Random Etc. Notes to self. Work, play, and the rest.

Posts Tagged ‘Code’

js-vector-maps on github

I've been experimenting with some javascript classes that mimic the structure of mapnik's Layer/Style/Rule classes and render OSM data (via GeoJSON) to a <canvas> element. I've also finally taken a look at how github works, so I've decided to share the initial code there in case people are interested. If you don't want to check the code out for yourself there's a demo page here (tested in Firefox and Safari only, so far).

Android Tinkering

I got an Android dev phone. Geeks talk.

I've heard it said that this would be the best phone in the world if it wasn't for the iPhone*. I can believe it. So this is the second best phone in the world, and you write software for it using Java and (optionally) Eclipse. I know Java and I use Eclipse all the time for writing Flash apps, so this is a tempting prospect: world class hardware, easy to use software. Let's go!

* We can debate what it means to be the best phone in the world at the moment - suffice to say that I know that hardware alone will never do it. Apple's retail experience, customer support, iTunes store, developer tools etc. all leave Android and others with a lot of work to do. But it is a nice phone, certainly. I also haven't been using the phone for voice, nor have I been syncing my emails and calendar with the phone... so this isn't a review by any stretch of the imagination.

There's a brand new update available for the Android OS, version 1.5 aka "Cupcake". My phone came with 1.1 and despite some prodding it wouldn't go ahead and upgrade itself. So I had to download the 1.5 updates and do it myself. That page is full of long and complicated explanations but basically you're just copying files, renaming them to update.zip and rebooting the phone, twice. (Mine got confused in the middle because it finally started to automatically update itself and I let it. If that happens just ignore it and continue with the manual process and everything should be fine.)

My main focus with tinkering with the phone has been to get the API demos running so I can get a sense for how easy it is to work with the Google MapView classes and also how much boilerplate code I need in order to load data over the network and draw pretty things with OpenGL. The Hello World tutorial worked straight away: if you have the phone plugged in it automatically installs your app and runs it on the device, if not then it fires up an emulator. Getting the API demos up and running was a little trickier because it involved importing the project from android-sdk-mac_x86-1.5_r1/platforms/android-1.5/samples/ApiDemos first, but it did work after I upgraded to Cupcake.

For the MapView to work you need to jump through some app signing hoops before you can get a Google Maps API key that will allow the device to load map tiles. The documentation is quite dense but if you're just playing around in Eclipse you can sign things with your debug key; in this case the API key signup page tells you what to do. Just be sure to log in with the same Google account you'll be using in the Android Marketplace, if you get that far.

Once I'd kicked the tyres with the demos I decided to jump straight in and try my hand at an app that loads data from a web service and displays it on a map. The learning curve was OK, here's a list of things I wish I'd known about before I started:

All in all it took me just over a day to get to the point where I felt confident that the phone was doing what I was telling it, and that there wasn't too much magic and surprise crashes were rare. The next thing I want to investigate is the OpenGL ES implementation, which I'm hoping is as slick as the iPhone's. I've been keeping a list of android links I think are worth reading at del.icio.us/TomC/android - let me know if there are any other neat/essential APIs in the Android universe that you think I should take a look at.

Text along a path in Flash

Trevor McCauley did the hard part years ago, as is often the case, but it seems like there's no source code out there showing text along a path in Flash using actionscript 3. I'm not the only one thinking about this – the degrafa folks have got the extremely capable algorithmist Jim Armstrong looking into the problem too.

I don't have time to write a full explanation tonight (packing calls, tomorrow I'm in Montréal for Design Engaged), but I've got a quick solution which might be of use to you if you googled upon this page. Read on for more if you're interested in a quick overview.


Fix for buggy Flash TextField selection (on mouse leave)

Today's post is about tiny details.

I've noticed a frustrating problem with text in Flash that I've finally managed to find a workaround for. I'm testing in Mac OS X using Firefox 3 and Flash 9, but I've seen it on other systems too, and recently had help reproducing this bug from our client at MSNBC, so I'm pretty sure it's widespread.

Since this is a fairly esoteric issue that will only bother Flash programmers, I'll continue only in the full version of this post.


Modest Maps vs Processing

Update 2011-10-10: This project is now hosted on github, please download the latest version there and file an issue if it's not working for you. Thanks!

Since Mike simultaneously outed me and out-did me and linked to the Processing folder of the Modest Maps source at the same time, I thought I'd better post a version of the library I've been working on so that I can stop thinking about it for a while.


Modest Maps is a BSD-licensed display and interaction library for tile-based maps in Flash (ActionScript 2.0 and ActionScript 3.0) and Python...

...And Processing


A quick (less certain) note on using Lucene in Processing

In the spirit of continuing our impromptu database week on Processing Blogs (my post, toxi's post, then Florian Jennet updating the sql library), I thought I'd post another quick example using Lucene.

Last week Ryan and I needed a reliable way to search inside a data set we were working with. I had previously tried and failed to write my own useful search routine for the same data, so I wanted to take a look at Lucene instead. (This week, I might have used SQLite, but I hadn't tried it last week!).

Lucene isn't a relational database like MySQL or SQLite, although it has a few similarities with the way most database engines speed up queries using indexes. That's because Lucene is "just" the indexing part. You tell Lucene about your data, one part at a time, and then construct queries to ask it which parts of your data match the query. The key thing is that you keep hold of your data yourself and structure it any way you like, Lucene keeps its own representation of the data for searching. Because of this it can index much more data than you can store in memory.

Anyway, I put up an simple example Lucene applet here that indexes the text of Time Machine by H.G. Wells from Project Gutenberg and lets you type queries against it. The text itself and the Lucene index it builds are both quite small (tens of KB, compressed), but the applet is around 750KB. This is because Lucene's core jar file is about 500KB so it's more suited to standalone projects and applications.

The code is kind of documented, but Lucene was really too much for me to understand properly in just one day. Nevertheless, again, I hope people find it useful!

A Quick Note on using SQLite in Processing

SQLite is a great standalone SQL database engine - not ideal for every situation (particularly large websites), but more than good enough to have already made its way into desktop projects from Apple, and more recently Adobe and Google.

My colleague Mike recently used it as a way to distribute data from a 511.org transit website scraping project he's been doing. I wanted to see if I could download his data (gathered and processed using python) and access it using Processing.

Web searches for SQLite and Java (java wrapper sqlite, etc.) turn up lots of matches, including this promising tutorial from Tim Anderson, but sadly the most prominent matches didn't work for me. It's a real pain to get up and running and installed in a reliable way, mainly due to the need to compile SQLite natively for each platform and then talk to the native code using Java.

Enter this amazing project, a JDBC library for SQLite written in pure java that uses NestedVM to compile the C code for SQLite into something any Java VM can use. It's frightening to think about the amount of misdirection, abstraction and interpretation going on here, but it worked first time and plenty fast enough for my purposes.

Take a look after the jump for the code I ended up with. I hope people find it useful:


Testing Posting Code

Just wondering how the <code> tag works in html with Blogger.

// nothing to see here, just pretending that I've posted some code

for (int i = 0; i println("nothing to see here");

Does that work? Who knows? I bet it breaks Processing Blogs, but then so does posting images to this blog, for some reason. What's a blogger to do?

on edit: surprisingly seems to work as long as you stay in "edit html" and don't flick into compose or preview. Seems well padded with this style sheet though, so no need for leading or trailing line breaks in the code.

on second edit: Oh, and indenting doesn't show up, but at least it wraps long lines. Can't ask for everything!

on aggregation: Seems I was right - though it works on the page itself, it doesn't seem to get picked up by Bloglines or my Processing Blogs aggregator. Looks like it's missing from the atom feed entirely... I think I'll post a bug.