API page 9 - Dave's Blog

Theme Options

2007 Dec 24, 12:41These days it seems like there's a social sharing website for everything representable as bits. Like Scribd for (mostly legal) documents, SciVee for scientific research videos, Wordie for words, and Kuler for color themes. Kuler seems like a ridiculous website (overkill) but I had been meaning to update my homepage's color design and Kuler has an RSS based REST API. The API lets you obtain things like the most recently added color themes or the most popular or all themes containing the color dark red, etc... So of course rather than update my website's design I hooked up my css to the color themes coming out of Kuler. Select my main page's color theme from a list of random Kuler themes. As I'm sure the regular readers can guess I use an xslt and blah blah blah... It looks OK with Silver Surfer and Happy Hipo but in general changing the colors this way doesn't produce something pretty.

When reading about Kuler I found that they may have stolen the whole idea wholeslae from ColourLovers. They discuss the thievery in an article on their blog. I would have switched over to ColourLovers out of principle but they don't have an easily accessible API.colourlovers color xslt theme homepage technical kuler design

California Trip

2007 Dec 23, 11:18Sarah and I went down to California at the end of last month for a Thanksgiving visit with my parents. We visited the famous Monterey Bay Aquarium (fun fact: the aquarium scenes in Star Trek IV were filmed here) and saw many jelly fish. We wandered around Capitola where we visited many local shops and ate on the wharf. We shopped in Carmel and ate at the Forge in the Forest (fun fact: Clint Eastwood was the mayor of this city in the late 80s). We visited the Santa Cruz Beach Boardwalk which was very cold and closed.
My parents took us out to dinner on the first night and the rest of the nights we ate dinner at their house. They had the Shelton's over and I got to see Chris and Alison. It was fun to talk with them and catch up since its been quite a while since I'd seen them.
We stayed in the lovely beach house of our family friend's the Goodwins. My parents have been helping them fix it up and decorate it and it looks great. It was quite a treat staying in a house right on the ocean. Also of note, this was the first trip on which I was old enough to rent the car and accordingly I did all of the driving. This trip was very fun and relaxing.aquarium friends parents personal beach california vacation

Wp64 Issues

2007 Aug 6, 3:43Miladin told me about the Visual Studio compiler's promising option Wp64 that finds 64bit portability issues when compiling in 32bit. If, for instance, you cast from a (long*) to a (long) you get a W4 warning. However, the #defines are still set for 32bit builds. This means that other parts of the code can make assumptions based on the #defines that are valid on 32bit but generate 64bit errors or warnings.

For instance, in winuser.h the public published Windows header file there's the following:

...
#ifdef _WIN64
...
WINUSERAPI
LONG_PTR
WINAPI
SetWindowLongPtrA(
    __in HWND hWnd,
    __in int nIndex,
    __in LONG_PTR dwNewLong);
...
#else  /* _WIN64 */
...
#define SetWindowLongPtrA   SetWindowLongA
...
#endif /* _WIN64 */
...

In 64bit everything's normal but in 32bit SetWindowLongPtrA is #defined to SetWindowLongA which takes a LONG rather than a LONG_PTR. So take the following code snippet:

...
LONG_PTR inputValue = 0;
LONG_PTR error = SetWindowLongPtrA(hWnd, nIndex, inputValue);
...

This looks fine but generates warnings with the Wp64 flag.

In 64 bit, p is cast to (LONG_PTR) and that's great because we're actually calling SetWindowLongPtrA which takes a LONG_PTR. In 32 bit, p is cast to (LONG_PTR) which is then implicitly cast to (LONG) because we're actually calling SetWindowLongA. LONG and LONG_PTR are the same size in 32bit which is fine but if you turn on the Wp64 flag there's a W4 warning because of the implicit cast from a larger size to a smaller size if you were to compile for 64bit. So even though doing a 32bit or 64bit compile would have worked just fine, if you turn on the Wp64 flag for 32bit you'd get an error here.

It looks like I'm the most recent in a list of people to notice this issue. Well I investigated this so... I'm blogging about it too!wp64 technical 64bit compiler c++ visual-studio setwindowlongptra

Backup Notes

2007 Jul 13, 8:30I bought an external backup drive a few weekends ago. I've previously setup a Subversion repository so I decided to move everything into the repository and then back it up. So in went the contents of all of my %USERPROFILE% and ~ directories with a bit of sorting and pruning. Not too much though given its much easier to dump in everything and search for what I want then to take the time to examine and grade each file. What follows are the notes I took while setting this up. It takes me a bit of time to look up the help on each command so I figure I'll write it all down here for the benefit of myself and potentially others...

Setting Up the Backup Drive For Linux
I first changed the filesystem on the drive to ext3. I plugged it into my USB2.0 port and ran fdisk:

sudo fdisk /dev/sda

Useful commands I used to do this follow mostly in order:

m

help

p

print current partitions

d

delete current partition

n

create new partition (I used the defaults)

w

write changes and exit

Then I formatted for ext3.

sudo mkfs.ext3 /dev/sda1

I made it easy to mount:

sudo vim /etc/fstab
# added line to end:
/dev/sda1 /media/backup ext3 rw,user,noauto 0 0

I setup the directory structure on the disk

mount /media/backup
sudo mkdir /media/backup/users
sudo mkdir /media/backup/users/dave
sudo chown dave:dave /media/backup/users/dave

After all that its easy to make a copy of the Subversion repository:

mount /media/backup
cp -Rv /home/dave/svn /media/backup/users/dave/
umount /media/backup

Next on the agenda is to add a cron job to do this regularly.

Subversion Command Reference
On a machine that has local access to the Subversion repository you can check out a specific subdirectory as follows using the file scheme:

svn co file:///home/dave/svn/trunk/web/dave%40deletethis.net/public_html

Note also that although one of my directories is named 'dave@deletethis.net' Subversion requires the '@' to be percent-encoded.
Other useful subversion commands:

svn help

help

svn list file:///home/dave/svn/

list all files in root dir of svn depot

svn list -R file:///home/dave/svn/

list all files in svn depot

svn list -R file:///home/dave/svn/ | grep \/$

list all directories

svn status

List status of all files in the working copy directory as in - modified, not in repository, etc

svn update

Brings the working copy up to date wrt the repository

svn commit

Commit changes from the working copy to the repository

svn add / move / delete

Perform the specified action -- occurs immediately

Setting up Windows Client for Auto Auth into SVN
When using an SVN client on Windows via svn+ssh its useful to have the Windows automatically generate connections to the SVN server. I use putty on my Windows machines so I read the directions on using public keys with putty.

putty.exe dave@deletethis.net
cd .ssh
vim authorized_keys # leave the putty window open for now
puttygen.exe
Click the 'generate' button
Move the mouse around until finished
Copy text in 'Public key for pasting into OpenSSH authorized_keys file:' to putty window & save & close putty window
Enter Key passphrase & Comment in puttygen
Save the private key somewhere private
pageant.exe
'Add Key' the private key just saved.

Checking out using Tortoise SVN
On one of my Windows machines I've already installed Tortoise SVN. Checking out from my SVN repository was really easy. I just right clicked in Explorer in a directory and selected "SVN Checkout...". Then in the following dialog I entered the svn URI:

svn+ssh://dave@deletethis.net/home/dave/svn/trunk/web/dave%40deletethis.net/public_html/

Note again that the '@' that is part of the directory name is percent-encoded as '%40' while the '@' in the userinfo is not.

Windows Command Line Check Out
On my media center I didn't want to install Tortoise SVN so rather I used the command line tool. I setup pageant like before the only difficulty was getting the SVN command line tool to use putty. With the default configuration you can use the SVN_SSH environment variable to point at a compliant SSH command line tool. The trick is that its interpreted as a backslash escaped string. So I set mine thusly:

set SVN_SSH=C:\\users\\dave\\bin\\putty\\plink.exe

The escaping solved the vague error I received about not being able to create the tunnel.backup technical personal windows svn linux subversion

Second Life Translator

2007 Jul 4, 10:58Hackdiary
I really enjoy reading Matt Biddulph's blog hackdiary. An entry some time ago talked about his Second Life flickr screen which is a screen in Second Life that displays images from flickr.com based on viewers suggested tags. I'm a novice to the Second Life scripting API and so it was from this blog post I became aware of the llHTTPRequest. This is like the XMLHttpRequest for Second Life code in that it lets you make HTTP requests. I decided that I too could do something cool with this.

Translator
I decided to make a translator object that a Second Life user would wear that would translate anything said near them. The details aren't too surprising: The translator object keeps an owner modifiable list of translation instructions each consisting of who to listen to, the language they speak, who to tell the translation to, and into what language to translate. When the translator hears someone, it runs through its list of translation instructions and when it finds a match for the speaker uses the llHTTPRequest to send off what was said to Google translate. When the result comes back the translator simply says the response.

Issues
Unfortunately, the llHTTPRequest limits the response size to 2K and no translation site I can find has the translated text in the first 2K. There's a flag HTTP_BODY_MAXLENGTH provided but it defaults to 2K and you can't change its value. So I decided to setup a PHP script on my site to act as a translating proxy and parse the translated text out of the HTML response from Google translate. Through experimentation I found that their site can take parameters text and langpair queries in the query like so: http://translate.google.com/translate_t?text=car%20moi%20m%C3%AAme%20j%27en%20rit&langpair=fr|en. On the topic of non US-ASCII characters (which is important for a translator) I found that llHTTPRequest encodes non US-ASCII characters as percent-encoded UTF-8 when constructing the request URI. However, when Google translate takes parameters off the URI it only seems to interpret it as percent-encoded UTF-8 when the user-agent is IE's. So after changing my PHP script to use IE7's user-agent non US-ASCII character input worked.

In Use
Actually using it in practice is rather difficult. Between typos, slang, abbreviations, and the current state of the free online translators its very difficult to carry on a conversation. Additionally, I don't really like talking to random people on Second Life anyway. So... not too useful.personal translate second-life technical translator sl code google php llhttprequest

Wiimote wiissues

2007 Jun 7, 5:29The other day I had the best idea for my Wii remote. Clearly I should use it to control the rotation of Tetris pieces in my N-dimensional Tetris game Polytope Tetris. One of the issues I described with Polytope Tetris is user input. Given a Wii remote the user could rotate a piece through 3 dimensions in a manner that's much easier to adjust to than particular keys on the keyboard.

Anyway, I did a little research into how this might work. I knew that the Wii remote used infrared for absolute positioning and Bluetooth for everything else (LEDs, speaker, accels.) I bought a Bluetooth adapter for my PC after realizing that none of my computers had one already. I used GlovePIE to ensure that my Wii remote could connect and successfully communicate with my computer. GlovePIE is actually pretty cool -- it provides a simple script layer over the Wii remote to control things like your mouse.

Since Polytope Tetris is in Java I looked for and found a Java library for operating with the Wii remote and a long forum thread discussing its use. I then read up on Bluetooth in Java. Apparently JSR 82 is the name of the standard that describes the API a Bluetooth stack should expose in Java. That is, to get Bluetooth working in Java one needs an additional package for Java that actually implements the Bluetooth Java API. This package would depend on the system so I suppose I can't fault Sun for not including it... Where to find such a package? I found a comparison list of implementations and tried the ones that support javax.bluetooth. None of them worked for me because none can address USB devices it seems or they cost money and I couldn't get the trial version working. I also tried bluesock (not listed on the previous list) which seemed promising and could produce an address for my Wii remote as a connected device but couldn't use that address.

And I thought that after I found the Wii remote Java library it would be easy... Oh well...java bluetooth wii technical remote jsr82 tetris polytopetetris wiimote