I'm currently using a UIImageView with an array of images to create a small looping animation sequence with about 20 images in there (at 320x480). Whilst this works okay for 20 - 30 images, any more and the app quits on the iphone. There is nothing else in my test app at the moment so I know it's just down to the animationImages sequence.
Has anyone come across any samples of doing this type of thing through Core Animation to achieve better performance and allow many more images? From what I've read it sounds like its possible to set up a ton of CALayers and put an image in each, and then create the animation by manipulating the layers on and off in sequence. Is this a good way to do it?
Or, alternatively, as I'm basically after the effect of a looping movie, is there a way to use the moviecontroller to achieve the effect without it fading in and out at the start and at the end?
I'd be grateful for any pointers. Many thanks.
This could be a simple memory issue. 20 images (320x480) is about 3 MB of memory, assuming 8bpp (if they're higher color, obviously even more). You might try loading and unloading as needed (though, of course, that'll mean rolling your own animation, rather than using UIImageView).
Sounds like a simple memory issue.
You could load one or two frames at a time, or actually play a movie instead.
Related
I am trying to create an animation using a UIImageView with an array if images. It works great, except that I need a different delay between some of the frames. In an animated gif you can set the delay between frames. Every example I see of an animated UIImageView has a fixed delay between images.
Does anyone know how I can set a different delay between frames? Or, is there an example of such?
Maybe UIImageView is not the right thing to use, so if anyone has an alternative please let me know.
I have posted a similiar question in other forums and no one seems to be able to answer this. It seems like it should bo doable, since .gif images have had this forever.
Thanks
It may seem hacky, but:
From UIImageView documentation:
animationImages
An array of UIImage objects to use for an animation.
#property(nonatomic, copy) NSArray *animationImages
Discussion
The array must contain UIImage objects. You may use the same
image object more than once in the array. Setting this property to
a value other than nil hides the image represented by the image
property. The value of this property is nil by default.
So you need to add your UIImage several times to the array for a delay.
UIImageView does not support a different delay between different images. You will have to use multiple UIImageViews and manage the transition between them manually if you want to have different delays between frames.
Another approach would be to use a UIWebView which is sized exactly to fit a .gif image that has the delay settings you want.
You have to use different UIImageView to get this working. Try this application page. Might be helpful for you. Link: http://www.raywenderlich.com/2454/how-to-use-uiview-animation-tutorial
If you would like to try my animation library in your iOS app, it offers a complete solution to this problem. For example, you could take a look at the APNG app, it is a free app in the iTunes store that displays animated APNG files. This app was created using my AVAnimator library which contains APNG and GIF decoding support. The APNG format works just like a GIF in the sense that each frame can have a delay time, you would use existing software to create the APNG in this case. But, it is easier to just encode a new .mvid file (this is a custom video file format) from a series of PNG imags. To create a longer delay, you simply repeat frames that do not change in the input PNG image series. Either approach could be used to create an input movie that could display with a variable amount of time in between specific frames (the overall FPS would be the same, but specific frames can simply repeat so that they do not change for say N frames in a row). You can also implement specific user interactions like starting an animation, pausing on a specific frame, and then starting again from that same frame.
I'm working on an iPhone App where I rely heavily on timers and animations, but I've realized my game is really slowing down and lagging on certain aspects of the game. I'm not quite sure how to improve this without removing any animations or anything.
Essentially what I'm using is the accelerometer to update my character's position (Left/Right). I also use several timers to read from different URLs, update images and the one that lags the most is one that loops an image to move from left to right.
Basically I'm using about 6 or 7 timers and the Accelerometer, is there a way I can improve the performance of my game without having to remove any of my animations or changing the interval of the timers?
Thanks in advance!
Try use Allocation
RUN-> RUN WITH PERFORMANCE TOOLS->Allocation
to see which part is overload in the application
Instead of using NSTimer to animate, you might want to look at using the animationImages property in UIImageView (which lets you show multiple frames of animation, possibly looping) or beginAnimations within UIView (which lets you move an object along a path, among other things).
A good place to start is with this question on recommend reading for iPhone animation, although for reference the documentation in XCode and Apple's programming guides are good sources by themselves.
What others have suggested - in terms of using a game loop - make sense, too, but depending on the complexity of your game, sometimes just letting the iOS SDK take care of your animations for you can be good enough.
thanks for all your advice I took out of this forum over the last weeks.
Now I've a problem where I would need your help:
I want to show a series of short animations (5 animations, 10 sec each) on the iPhone. The animation would loop but the code will decide if the current loop is repeated or another loop will be started (Laughing face, shouting face, crying face etc.).
I am a little concerned that if I would design this animation with single images to be played the size of the app would explode. So video came to my mind. On the other hand we need to overlay the animation with changing images, so video could be a kind of hassle.
Any ideas about the best way to go?
Thanx for all your advice.
Tom
For 5 animations of 10 seconds each, i would suggest using single images. And you can use UIImageView's inbuilt animation with repeat count. It will be very easy to code.
Only make sure not to use [UIImage imageNamed:#""] while creating image arrays as you might have many images. This method creates an autorelease object and you wouldn't want many such objects hanging around in your app.
Specs: about 320 x 270 px, 5 seconds. I don't know exactly how many images needed for a fluid animation, but let's assume 30.
What would be the best way to playback this? As a movie file in some kind of quicktime view (if available), or as an animated image sequence with UIImageView? I'm not sure but I believe loading 30 images per second is nearby impossible on the ipod touch. Any idea?
In general, a movie will have applied some compression and possibly even used a lossy compression. This means the processor would need to work harder but it has a lot less memory to read. The CPU is a fast resource. Compared to the CPU, memory is slow. Thus a compressed movie would (logically) have the better performance.
In practice, it could depend on a lot of factors, although movies do tend to be better optimized for animations. With a slow CPU and extremely fast memory, a multi-image animation might just be faster. Also, it depends on how you store those many images. But in 99% of all situations, movies will have better performance.
Well, I guess it depends.... if it supposed to be static, than a movie is the most appropriate way... it's hardware accelerated, and easy to write the code for using it. If you plan to modify the animation, and reuse it, you could load and modify images, or load a bunch of them in succession, but I imagine it's quite coding overkill for the task.
Why would you not want to use a video file? If you don't have very specific reasons, I would recommend just using the standard video playback functions provided by Apple.
This gives you several advantages:
Even if your proposed method would run fluidly, it certainly wouldn't be as well optimised for the graphics chip and therefore use up more battery
It's very easy to implement, whereas your idea would be rather complicated, and you'd spend a lot of time on a probably less important part of your app.
It's won't introduce any new bugs and is most likely a lot better tested than your custom solution.
Check out this to get started:
http://developer.apple.com/iphone/library/navigation/index.html?section=Topics&topic=Audio%20%26amp%3B%20Video
My app is doing some pretty but heavy weight core animations during scrolling. Sometimes it crashes due to bad performance. So I need some way to find out if there is enough capability to make the animations, and if not, I just leave them away. Best way would be if I could ask the system how busy it is.
UPDATE: I mean especially Core Animation.
By animation, do you mean frames that play after one another (like an animated GIF) or some CoreAnimation (OpenGL) effect that is moving polygons with mapped textures around?
If it's the former, I'd really consider some way of optimizing the animation or eliminating it in all cases.
If it's the latter, I'd do some deeper digging into the source of the problem. Core Animation under normal circumstances will drop frames in order to keep from getting into situations like this in the first place.
In either case case you might consider loading the texture assets a little earlier. I have had some trouble in my apps with animation methods that take a UIImage parameter when I created the UIImage in the function call. Preloading the asset a little earlier in my code took care of the problem nicely.
As an example:
BAD
[[UIImage imageNamed:#"checkmark.png"] drawAtPoint:p];
BETTER
//declared at top of class
static UIImage *checkmark = nil;
in init:
checkmark = [UIImage imageNamed:#"checkmark.png"];
in drawRect:
[checkmark drawAtPoint:p];
You would need to adapt this technique to your particular situation. In my case, checkmark is used often, and it quite small, I don't mind dedicating the memory to it permanently.
I wonder if your crashes could be fixed by making sure the assets were ready to be used by the application.
I wouldn't do that. If your app crashes, it's to heavy. You could run your app with some instruments to see where your bottlenecks are.
So, without trying to sound too harsh, your best way is to rewrite some parts in order to make you app run on an iPhone at all times.