Re: Plot colour issue - Strange change of shade

[Etienne Brouillet-Coquillat]

> Hi Kai,
>
> Thank you for your reply, I am on windows 10 and I use the Octave 5.2.0
> version a so far as I an aware I didn't use a graphics_toolkit () unless
> there is a default one. My data was recorded with a sampling rate of 10
> Hz over 240 min so with a lot of datapoints. I attached the file I used.
> To plot I did:
>
> load RS52.txt;
> x = RS52(:,1);
> y = RS52(:,2);
> plot(x, y, "color", [0, 0.45, 0], "linewidth", 3);
>
> Regards,
>
> Steve
> 
> 
> 
> Thank you for the details.  Please keep the mailing list in the CC, so
> others may benefit from our conversation as well and answer at the
> bottom of the email (bottom-posting [1]) to facilitate our conversation.
> 
> In my MS Windows 10 virtual machine I could reproduce your problem, not
> on Linux.  It seems like this is related to bug #54554 [2]?  Because
> where there are many data points, the green line becomes more light
> green (invisible elements?).
> 
> HTH,
> Kai
> 
> [1] https://en.wikipedia.org/wiki/Posting_style#Bottom-posting
> [2] https://savannah.gnu.org/bugs/?54554

Thanks, I eventually found the page mentioning bug  #54554 and I believe I encounter the same issue which is, as you said, caused by the large number of data points. 

I followed the advice given and renamed the opengl32.dll file and it solved the problem.

Thanks for you help,

Steve

On Wed, 11 Mar 2020 at 13:34, Kai Torben Ohlhus <address@hidden> wrote:

On 3/11/20 6:18 PM, Etienne Brouillet-Coquillat wrote:
>
> On Wed, 11 Mar 2020 at 02:34, Kai Torben Ohlhus <address@hidden
> <mailto:address@hidden>> wrote:
>
>     On 3/11/20 1:24 AM, steve wood wrote:
>     > Hi all,
>     >
>     > My apologies if my issue is due to my inexperience and is a simple
>     fix but I
>     > only started using Octave (or any software of the type) yesterday.
>     >
>     > The colour in my graph appears strange and seems to have different
>     shades or
>     > go greyish (see image). I just want it to be the same shade of
>     dark green
>     > all along. Is there too many datapoints or something like that ?
>     >
>     >>> plot(x, y, "color", [0, 0.45, 0], "linewidth", 3);
>     >
>     > Many thanks,
>     >
>     >
>     > <https://octave.1599824.n4.nabble.com/file/t373672/Octave_Graph.png>
>     >
>
>     Indeed, this does not seem right.  The problem must be in your
data, as
>     I cannot reproduce it with made up x,y data.  Can you store it at some
>     temporary file hosting service and send the link to this list?
>
>     Additionally, it is nice to know, which operating system and Octave
>     version you are using.  In case of plotting, it might also be
>     interesting to know the output of
>
>        graphics_toolkit ()
>
>     HTH,
>     Kai
>
> Hi Kai,
>
> Thank you for your reply, I am on windows 10 and I use the Octave 5.2.0
> version a so far as I an aware I didn't use a graphics_toolkit () unless
> there is a default one. My data was recorded with a sampling rate of 10
> Hz over 240 min so with a lot of datapoints. I attached the file I used.
> To plot I did:
>
> load RS52.txt;
> x = RS52(:,1);
> y = RS52(:,2);
> plot(x, y, "color", [0, 0.45, 0], "linewidth", 3);
>
> Regards,
>
> Steve
>


Thank you for the details.  Please keep the mailing list in the CC, so
others may benefit from our conversation as well and answer at the
bottom of the email (bottom-posting [1]) to facilitate our conversation.

In my MS Windows 10 virtual machine I could reproduce your problem, not
on Linux.  It seems like this is related to bug #54554 [2]?  Because
where there are many data points, the green line becomes more light
green (invisible elements?).

HTH,
Kai

[1] https://en.wikipedia.org/wiki/Posting_style#Bottom-posting
[2] https://savannah.gnu.org/bugs/?54554