For a universal app to support iphones and ipads, there are several resolutions, retina or non-retina screen, portrait and landscape orientation, so that there would be many *.png, this will hugely increase the final size of app bundle size.
Is there any good advice for reduce image sizes?
You can try Imageoptim, which can optimize also png and jpeg images.
Also, you can use a .jpg as a splash.
Just remember to change the UILaunchImageFile = "splash.jpg" setting in the info.plist file.
I'm using it in my latest app. A 700K png is only a 180k jpg.
The best way is to use pngcrush. You can use it to try all possible encoding methods and get the smallest files possible.
Related
I have designed a lock icon in Sketch to add to a button in my application:
I exported it both in pdf and png (2x, 3x) to add to Xcode assets. Problem is when I run the app on iPhone (SE), heavy pixelation can be seen around the edges of the icon:
I've tried both pdf and png formats, but result stays the same. Am I missing any settings that need to be applied for image to look sharp on screen?
Bigger is not necessarily better for a UIButton's image. Try to export your icon in more or less the same size with which it will be used. (Note that this also frees up memory in comparison to a way bigger image).
To adapt to different screens' resolutions, you should provide up to three images (#1x, #2x, #3x). You should read this excellent Apple's documentation on Image Size and Resolution. It explains perfectly how big should the images you provide in Xcode be.
They also have a good explanation on which format you should use according to the purpose of the image.
EDIT:
You can also use vector ressources (.pdf files for instance) that will render perfectly for any resolution. You can read this article about how to implement it in your Xcode project (If you do so, please be careful in the attributes of the asset to check Preserve Vector Data and the Scales to Single Scale, otherwise it may not render well).
It will happen if image sizes are not correct
check the size of images. 1x,2x and 3x sizes are should be as followed
1x = 24x24 px
2x = 48x48 px
3x = 72x72 px
If images size are too big than ImageView then pixelate will happen
Hope this will help you
Can someone tell me which iOS devices use which image sizes (1x,2x,3x)? and when creating an image would it be best to make it small and upscale it or make it bigger and downscale it?
If you are supporting iOS8+ iPhones 1x images are not required any more, but still required only for iPad2.
For scalable images, i think that you should use bigger image and downscale it.
Ok, I have a universal app, which means it has to have an iPhone non-retina launch image, retina image, and iPhone 5+ size retina image. It also has to have non-retina iPad launch for portrait and landscape, retina for portrait and landscape, and then alternate versions as well with slight changes to dimensions. For example, on iPad I have to have a 768 x 1024 and a 768 x 1004. With 8 images required just for the iPad launch image, the file size of my app is huge, as each iPad launch image is between 1.5MB and 5MB. Any suggestions for how I can keep the size down, since it is only high due to large launch images?
Here is what I mean by all the images required for iPad. 8 images???
What you can do to reduce the size greatly is provide jpeg images instead of png. Yeah, I know, Apple asks for png, but you can submit an app with jpg images (I did this for my iPad app).
Use Preview to open the images. save them as JPEGs with a really low quality - or experiment with the quality setting. You will be amazed at how nice a really compressed JPG image can look.
Oh, your launch time might increase by a few milliseconds due to Apple translating the jpg to png during launch.
My experience was submitting when iOS5 was out, so its possible that not using PNG will be a blocker with iOS7. However, I even have a solution if that is needed. Do as I suggest - save the images as highly compressed jpg images first. Then convert THOSE images to pngs - the jpg compression done first should make it easier for png to compress the those images, reducing the size.
There are several PNG "crushers" - programs to reduce PNG size - that work great. Just make sure that you unselect the option to have Xcode "reduce the PNG sizes" - since it actually increases their size!
I'm releasing a new update for one of my apps and I was disappointed to see that it just barely surpasses 20MB estimated size (20MB is the point where it can no longer be downloaded over cell data).
My app contains a lot of images, so I could greatly reduce the size if I didn't have all those non-retina images. I know that there are some non-retina devices that will be running my app. So here are my questions:
How will a non-retina device react if I have an image with the #2x suffix but no non-retina image without it.
If I use a retina sized image without the #2x suffix and scale it down to the size I want to display it at programmatically and/or
through interface builder, will it still maintain full quality on
retina devices? Will the quality be worse on a non-retina device
than using an image I downscaled from the original using GIMP
instead?
How will a non-retina device react if I have an image with the #2x suffix but no non-retina i
image without it.
I use that approach on a couple of apps of mine and it works flawlessly. I am not able to detect any performance or visual issues on non-retina display devices (concretely, iPad 1/2 and mini).
I am not sure what can happen on older iOS version, since I only support iOS5+ on those apps.
If I use a retina sized image without the #2x suffix and scale it down to the size I want to display it at programmatically and/or through interface builder, will it still maintain full quality on retina devices? Will the quality be worse on a non-retina device than using an image I downscaled from the original using GIMP instead?
This comes down to how you set interpolation options while doing the scaling. See this other question for more details on how interpolation quality affects scaling down an image. In GIMP or Photoshop you also have control on the interpolation to be used for scaling, btw.
But in the end I don't think you need to go this way.
Most importantly, that bandwidth limit has been raised to 50MB.
OK.
If you only provide one image then you have one of two possibilities.
The image is a non-retina image. This will look fine on the non-retina. It will look identical on a retina device. But will look low quality next to a retina image.
The image is a retina image. On the retina device it will still load as a retina image. It will look fine. However, on the non-retina device it will have to scale down the image. This takes extra cycles of the CPU so could affect performance and it may not look how you want. It may shrink the image using a different method than you want and so may make the image look odd.
This is the same with or without a suffix.
The best solution is to create retina images and then use your editor of choice to create the standard versions. Nothing will stop you only providing one image but it may lead to a look and performance that you don't want.
On a side note. The size for downloading over cellular data was increased to 50MB.
Try these things using the simulator and find out for yourself.
I think the answer is that UIImage will ignore the #2x choice if you're relying on [UIImage imageNamed:#"without2xSuffix.png"] and not find anything, but I haven't tried it. Deliberately requesting the #2x file will work, but whether the image will be scaled, tiled, stretched or centered (or something else) is up to the place where it's used.
Note that the documentation says that unless you use the name without the #2x suffix and let iOS find the 2x version for you, it will set the scale of the image to 1.0 rather than 2.0, which complicates drawing. You'd have to load the image using imageWithData:scale: to fix this.
I am developing a cocos2d game. I need to make it universal. Problem is that I want to use minimun amount of images to keep the universal binary as small as possible. Is there any possibility that I can use same images I am using for iphone, retina and iPad somehow? If yes, how can I do that? What image size and quality should it be? Any suggestion?
Thanks and Best regards
As for suggestions: provide HD resolution images for Retina devices and iPad, provide SD resolution images for non-Retina devices. Don't think about an all-in-one solution - there isn't one that's acceptable.
Don't upscale SD images to HD resolution on Retina devices or iPad. It won't look any better.
Don't downscale HD images for non-Retina devices. Your textures will still use 4x the memory on devices that have half or even a quarter of the memory available. In addition, downscaling images is bad for performance because it has to be done by the CPU on older devices. While you could downscale the image and save the downscaled texture, it adds a lot more complexity to your code and will increase the loading time.
There's not a single right answer to this question. One way to do it is to create images that are larger than you need and then scale them down. If the images don't have a lot of fine detail, that should work pretty well. As an example, this is the reason that you submit a 512x512 pixel image of your app icon along with your app to the App Store. Apple never displays the image at that size, but uses it to create a variety of smaller sizes for display in the App Store.
Another approach is to use vector images, which you can draw perfectly at any size that you need. Unfortunately, the only vector format that I can think of that's supported in iOS is PDF.