Ask Ubuntu General Room

5:00 PM

@Tim no worries. now that we know what it was it isn't such a big deal. Just don't edit so many at once that it floods the front page :)

user136984

@Serg: There are 79228162514264337593543950336 different possible colours that can be used in an image's pixel.

user136984

So how is the highest one represented then in the image?

Nathan Osman

How many bits are used to store each pixel?

For a 24-bit image, it's only 2^24 unique colors.

user136984

But we are thinking about a 32-bit one.

Nathan Osman

24 bits+8 bit alpha channel?

Tim

5:02 PM

@ParanoidPanda cut off the end of the number by x chars and then divide. Just remember to * the answer by 10^x... idk if that's accurate at all

@Seth Okay, Is 10 at once too much? What should I limit it to - considering this is sent over about 1 second per edit?

user136984

@NathanOsman: All I know is that I am using 32 bit, so that is (2^32)^3.

Nathan Osman

Huh...

32-bits per channel?

That must be a typo. I'm not aware of any image workflow that uses 32-bits per channel. Nor am I aware of any consumer device capable of capturing an image with that bit depth.

Tim

2^32^3 = 12884901888

user136984

Wait...

Tim

@ParanoidPanda you could use the modulo...

Nathan Osman

5:04 PM

And why are we raising the number to the third power?

I'm very confused. Perhaps someone could explain where the numbers are coming from...

user136984

@kos: Wasn't the third number your one?

Seth

@Tim yeah, could you limit it to 5 at a time please? 10 takes up pretty much the entire (visible) front page. Mass removing the installation tag isn't really a problem so I'd rather if you are going to work on it you do it slower so that normal site use gets distrupted as little as possible. It'd be cool if you could focus on questions that only have the installation tag too as once those are gone we can get a SE community manger to remove it from the rest of the questions.

user136984

@Tim: According to all my calculators, 2^32=4294967296, and 4294967296^3=79228162514264337593543950336...

ByteCommander

@A.B. Fabby is probably still drunk from celebrating his 115th birthday yesterday... You don't want to have him in here with a hangover, I think! ;-)

Tim

@Seth okay, and how often can I do 5? every 30 seconds or every minute?

user136984

5:07 PM

Maybe I'm typing it in wrong... :D

Tim

2*32 = 4294967296

4294967296**3 = 79228162514264337593543950336

Nathan Osman

Why are we taking 2^32 and then taking it to the third power?

Anyone?

Tim

yep you're right

@NathanOsman no idea, the lols?

user136984

@NathanOsman: Ask @kos.

user136984

:D

user136984

5:08 PM

:P

ByteCommander

@NathanOsman He really thinks his image has 96bit...

Nathan Osman

@ByteCommander That's... not very likely.

user136984

@Tim: If you put in google "2 to the power of 32", and then "4294967296 to the power of 3", that is what I get.

ByteCommander

No, it isn't indeed.

Nathan Osman

That still doesn't explain why we're doing 2^32^3 instead of 2^32*3.

Tim

5:09 PM

yeh, python32 was srange

@ParanoidPanda does your big number end in lots of 0s?

ByteCommander

Oh.

Right.

user136984

yesterday, by kos

@ParanoidPanda Ok so it's (2^n)^3, where n it's the number of bits used for the representation

ByteCommander

That is...

Erm...

user136984

@Tim 2 times 32 is 64...

user136984

:D

Nathan Osman

5:11 PM

Besides, if that's all you want to find out - here's the answer: wolframalpha.com/input/?i=2^32^3

ByteCommander

Buffer overflow. Please immediately remove some bits and feed with fresh cake!

Tim

oh

user136984

@NathanOsman: So are my calculations incorrect then?

Nathan Osman

Hrm... that did not paste correctly...

ByteCommander

@NathanOsman Markdown breaks links.

Nathan Osman

5:12 PM

Hang on...

user136984

Because they need to be very accurate for this to work.

Nathan Osman

Here we go: bit.ly/1cZEvK7

kos

@ParanoidPanda n is meant to be the number of bit used for the representation of a single channel, which is 8

ByteCommander

Link to wolframalpha

Nope, not even that.

Nathan Osman

See - there are valid reasons for link shorteners :P

kos

5:14 PM

@ParanoidPanda so in RGB24 (which has 3 channels): 2^8^3

ByteCommander

But that is the right formatting, isn't it?

Nathan Osman

@kos No, no, no.

2^32*3

ByteCommander

AH!

Forgot the http

Nathan Osman

If there are three channels, you multiply by 3.

Seth

@Tim Neither of those gives the front page much time to repopulate with organic questions.

user136984

5:14 PM

@kos @NathanOsman: Please people, make up your minds!

kos

@NathanOsman Indeed, that's my brain melting down

Tim

@Seth hmm okay

@Seth so wait 5?

user136984

So what equation am I doing?

ByteCommander

That number will have almost 10,000 digits!

Nathan Osman

@ByteCommander Not exactly.

kos

5:16 PM

Final formula: (2^n1)*n2, where n1=number of bit for the representation of each channel, n2=number of channels

Nathan Osman

@kos Correct.

Seth

@Tim like I mentioned earlier the installation tag really isn't a problem, so if you're going to hack at it you're going to have to do it slowly. Why don't you start with 10.

Not disrupting site function is much more important than clearing an old tag.

Serg

@ParanoidPanda what is the number ?

Nathan Osman

@ByteCommander Here's where operator associativity comes into play.

user136984

@kos: So that is "(2^8)*3"?

kos

5:17 PM

So in RGB24 it's 2^8*3, and in RGB32 it's 2^8*4

Serg

crazy thought, but what if IEEE format could handle that

kos

@ParanoidPanda ^^

Serg

@kos perfect timing ;D

Nathan Osman

2^32^3 doesn't do what you expect in most programming languages. The exponent operator has right-associativity. That means it's actually doing 2^(32^3) instead of what you are probably expecting, (2^32)^3.

ByteCommander

@NathanOsman I meant 2^32^3.

user136984

5:17 PM

So as I am using 32bit it is 4?

ByteCommander

@ParanoidPanda A 32bit image has either 8bit per RGB channel + 8 bit alpha (transparency) or uses 11 bit red, 11 bit green and 10 bit blue (or another way round) or is really just 24bit and discards the 4th bit as dummy.

So it depends.

Nathan Osman

@ParanoidPanda When people refer to a 32-bit image, they typically refer to three 8-bit color channels and one 8-bit alpha channel.

user136984

So the number is 1024?

Nathan Osman

And as @ByteCommander stated, sometimes the fourth "channel" is just ignored in order to help with byte-alignment.

ByteCommander

1024 what?

user136984

5:20 PM

Colours.

user136984

That can be in a pixel.

Nathan Osman

Uh...

ByteCommander

That would be 10bit.

How do you get to 10bit?

I've never seen a 10bit color in my life.

user136984

Look, how many possible colours could I put in a pixel?

user136984

I need the number!

ByteCommander

5:21 PM

Depends on the image format!

user136984

:D

ByteCommander

That is like:

How many apples can I fit in a box.

That depends on what box you want to use.

Mateo

How big is the box ;p

user136984

So if it bmp?

Nathan Osman

b = total bits used to store all color channels of a pixel
possible_colors = 2^b

user136984

5:22 PM

How many colours would that be?

Mateo

Bit depth?

ByteCommander

BMP would just say in our example, that it is a box made of wood.

But not how big that box is.

Nathan Osman

@ParanoidPanda Bitmaps have a number of different formats for storing pixel data.

user136984

Well, give me an example of the largest.

ByteCommander

Bit depth is the keyword, as @Mateo said. And how those bits are used.

Nathan Osman

5:23 PM

Hang on... one sec...

ByteCommander

Well:

You can have 8bit per pixel --> 256 colors.

Nathan Osman

True, but that isn't storing the colors themselves.

8-bit bitmaps store a palette.

ByteCommander

That is not the question.

But there are 256 different colors.

Nathan Osman

I know. Just thought I'd throw some extra trivia in there :)

Mateo

You can have higher bit depth gifs...

ByteCommander

5:24 PM

So don't confuse our Panda! :)

Serg

T_T installed 14.04 on 32 gb usb drive, but it's kinda slow

user136984

So how are the colours actually defined in the code of the image? Are they hex values or what?

ByteCommander

Grah!

Linux law #1: Everything is file!

Computer law #1: Everything is data!

And what is data?

It is not hex numbers and it is not binary or decimal or base64 numbers.

Nathan Osman

ByteCommander

Or it is all of them at the same time.

Mateo

5:26 PM

Nathan Osman

I think the Gimp has more options...

Mateo

Ooo 32 bit :)

ByteCommander

@ParanoidPanda So if you say (real-life example) you have the information "penguin" (the word), you can translate that to English, Spanish, French, Hindi, whatever.

Nathan Osman

Yup. The fourth "channel" is either ignored or used for alpha.

ByteCommander

Same is with your file's data.

Mateo

5:29 PM

With transparency!

ByteCommander

The data stays the same, but you can view it as binary digits, octal, decimal, hexadecimal numbers.

Mateo

Or a spot gloss ;)

ByteCommander

You can encode them with ascii or unicode.

Serg

who speaks german here ? askubuntu.com/q/629004/295286

ByteCommander

It stays the same data.

Nathan Osman

5:30 PM

Incidentally... and because I'm bored...

ByteCommander

@Serg raising hand

Nathan Osman

Oh wait.

Stupid chat won't let me paste this...

Serg

@ByteCommander ^_^ there's a question there in german, might need a translation and an edit

ByteCommander

That is not even good German.

This guy needs another two years of primary school!

Serg

@ByteCommander -___- remember, we're on askubuntu, not german.stackexchange.com, although you could point the guy there

ByteCommander

5:32 PM

But!

Serg

we computer guys don't spell well,

A.B.

That's terrible German.

ByteCommander

If that guy writes his Q in German on an English site, that makes me assume his mother tongue is German.

user136984

What does ffffff mean?

ByteCommander

And at least in one language one should be able to form clear and understandable sentence with some grammar and spelling.

@ParanoidPanda 24bit number, all bits set. that is hexadecimal.

Serg

5:34 PM

f in hex = 1111 in binary

^_^ computer science 101 yo !

Now , if we're talking about 32 bit number, that might be in IEEE floating point format

kos

@ParanoidPanda FFFFFF(hex) = 111111111111111111111111(bin)

user136984

And in decimal?

ByteCommander

16777215.

Come on!

user136984

So I am very confused about all these colours...

Serg

@muru o/

user136984

5:36 PM

As that seems to be the amount.

user136984

Of possible colours that I could choose.

Mateo

@ParanoidPanda google says: color-hex.com/color/ffffff

user136984

Or perhaps there are even more.

ByteCommander

binaryhexconverter.com/hex-to-decimal-converter

Depends on your image.

Nathan Osman

2^32^3... is...

:)

muru

5:37 PM

@Serg \o

ByteCommander

WADDAFUUK?

Serg

Interestingly enough when I was messing with gnome-terminal settings the other day #ABAB9B9B6060 is a 6 byte number, right ?

user136984

@NathanOsman: But didn't we calulate that that was not right?

Nathan Osman

Oh my calculation is right - it just doesn't apply to what we were talking about.

Serg

1

Q: How can I set the background color of gnome-terminal using gconftool-2?

I am using Ubuntu 14.04 and I want to set the background color of my gnome-terminal using the command line. From what I can tell gconftool-2 is the way to do this but I cant work out what the command is to do this. my ~/.gconf/apps directory looks like: ├── %gconf.xml ├── gnome-terminal │ ├──...

gconf

user136984

5:38 PM

I am trying to create a custom image file type and just want to know how many possible colours there are that could be set to the pixel.

ByteCommander

That are 6byte, right.

Serg

@NathanOsman O_O nice one

muru

Isn't there a gsettings command for that, @Serg?

ByteCommander

@ParanoidPanda As many as you want, as it is a custom file type.

Serg

@muru yas, but that didn't work neither for me nor for OP

Mateo

5:39 PM

@NathanOsman wow, that took so long to load, that I thought you put in the loading gif...

ByteCommander

You just won't be able to display more than 32bit on your screen.

Nathan Osman

:P

ByteCommander

Which are probably just 24bit anyway... Because processors take 4byte faster than 3byte.

Nathan Osman

@ByteCommander You won't be able to display more than 24 bits on your screen.

The other 8 bits are ignored.

user136984

So what is the maximum that I could display on my screen?

Nathan Osman

5:39 PM

@ParanoidPanda 24 bits. 3 colors * 8 bits-per-channel.

ByteCommander

^^just added.

user136984

I thought it was 32 bit?

Nathan Osman

The pixels are aligned to 32-bits.

Serg

OK, boys , I need to go take care of a few things. Adios ! Hopefully, I'll still come back tomorrow. If not - I'll be back in July

ByteCommander

stored as 32bit, but containing 8 dummy bits for better CPU performance.

Nathan Osman

5:40 PM

But only 24 of them are used for color data.

@ByteCommander Exactly.

ByteCommander

Or containing another transparency channel with 8 bit.

user136984

So what is the number of actual colours that I could display on my screen in a pixel?

Nathan Osman

@ByteCommander That's usually done for textures.

@ParanoidPanda 2^24.

user136984

I just want the number...

user136984

:D

ByteCommander

5:41 PM

But your monitor would be the first if it can display transparency in another way than showing the color of the background window.

Nathan Osman

@ParanoidPanda 16,777,216 unique colors.

user136984

Why 24?

Nathan Osman

1 min ago, by Nathan Osman

@ParanoidPanda 24 bits. 3 colors * 8 bits-per-channel.

user136984

What happened to the third number?

Nathan Osman

@ParanoidPanda Third number?

user136984

5:42 PM

Or is that no longer relevant?

user136984

Yes, don't you remember it was *3 again?

ByteCommander

The fourth byte, you mean. (bit 24-31, if we start counting at 0): Alpha or dummy.

Nathan Osman

Here's the formula you're looking for:

2^8*3

ByteCommander

No, 24 = 3*8, right?

Nathan Osman

Or to avoid a possible misreading:

ByteCommander

5:43 PM

No braces @Nathan?

Nathan Osman

2^(8*3)

ByteCommander

It's power before dot, usually...

Serg

By the way, what's the best way to nuke a hard drive ?

Nathan Osman

@ByteCommander ~~Exactly why they aren't technically needed.~~

@Serg TNT? :P

user136984

@NathanOsman: What happened to "2^24"?

ByteCommander

5:44 PM

Works.

Nathan Osman

TNT works too.

Serg

@NathanOsman I didn't mean literally @_@ but that works

ByteCommander

Too expensive and restricted by law.

Nathan Osman

Is it a mechanical drive or an SSD?

Serg

Mechanical, good old hdd

2.5 inch sata

Nathan Osman

5:45 PM

Well, it depends on if you want to use it again or not.

kos

How are actually greyscale masks used btw? I guess that in case of a 24bit RGB simply the value of each channel is converted to a certain frequency and sent to the led, how is the 4th channel computed into the others?

Jorge Castro

@Nathan hey did you manage to go to ODS?

Nathan Osman

@JorgeCastro Yes and no.

I went downtown and got a chance to meet Marco.

But I didn't go to the Summit itself, no.

Serg

I am considering taking it accross the border, but kinda don't want any Russian/Ukrainian forces installing spyware or other sh*t there

user136984

2 mins ago, by Paranoid Panda

@NathanOsman: What happened to "2^24"?

Nathan Osman

5:46 PM

(P.S. chat is rate-limiting my messages. I must be typing too fast.)

user136984

@NathanOsman: ^^

Nathan Osman

@ParanoidPanda 3*8=24

user136984

So are they the same equation?

user136984

:D

ByteCommander

You have 2 possible states per bit and you use 8 bit per color channel and you have 3 color channels (red/green/blue).

Jorge Castro

5:47 PM

@Nathan aw man, no pics?

Nathan Osman

@ParanoidPanda 2^(8*3) = 2^24

ByteCommander

So Sherlock Holmes would deduce from this, that you can display 2^(8*3) = 2²⁴ different colors.

Nathan Osman

@JorgeCastro Unfortunately, no. I never thought of it.

Tim

@Serg where are you?

Mateo

@Serg a nuke yes. That is THE best.

Jorge Castro

5:49 PM

@Nathan did he buy you a beer at least?

Nathan Osman

@JorgeCastro He treated me to Starbucks.

Serg

@Tim I'm in the US so far, but gonna go visit my hometown in ukraine soon

Jorge Castro

notbadobama

Serg

@Mateo how about something less expensive and radioactive ?

Tim

@Serg ahh. You thinking the NSA haven't put something on already? :P

Nathan Osman

5:50 PM

@Serg If you don't need it again, just disassembling the platters will render it useless to basically anyone. If you do need it again, you need one of those drive wiping tools that writes a stream of random bytes to the disk a few times.

ByteCommander

@NathanOsman Not necessarily.

Nathan Osman

...to which scenario?

ByteCommander

(I mean opening destroys the disk)

user136984

@NathanOsman: So that is 1000000?

Nathan Osman

Unless you have an electron microscope and tons of money, that's a 100% effective method.

ByteCommander

5:51 PM

that=what?

kos

@Serg Degaussing also is an option

The safest also

Tim

@ByteCommander well no but it doesn't take much to destroy. Wipe the magnets agross and then hit with a hammer a few times for fun

Mateo

@Serg Industrial grinder, you can rent them

Serg

@Tim eh, true enough

Nathan Osman

@kos ...but that requires a degausser.

user136984

5:52 PM

@NathanOsman: So that is 1000000?

Nathan Osman

My example only requires a screwdriver :P

Serg

@Mateo That works :3

ByteCommander

1 min ago, by ByteCommander

that=what?

Nathan Osman

@ParanoidPanda What is?

Tim

@NathanOsman can't you just put it next to a crt screen and degaus?

user136984

5:52 PM

The number 1000000.

Serg

@NathanOsman actually quite cost effective method, but could someone assemble it back ?

Nathan Osman

@Tim Those aren't strong enough.

user136984

@NathanOsman: Is that the hex way of writing the number you gave me?

ByteCommander

@ParanoidPanda That is one million. Happy?

Nathan Osman

@Serg Yes, but the head and platters would be misaligned. And nobody other than a state-funded data recovery organization would be able to do anything with it.

user136984

5:53 PM

2^24 = 1000000 ?

user136984

In hex.

Mateo

@Serg may be possible depending on how much they spend vs how paranoid you are

Nathan Osman

@ParanoidPanda Yes.

user136984

Good

ByteCommander

You write 0x01000000 for hex numbers. or 01000000h.

BUT @ParanoidPanda

kos

5:54 PM

@NathanOsman Yes but many companies offer the service. Indded it's a bit expensive, but if one is really concerned... tough i'd go with dd either

user136984

But what @ByteCommander?

ByteCommander

The highest number you can store within 24bit is 2²⁴-1, so 0x00FFFFFF. You know that?

Because it starts with zero.

Nathan Osman

@ByteCommander Er... not quite. 24-bits means you can store 2^24 unique values.

Tim

@NathanOsman the crt? oh

Serg

Frankly , I am pro-US guy. True, what Snowden revealed was kindof a kick in the nuts to the public , but I understand that was a reaction to the whole 9/11 thing. But with Russia, that's just dickery directed by a self-proclaimed emperor >.> name starts with P

ByteCommander

5:55 PM

@NathanOsman Yes, but that is just a matter of encoding.

Nathan Osman

Right.

Mateo

If it is the next iPhone plans - the only way is to make sure it is a pile of dust, but the people keep leaving them laying around in bars so not much use in that anyway....

user136984

So there are 1000000 hex numbers or less or more?

ByteCommander

I can also encode it as Unicode or say 0x00000000=apple, 0x00000001=banana,...

@ParanoidPanda one million... :p Write 0x... or ...h please if you refer to hexadecimal values that don't contain abcdef

Tim

@Serg I have to agree, I much prefer GCHQ (the british NSA) listening to my phone calls and emails than me being blown up each day.

Nathan Osman

5:56 PM

The "fruit" encoding.

ByteCommander

Yep.

Then you will have 16777216 different fruits available for your dessert. :)

Mateo

@JorgeCastro what did he do now ;p

user136984

@ByteCommander @ByteCommander @ByteCommander: Yum!

Serg

Anyhow, I must go. If I don't take care of the list, my friend will skin me like a cat. Adios !now for real

Nathan Osman

@Mateo I think he's referring to this:

ByteCommander

5:59 PM

@Serg You guys skin cats? o.O

Mateo

@NathanOsman Ah :)

Nathan Osman

Kind of like "sadtrombone.mp3"

ByteCommander

@NathanOsman This line looks... empty?

Mateo

I've been playing this awesome metroid like game called axiom verge - very cool just this one person developed it

Nathan Osman

Meanwhile on AMO:

> "Queue Position: 10 of 91"

Okay guys, let's not get carried away.

ByteCommander

6:05 PM

You censorship applied: BEEEP are editing it all the time!

Nathan Osman

We have a Sandbox.

ByteCommander

No wonder my speakers don't get quiet!

user136984

@ByteCommander: No, I was trying to delete it...

user136984

But my browser kept reloading what it previously did!

user136984

:D

user136984

6:06 PM

It is doing this a lot with scripts, and forms, and pages now!

user136984

I will have to reinstall it or something...

user136984

It is becoming rather unusable...

Nathan Osman

→ 35 messages moved to Sandbox

Mateo

#DOCOMO uses #Ubuntu to show Data transfer 5GB per second. https://www.facebook.com/bbc4tech/photos/a.599341003456400.1073741826.127616880628817/931825753541255/?type=1&fref=nf http://t.co/cn5qBy5lZ3

Tweeted by novatillasku on May 27, 2015 at 4:52 AM

Nathan Osman

Nice.

Mateo

6:08 PM

Cool ^

Technology for 2020 0_o

ByteCommander

Translated Q from German, no please apply close votes (dupe): askubuntu.com/q/629004/367990

ByteCommander

6:36 PM

Oh no!