Wikipedia:Reference desk/Archives/Computing/2014 May 1

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May 1

Thunderbird, whaa?

Yesterday I installed a new version of Thunderbird. It worked fine this morning.

This evening when I try to send mail from Thunderbird I get a popup:

You are about to override how Thunderbird identifies this site.
Legitimate banks, stores, and other public sites will not ask you to do this.

Server
 Location: [ my SMTP server ]  ( Get Certificate )

Certificate Status
 This site attempts to identify itself with valid information.  ( View... )
 Wrong site
 Certificate belongs to a different site, which could indicate an identity theft.

( Confirm Security Exception )    ( Cancel )

I changed to another SMTP server and got the same result. What gives? —Tamfang (talk) 06:08, 1 May 2014 (UTC)

Due to Heartbleed, some hosting companies (e.g. Dreamhost) changed their certificate, on the theory that it might have been compromised. This is the dialog you'll see when Thunderbird only knows about the old certificate. Check your host's blog or status pages to see if they've done so. -- Finlay McWalterᚠTalk 08:01, 1 May 2014 (UTC)

That's probably not it: Pobox changed its certificates three weeks ago. —Tamfang (talk) 18:52, 1 May 2014 (UTC)

Are both SMTP servers related or not? If they are, it wouldn't surprise me if it's simply someone screwing up their certificates. (This happens a lot on the web, particularly with websites using CDNs.) If both aren't related, it seems less likely both screwed up but you never know. Info on what the SMTP server you're trying to access (and what the 'wrong site' is) could help but perhaps you excluded these for privacy reasons. Nil Einne (talk) 03:47, 2 May 2014 (UTC)

No relation: sasl.smtp.pobox.com and (the host of) my personal website. — Just now I tried smtp.gmail.com, successfully. —Tamfang (talk) 07:12, 2 May 2014 (UTC)

Truetype fonts without enclosed areas.

In most san-serif fonts, a capital "I" is generally a rectangle. An 'E' is an enclosed polygon with two concavities. What I need is fonts where an "I" is just a vertical line and an "E" is one vertical line and three horizontals...the strokes you'd make with a pen rather than a description of a volume enclosed by the letter.

(I'm writing very small text using a laser cutter - and drawing the full outline of a truetype font character results in a blurry mess!)

Some questions:

1. Is there a source of fonts that are just disconnected lines like this?
2. Does the various common font formats even allow for disconnected lines rather than enclosed spaces?
3. Do font design tools let you make fonts like this?

I guess 'truetype' is the format I'm most interested in...but if other font formats can handle it - that would be interesting too.

SteveBaker (talk) 16:49, 1 May 2014 (UTC)

It sounds to me like you want a vector font. StuRat (talk) 17:03, 1 May 2014 (UTC)

More precisely, a stroke font. —Tamfang (talk) 18:53, 1 May 2014 (UTC)

This blog post may be helpful. Single-line fonts are not supported by TrueType or related font design tools as far as I know. -- BenRG (talk) 17:23, 1 May 2014 (UTC)

Does http://www.onelinefonts.com/ help you at all Steve? - Cucumber Mike (talk) 21:09, 1 May 2014 (UTC)

Turbo C and Turbo Pascal had some nice vector fonts, including I think a single-line one, as part of their graphics library. The format is pretty easy to parse, too, you could extract stroke coordinates in 100 lines of C or so I'm not saying this is legal, but assuming this is some homebrew µC/stepper-motor project, this is where I'd go for fonts, and also Borland is sadly defunct anywayAsmrulz (talk) 08:41, 2 May 2014 (UTC)

I do miss Borland Turbo Pascal. Nice development environment, and could run either an interpreter or a compiler. StuRat (talk) 17:48, 2 May 2014 (UTC)

I don't think they ran a "Pascal interpreter" at all. The DOS version compiled either a regular EXE file or an EXE image in RAM. The latter was really fast, mainly because I didn't write any long programs back then, and they didn't optimize the code when compiling to RAM.

The newer versions (6+) were not that good either. With their clumsy GUI they felt like some "qBASIC but Pascal" clone – but they still compiled the code, so you didn't get the joy of qBASIC-style syntax errors at run-time. - ¡Ouch! (^{hurt me} / _{more pain}) 05:55, 6 May 2014 (UTC)

The graphics package was called BGI and common to Borland Pascal, other Borland languages including C(++) and Quattro Pro. It was an ugly hack, too; if it didn't find the drivers (which were separate files even in the DOS years) the program didn't quit with a "missing file" message but gave a "Missing InitGraph()" message when attempting the first graphics operation.

Three versions of Turbo Pascal, the smaller Borland Pascal package, are available free of charge now. (That doesn't automatically make the BGI fonts "free software".) - ¡Ouch! (^{hurt me} / _{more pain}) 05:55, 6 May 2014 (UTC)

Old laptop running XP

Hello, I have recently been fortunate enough to have been given a laptop for free. It is about ten years old, hasn't been used for about 8 years, and is running Windows XP. It works totally fine, except when I try to connect to the internet I'm getting all these messages about the Certificate for this Page is not valid, even though the sites are definately reputable ones (google, hotmail, etc). I'm entirely unable to connect to any page with a login on it on Firefox and Chrome, whatever I do. I'm aware that Microsoft recently withdrew support for XP, but didn't think it would relate to certificates on websites. Is there a way I can persuade it to connect, or do I have to install a whole new OS on it? Thanks, Horatio Snickers (talk) 16:54, 1 May 2014 (UTC)

I believe you can set your security settings to allow connection to sites regardless of certificate status. Somebody else can provide the details of how to change the setting.

BTW, I suggest you back up everything before you start accessing the Internet, as something you are exposed to there could stop your laptop from working or slow it down to an unacceptable degree. StuRat (talk) 16:56, 1 May 2014 (UTC)

The modern and secure solution is: Install a Linux OS such as Mint. Then, install a virtual machine such a VirtualBox, then reinstall XP into it. Don't allow XP to connect to the web. Email, FTP, Googling and all that sort of stuff can be safer done on the Linux host. This leave you free to carry on using XP as normal. Also, if its 8 years old you really need to reinstall it anyhow.--Aspro (talk) 20:12, 1 May 2014 (UTC)

For instance. If you find that a Ubuntu live CD works just fine on your laptop, then install that and maybe robolinux - with visualization all ready and waiting to go at you command. All these massages won't then appear because your host will be Linux. These messages are are a simply microsoft artefacts, to convince you, that you need to pay out money for a newer microsoft operating system that wont in actuality perform any better than what you already have.--Aspro (talk) 20:43, 1 May 2014 (UTC)

I even have an old 15-year computer with Win98 and he's asked for certificates only a couple of times while in teh internets. My other computer with WinXP has no problems either. --Lüboslóv Yęzýkin (talk) 23:17, 1 May 2014 (UTC)

It sounds like you're getting phished. If you're getting errors that the certificates aren't valid, that means you're not really connecting to the websites you think you are. Try running a few antivirsus software programs to clean out your system. Or even better, reformat the hard drive and reinstall Windows from scratch. Your bios may be compromised so you may want to flash that as well. Also, make sure you're behind a router or a hardware firewall before you connect the laptop to the Internet. A Quest For Knowledge (talk) 10:50, 2 May 2014 (UTC)

Hi all, thanks for your advice. StuRat, the laptop has literally nothing on it - my friend deleted all her files before she gave it to me. It does, however, have things like Photoshop installed on it that I would ideally not want to lose if I have to reinstall the operating system. It works totally fast and stuff - but I'd be worried about infecting it. Is that likely if I'm only really using it to access hotmail, google, etc? Horatio Snickers (talk) 10:45, 2 May 2014 (UTC)

It sound like that the best part of the gift was the hardware (ie laptop) and now you need a no hassle operating system to use it without hassle. But first. Does your friend still have the photoshop discs? She might have them some where and forgotten about them (photoshop is not cheap so it is more than likely that she has them somewhere). Secondly, what do you need photoshop for? If you are professional photographer, the cost of a new photoshop installation is just another business expense to be off sett against tax. If however, you would like to use it for your own photographs then you'll probably find GIMP does everything you want and it is free. If she still have the discs - great. A Linux host will also provide a more secure access to hotmail, google, etc. and run photoshop so there is less problem there. Finally, it may appear to be working totally fast to you but a new reinstall should work wonders --Aspro (talk) 17:26, 2 May 2014 (UTC)

The best time to do a backup is when it's clean, like it is now. You will likely start reading email, then find one contains a video that requires a download to play, another contains audio that requires a download, and another has a link to a PDF file, so you need a PDF viewer. Before you know it, you've downloaded all sorts of crap, and your laptop is running like a snail. That's when you'd wish you had a backup to go back to. StuRat (talk) 17:44, 2 May 2014 (UTC)

@Horatio Snickers:I guess everyone missed my post.[1] Most likely, Horatio Snickers is being phished. A Quest For Knowledge (talk) 19:21, 2 May 2014 (UTC)

There you have it. Both A Quest For Knowledge and myself advise reinstalling the OS. To inherit a machine does not mean you have to inherit all the malware baggage and other stuff such as regedit.exe problems, accumulated by the previous owner.--Aspro (talk) 15:32, 3 May 2014 (UTC)

If the laptop is that old, it's possible that the CA certificates preinstalled in the browser have expired. I seem to remember that there were a bunch that expired in 2013 or so. Are you running up to date versions of those browsers (Firefox, Chrome)? Can you check the certificates? You can update the certificates with a bit of wangling, but reinstalling the browsers is probably simpler. Really though, I agree with the suggestions to ditch XP altogether and use either a Linux-based OS, or (if you must) Windows 7. 192.249.63.59 (talk) 19:46, 4 May 2014 (UTC)

XP does not have support for Server Name Indication. Phedrence (talk) 18:03, 13 January 2018 (UTC)

help required with code

Hi there! I am trying to make a matlab code using nearest neighbour algorithm to segment out red green and blue colors in a given image so that green and blue color objects in the end are shown as black, red as color value # 50 in the final image. But this code is giving me not the right segmentation as mentioned. Can anyone help me out to debug or to find the error i might be doing? Thanks

clc
% training data
ii=imread('4ball.jpg'); 
rr= imread('red1.jpg');
gg=imread('g1.jpg');
bb=imread('b1.jpg');
% converting to 8 bits
i=uint8(ii);
r=uint8(rr);
g=uint8(gg);
b=uint8(bb);
% Accessing 20x20 samples from training data
figure; imshow(i);
red=r(1:20,1:20,1:3);
green=g(1:20,1:20,1:3);
blue=b(1:20,1:20,1:3);

uu=size(i);
[n m]=size(red);
d=uint8(zeros(size(i)));

for a=1:uu(1,1)
    for h= 1:uu(1,2)
         for u=1:20
             for v=1:20
                 
                 s1= ((i(a,h,1)-blue(u,v,1)).^2 + (i(a,h,2)-blue(u,v,2)).^2 +
                     (i(a,h,3)-blue(u,v,3)).^2).^1/2;
                 
                 s2= ((i(a,h,1)-red(u,v,1)).^2 + (i(a,h,2)- red(u,v,2)).^2 +
                     (i(a,h,3)-red(u,v,3)).^2).^1/2;
                 
                 s3= ((i(a,h,1)-green(u,v,1)).^2 + (i(a,h,2)-green(u,v,2)).^2 +
                     (i(a,h,3)-green(u,v,3)).^2).^1/2;

                 if (s1<s2) && (s1<s3)
                     disp('belong to blue');
                     d(a,h)= 0; % for blue
            
                 else if  (s2<s3)&& (s2<s1) 
    
                     disp('belong to red');
                     d(a,h)=50; % for red
            
                 else if (s3<s1) && (s3<s2)
                     d(a,h)=0; % for green
                     disp('belong to green');
              
                 else
                     d(a,h)=i(a,h);
                     disp('else');
                 end
                
            end
    end
end
            end
      end
end
    
d
figure;
imshow(d);

— Preceding unsigned comment added by 39.41.1.31 (talk) 18:14, 1 May 2014 (UTC)

I added markup to improve the appearence of the source listing. It could be further improved by having a consistantly applied indentation scheme (I would have done this as well, but I'm unfamilar with Matlab). Astronaut (talk) 01:47, 2 May 2014 (UTC)

I did a bit more tidying and syntax coloring. It also might help if OP could post examples of input and output image. Lastly, there appears to be some superfluous "end"s in there, but MATLAB is a little unpicky about end statements. SemanticMantis (talk) 03:13, 2 May 2014 (UTC)

I do not know MATLAB, but I do see a few items that you could look at.

• You have loops nested four levels deep and are repeatedly assigning values to a two dimensional array d(a,h) = .... All but the last assignment of each element will be overwritten.
• Not sure, but from what I've read, the statement uu=size(i) will assign a one dimensional vector to uu. I question whether the later references to uu(1,1) and uu(1,2) are correct.
• I believe the (...)^1/2 expressions should be (...).^(1/2). The first might be interpreted as "power of 1 ... matrix divide by 2".
• As a side note, the extra end statements are required because of the space in else if. This produces nested if-else-end statements. If elseif (no space) were used instead, you would have a chained if-elseif-...-else-end sequence, which requires only a single end.

-- Tom N talk/contrib 17:18, 3 May 2014 (UTC)