waveform display in browser

I don't know how to persuade a browser to auto-refresh, but GIF format uses run-length limiting for compression. That means that line drawings of few colors tend to be very small -- you'll use up way more bits on text than on the pictures.

There is some simple HTML thing that makes a page reload periodically. That's apparently easy to do.

A BMP would be easy to make inside the FPGA, but that would be slow to load. Maybe the ARM could make a GIF or PNG. That would avoid all the javascript nonsense. We'd just have to find the code somewhere.

This bmp is 556K bytes.

That wouldn't be really terrible to send once a second or so over 100 MBPS Ethernet. But my FPGA doesn't have enough RAM.

Den fredag den 24. juli 2015 kl. 01.22.11 UTC+2 skrev John Larkin:

might use svg instead

-Lasse

Bumpfiles are simple, so that's a win. I usually generate those in my code, then (in a script) call ImageMagick's 'convert' to make them into .jpg or .png or whatever.

Cheers

Phil [system("convert foo.bmp foo.png") covers a multitude of sins]Hobbs

That is cool. The code is there, and the HTML is tiny.

Java might be a tad slow. SVG might be better. But thers a bunch of API's out there, search javascript stripcharts.

Cheers

Yeah, svg looks promising. If I let the FPGA do the acquisition (some clever auto-trigger-oscilloscope algorithm based on the ADC data?) and buffer maybe 250 or so points per waveform, the ARM could read that data and build a not-absurdly long svg/html thing to send back, once a second maybe.

Might be worth you talking to Bob Masta (sp?) who does Daqarta.

Not sure if any of his stuff is in Java though.

AJAX, works ok. Theres a difference in implemntation between browsers tho. I used that to send indicator/display information. Be willing to support future browsers with a firmware update.

Cheers

TIFF is Tagged Image File Format. It's not an compression format, though it supports many compressions. With monochrome data, the G4 fax encoding is truly spectacular.

You could probably implement GIF with a vestigial compression that merely looks like LZW. You wouldn't get any compression, but a reader would still find that it's a complying format.

SVG wasn't available in IE prior to version 8. Other older browsers that didn't do SVG have almost all been upgraded, so its reasonable to require that.

If you want to use SVG, but fall back to VML back as far as IE5, I recommend the Raphael Javascript library at . It does what it says on the box. But these days I'm just using SVG.

Clifford Heath

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.

Steve Jobs didn't want anything to do with flash so it isn't supported on iOS and we have HTML5 now

-Lasse

If we could only get more websites to use it. Does HTML5 have similar capabilities to host games? I see any number of Flash games, but so far none in HTML5.

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.