ericd.net blog

AS3 Timer accuracy

2009-07-09T16:36:00.003-04:00

I've just bit into some weirdness. I have a Timer that I want to fire every 100th of a second. So it would be new Timer( 10, x ); However when testing this isn't not accurate (I am printing the time to the screen). So if I drop the Timer down to fire every 7ms instead of 10, it aligns with my watch, my computer, and my stop watch on my iPhone.

That's great, but what when I move this to another machine? It will probably be slightly off.

What is even stranger is that when I do new Timer( 7, 1800 ); - it still reaches 18 seconds, even though it should have fired a complete before that.

Is there a really accurate way of timing something as close to possible? I know this is a pretty old topic, maybe someone has found something really reliable.

Flash is amazing, my quick random PSA

2009-07-09T12:38:00.004-04:00

We all know it, and we've known it for a long time. Just about anything you want to do can be done using Flash Player 10. Sometimes we lose sight of the power of this technology when we're knee deep in the slop of application development and we're just focused on doing and getting the job done.

Today I had a moment when I stepped back from my desk and marveled at what I was doing. Not in that way. It's just that an hour before an idea had already formulated itself into a working, beautiful, and easy to use thing. Any kind of functionality I wanted to create simply happened and wasn't a struggle.

Flash is beautiful. To those whose only experience with it are those online advertisements... think about how lousy those advertisements would be without Flash. Think of the good ones you've seen that respected your audio space. The ones incorporating video and games and inclusion of dynamic data with cool visualizations.

Yes, sometimes people take it too far. But so what. It's all good. Enjoy the freedom to express yourself and do cool things. That's all for this PSA, back to work. Which I love.

AS3 range slider with multiple thumbs?

2009-07-08T22:30:00.010-04:00

Update 2:

Here is a quick example of the working component as it stands right now. Implements setting thumb positions and all that jazz.

Update:

I started coding up an AS3 quasi-component and it's working pretty well. It's kind of hard-coded for my immediate needs, but I may just release it so you can implement custom events for it and roll it as a proper component.

It doesn't look like the sample below, the thumbs carry along their current value based on the max value set for the whole slider, use color-coded sections to better help visualize, etc.

If I get some spare time, I'll probably roll it into a proper component since it's not too hard but rather time-consuming. As most things I suppose.

If you are at all interested in using a range (partition) slider outside of Flex (that doesn't require Flex at all), then you may want to pay a little extra attention to this blog in the near future.

I've seen sliders, I've seen Flex sliders with two thumbs, but I have yet to see a slider that has more than two thumbs. I've been searching all over the place and I just haven't found one yet. I was hoping to locate one to save me the time and energy of coding one up myself from scratch. It's not terribly difficult, just really time consuming.

If you've seen one of these around, please let me know. I am hoping to save development time for my actual application and not having to cut out some of that time to create a multi-range slider.

Yes, I know the use case for a slider that can support 2+ thumbs is rare. Any help would be appreciated.

Here is an image of a component I already started:

How I imagine it. The slider has a base min and max. Defaults to 1 thumb maybe. You can add thumbs and when you do you specify a value for it's initial placement.

To make it easy, any time any of the thumbs are moved, values for all are set for the change event, in the order of the thumbs, say an array of values. You can't drag a thumb over another thumb.

iPhone: CorePlot

2009-07-08T13:24:00.003-04:00

There is an open-source graphing library available for both Mac OS X and the iPhone called CorePlot. If you've gotten accustomed to the graphing packages available for Flex and Flash applications, you'll get a little tingle when you see this graphic library.

In order to integrate into your iPhone application, after checking the code out of the repository or downloading you can follow this information:

Because frameworks cannot be used in Cocoa Touch applications in the same way as on the Mac, the means of including Core Plot within an iPhone application are slightly different.

First, drag the CorePlot-CocoaTouch.xcodeproj file into your iPhone application's Xcode project (making sure that nothing's copied and the paths are relative to your project). Then go to the Targets tab in Xcode, select your application's target, and bring up the inspector. Go to the General settings page and add the CorePlot-CocoaTouch library as a direct dependency.

Core Plot is built as a static library for iPhone, so you'll need to drag the libCorePlot-CocoaTouch.a static library from under the CorePlot-CocoaTouch.xcodeproj group to your target's Link Binary With Libraries folder.

You'll also need to point to the right header location. Under your Build settings, set the Header Search Paths to the relative path from your application to the framework/ subdirectory within the Core Plot source tree. Make sure to make this header search path recursive. You need to add -ObjC to Other Linker Flags as well.

Core Plot is based on Core Animation, so if you haven't already, add the QuartzCore framework to your application project.

Finally, you should be able to import all of the Core Plot classes and data types by inserting the following line in the appropriate source files within your project:

#import "CorePlot-CocoaTouch.h

I have yet to try this out myself since I don't immediately have a need for it, but I am seeing some people encountering problems with the steps outlined. They get a EXC_BAD_ACCESS error. Perhaps this library isn't set up in it's downloaded form properly and may require some tinkering to get it rolling properly. Here is the Issues List where you can tool around to see what problems currently exist that have been commented upon.

Raphaël—JavaScript Library: vector graphics on the web

2009-07-08T08:22:00.006-04:00

I received a cool message from a friend of mine to go and check out the Raphaël—JavaScript Library. What is it? Here are the introductory paragraphs from their website:

Raphaël is a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library.

Raphaël uses the SVG W3C Recommendation and VML as a base for creating graphics. This means every graphical object you create is also a DOM object, so you can attach JavaScript event handlers or modify them later. Raphaël’s goal is to provide an adapter that will make drawing vector art compatible cross-browser and easy.

Raphaël currently supports Firefox 3.0+, Safari 3.0+, Opera 9.5+ and Internet Explorer 6.0

It's as easy to implement as this. Include the raphael.js into your page and start having fun like so:

// Creates canvas 320 × 200 at 10, 50
var paper = Raphael(10, 50, 320, 200);
// Creates circle at x = 50, y = 40, with radius 10
var circle = paper.circle(50, 40, 10);
// Sets the fill attribute of the circle to red (#f00)
circle.attr("fill", "#f00");
// Sets the stroke attribute of the circle to white (#fff)
circle.attr("stroke", "#fff");

There are plenty of demos to check out at the site, it looks pretty interesting to say the least.

Are you using Amazon's Product Advertising APIs? You could be in trouble.

2009-07-07T20:30:00.010-04:00

If you are using Amazon's Product Advertising APIs in your iPhone application, guess what? You could be libel and be on the tail-end of some legal action.

You see, the APA APIs stipulate that use of the API is prohibited from use on a mobile device.

From the agreement: 4. Usage Requirements, (e):

You will not, without our express prior written approval requested via this link, use any Product Advertising Content on or in connection with any site or application designed or intended for use with a mobile phone or other handheld device.

So you might be in violation and not know it yet. I'd imagine an application with a small user footprint will probably go unnoticed. You may want to look into this if you are using Amazon's service.

Pennsylvania State of Champions

2009-07-07T12:32:00.003-04:00

The city of Pittsburgh has reclaimed its reign as the "City of Champions" with the Steelers' Super Bowl XLIII title and Penguins' Stanley Cup victory just months removed from each other. But if you include the defending World Series Champion Philadelphia Phillies, the state of Pennsylvania could probably adopt the moniker "State of Champions."

In an unprecedented event, all three championship trophies - the Stanley Cup, the Lombardi Trophy and the World Series Trophy - were all on hand in Harrisburg Tuesday afternoon to commemorate the outstanding achievements of Pennsylvania's professional sports teams.

The three reigning championship teams brought their respective trophies to Harrisburg for the festivities. The trophies made their way to Governor Ed Rendell's office (photo taken from the Governor's Reception Room). Later, the championship trophies made an appearance at the Capitol Rotunda, which is where important ceremonial events take place.

The event was an opportunity to recognize a very unique situation in which with three current professional championship teams all hail from the same state.

A new template system activated

2009-07-07T11:12:00.002-04:00

After a number of after-the-fact template tweaks being pushed online, the main template here has been upgraded. Nothing too fancy, and that's the point. I have a version that I painstakingly developed over a month at night that is very, very cool and "designy" -- but it failed in it's purpose outside looking cool.

It didn't deliver information in a easily digestible way. It had scripts to place my last 20 twits in a sidebar (not Flash but rather Javascript). Who cares? If you were interested in my tweets, you'd be following me anyway. I printed previous posts, previous comments, a calendar of posts, all with a lot of animation and AJAX goodness.

I removed the sidebar altogether. Most everyone with a blog has one, and they seem to look alike in some respects. Since I am posting some Objective-C code from time to time, the extra width is going to really help since the language and methods are so incredibly verbose.

Because of the extra width, I realize that sometimes that's too wide for the eye to follow when reading a text-heavy post. So I am using CSS3 for columned information... two and three columns. I try to keep the posts short enough to avoid having to scroll up and down in order to read a columned post.

The search still needs tweaked a bit, and the blog doesn't match the rest of the site, but for now it works, it's a lot cleaner, and it's made me rethink what this whole domain is going to evolve into. Enjoy.

WTF: Level of Industry?

2009-07-07T00:41:00.004-04:00

I was tooling around online and was reading up on some UML things when it struck me: whatever happened to Saffron UML? I went to the website and found nothing at the URL I just linked, and the root of the site now some website design service company, website design from A to Z or some such thing. It has a 2009 copyright in the footer, so these are fairly new bits. What gives? What happened? Now I know Saffron is doomed. At least it could have been open-sourced if it's not in another possession... or I should say... if it ever existed it would have been nice to open-source it. Boo.

Kielbasa Mysliwska: Golemo Market in Worcester, MA

2009-07-06T23:50:00.004-04:00

As with many worthy Polish Markets, Golemo offers up various types of kielbasa. As a rule there are about one hundred different kinds of kielbasa, and Golemo has about twelve or so. I can't say exactly how many, but that looks like what they have out on display behind the counters. They do offer fresh kielbasa that has not yet been smoked, you have to ask for that.

As I had my order in hand, I stepped in line at the tail of a smiling ethnic serpentine of patience. Not a word of English was spoken, except if the youngsters behind the counter believed a customer to be non-Polish speaking. I finally made it to the register, handed over my mustard, periogies of various kinds, and asked for three pounds of Kielbasa Mysliwska.

This is known as "Hunter's Sausage" and by it's coloring, it's the closest thing I have found to the stuff I was raised on. We used t get Wardinsky's from Buffalo a bit, and some from Oil City, PA.

This is a smoked, dried, firm and full-bodied sausage made from select cuts of pork and beef with a hint of juniper for flavoring. In addition to its delicious taste, this kielbasa requires no refrigeration. (Drying removes the sausage’s excess moisture – the main reason for spoilage.) As its name suggests, this sausage was eagerly taken into the wilds by hunters, fishermen and other outdoorsmen. The only other things they needed to keep body and soul together was some good Polish rye bread and a nip of jalowcowka (a juniper vodka similar to gin)." (Polana).

You can boil it, bake it, grill it, etc. But I like my perogie fried in a skillet, the same for my kielbasa. I cut it into slices and cook both sides. If you think kielbasa is that Hillshire Farms junk at the grocer, you haven't experienced good kielbasa yet.

Google Book Search Settlement

2009-07-06T17:02:00.001-04:00

I just received some snail mail in regards to a Google Book Search Settlement. Has anyone else received this? What are your plans in regards to it?

iPhoneSimulatorExchange

2009-07-06T16:55:00.002-04:00

There is a new program out for iPhone developers that allows you to create a one-click installer of your iPhone application that allows you to package up your app so it can be run on someone else's Simulator. It's said to help with testing and also for allowance of screencasts for review purposes.

I can see the value for the screencasts certainly, and use for other developers is neat without them having to worry about your frameworks, etc. I do think that it might almost be easy enough to zip up a project file and have another developer just compile the thing you want tested, but I could certainly be wrong about that. Check it out.

This is a test posting of some CSS3 content

2009-07-06T14:17:00.003-04:00

"Heavens! what a virulent attack!" replied the prince, not in the least disconcerted by this reception. He had just entered, wearing an embroidered court uniform, knee breeches, and shoes, and had stars on his breast and a serene expression on his flat face. He spoke in that refined French in which our grandfathers not only spoke but thought, and with the gentle, patronizing intonation natural to a man of importance who had grown old in society and at court. He went up to Anna Pavlovna, kissed her hand, presenting to her his bald, scented, and shining head, and complacently seated himself on the sofa.

"First of all, dear friend, tell me how you are. Set your friend's mind at rest," said he without altering his tone, beneath the politeness and affected sympathy of which indifference and even irony could be discerned.

"Can one be well while suffering morally? Can one be calm in times like these if one has any feeling?" said Anna Pavlovna. "You are staying the whole evening, I hope?"

"And the fete at the English ambassador's? Today is Wednesday. I must put in an appearance there," said the prince. "My daughter is coming for me to take me there."

"I thought today's fete had been canceled. I confess all these festivities and fireworks are becoming wearisome."

"If they had known that you wished it, the entertainment would have been put off," said the prince, who, like a wound-up clock, by force of habit said things he did not even wish to be believed.

"Don't tease! Well, and what has been decided about Novosiltsev's dispatch? You know everything."
"What can one say about it?" replied the prince in a cold, listless tone. "What has been decided? They have decided that Buonaparte has burnt his boats, and I believe that we are ready to burn ours."

Prince Vasili always spoke languidly, like an actor repeating a stale part. Anna Pavlovna Scherer on the contrary, despite her forty years, overflowed with animation and impulsiveness. To be an enthusiast had become her social vocation and, sometimes even when she did not feel like it, she became enthusiastic in order not to disappoint the expectations of those who knew her. The subdued smile which, though it did not suit her faded features, always played round her lips expressed, as in a spoiled child, a continual consciousness of her charming defect, which she neither wished, nor could, nor considered it necessary, to correct.

A Glimpse of Awesome on 128 in Boston

2009-07-01T21:09:00.005-04:00

My wife was in really slow moving traffic on 128 tonight heading up to Winchester, MA. She sent me this picture from her Blackberry. That's right, a little bit of awesomeness all the way from the City of Champions right here. Sweet.

I'll be traveling near there this summer, so I'll be visiting Primanti Bros, Heinz Field to see the Magnificent Six, probably the zoo and of course the new rink being built for the Penguins.

How you target 2.x with the 3.0 SDK...

2009-06-29T21:04:00.002-04:00

If you are using the 3.0 iPhone SDK, you'll notice that by default Xcode only shows you 3.0 as a target (Simulator and device). Before you were able to target all the SDKs you had installed. I personally don't worry about this default behavior, but when you're building an iPhone application, you may want to target previous SDKs.

I read about this online someplace, and this will get 2.x available again.

Select your project file and Get Info.
Under the General tab, you'll see a drop down for Base SDK for All Configurations and choose your SDK there.
You're done. You'll see all the SDKs listed now in the normal drop down you're used to using.

James Last: Russia (1973)

2009-06-29T13:20:00.008-04:00

This one goes back quite a while, and you've probably never heard of James Last. Which is a bit understandable, because the only reason I know of James Last is through my father.

When I was a child (not too much older than the age my own son is right now), my father had a pretty extensive collection of classical LPs and some 8-tracks. He had a large home system with huge BA wooden speakers, tube-powered amplifiers, the best needle in the business, etc.

We used to make fun of his collection of music as being old fogey-type stuff, but we were really just trying to act cool. Some of it was amazing and fun. I've apologized several times in the past about how we used to make fun of this stuff. In many ways, classical and ethnic music is more powerful than any "spirit of the decade" music could dream of being.

My sister and I used to play the 8-track of James Last's Russia. A few of the tracks any way. You'd have to click through spots on the tape and wait for your song to start, I remember four rectangular green lights that would tell you which approximate spot the tape was currently in. I don't remember if you could flip the tape upside down or not, I think so.

Anyway... we used to play song two: "Kalinka" (an example only video link) which slowly builds up with choir to result in ripping horns and a thunderous beat with some Russian chanting (well, perhaps not chanting but we didn't know what they were singing). We used to bounce off the walls laughing and having a good time.

Another favorite was "Russian Folk Dance" (Russischer Volkstanz) - which has a similar pattern to Kalinka. Mad fun.

A few years ago my father gave me that 8-track from his collection in the hopes to transfer it to CD. I never got around to it, I'd have to go to a place with the capability, pay cash, etc. But it always burned there in the back of my mind. For a few years whenever I remembered that album, I'd take a spin around the internet looking for it.

Now that I actually have this album, you might want to look it up, it's extremely hard to find (I don't do torrents or anything like that so I can't help you there), but if you're up for some really awesome ethnic music with true power behind it (I'm not talking about Polkas here, I'm taking about great horns, moving compositions, a big symphony sound with some modern instrumentation, and a great choir) then you should look into it. It's different.

It's not on iTunes, unfortunately. Get the LP if you can (if you can play those anymore).

Perhaps my father, my sister and myself will be the only ones who really enjoy this album and that's fine with me, I just wanted to put it out there. I am going to soak in "Nicht der Wind" (Not the Wind) for the fifth time now. Headphones up.

Ahhh.

CocoaREST rocks -- build the next great Twitter client

2009-06-29T13:08:00.003-04:00

I just looked into sdegutis's CocoaREST library (for Cocoa and Cocoa Touch platforms) - which allows developers to interact with RESTful APIs.

It's mainly targeted at Twitter at the moment, but many more services are under development and you can add extend support for others (ie. extend Twitter support for use with it's Search API). Using it is actually fairly easy... build the next great Twitter client!

Here is a quick screen-shot taken of Tweetie running beneath the included example OS X desktop application:

Check this library out if you're at all interested in using it. It rocks.

Could not support development

2009-06-29T08:57:00.002-04:00

I have no idea why it happens, but I do know that it's an annoying part of developing for the iPhone. For the most part developing for OS 3 on the iPhone is a joy, really it is. But every Monday I come in to work and connect the device, fire up XCode and try to build to it finding out that I need to reboot the device before XCode can deploy to it.

It costs me only a few minutes time, but I wish it was something that would magically go away in the near future. It's monday, my caffeine quotient has not been met, it's rainy in Boston, and perhaps I'm a little gray at the moment.

[iPhone] Getting images from your bundle without hardcoding

2009-06-25T17:38:00.005-04:00

Update 3. Better yet:

totalCount = 0;
NSArray *d = [[NSBundle mainBundle] pathsForResourcesOfType:@"jpg" inDirectory:nil];
 for(NSString *s in d){
  if([[s lastPathComponent] hasPrefix:@"image_"]){
   totalCount++;
  }
 }

Update 2. Since the file structure normally gets flattened out within your iPhone application (I guess there are some compiler tricks you can do), you'll always be targeting the root of the app directory. With that in mind, you'll want to probably use some kind of naming convention to separate any special files you'd like to collect from the bundle. You can also use extension. Say collect up and get the count of all images in your bundle that are JPGs and contain "image_" in the title:

totalCount = 0;
NSArray *d = [[NSBundle mainBundle] pathsForResourcesOfType:@"jpg" inDirectory:nil];
for( int i=0;i<[d count];i++){
  NSString *searchForMe = @"image_";
  NSString *s = [[NSString alloc] initWithString:[d objectAtIndex:i]];
  NSRange range = [s rangeOfString:searchForMe];
  if( range.location != NSNotFound ){
   totalCount++;
  }
 }

Boom.

Update. I'm a moron. I should have just looked into NSBundle.h.

NSUInteger jpegCount = [[[NSBundle mainBundle] pathsForResourcesOfType:@"jpg" inDirectory:subDirName] count];

You can get the number of a type of item in your bundle on the iPhone, and this can come in very handy. No magic numbers. This code example doesn't look in a resource directory, but you could supply the inDirectory with something like @"backgrounds" and thus build up arrays of images of differing types, etc. There may be a better way of doing this (ie. if you only want to get the count of the items), but I don't know about it yet.

NSMutableArray * imageArray = [[NSMutableArray alloc] init];
    NSEnumerator * imageBundlePathEnumerator = [[[NSBundle mainBundle] pathsForResourcesOfType: @"jpg" inDirectory: nil] objectEnumerator];
    NSString * imageBundlePath = nil;

    while (imageBundlePath = [imageBundlePathEnumerator nextObject])
    {
        [imageArray addObject: [[[NSImage alloc] initWithContentsOfFile: imageBundlePath] autorelease]];
    }

    NSLog(@"Number of images loaded : %d", [imageArray count]);

    NSImage * anImage = nil;
    NSEnumerator * imageEnumerator = [imageArray objectEnumerator];

    while (anImage = [imageEnumerator nextObject])
    {
        NSLog(@"image = %@", anImage);
    }

Tada. I hope to find some more examples.

City of Champions

2009-06-12T23:47:00.004-04:00

Pittsburgh is yet again the City of Champions. We win a SuperBowl and a Stanley Cup. For a city to win one championship is special. Amazing win tonight beating Detroit in their own building where they had been so dominant.

Well done. Enjoy Pittsburgh... get to raise that banner in a new barn.

I ordered my gear a few minutes after the players skated around with the cup and it's all already backordered. Oh well, I can wait a little while.

"Lord Stanley, Lord Stanley, gimme the brandy!"

Flashbelt Fiasco

2009-06-12T16:54:00.003-04:00

I didn't attend Flashbelt. I have only read multiple tweets and blog postings about what happened. You can read more about that here.

I personally think that there is no place for this kind of thing at a paid professional conference. If it was held in the corner of a bar with cigars, beers, a laptop & a projector, I wouldn't think it was appropriate either.

There, I said it. Let's just hope this kind of thing never happens again.

Flash rant for the day

2009-06-11T20:43:00.002-04:00

1. I can't wait for Apple to include Safari-specific audio controls. Too many websites activate Flash video audio by default and it's jarring.

2. I can't wait for Safari for Snow Leopard to allow plugins to crash without bringing the browser down with it.

Thread 14 Crashed:
0 com.apple.CoreFoundation 0x914663cb CFReadStreamGetStatus + 43
1 ...romedia.Flash Player.plugin 0x176939d1 0x173b8000 + 2996689
2 ...romedia.Flash Player.plugin 0x1768c43f 0x173b8000 + 2966591
3 ...romedia.Flash Player.plugin 0x1768c713 0x173b8000 + 2967315
4 ...romedia.Flash Player.plugin 0x1768c7c1 0x173b8000 + 2967489
5 ...romedia.Flash Player.plugin 0x1746b727 0x173b8000 + 735015
6 ...romedia.Flash Player.plugin 0x1746bab3 0x173b8000 + 735923
7 ...romedia.Flash Player.plugin 0x1746bf69 0x173b8000 + 737129
8 ...romedia.Flash Player.plugin 0x1746c362 0x173b8000 + 738146
9 ...romedia.Flash Player.plugin 0x1746c68d 0x173b8000 + 738957
10 ...romedia.Flash Player.plugin 0x176935ff 0x173b8000 + 2995711
11 libSystem.B.dylib 0x91fdc155 _pthread_start + 321
12 libSystem.B.dylib 0x91fdc012 thread_start + 34

[ot.steelernews rings]

2009-06-10T08:54:00.002-04:00

The Pittsburgh Steelers got their rings yesterday and then many proceeded to go over to watch the Penguins playoff game versus the Red Wings. These rings are simply enormous, gaudy, and I think are pretty beautiful.

Xcode: Uncaught exceptions with breakpoint!

2009-05-28T09:54:00.003-04:00

While developing for the Mac or the iPhone, you're going to bump heads with the TERMINATING_DUE_TO_UNCAUGHT_EXCEPTION a bit. While this is nominally useful information, you never are told where the exception happened, only the reason that it did. If your application isn't very large in scope, this may be all the information you'll need to debug the problem. However, for larger applications this isn't the best.

One thing I just discovered is that you can have Xcode automagically place a breakpoint where the exception occurs, thus showing you just where the exception was thrown. Paired with the information on why, this is a big help in debugging.

To set this up, open up your Breakpoints window (in my version of Xcode I double-click on the Breakpoints items in the editor window Groups & Files tree control. You'll see a breakpoint item "Double-Click for Symbol" - set the breakpoint to "objc_exception_throw" and you're done. It should look something like this:

Now when you get an exception, you should be able to click the exposed line in the debugger stack trace which will take you to the offending line of code in your project.

Pixel formats in cocos2d v0.7.3+

2009-05-28T08:26:00.002-04:00

[per riq] Since cosos2d v0.7.3, you can specify the texture's pixel format of your PNG/TIFF/BMP/GIF images.
The texture's pixel format is the way the image is stored in GPU memory.

Possible pixel formats:

RGBA8888 (32-bit) (kTexture2DPixelFormat_RGBA8888)
RGBA4444 (16-bit) (kTexture2DPixelFormat_RGBA4444)
RGB5_A1 (16-bit)(kTexture2DPixelFormat_RGB5A1)
RGB565 (16-bit) (kTexture2DPixelFormat_RGB565)

RGBA8888:

8 bits are assigned to the red channel, 8 bits to the green channel, 8 bits to the blue channel and 8 bits to the alpha channel.
Use this pixel format when you need the maximum possible quality for your image.
But it will consume the double of memory compared to 16-bit textures. Memory is a precious resource on the iPhone
Usually it is also slower to render.
Useful for: background image of your intro scene, and for images with lots of gradient colors

RGBA4444:

4 bits are assigned to the red channel, 4 bits to the green channel, 4 bits to the blue channel, and 4 bits to the alpha channel
It gives you good quality in all channels, good speed, good memory consumption.
Useful for: sprites that have different values of transparency

RGB5A1:

5 bits are assigned to the red channel, 5 bits to the green channel, 5 bits to the blue channel, and only 1 bit to the alpha channel
It gives you good quality in RGB channels but poor quality on the A channel. It also gives you good speed and good memory consumption.
Useful for: sprites that have transparent parts, but the transparency is either On or Off

RGB565:

5 bits are assigned to the red channel, 6 bits to the green channel, and 5 bits to the blue channel. It has no alpha channel support
It gives you the best possible quality for 16-bit textures, but without alpha channel support.
Useful for: background images in your game.

The default pixel format in v0.7.3 is RGBA8888.

How to use it:

// Set the pixel format before loading the image
// RGBA 8888 image (32-bit)
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGBA8888];
Sprite *sprite1 = [Sprite spriteWithFile:@"test-rgba1.png"];

// Set the pixel format before loading the image
// RGBA 4444 image (16-bit)
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGBA4444];
Sprite *sprite2 = [Sprite spriteWithFile:@"test-rgba2.png"];

// Set the pixel format before loading the image
// RGB5A1 image (16-bit)
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGB5A1];
Sprite *sprite3 = [Sprite spriteWithFile:@"test-rgba3.png"];

// Set the pixel format before loading the image
// RGB565 image (16-bit)
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGB565];
Sprite *sprite4 = [Sprite spriteWithFile:@"test-rgba4.png"];

// restore the default pixel format
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_Default];