I'm using some animated gifs on our mobile-site. It's a clock-animation and since the iOS 5 update it sometimes happens that the clock gets blue instead of red, as planned. Happens on iPhone4 and iPhone5 with the new os.
Any ideas what could cause the problems? It's hard to reconstruct this failure but it happens from time to time.
Any help would be appreciated.
Sometimes ios devices may not be able to process all the images because of its relatively low graphics ability compared to that of a computer. Instead of using a GIF I would suggest using an animated PNG. This has been more popular among the ios devices as using GIFs has become obsolete when working with ios devices. I am not sure how fast this would be, but I would say it can apply less stress then that of a gif. Another idea, because it is a clock gif is to analyze the gif in a program and determine any problems. Also use imgoptim (for mac) or pngcrush for windows to reduce the size of the gif to reduce the stress on the processor.
use GIF 128 Dither and Please make sure that images size has to be base on the resolution it happen some time if your images size is not depend on retina or normal resolutions. And if I am not wrong you facing problem only in retina device, may be below details will help
iPhone Retina Display
~~~~~~~~~~~~~~~~~~~~~~~
Width - 640px
Height - 960px : including 40px status bar
DPI - 326
You can use Cocos2D framework, Cocos2d and UIKIT both work great with out any graphic related errors... Sprite sheets reduces the memory usage and also support all transparant images , you can run animation ,stop and repeat them. Good luck..
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I have a multiplatform iOS/Android game that I programmed in Cocos2d-x. I have only one set of images to use (I'm only after high res devices) that get scaled according to the device's resolution. For example all images are for the iPad but if you are using a Galaxy S then the image locations and scaling are affected by GalaxyS_screenWidth/iPadscreenWidth.
This works fine for all Android devices and on iPad, iPad2 and old iPhones, but with Retina iPhone there is a problem. On the iPhone 4 all my images look extremely pixelated, a result from the images being scaled to iPhone non-retina resolution then scaled back up to fill the screen.
I tried enabling Retina Mode and the images are half of their intended size (maybe due to the usage of get winsize() which uses points) and scaling manually causes other sorts of problems. I tried playing with a lot of options and attributes but to no avail, so what should I do now?
EDIT:
This is not only a graphics issue, as text gets automatically scaled down then up and appears pixelated.
EDIT 2:
Fonts are bitmaps so my bad. But I don't want to use retina as all images are already retina by default. All of my images are set up for the iPad so for iPhone 4 I just scale them down a bit. This works with Android phones.
For example I have an image, depending on screen resolution obtained through getwinsize():
If current resolution width is 1024 then image stays the same.
If current resolution width is 900 then image gets scaled by 900/1024, no problem.
If device is iPhone 4 resolution width is 480, so image gets scaled by 480/1024, then cocos2d-x automatically scales the resulting image by 2 thus the pixelation. I tried using getwinsizeinpixels, I tried multiplying the screen size, I tried many things but nothing worked out of the box unless I am to redo many of my code.
So the question is, how can I just let the damn engine treat the iPhone 4 as an Android phone with resolution of 960x640?
If you want Retina resolution images to look like Retina resolution images, then those images need to be in Retina resolution (960x480).
If you first scale down the image to 480x320 and then upscale it on the device, it will of course look blurred. You can't magically make the Retina pixels appear from a lower resolution image by scaling it up.
SI couldn't get to the bottom of it so I employed a hack. I enabled Retina Display then I scaled everything x2 through code except for the text. Sounds stupid, but it worked, and pixelation is gone. Thanks everyone who spent time trying to help me.
I tried enabling Retina Mode and the images are half of their intended size
when you enable retina support, cocos2d gets images by appending #"-hd" to their provided filenames. Such images are meant to be double the "visual" size (in iOS terms, pixels vs. points), so that they can be sort of scaled down to make full use of device resolution.
If you have a look at the CCDirectorIOS class, you will find there a couple of methods dealing with this, especially those dealing with the scalingFactor. I don't know what kind of changes you should do to make it work, but if you step into those methods and look at the value of various objects, you might find a way to modify cocos2D default behavior for your specific case.
If this seems to complicated, one thing you could try is changing the CC_RETINA_DISPLAY_FILENAME_SUFFIX so that cocos2d will not look for specially-named files for the retina iPhone, but just use the normal ones.
For example all images are for the iPad but if you are using a Galaxy S then the image locations and scaling are affected by GalaxyS_screenWidth/iPadscreenWidth.
Another thing you might try is not using winSize, but winSizeInPixels, so that when you scale down, you down do it down to the point resolution, but just to the pixel resolution (which is double the point resolution).
Hope this helps.
I have an app which display images in full Screen. Some of the images are 1952x3680 pixels and these images are raising memory warning level=1 and level=2.
How should i handle these image?
Scale your images down considerably. There is absolutely no reason you need images at that resolution in an iPhone app.
Don't use them. Either get your server to deliver a thumbnail version of the image (maybe using a thumb.php/jsp/asp/... file with GET params x=<width>&y=<height>), or scale the image down on the iPhone and discard the original data. The former method is vastly preferred as it saves on both bandwidth and large memory allocations client-side.
The largest images you should be working with are 480x320 (iPhone 3GS and earlier) and 960x640 (iPhone 4).
EDIT: The other situation I didn't think of is if you're bundling these images with the app. Please, please don't do that. If you have images that big, scale them down in Apple's Preview or any image editor to the sizes noted, and ideally have two copies, image.png and image#2x.png which are shown depending on the scale of the device's screen.
The screen itself is only 320x460 (not considering the clock bar on top), and 640x960 for retina display. There is no reason to have images this large to begin with. Scale them down. It'll both prevent the memory warnings and stymie unnecessary image size.
As said before, scale it down if you only want to show the image without zooming in fullscreen.
If you need to zoom and show it detailed, google for CATiledLayer. There are good examples around.
I am currently working on an image gallery for iPad. As of now there are about 100 images and the count may increase further. The images I am using are of the resolution 2134x1602 # 300dpi. Now with ~2.5MB, i have lost the smoothness in scrolling the images to next image. Also I want to zoom the image up to 8X. The images I am using are all PNG type.
The app works fine in the simulator but crashes bad on the device. Instruments show no leaks and no bad allocations too. It must be some Internal memory issue for sure since the gdb reports memory warning while running on the device. I would like to tell you that I am lazily loading the images.
Can anyone help me with this issue and the strategy i should use to get rid of the slow loading and scrolling. Also I'll be glad if you let me know how an iPad's GPU processes the images it wants to load. Also i would like to cite that changing DPI didn't work out well.
Eagerly waiting for some help.
Thank You.
Your app is crashing because you are running out of memory.
What you will need to do is scale/tile the images. Have a look at how Google Maps works in a web browser on a normal PC, you will need to do something like this. The screen resolution on the iPad is 1024x768 pixels, so there's no point loading more than that amount of data at any one time. When displaying your image at > 0.5x scale, tile it into sections that are max 1024x1024, pre-scaled. Cache everything to disk. When displaying your image at < 0.5x scale, consider having thumbnails at different resolutions. In between different resolutions, do an alpha blend of two images of different scales: eg for scale 0.75x, do a 50% blend of four tiled scale 0.5x images and one scale 1.0x image.
Images that I add to the layer in Cocos2d look pixelated around the edges of the image (i.e. a hillside, the rounded part of the hill, where the sky and the hill meet). I don't know if it's the image quality, or just because the graphics processor on my 'older' MacBook Pro is not as advanced as the iPhone 4 or iPod Touch 4 or iPad 2. Is it because of that?
I have ran into an instance where a large resolution image was being used in the context of a locally packaged HTML file in a UIWebView. The image looked fine in the simulator, but when ran on a hardware device, a bug was exposed in the rendering engine where it would invert the colors. Here's a bug report as an example of this. The solution was to scale the image down a bit in photo editing application.
While an extreme corner case, this is an example of the simulator not quite living up to how things will work on a hardware device.
The simulator usually does a pretty good job representing what the final image will look like. For the image quality on a normal computer to be worse than that of an iPhone for it to make a large enough difference, your MacBook Pro has to be really bad. So I doubt it.
However, if you really want to make sure, the best way to check would be to transfer the image you are using to another machine to see if it still looks pixelated. If it does, its a problem with your image.
Hope this helps and good luck!
i just have a 3gs for testing (here in romania i still cant get a iphone 4)
When I just create full screen images for iPhone 4 .. would they be displayed resized on the 3gs?
I just cant make a bundle version for 3gs and 4 with 2 times my images, they are already a lot. Do I have to make now 2 Apps ??
Could this be a trick: In my xib i define a 320x480 UIImageView (it will be resized automaticly on the iPhone4) when I there define "scale to fill" and make high resolution images, would they come more sharp on the iPhone 4?
Now I am just wondering how to work best right now for big animations.
thx
Just found out in my case its fine to use higher resolution pics into a 320x480 frame like for 3GS and make Aspect FILL.
When I test on a iPhone 4 Simulator it shows much higher resolution and same on iPad if I click 2x :)
you can also create alternative high resolution images with a name ending in "#2x". so if you have an image called "arrow.png", create one with twice the resolution called "arrow#2x.png" and the iphone 4 will use that.
check out this article: http://thomasmaier.me/2010/06/dealing-with-iphone-4-resolution-2x-inside-of-photoshop/
Try it and find out, but my suspicion is that even if they do work, they won't work on OS 3.0 or OS 3.1, and plenty of people have not upgraded yet.
Also note that even if it displays them at half-size, I'm pretty sure that they'll still be "#2x" images. This means they'll use more memory and generally perform worse.
What's wrong with adding a handful of new images? The normal-size images are a lot smaller than the #2x images.
EDIT: If you have a lot of images, you may find it beneficial to use JPEGs where appropriate (e.g. for photos or photo-like backgrounds). I'm not sure, but I think they should work with +[UIImage imageNamed:] though you might have to specify ".jpg" explicitly.