The Roberto Selbach Chronicles

About |  Blog |  Archive

Blog

Chrome and the new Lion full-screen behaviour

Posted on by Roberto's Chronicles

Three wise monkeys by Anderson Mancini

While I was ranting about the annoyances I found in OS X Lion today, a friend commented he had no issues at all, except for the full-screen mode. I got curious because the new Lion full-screen mode is probably the only new feature I found interesting. What did Apple do so wrong?

The answer: Google Chrome.

Wait, what? My friend was complaining that in Chrome you needed to use a keyboard shortcut in order to leave full-screen mode. That, he continued, was because Apple had given programmers too much freedom to implement the new feature any way they wanted. And he knew that, he assured me, because he had searched Google and confirmed it.

The new full-screen mode in Lion is implemented as a window behaviour not enabled by default, but adding it to a window is remarkably easy*:

[go]
NSWindowCollectionBehavior behavior = [window collectionBehavior];
behavior |= NSWindowCollectionBehaviorFullScreenPrimary;
[window setCollectionBehavior:behavior];
[/go]

Adding the NSWindowCollectionBehaviorFullScreenPrimary behaviour to a window will enable a small button to its top right corner. When enabled, the mode will allocate a new Desktop for the full-screen app and will also add an icon to the system menu to allow you to quickly leave full-screen mode.

And that’s the little icon my friend complained Chrome wasn’t showing, forcing him to use a keyboard shortcut. Imagine the trepidity! And all because of Apple.

I tried to explain that the problem was that Chrome’s windows still didn’t support the new full-screen behaviour but my friend’s version of reality was unswayable: Chrome supported the new behaviour and the problem was Apple. He had searched Google to confirm it. What could I possibly do?

Search it myself is what. And search I did. And I found this comment on Chromium’s bug tracker:

Comment 39 by rsesek@chromium.org, Jul 15, 2011

We had a conversation with one of our designers, and what we’re going to do right now is remove the fullscreen button so we don’t advertise a behavior that we don’t really implement. That change just landed and will hit Canary/Dev channels soon.

Long-term, we’re going to implement a proper fullscreen interface for Lion. In this interface, we’ll also experiment with having a collapsable toolbar. Until then, fullscreen will operate as it does on Leopard/Snow Leopard.

So there it is, straight from the source. Chromium — same as Chrome — still doesn’t support the new behaviour. Done. Nothing like reality to end a discussion.

Except my friend would not yield. Apple still needs to fix Chrome and anyone who disagrees — presumably that Chromium developer himself — is to be disregarded as an Apple fanboy.

If however you don’t want to wait for Google (or is it Apple?0 to release Chrome with the new full-screen behaviour, you can get by using Maximizer, which adds the behaviour to any application window.

  • Yes, I do realize that if you’re supporting multiple OSX versions and, even worse, multiple platforms, things get slightly more complex, but still.

(Image by Anderson Mancini)

“¿Por qué están todos hablando inglés?”

Posted on by Roberto's Chronicles

I’ve been spending an insalubrious amount of time on Google +. I managed to plump for a pretty good group to follow and as a consequence I’ve been getting consistently interesting content. As for myself, I mostly I post in English. A couple of days ago, I posted something most inconsequential and it would have been an unreservedly unremarkable post wasn’t it for the fact that it was geolocated in Cordoba, Argentina, which caused it to attract the attention of people nearby. In the middle of the comments, someone asked, in Spanish: “why is everyone speaking English?” That was a fair question and it touched something that has bugged me in the past.

Some part of my brain must miss the good old times of hunting and gathering as I ended up as a nomadic man—albeit one who doesn’t hunt and at most gathers food from grocery stores, so there might be a flaw in my theory. My rootless nature made me move a lot. This and the nature of my work caused me to make friends in several places other than my native Brazil[1].

We’ve already established that I communicate in Portuguese. Working at a US-based multinational as well as with open source, I also use English quite a bit—and my aforesaid rootlessness has taken me to inhabit the beautiful state of Oregon in the past. Oh and did I mention I am currently putting in a tour of duty in Argentina?

The Myth of the Tower of Babel

The result of all of this—in blatant contrast with the pre-Tower of Babel times when everybody obviously spoke English—is that I communicate daily in multiple languages. There isn’t a day—well, weekday—I don’t have to speak Spanish, Portuguese, English and French with someone or another. And that is fine and actually quite nice: you do lose languages if you don’t use them. Not like riding a bike, I suppose. Regardless, it is not a problem to communicate 1:1 in those languages. But what about 1:many conversations?

Blogging is a clear example. Should I blog in Portuguese as some keep telling me I should? I cannot reasonably expect my non-Brazilian readers to understand Portuguese. If I write in French, my Quebecer friends will be happy but what about the rest? Nationalistic rants aside, English is an international language nowadays, just as Latin and French once were. Aside from very few people, the vast majority of the people I know can understand English and that’s why I use it most often than any other.

Ideally, one would use their own native language and computer translation would do the rest. Unfortunately we are not there yet. I will admit that computer translation is getting better and better and it is fairly good if you write clear, short sentences. And it will get better. But I am skeptic that we will ever get to the point where the algorithms will be able to deal with subtleties, innuendos and all the puns that make up human interactions.

The way I see, I currently have a few options –

  • I write in Portuguese, as the ever vigilant Brazilian crowd demands it. That would soothe the wrathful nationalists who believe me a Traitor Of The Fatherland™. But it also limits my already limited audience; not good.

  • I write multiple versions of the same thing in each language. That would begin to feel like actual work, not fun. Also, having tried that in the past, I’ve learned that after I was done with the first version, the others never came out naturally.

  • I write in English. Sure it makes me a bootlicking lackey of the imperialist Yankees in the eyes of the insecure, but it also helps me reach pretty much everyone I know.

But using English is not a perfect solution either. For once, I am obviously not a native speaker and thus have an imperfect and narrow vocabulary. As well, I don’t share the cultural experiences that help define the subtleties of English. And finally, there are heaps of topics that just feel wrong in English: such as local—as in Brazilian—topics. It just feels weird.

Back to Google+, I have created Circles for Portuguese and French, but these are not much valuable until Google comes up with some system of set arithmetic that would allow me to say something to the effect of “Post this to members of Circle X who also happen to be members of Circle French.” Until then, English is my best bet.

[1] Experience tells me that I am required to point out that we, cheerful Brazilians, speak Portuguese, not Spanish.

(Image Credit: ThomasThomas, Creative Commons)

Godwin’s Law is anything but

Posted on by Roberto's Chronicles

I’ve got many gripes with the internet, I’ll admit. One of those is the overuse of Godwin’s Law. Actually, it’s a double offence because not only people overuse it, but this Law is anything but.

But let’s start with the misuse. I posted a while ago to Facebook that I had finished reading The Rise and Fall of the Third Reich and I mentioned how scary it was that a place right in the heart of “civilized” Europe could have fallen to that madness so quickly. A small discussion formed with some people until one of my geek friends commented something to the effect of—

Let’s stop this because Roberto already Godwinned in the original post!

You see, us geeks are good at that: repeating some meme without thinking much about them.

But that’s how I see “Godwin” being used all over the place. A discussion killer. And the discussion did get killed, unfortunately. It’s like Godwin’s Law says “if someone mentions Nazis, the discussion is over” but that’s not what the “law” says—

As an online discussion continues, the probability of a reference or comparison to Hitler or to Nazis approaches 1.

Which is actually true. Just like—

As an online discussion continues, the probability of a reference or comparison to Snow White and the Seven Dwarves approaches 1.

Obviously, as a discussion grows, the probability of referencing anything will approach 1! Here’s Godwin himself back in 2008 about his “law”—

Although deliberately framed as if it were a law of nature or of mathematics, its purpose has always been rhetorical and pedagogical: I wanted folks who glibly compared someone else to Hitler or to Nazis to think a bit harder about the Holocaust.

I find it ironic that his little experiment for making people think harder about the Holocaust is now used as a tool to avoid mentions to it.

You see, I get where Godwin was trying to go. You see glib comparisons with the Nazi all the time and yes, they suck. But going from that to making one of the most defining moments of the last Century completely off-limits is preposterous! Nazi comparisons are often valid and should not be avoided, especially by misusing an old usenet meme.

Again, His Godwinness—

Still, I sometimes have some ambivalence about the Law, which is far beyond my control these days. Like most parents, I’m frequently startled by the unexpected turn my 18-year-old offspring takes. […] When I saw the photographs from Abu Ghraib, for example, I understood instantly the connection between the humiliations inflicted there and the ones the Nazis imposed upon death camp inmates—but I am the one person in the world least able to draw attention to that valid comparison.

Avoiding comparing things to something as defining as Nazi Germany is an arbitrary limitation that makes no sense.

That’s not to say that all Nazi comparisons are valid. There really are plenty of dishonest Nazi comparisons out there, such as this one, by an American governor—

We the people have been told there is no choice. You must buy health insurance or pay the new Gestapo — the IRS.

This because the Supreme Court of the United States had upheld a law that represented the first steps of that country in following the rest of the civilized world in providing its citizens with basic healthcare. Healthcare! Oh the evils of that Gestapo!

But it’s unreasonable to expect people to completely ignore a huge part of our history in hope that dishonest governors won’t make silly comparisons, which they’ll do anyway.

Anagramizer, a simple anagram solver in Go

Posted on by Roberto's Chronicles

This weekend I took the family to celebrate Father’s Day away from town. We went around getting to know parts of the province we live in and never been to.

We came back yesterday and the plan today was for a nice, calm day at home (it’s a holiday of some sort here.) Then I got engaged in a game called Hanging with Friends, a mix of the traditional hangman with a bit of Scrabble.

Since English isn’t my first language, I have a limited vocabulary, which leaves me at a disadvantage against my English-speaking friends. I can handle the “hangman” part of the game where I have to guess the word my friends come up with; but when it becomes “Scrabble” and I’ve got to form words using only a given set of letters and still make them difficult enough that a native English speaker will have problems figuring them out, then it’s tough.

An itch that needed some scratching. Enter Anagramizer.

When I woke up this morning, I decided to write a little program to help me. You call it cheating, I call it having a bit of nerd fun.

Being that I’m currently in love with Go, I decided to write in that language and it was really easy and quick to do it. It took me about half an hour to write the program that did what I needed. But then…

I succumbed to the temptation and started adding bells and whistles. Admittedly it was mostly for my own amusement and trying stuff in Go, but by the time we were leaving for lunch, the program had more options than the KDE audio volume utility (see what I did just there?)

I decided to make it available to anyone who wants to play with it. It served its purpose of entertaining me for about half a day 🙂

It’s now available on Github and released under a BSD licence.

Euler 9 in Go

Posted on by Roberto's Chronicles

This was surprising to me. For fun I picked one of the Euler algorithms I played with in the past and rewrote it in Go. The idea was to rewrite it idiomatically to see how different things might look. Nothing else. The very first thing I did was to get the exact algorithm and rewrite, no idiomatic changes.

[go]
package main

import "fmt"

func isTriplet(a, b, c int) bool {
return a * a + b * b == c * c
}

func main() {
for a := 1; a < 1000; a++ {
for b := a + 1; b < (1000 – a) / 2; b++ {
c := 1000 – a – b
if isTriplet(a, b, c) {
fmt.Println(a * b * c)
return
}
}
}

}
[/go]

What surprised me is that this thing runs in 0.005s, which is faster than the Python implementation and very close to the one in C. It surprised me because this wasn’t really supposed to happen. The Go compiler isn’t well optimized, especially compared to compilers with a many-years headstart.

How to set up Emacs on Windows

Posted on by Roberto's Chronicles

Just so I have it documented somewhere for future reference, here’s how to quickly set GNU Emacs up on Windows.

  1. Download it from http://ftp.gnu.org/gnu/emacs/windows/

  2. Unzip it to, say, C:emacs or something like that

  3. Set the environment variable HOME to C:emacs and include C:emacsbin to the PATH

  4. If you want to have a “Open with _G_NU Emacs” option on the context menu, just create a registry file (call it emacs.reg or whatever.reg) with the contents below and double-click it to import it into the registry.

    REGEDIT4
    [HKEY_CLASSES_ROOT*shell]

    [HKEY_CLASSES_ROOT*shellemacsmenu]
    @=“Open with &GNU; Emacs”

    [HKEY_CLASSES_ROOT*shellemacsmenucommand]
    @=“C:emacsbinrunemacs.exe ”%1“”

Et voilà! As well, for my preferred colour scheme, we need to use color-theme from http://www.nongnu.org/color-theme/ and set it up in your .emacs file:

(add-to-list 'load-path "c:/emacs/.emacs.d")
(require 'color-theme)
(color-theme-initialize)
(when (display-graphic-p)
  (color-theme-subtle-hacker)

Euler 15 in Python

Posted on by Roberto's Chronicles

This one isn’t even funny…

Starting in the top left corner of a 2×2 grid, there are 6 routes (without backtracking) to the bottom right corner.

How many routes are there through a 20×20 grid?

Your first thought would be to generate the routes, but for a 20×20 grid, those amount to BILLIONS and you’d try to do it recursively too! Forget it.

But if you have some CompSci-level math background, though, you’ll remember this one—reading The Art of Computer Programming, Vol. 4 also helps. It’s a matter of combinatorics and if we take w for the width and h for the height, all we need to do is calculate,

[latex size=“3”]frac{(w + h)!}{w!h!}[/latex]

and that’s it. I didn’t even write a program for this, instead using Python’s interactive shell, but just for the same of completeness, here’s a “program” to calculate the possibles paths in a 20×20 grid.

import math
w = h = 20
print math.factorial(w + h) / (math.factorial(w) * math.factorial(h))

That’s it.

Euler 11 in Python

Posted on by Roberto's Chronicles

Project Euler’s problem #11 statement goes:

In the 20×20 grid below, four numbers along a diagonal line have been marked in red.

08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48

The product of these numbers is [pmath]26 * 63 * 78 * 14 = 1788696[/pmath].

What is the greatest product of four adjacent numbers in any direction (up, down, left, right, or diagonally) in the 20×20 grid?

This one is remarkably easy but also was quite fun. I think it’s because it reminds me of the kind of work we’d do during our Algorithms classes during my first year in college. And so this one goes to my Algorithms teacher, Ricardo Vargas Dornelles—best teacher I’ve ever had too.

import operator
numbers = [[8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8],
[49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0],
[81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65],
[52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91],
[22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80],
[24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50],
[32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70],
[67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21],
[24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72],
[21,36,23,9,75,0,76,44,20,45,35,14,0,61,33,97,34,31,33,95],
[78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92],
[16,39,5,42,96,35,31,47,55,58,88,24,0,17,54,24,36,29,85,57],
[86,56,0,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58],
[19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40],
[4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66],
[88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69],
[4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36],
[20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16],
[20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54],
[1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48]]

maxp = 0
for row in range(0,16):
        for col in range(0,16):
                maxp = max(maxp, reduce(lambda x,y: x*y, 
                                        [n for n in numbers[row][col:col+4]]))
                maxp = max(maxp, numbers[row][col] * numbers[row + 1][col + 1] * 
                                 numbers[row+2][col+2] * numbers[row+3][col+3])
                maxp = max(maxp, reduce(lambda x,y: x*y, 
                                        [n[col] for n in numbers[row:row+4]]))
                if col > 3:
                        maxp = max(maxp, numbers[row][col] * 
                                         numbers[row + 1][col - 1] * 
                                         numbers[row+2][col-2] * 
                                         numbers[row+3][col-3])

print maxp

As well, this runs in 0.020s, so not bad at all.

Euler 10 in Python

Posted on by Roberto's Chronicles

I decided to take on Project Euler’s problem #10. Its statement goes like this:

The sum of the primes below 10 is [pmath]2 + 3 + 5 + 7 = 17[/pmath].

Find the sum of all the primes below two million.

My first attempt used brute force and testing primality using only previously found primes:

primes = []

def is_prime(n):
        if not (n < 2 or any(n % x == 0 
           for x in filter(lambda x: x < math.ceil(n ** 2), primes))):
                primes.append(n)
                return True
        return False

sum_primes = 0
n = 1   
while n < 2000000:
    if (is_prime(n)):
        sum_primes += n
    n += 1  
print sum_primes

It worked if you consider an execution time of over 7 minutes reasonable. Clearly a bad solution. So I decided to rethink it a bit and tried again. This time, I decided to use a little creative thinking. For every number I tested for primality, I took the time to mark its multiples as not primes (when I first test, say, 3, I already know that [pmath]6, 9, 12, … n * 3 < 2000000[/pmath] will not be a prime numbers, so I don’t have to test their primality later.)

max_primes = 2000000
numbers = [0] * max_primes

def is_prime(n):
        if n <= 2:
                return True
        if numbers[n] == 1:
                return False
        c = 2
        m = 0
        while True:
                m = n * c
                if m < max_primes:
                        numbers[m] = 1
                else:
                        break
                c+= 1

        #if any(n % x == 0 for x in xrange(2, int(n ** 0.5) + 1)):
        i = 2
        while i < int(n** 0.5 + 1):
                if n % i == 0:
                        return False
                i += 1

        numbers[n] = 1
        return True

def sum_primes():
        soma = 0
        for i in range (2, max_primes):
                if is_prime(i):
                        soma += i
        return soma

print sum_primes()

This is a much better algorithm and it gave the correct result in 54 seconds. Project Euler has a “one-minute rule”, which state that all its problems should be solvable “on a modestly powered computer in less than one minute,” which means the solution applies. Still, it’s a brute force solution and I wanted a better one.

So today I picked my copy of Concrete Mathematics and read about primes. Honestly, I’ve been reading more about primes lately than I even thought I would.

Anyways, Knuth—yes, I know the book has three authors, but I can’t help thinking of it as a Knuth book—talks about several strategies to test primality, but it also mentions sieve algorithms that are used to generate lists of prime numbers. Exactly what I wanted!

def prime_list(limit):
        if limit < 2:
                return []
        sieve_size = limit / 2
        sieve = [True] * sieve_size

        for i in range(0, int(limit ** 0.5) / 2):
                if not sieve[i]:
                        continue
                for j in range((i * (i + 3) * 2) + 3, sieve_size, (i * 2) + 3):
                        sieve[j] = False

        primes = [2]
        primes.extend([(i * 2) + 3 for i in range(0, sieve_size) if sieve[i]])

        return primes

print reduce(lambda x,y: x+y, prime_list(2000000))

Et voilà! Correct result in 0.456s! The code is based on the description of the Sieve of Eratosthenes found in Concrete Mathematics. Also interesting to note, my idea in the second algorithm above is actually the basis of this sieve algorithm, I was just thinking “backwards.”