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Groups > comp.arch.embedded > #21534

Re: waveform display in browser

From Jasen Betts <jasen@xnet.co.nz>
Newsgroups sci.electronics.design, comp.arch.embedded
Subject Re: waveform display in browser
Date 2015-07-25 09:28 +0000
Organization "JJ's own news server"
Message-ID <movkrh$pm0$1@gonzo.alcatraz> (permalink)
References (8 earlier) <66t2ra1mebptuknfc16kc11ko5m07t4hfv@4ax.com> <7IKdnb8i8rB2BS_InZ2dnUU7-ScAAAAA@giganews.com> <mou6cp$25v$1@reader1.panix.com> <mouf44$ch0$3@gonzo.alcatraz> <ijBsx.134279$gG6.66501@fx31.iad>

Cross-posted to 2 groups.

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On 2015-07-24, Clifford Heath <no.spam@please.net> wrote:
> On 25/07/15 08:44, Jasen Betts wrote:
>> On 2015-07-24, Grant Edwards <invalid@invalid.invalid> wrote:
>>> On 2015-07-24, Tim Wescott <seemywebsite@myfooter.really> wrote:
>>>
>>>> If I recall correctly, GIF encoding is on the lines of
>>>>
>>>> 100 black, 1 white, 25 black, etc., for each line.
>>>
>>> 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.
>>
>> no, N bits per colour with a 3*2^N table ( 1 <= N <= 8 )
>
> That's incorrect. GIF uses an 8-bit (256 element colour map) that has 
> 3x8-bit RGB elements. The actual image data is 8-bit indices into that 
> colour map, LZW compressed - exactly what Grant said.

You're making shit up.

 I just made a gif file here that's 73 bytes. explain that.

 1 bit per pixel (before compression) monochome gifs were done 
 and other colour depths too. the palette is variable length 
 (I can't remeber if it's fixed to 2^n slots or allowed to be 
 intermediate sizes.
 
 GIF was invented in 1987 when very few people had 8-bit colour
 displays. 

jasen@fozzie:~$ cat 1.pbm
P1
1 1
1 
jasen@fozzie:~$ convert 1.pbm 1.gif
jasen@fozzie:~$ ls -l 1.gif
-rw-r--r-- 1 jasen jasen 73 Jul 25 21:14 1.gif
jasen@fozzie:~$ giftrans -l 1.gif 
Global Color Table:
Color 0: Red 0, Green 0, Blue 0, #000000 (black, gray0, grey0)
Color 1: Red 255, Green 255, Blue 255, #ffffff (white, gray100, grey100)

 
-- 
umop apisdn

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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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