Re: waveform display in browser

From	Dimiter_Popoff <dp@tgi-sci.com>
Newsgroups	sci.electronics.design, comp.arch.embedded
Subject	Re: waveform display in browser
Date	2015-07-24 01:19 +0300
Organization	TGI
Message-ID	<morp62$aso$1@dont-email.me> (permalink)
References	<q2b2rah6msviaqt4su4r6t3tgml9u8b5lg@4ax.com> <55B14FE8.3070806@electrooptical.net> <morjtb$jnr$1@dont-email.me> <morlak$pll$1@dont-email.me> <l6o2ra56j3k3q75f4s1k6ekivq4knp3qij@4ax.com>

Cross-posted to 2 groups.

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On 24.7.2015 г. 00:50, John Larkin wrote:
> On Fri, 24 Jul 2015 00:13:19 +0300, Dimiter_Popoff <dp@tgi-sci.com>
> wrote:
>
>> On 23.7.2015 ?. 23:49, rickman wrote:
>>> On 7/23/2015 4:34 PM, Phil Hobbs wrote:
>>>> On 7/23/2015 2:18 PM, John Larkin wrote:
>>>>>
>>>>>
>>>>> I'm designing a tachometer box and it will have a web page interface
>>>>> as one way to talk to it. I thought it would be cool to include an ADC
>>>>> so we could display waveforms, too. My software guys here are mostly
>>>>> embedded types so we don't know a lot about Javascript and such. I did
>>>>> a little searching and mostly found things for displaying audio
>>>>> envelope cartoons; I want a real oscilloscope-looking thing, so users
>>>>> can see what happens as they change gains and filtering and trigger
>>>>> level settings. Dual trace would be nice, the analog waveform and
>>>>> corresponding comparator outputs.
>>>>>
>>>>> Has anybody done this? We'd consider getting outside help, either
>>>>> advice or actual coding.
>>>>>
>>>>> I assume our box will, through some port, deliver HTML, Javascript,
>>>>> and maybe some zipped JS libraries to the browser. And the company
>>>>> logo of course. The browser will send us text strings to parse if the
>>>>> user wants to change parameters or such. We would also deliver blocks
>>>>> of waveform data on request. That's my PHB perspective on things; I'm
>>>>> just the hardware designer.
>>>>>
>>>>>
>>>> One approach is a CGI script that runs gnuplot under the covers.  IIRC
>>>> quite a few folks do that.  (I'm a static HTML guy myself.)
>>>
>>> Isn't there an actual oscilloscope display package under Linux?  It
>>> should be fairly straightforward to drive that from an internet
>>> connection.  I guess requiring the customer to installing such a package
>>> is not preferred.
>>>
>>
>> He is after a browser plugin - something like VNC, the way I do it
>> on our spectrometers (I do not use a plugin but I could if I wanted to).
>
> Actually, I don't want a plugin, just a way for the browser to display
> a waveform, using some javascript. We can store any reasonable zipped
> javascript libraries in our gadget and deliver them to the browser.

I am not sure I have seen that done for live graphics - then scaling,
perhaps autoranging etc., even if doable it would be a massive pain
to support with all browsers as they keep on evolving.
Your best bet might be to produce locally a .gif (or .png or
whatever) bitmap, maintain it live and persuade the browser to refresh
it regularly. Don't know how the latter is to be done though.

>>
>> However this implies a fullblown RFB connection to a stand alone
>> system having its display and GUI locally (within his oscilloscope
>> thing) which is far from being trivial.
>
> The tach box will have no display or GUI, and in fact no official OS.
>

Not having a display is not a problem, some of our spectrometers do
not have one, they just maintain the display bitmap in system
memory - which is viewed via RFB (VNC)(RDP which Rick suggested
is very similar, same thing really but over a non-public protocol).
Not having an OS - nor a VNC server nor the image to be
displayed - obviously makes this impractical in your case.

Dimiter

------------------------------------------------------
Dimiter Popoff, TGI             http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/

Thread

waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-23 11:18 -0700
  Re: waveform display in browser Joerg <news@analogconsultants.com> - 2015-07-23 11:53 -0700
  Re: waveform display in browser Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2015-07-23 16:34 -0400
    Re: waveform display in browser rickman <gnuarm@gmail.com> - 2015-07-23 16:49 -0400
      Re: waveform display in browser Dimiter_Popoff <dp@tgi-sci.com> - 2015-07-24 00:13 +0300
        Re: waveform display in browser rickman <gnuarm@gmail.com> - 2015-07-23 17:39 -0400
        Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-23 14:50 -0700
          Re: waveform display in browser Dimiter_Popoff <dp@tgi-sci.com> - 2015-07-24 01:19 +0300
            Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-23 15:30 -0700
              Re: waveform display in browser rickman <gnuarm@gmail.com> - 2015-07-23 18:46 -0400
              Re: waveform display in browser Tim Wescott <seemywebsite@myfooter.really> - 2015-07-23 17:54 -0500
                Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-23 16:22 -0700
                Re: waveform display in browser Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2015-07-23 19:56 -0400
                Re: waveform display in browser Tim Wescott <seemywebsite@myfooter.really> - 2015-07-24 14:55 -0500
                Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-24 14:11 -0700
                Re: waveform display in browser Tim Wescott <seemywebsite@myfooter.really> - 2015-07-24 17:00 -0500
                Re: waveform display in browser Herbert Kleebauer <klee@unibwm.de> - 2015-07-25 09:04 +0200
                Re: waveform display in browser Tim Wescott <seemywebsite@myfooter.really> - 2015-07-24 14:58 -0500
                Re: waveform display in browser Grant Edwards <invalid@invalid.invalid> - 2015-07-24 20:15 +0000
                Re: waveform display in browser Tim Wescott <seemywebsite@myfooter.really> - 2015-07-24 16:48 -0500
                Re: waveform display in browser Grant Edwards <invalid@invalid.invalid> - 2015-07-24 22:08 +0000
                Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-24 22:46 +1000
                Re: waveform display in browser Grant Edwards <invalid@invalid.invalid> - 2015-07-25 14:32 +0000
                Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-24 22:44 +0000
                Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-24 23:31 +0000
                Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-24 22:49 +1000
                Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-25 09:28 +0000
                Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-25 08:43 +1000
                Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-25 22:27 +0000
                Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-25 20:57 +1000
                Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-24 22:41 +0000
                Re: waveform display in browser rickman <gnuarm@gmail.com> - 2015-07-24 22:03 -0400
                Re: waveform display in browser Tim Wescott <seemywebsite@myfooter.really> - 2015-07-24 15:05 -0500
  Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-23 21:37 +0000
    Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-23 15:32 -0700
  Re: waveform display in browser Martin Riddle <martin_ridd@verizon.net> - 2015-07-23 20:24 -0400
    Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-23 21:08 -0700
      Re: waveform display in browser Martin Riddle <martin_ridd@verizon.net> - 2015-07-24 07:52 -0400
        Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-24 14:08 +0000
          Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-24 22:53 +1000
            Re: waveform display in browser Jasen Betts <jasen@xnet.co.nz> - 2015-07-25 09:46 +0000
              Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-25 08:46 +1000
  Re: waveform display in browser Clifford Heath <no.spam@please.net> - 2015-07-24 00:37 +1000
  Re: waveform display in browser Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2015-07-24 11:46 +0100
  Re: waveform display in browser YD <ydtechHAT@techie.com> - 2015-07-24 14:25 -0300
    Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-24 10:55 -0700
      Re: waveform display in browser rickman <gnuarm@gmail.com> - 2015-07-24 14:09 -0400
      Re: waveform display in browser Grant Edwards <invalid@invalid.invalid> - 2015-07-24 18:42 +0000
        Re: waveform display in browser YD <ydtechHAT@techie.com> - 2015-07-24 19:12 -0300
          Re: waveform display in browser Grant Edwards <invalid@invalid.invalid> - 2015-07-25 14:36 +0000
      Re: waveform display in browser Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2015-07-24 14:55 -0400
  Re: waveform display in browser John Larkin <jlarkin@highlandtechnology.com> - 2015-07-27 17:52 -0700
    Re: waveform display in browser Phil Hobbs <hobbs@electrooptical.net> - 2015-07-28 17:58 -0400
  Re: waveform display in browser "jurem" <51422@EmbeddedRelated> - 2015-07-28 09:49 -0500

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