Wikipedia:Reference desk/Archives/Computing/2017 October 19

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October 19

Alpha To Unique Colour

I have a bunch of pngs with alpha that I need to convert into bitmaps, process, then convert back to png's. I'd like to just replace the alpha channel with a solid colour, so when I am going back to png I can just turn that colour to alpha. However, I have a large number of files to process and it would take a lot of time and consideration to make sure that the colour I select to replace the alpha channel is unique (moreover, I'm not 100% sure how to do alpha -> colour in GIMP, or anything else for that matter). Any help or suggestions would be greatly appreciated:-) (This is kind of a hack job, I have a bunch of files that are made up of a set of tiles, but I need them in a different format, it is easy to cut and paste the tiles around with a small script, but it is dealing with the alpha that is the issue - I don't know enough about png to figure out how to easily open them up in code and work with them; I'm sure I could figure this out, but it would, probably, take a good deal longer to do that than to do it this way [it's a one time need]).Phoenixia1177 (talk) 07:41, 19 October 2017 (UTC)

Nevermind - I didn't realize that you could do alpha for a 32bit bmp, everything worked out rather nice, whilst I feel foolish having brought this here.Phoenixia1177 (talk) 11:20, 19 October 2017 (UTC)

Stopwatch, Timer, and Interval software app

I possess "Sony Xperia XA Ultra Dual". A (built-in) 'clock' app consists of four tabs (Alarm, Worldclock, Stopwatch, Timer), the latter are used quite often, but not sufficient.

I'm looking for an app that consist more than one 'stopwatch' in a "Stopwatch"'s tab and more than one 'timer' in the "Timer"'s tab.

Note: Both of are required to work simultiniously if necessity arrives.

P.S.: Please also include any software for PC known and/or hardware product known.

119.30.39.8 (talk) 12:20, 19 October 2017 (UTC)

Until Win 7 there was the Windows Task Scheduler. --Hans Haase (有问题吗) 14:58, 19 October 2017 (UTC)

Windows Task Schedule still exists in Windows 10 Fall Creator's Update. It's very unlikely to be going away any time soon. I have no idea what it has to do with the question though. Nil Einne (talk) 12:08, 24 October 2017 (UTC)

PCs and laptops just don't seem like good platforms for stopwatches, to me. Mine periodically pauses for a few seconds, to start some update, etc. Even if it could deal with that and not mess up the timer if one of those pauses was entirely within the timed period, there's still the delay in pressing the start and stop buttons, should one of those pauses happen then. I use my cell phone stopwatch, and an actual stopwatch would likely be even better. StuRat (talk) 15:27, 19 October 2017 (UTC)

Currently doing this but are not sufficient. I possess an 'interval' (hardware) thing, but only one interval mode can be used at a time, plus you need a battery every 5 days. I require lots of stopwatches, lots of timers, and lots of interval modes, to be used simultaneously according to desire, without effecting each other...

Current built-in app only does two in one go, once, once only - if you know what I mean. 123.108.244.144 (talk) 17:56, 19 October 2017 (UTC)

Any reasonably competently written PC stopwatch app would not continually increment/decrement the time, it would merely subtract the start time from the current time, so occasional CPU starvation of the app would not affect its accuracy. There are a number of online stopwatches that support multiple concurrent timers, such as [1] and [2]. There are probably many downloadable apps as well, but I don't want to download them myself to see how they work, and in any case the OP didn't specify what operating system they're using. CodeTalker (talk) 19:41, 19 October 2017 (UTC)

Yes, and I did mention this, and how it doesn't fix the problem of not being able to hit the start and stop buttons on time because the system decides to "go out to lunch" just then. StuRat (talk) 20:35, 21 October 2017 (UTC)

Well I don't think your experiences with computers are particularly useful, since history suggests they are either 10 years out of date, or they are otherwise extremely outside the norm for some reason. E.g. "Mine periodically pauses for a few seconds, to start some update" is something most people probably haven't experienced much for 10 years. By comparison, I was using a 4? year old smart phone yesterday and the POS had regular slow downs, yet you seemed to imply that a mobile phone would be a better choice. Nil Einne (talk) 12:08, 24 October 2017 (UTC)

I said a "cell phone", by which I meant to exclude smart phones, which have the same problems with downloaded apps that do periodic updates, etc. And, yes, I do try to avoid the "bleeding edge", to save money and aggravation. I do have a smart phone, but I use the stopwatch function on my good old cell phone, instead. It has 50 lap settings, and I've never seen it decide to pause for no apparent reason in the middle of use.

As for PCs/laptops, having a newer model, with more RAM, faster CPU(s), etc., doesn't guarantee there will never be lag. It does mean that more and bigger (resource hog) processes would need to run simultaneously to cause such a problem, but from the OP it does sound like they are running a lot that needs timing. Also, if they are timing applications from the start to stop, these are times when lag is most common. A fundamentally different architecture is needed to make lag impossible, where each application has it's own dedicated resources, and no other app can infringe on them. This gets particularly tricky when talking about shared resources like the mouse, used to run different applications at once. Until they do this major rewrite, there will be no amount of resources which can make it impossible to ever lag, bearing in mind that PCs with more resources just lead to apps which require more resources. StuRat (talk) 16:41, 24 October 2017 (UTC)

Simple single task electronics like amazon dash buttons

Is there any simple, single task programmable electronic gizmo like amazon dash buttons? Something that could send a signal when pressed, and be in standby for a long time. Something simpler than an arduino? --Hofhof (talk) 17:12, 19 October 2017 (UTC)

The most exact hackable analog to Amazon Dash has got to be the "AWS IoT Button"[3]. It's literally Dash hardware that can be assigned to arbitrary AWS commands.

But maybe having it go through AWS isn't what you have in mind. Flic[4], Pebblebee[5], or Particle[6] might be more to your liking. They both seem to be phone related, though. Dunno if that's what you want either. ApLundell (talk) 18:22, 19 October 2017 (UTC)

Or, for the ultimate flexibility, and not relying on third-party cloud services, you could do like this guy did, and make your own. I'm pretty sure there's less than $15 of parts here : "IFTTT Smart Button"[7]

ApLundell (talk) 18:38, 19 October 2017 (UTC)

IFTTT is a "third-party cloud service". Not that either that, nor AWS, are a bad thing.

The hardware behind this is the ESP8266. A "couple of bucks" each, even as one-offs, with a minimal processor, enough hardware I/O to connect to a button or two, and built-in Wi-Fi for connectivity. You can point it at AWS, at IFTTT, or at a server of your own - either inside the house network, or on some external internet hosting. If set up correctly, they're also near-zero battery drain in standby. Andy Dingley (talk) 20:14, 19 October 2017 (UTC)

Oh, when I said that, I meant that if you make your own, like that guy did, you don't have to rely on third party services. Not that you couldn't use them if you wanted to.

If you have even a loose grasp on programming, it's pretty trivial to modify that build to do something else.

Like you say, the core is the ESP8266, which isn't too hard to use anyway, but the example I linked uses it as a energy efficient IoT button, so if that's exactly what you want, it's a good place to start. ApLundell (talk) 22:07, 19 October 2017 (UTC)

latex question

Can anyone show me a simple self-contained .tex file that displays Handel Gothic Bold? Thanks, Robinh (talk) 21:27, 19 October 2017 (UTC)

please fix this article

This Ticket (IT security) article is unreferenced but could be interesting, please fix it. Dysklyver 22:43, 19 October 2017 (UTC)

Yes, it's only a stub, but maybe worth expanding. Can you, A Den Jentyl Ettien Avel Dysklyver, find any references for the article? If not, then Wiktionary has the definition. Dbfirs 19:48, 21 October 2017 (UTC)

No, it gets mixed up with other types of ticket, a ticket is normally used to define a help request for example, or to go to a theatre. I was hoping someone might have the knowledge to find a suitable search term to cut through that unrelated stuff. Dysklyver 19:57, 21 October 2017 (UTC)

Yes, I had the same problem. If we can't find refs then we should fall back on the Wiktionary definition. Any experts? Dbfirs 20:10, 21 October 2017 (UTC)

Kerberos Andy Dingley (talk) 20:58, 21 October 2017 (UTC)

Thanks, Andy. Kerberos (protocol) is a much fuller article, but it also requires in-line citations. Is Kerberos the best-known implementation of Ticket (IT security) (or the only implementation)? Dbfirs 06:43, 22 October 2017 (UTC)

Kerberos was the first - so long ago that it was seen as over-complicated and over-engineered for years before it was widely adopted. As it's defined through the RFC mechanism, it's possible to use parts of it and replace others. So verification systems can be ""Kerberos compliant" without being Kerberos itself.

There are a couple of irritating errors in the lead. Kerberos isn't there to do authentication, it's there to do verification. Nor does it depend on a trusted third party (it usually does, but you don't have to do it that way). Half of my career has been in designing systems based on verification, then having some idiot change it so that they use authentication instead. Then they are compromised in some way and then personally identifying information leaks out. The virtue of verification alone (which depends heavily on using tickets) is that it's possible to build a system which can provide a secure ticket to some service, stating "The bearer of this ticket is entitled to use this service" and without needing to state "This is Fred. Fred is allowed to use this service." Authentication is based on identity, verifying that identity and then verifying what that identity is allowed to do. But the identification aspect ("This is Fred") is very risky, and its exposure should be limited to as little as possible. It is a much better system when it can do this anonymously. Kerberos was one of the first frameworks to really make this viable. Andy Dingley (talk) 18:51, 22 October 2017 (UTC)