. And I think that a lot of my customers may not install Flash.

Horrendous learning curves will be hard to sell here, too.

I wasn't aware of the reports of its death, perhaps like Mark Twain's, greatly exaggerated. I am no fan for sure. It is for sure the buggiest software on my computer and reminds me of my days with Windows 95 eventually reaching a MTBF of mere hours.

If you do it in Flash, it won't work on iPads, or in the current version of Firefox (which blocks flash), or in any browser configured by sane people everywhere.

Flash is a giant security hole, and the more your site uses flash the more it will be despised by technical people the world over.

Yeah, there are way too many Flash vulnerabilities.

Cheers

Phil Hobbs

LM317L_ilim.bmp

Kinda hard for John to do since he has no OS (if I remember this whole thread well enough).

LM317L_ilim.bmp

I haven't personally done this, but I've poked at it, and an office-mate of mine did it, before all the file conversion stuff was readily available.

If I recall correctly, GIF encoding is on the lines of

So if you could generate a bmp in your FPGA, you could generate the meat of a GIF almost as easily, then have the ARM processor wrap it with the appropriate header and footer and send it out.

I'll even do it for you -- if you wait until November for me to get started on it.

LM317L_ilim.bmp

Whoops -- it's LZW encoding. It should still be fairly easy to implement, possibly even in FPGA-land. And, if not, there's probably code chunks out there in C.

That's call run-length encoding, and it's what TIFF uses.

GIF files are encoded as 8-bits-per-pixel (with a 256-byte color lookup table), and then compressed using the Lempel-Ziv-Welch algorithm.

Implementing LZW in an FPGA would be a daunting, but people have done it.

And I won't have much ram; 256K bytes in the ARM, and some in the FPGA, but not enough to store an entire bmp anywhere.

SVG looks good so far; all we'd have to do is send the data points, as text, not an image. A couple of kbytes might do it.

Huh. I musta had TIFF and GIF confused. TIFF may be suitable, if John doesn't end up using SVG.

I'm not so sure it would be all that bad, if you were writing something specific to GIF format.

My offer still stands, GIF or TIFF. John's looking at SVG, which isn't a bad choice if it's universal.

Current_Limiters/

I would make sure that SVG is universally available on browsers, but if it is -- go for it.

GIF or TIFF would reduce a typical O-scope image down to kbytes, too. TIFF, it appears, uses a bunch of different compression formats (including LZW); if you use the RLL version then the file is bigger than GIF, but still less than 100kB.

Just for giggles I did it, once to GIF, and once to TIFF using RLL. The GIF file here is 10kB, the TIFF file is 25kB:

I think you're right. It sounded nasty to me based on the descriptions of the LZW that I remember, but according to Google there have been a lot of people who've done it.

SVG is pretty nice, but until the past couple years, SVG support in browsers was pretty iffy. If you don't have to support old browser versions, SVG is worth looking at.

I have FF set to ask, and remember the ones I know and approve. Games mostly. A lot of pages are loading faster now. I had no idea how many ad-banners are Flash. Now there are grayed-out areas where they used to be.

- YD.

No, Gif uses LZW compression not RLE. there was a LZW compatible RLE encoder, but that was purely a patent dodge.

you don't need to generate the bitmap first, the pixel colour can be determine4d algorithmically (eg by running several bresenhan line algorithms in objects in a heap) gif compression only needs one pixel at a time. (but why bother, just send coordinates and call it SVG)

The color map doesn't have to be full.

How so you survive in a technical career without being able to use Google?

Clifford Heath.