Posts tagged Media Informatics
The User Interface
0This week we work also on the User Interface – the Flash GUI. It was challenging since neither me nor Loredana had previous experience in creating games under this application.
Because of this fact, we searched for some advices on the net and after quite a long trial and errors we found something interesting here . Even that it didn’t met all requirements, this tutorial was what we needed to get a quick start.
The animal images are free clip arts taken from http://www.free-clipart-
After following the steps and understood the concepts,we modified the application to :
- Change the resolution, as it has to run on a projector
- Redesign the entire scene graphics, but keeping basic elements like scoring and timer.
- Change the game’s AI from
- how many simultaneously balloons you can hit in a specific period of time to
- having only one target available at one time and you can get another one only if you hit the current one
- Remove the old targets and create 6 new ones more appealing.
- Implement the Arduino interface classes taken from here.
XCode: Modal windows – Google maps
1
From time to time, you’ll need to show in your iPhone application a view over the entire application without navigating and destroying your workflow of the application. I’ll present the mechanism of modal windows as it is implemented in Cocoa Touch.
Lets take a real case: you have a view in which you want to input an address. Near the address you have a button which will show the user the Map centered on the specific address that he inputted. How this can be implemented?
The answer is quite simple: you need to declare the view from which you launch the modal view as <UINavigationBarDelegate> in the header file (.h for newbies), like this:
@interface CtrlAddEvtView1 : UIViewController <UINavigationBarDelegate>
This way, the view will know “magically” how to interact with children views.
XCode : using MapKit with no geocoding available out of the box
1
One of the tasks in the CSCW lab was to create a map on which the users to see the location of a specific address.
So I started working on it, knowing that the newest framework brings a lot of goodies, through which there is also a map framework. But surprise! Apple provides only reverse geocoding, not forward geocoding. This means that you can only transform a pair of Latitude / Longitude to the Map and it will show it to the user. But what to do when user enters an address?
My point is that nobody caries with him a GPS to search for the address, get the coordinates and enter them into my map!
I was curious about it and after a little search I found that there was a big argue about the geocoding and Apple didn’t want to pay the price that Google and Tom-Tom asked for this feature.
The User Interface
0A game should not have only a great idea, but also nice graphical interface. For this, we created an immersive forest environment where the user to be able to ‘hunt’ some animals.
Underneath is the background of the application:
We’re going on Arduino
0From the last lab we had a week of accomplishments:
- we set our hardware to Arduino platform
- completed on Monday a little programming and testing of the hardware platform
- decided the final idea of the game
- and also set Adobe Flash as our interface and display application
The idea of the game remains as presented a week ago. We will have a screen acting as a pressure sensor (composed from at least 9 sensors to be more precise about the user’s hit point).
The Arduino board will be linked with the sensors and will provide via USB the signals to the serial port. Flash will be on top, acting as a mix of a Controller of the user’s input gathered by the interface and providing the data for the View, thus creating a fully ModelViewController implementation.
The advantages of the MVC will enable us to quickly create an application, easy bug removal and improved User Experience by easy customization of the View.
Objective-C: Base64 to NSString and NSString to Base64
0
While working on the CSCW Lab project, I encountered a situation in which the XML-RPC call returned an image, of course encoded as Base64. And guess what – in its known style, Apple doesn’t provide Base64 encoding and decoding – quite lame, given the fact that this encoding is used everywhere in data transfer over the internet – e-mail, browsers, web services – all of them use at some point this encoding to overcome the different local encodings on each one’s machine.
Once identified this problem, I had to solve it somehow – but guess what? – over the free sources there aren’t too many functions that provide this simple and basic encoding.
Finally, after few hours of searching, I finally found that Eric Czarny had a very successful implementation of this in its Cocoa XML-RPC Framework . After taking a quick look at its code, I end up using and importing into my project the
- NSStringAdditions.h. NSStringAdditions.m – providing the new category
+ (NSString *)base64StringFromData: (NSData *)data length: (int)length;
- NSDataAdditions.h and NSDataAdditions providing the new category:
+ (NSData *)base64DataFromString: (NSString *)string;
Being categories, they are automatically added to NSString and NSData automatically at runtime, thus their usage is straight forward :
UIImageView *uiIV;
// currentElementValue holds the string representation of the image, encoded in Base64
NSData *nsD = [NSData base64DataFromString: [dataLayer currentElementValue]];
if ([nsD ){
uiIV = [[UIImageView alloc] initWithImage:[UIImage imageWithData: nsD]];
}
Processing NSDate into an ISO8601 string
2
During the CSCW Lab, where I had the experience of working on iPhone, I had to connect to a XML RPC server. Some of the parameters of the request had to be formatted as ISO8601 standard. After some reading, I end up using the following code, managing both the conversion of a NSDate to NSString and a NSString to a NSDATE using the above format:
NSString –> NSDate
-(NSString *) strFromISO8601:(NSDate *) date {
static NSDateFormatter* sISO8601 = nil;
if (!sISO8601) {
sISO8601 = [[NSDateFormatter alloc] init];
NSTimeZone *timeZone = [NSTimeZone localTimeZone];
int offset = [timeZone secondsFromGMT];
NSMutableString *strFormat = [NSMutableString stringWithString:@"yyyyMMdd'T'HH:mm:ss"];
offset /= 60; //bring down to minutes
if (offset == 0)
[strFormat appendString:ISO_TIMEZONE_UTC_FORMAT];
else
[strFormat appendFormat:ISO_TIMEZONE_OFFSET_FORMAT, offset / 60, offset % 60];
[sISO8601 setTimeStyle:NSDateFormatterFullStyle];
[sISO8601 setDateFormat:strFormat];
}
return[sISO8601 stringFromDate:date];
}
Brainstorming 2
0In a previous post I explained the facts that forced us to re-think our project idea. Basically, our cool idea of an iPhone tied to a skateboard to create a exertion game require too much programming time. So we searched another idea who is required to be simpler and easy to be implemented in the remaining time.
So we got us a round table (the ones in BIT cafeteria are the best!) and put our minds to work.
First step : Use the Initial Design Techniques – Brainstorming (as learned in DIS I)
Our goal: collect as many ideas of exertion game as we can
Defer judgment, no criticism, no rejection of ideas
Include all ideas, allow also the leapfrog ideas
Result:
1. Virtual basket
2. Ping-pong game to the wall
3. Squash
4. Throw a ball to a target
5. Boxing
6. Throwing paper balls to garbage – fun in offices
After some debate we agreed to pursue in implementing the 4th idea. We will try to create an exertion game which will be composed from:
- a board which will act like a hit sensitive projection screen,
- a projector to display the target on the screen
- the software behind to calculate:
- hit points,
- decide if user hit the target
- scoring and level finishing
To have a clear idea of our game we created also a small storyboard:
Changing the idea of the project
0In the last meeting, our tutors, Mr. Heller and Mr. Karrer, shared with us some of their experience using the sensors which made us reconsider the project idea.
The idea
Because of the new introduction in iPhone programming and the rich set of sensors of this device, our project envisioned an iPhone attached to the board in order to track the skateboard movements. The data pulled out by the iPhone is the initial acceleration (the one when the user starts riding with the board), and lateral or up-down acceleration when he does turns or jumps with the board.
First, the iPhone accelerometer won’t do the trick of getting all the information needed from the board. As it outputs acceleration, we would have to integrate once to get the velocity and twice to get the position. This gets us into a lot of approximations which aren’t suited for movements in a few meters range.
Secondly, the iPhone sensor is not design to get an industrial-scale precision and accuracy in an outdoor activity, but more for fun activities like sensing shakes or directional changes.
Thus, combined with the above observation implies the fact that our data readed from an iPhone attached to a board would not be as accurate we need (also the integration introduces approximations first to the velocity vector and again when computing position). It also it contains a lot of noise because of the environment (the skateboard goes on the rough and bumpy surfaces).
The solution
Given the facts, our team agrees with the tutors that this project would have needed too much time in order to develop some sophisticated algorithms, compensating the noise and the two integrations approximations, hardly near impossible to be done in the time span allocated for this project.
The upper side of this discussion is that our knowledge about sensors and in particular iPhone sensors has improved thanks to our tutors. Our suggestion is that for the next lab a similar discussion and sensor presentation should be held in the first laboratory meeting, in order to guide the students even faster to concrete results.
Install Maven in Eclipse: the eclipse.ini -vm option
1
While setting up the Maven for Eclipse, if you use a Java JRE instead of JDK you’ll be prompted like this:
Clicking on the first active text takes you to their Help website – Running Eclipse section where you’ll find a plethora of attributes to set in order to customize your IDE.
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