The lecture period started this week.

This semester, together with a colleague, I am giving the lecture on “Scientific Visualization”. I am looking forward to it. However, this, of course, also means a lot of work. Mainly revising and updating the lecture slices and exercises. Therefore, I hardly had time to do anything else. Well, this is also part of my job.

The image of the article, by the way, shows a part of the “visible human” data set using direct volume rendering

Posted on No Comments Posted in Research & Teaching

I see myself am a Windows fanboy and an early adopter. I really do. (Don’t mistake me for a Microsoft fanboy. That is something completely different.)

This week, by chance, I found Windows 8.1 on my DreamSpark account. I was smart enought to ignore the preview so far, thus I was able to continue working, but since neither the title nor the description of the Dreamspark download mentioned anything about being a preview, I thought, this might be the real thing, released a bit early to Dreamspark users, like Microsoft sometimes does. That said, I downloaded it and installed Windows 8.1 on my laptop.

To spoiler: Right now, while I am writing this article, I am performing a clean installation on Windows 8(.0) on my laptop.

When I switched from Windows 7 to Windows 8, I quickly got used to the new interface, and I liked many of the new features. Of course, a start button would be nice and the start screen (aka full screen start menu) has a strange way of (un-)organization, but I was able to work rather efficiently with all of it.

Then I tried Windows 8.1 … I don’t want to write “yet another flame-post”, therefore I will limit myself to just one single feature: local accounts.

I have a local PC (stands for “personal” computer). I impersonate several roles when using this PC, e.g. being myself when I do online shopping, being my working self when answering e-mails from one of my mail accounts (I currently use 5 different accounts), being my gaming self when I do online gaming, etc. I could continue this list. What is important here, is that I fullfil different roles when using my computer, but I am always myself. Thus I use my account to do all this. And my account is my local account and not a Microsoft account forible tied with a Microsoft e-mail address.

I don’t want to use a Microsoft account on my local personal computer.

I don’t want to use a Microsoft account on my local personal computer.

I don’t want to use a Microsoft account on my local personal computer.

So, after some hardship I finally managed to use a local user account in windows 8.1 as well, but then suddenly I was no longer able to use several features of Windows. Several Apps stopped working. Yes, they state that I can log into my Microsoft account independently, but with some of the Apps, this really does not work.

More importantly: SkyDrive cannot be used with a local user account.

At least, I was not able to find any work-around to get any SkyDrive integration installed or working. This is a true show-stopper. The improved SkyDrive integration ensures that I will always have enough storage space on my cloud, since I cannot use it any more. Sad. Truely sad.

Well, as stated above, I am switching back to Windows 8(.0) and I will suppress my early-adoper-urges until I get proof that local accounts are again useable with the next windows.

If you want to read more about this misery, I liked reading this article: http://www.tweakguides.com/Windows81_1.html (especially page 3).

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The maybe most important coding project of myself which has impact on my private programming as well as on my work is thelib_icon16 TheLib. The basic idea is to collect all classes which we (two friends and myself) wrote and used several times in several different projects over and over again. These classes usually are wrappers for compatibility or convenience around API calls or library calls (e.g. STL, Boost, whatever). That’s where the name of our lib cames from: Totally Helpful Extensions. And, it is just cool to write: #include "the/exception.h".

However, I hear very often: “Why do you write a lib? There are plenty already for all tasks.”

If that would be true, none of us would write programs anymore and we would only “compose” programs from libs. Well, we don’t. Or, rather I don’t. Meaning: TheLib really is helpful. It is not a replacement for the other libs. It’s a complement, and extension.

On Example: Strings!

The string functionality in TheLib is not nearly as powerful as one would required to write a fully fledged text processor. This is not the goal of TheLib. We wrote these functions to provide somewhat beyond basic functionality. The idea is to enable simple applications or prototypical applications to easily implement nice-to-use interfaces for the user.

Especially unter Linux (but also unter Windows) there are usually a total of three different types of strings:

  1. char * or std::string which store ASCII or ANSI strings with locale dependent character sets
  2. char * or std::string which store multi-byte strings, e.g. using UTF-8 encoding
  3. wchar_t * or std::wstring which store unicode strings.

Depending on these types different API functions need to be called, e.g. for determining the length of the string:

  1. strlen
  2. multiple calls of mbrlen
  3. wcslen

On issue that arises between case 1 and 2 is that modern Linux often uses a locale which stores UTF-8 strings within the standard strings. As long as strings are only to be writte, stored, and displayed, this is a great way to maintain compatibility and gain the modern feature of special character availability. However, as soon as to perform a more complex operation (like creating a substring) this approach results in unexpected behaviour als the bytes of a single multi-byte character are threated like independent characters.

Example:

  • Your user is a geek and enters “あlptraum” as input string.
  • This string is stored in std::string using the utf8-en encoding.
  • Your application now wants to extract the first character for some reason (e.g. to produce typographic capitalization using a specialized font).
  • The normal way of doing this is accessing char* first_char = s[0]; and std::string remaining = s.substr(1);
  • Because the japanese “あ” uses two bytes, this results in: “0” + “Blptraum”

This not only applies to japanese characters, but obviously to almost all characters with diacritics. What is even more important: this issue also results in unexpected behaviour when using (or implementing) string operations which ignore case, e.g. comparisons.

Example of changing a string to lower case:

// we will do this the STL-way:
// http://notfaq.wordpress.com/2007/08/04/cc-convert-string-to-upperlower-case/

std::string data;
// contains 'data' is set to "あlptraum" encoded with utf8-en locale

std::transform(data.begin(), data.end(), data.begin(), ::tolower);
// well, content of 'data' is now: "0blptraum"
// ...

To avoid this problem, TheLib internally initializes the system locale for the application and detects if the locale uses UTF-8 encoding. If it does, all TheLib string functions will call the multi-byte API functions to work as expected. In addition TheLib provides some functions to explicitly convert from or to UTF-8 strings (e.g. for file io).

Of course, you don’t need TheLib to do this. You can use another lib (probably. I only know the IBM-Unicode-Lib, which seems like a huge hulk) or you can use your own workarounds or you can ignore such problems as “they will not occure in your application scenarios”. However, having TheLib doing the job is just handy. Nothing more.

Posted on No Comments Posted in My Tools

Software should solve problems. Sometimes this is the case.

I had a problem:

I have a somewhat older convertible laptop, an ASUS Aspire 1820PT. A nice and cheap convertible of it’s time. With touch screen support for up to two fingers and with an acceptable computational power. I have upgraded it in the meantime with an SSD and I am now running Windows 8. So far so good. The problem, however, is that the tilt sensor is no longer supported by Windows 8. :-(

So I needed a solution. Hacking drivers or even writing drivers myself is not up my alley. I am an application developer. But, if something does not work automatically (anymore), we just need to make the manual use as comfortable as possible. That’s why I wrote a tiny tool: the DisplayRotator.

The idea is simple: the tool is attached to the taskbar. As soon as it is started it shows DisplayRotatorScreena simple window with four buttons for the four possible display rotation settings. Press one of these buttons and the display settings are changed accordingly. With this, I can setup my desktop orientation of my convertible with two clicks, even two tapps with my finger, and rotate the desktop aynway I like.

DisplayRotator.zipDisplayRotator.zip Display Rotation Tool
[152 KB; MD5: 07c3efddd05a98bf4d02db595b87f2fe; Mehr Info]

And, because I can, the zip also contains the source code of the tool. It is written in C# and naturally uses the Windows API to change the display settings. Nice and easy. With the same code basis all display settings can be changes, like screen resolution and refresh rate. Even detaching or attaching monitors to the desktop is possible. Ok, the code for these functions is not in the tool, but the API calls are the same.

Maybe the tool can be of use to someone else too.

Posted on No Comments Posted in My Tools Tagged with ,

I like working at a university. I like solving problems without known solutions. I like improving existing solutions. I like working in my own directions. I like working with students. I like advising students with their work. I even like giving lectures.

However, what I don’t like, at least currently, is writing publications of my scientific results, which, of course, are the primary part in preparing a scientific career. This process ist currently awful, tiring and frustrating.

This year I wrote six articles. Each time I invested much work into preparation and presentation. However, *none* of them will be published this year. Not a single one. I never had such a bad year before. And from a realistic point-of-view, this is like a death blow for an accademic career.

Of course, this is not nice in itself, but what is even more frustrating are the reviews with which my articles got rejected. One of my papers hat numeric scores (1 = worst, 5 = best score) of: 4 + 4 + 3 +3. Also, the reviewer’s comments are sadly often nonprofessional, useless, and even polemic. Another paper was loved by two of the four reviewers. The third one found it borderline, but found it could be improved. The forth and primary one, however, worte something which I can only understand as “I don’t like it”. His review had more text but not much more contant than that. Result: rejected.

I had some discussions about this issue of an overcritical reviewing with several professors. All were aware of this problem and all agreed that this happens once in a while to a community. Sadly, in my opinion it has gotten continuously worse in the last seven years I have been working and publishing (except for this year) in the visualization community. Honestly, I don’t known what will be …

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