I'm a beginner with XCode and I've encountered an issue. When I build my application, it looks fine in the standard iPhone simulator, but when I change the hardware to a retina device, the UI elements of my application become pixelated. How can I fix this?
You're seeing that because the retina screen is stretching the image you're supplying across more points on the screen. You can supply hi-res images in your bundle by appending #2x to the filename
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIImage_Class/Reference/Reference.html: "If you load an image from a file whose name includes the #2x modifier, the scale is set to 2.0. You can also specify an explicit scale factor when initializing an image from a Core Graphics image. All other images are assumed to have a scale factor of 1.0. "
Here's a guide to supporting high-resolution screens.
As #RobotWoods mentioned, all images in your app need to have #2x versions.
If you're using OpenGL ES, custom code that creates images, or core animation, you need to make sure your code accounts for the display's scale.
If you're using only standard UIKit elements like UIButton, UILabel, UITableView, etc. then all you need to do is provide the #2x images.
If that doesn't help, please post screenshots and relevant code of what looks blurry.
Related
If i want my application to be compatible with the Retina display, am i obliged to recreate all my images by doubling their sizes? even the icon?
if you will not use high resolution images your images will look pixelated/blurr.So better to use high res images as well.Some Key points are:
Displaying graphics depending on the device model can be done by duplicating image files and adding an ‘#2x’ suffix. So, when the normal image file is named ‘button.png’, the hi-res version should be ‘button#2x.png’.
You don’t need any additional code for this. In Interface Builder or your code, assign the normal version (without the suffix) to an object. The same goes for the application icon. The resolution of the 2x icon should be 114 by 114 pixels. You will need to add a separate ‘Icon’ property in the Info.plist file for this icon.
If for some reason you do want to perform a check in your code, you can do so by checking the scale factor of the display. Older models will return a scale factor of 1.0, while the iPhone 4 will return 2.0. You can check this with:
float factor = [UIScreen mainScreen].scale;
Depending on the type of application you’re developing further optimizations can be made to utilize the new retina display the best you can.
A very good information here
hope it help you :)
You're not obligated, it just will look very pixelated if you don't.
As for the icon, I believe you are obligated to provide multiple sizes when submitting to the AppStore.
Maybe you'll want to take a look at iRetiner.
You could also check this previous stackoverflow thread : how to set image for ipad application that support retina display
A summary of the icons and what is required can be found in the human interface guidelines. I highly recommend providing high resolution artwork for the retina display even though it is not required. Your default now should be to design artwork at the higher resolution, then scale down for older devices. I doubt Apple would choose to highlight an application as new and noteworthy if it looks pixelated on the latest devices.
I have an iPhone Xcode project that currently only contains images for retina display (twice the size as normal and with a #2x.png suffix). When I run the app on the iPhone Simulator (non retina) the images are still being displayed. Does this mean I don't need to worry about including two sets of images: retina and non-retina?
This all seems a bit odd. I would assume that no images would appear on a non retina device if there are no non-#2x files included.
Note: I have not tested my app on a non retina device. Just the simulator.
I'm pretty sure that iOS will just use the #2x and scale it down if you don't have a non-retina graphic. Although that's sub-optimal since you're letting iOS do the scaling at runtime which will be slower than including the non-retina graphic and also iOS might not do as good a job as scaling as your graphics editor of choice.
Even if it works, it's not good practice, and if you have a media heavy app definitely it would impact performance and battery life and memory foot print and ....
By the way, is it just that you don't have the 1x graphics available to you or you are concerned about your apps (download size) or ...
If you are assigning the images in Interface Builder, and you set the image property on a UIImageView to image#2x.png, for example, iOS will not know that it's a high resolution "2x" image. In fact, on a retina display, iOS will look for an image named image#2x#2x.png. Since it won't find it, it will set the scale factor of the image to 1.0.
The contentMode property (just "mode" in XCode) will decide if any scaling of the image occurs to fit the constraints of the UIImageView. You may wish to set the mode to "Aspect Fit" to get the high resolution image to scale as needed for both retina and non-retina displays. In general, the image will display as seen in Interface Builder.
If you are using UIImage's imageNamed or similar function to load the image, and just specify image (where "image.png" doesn't exist, but "image#2x.png" does), then iOS will actually find the image on a non-retina display, though the scale factor will be 1.0. As previously, you'll need to scale it to fit your view. The image will work normally on a retina device, and the scale factor will be set to 2.0, since iOS looks for a "2x" image first, and it doesn't matter if the other file exists or not.
This is from Apple's documentation on imageNamed:
On a device running iOS 4 or later, the behavior is identical if the
device’s screen has a scale of 1.0. If the screen has a scale of 2.0,
this method first searches for an image file with the same filename
with an #2x suffix appended to it. For example, if the file’s name is
button, it first searches for button#2x. If it finds a 2x, it loads
that image and sets the scale property of the returned UIImage object
to 2.0. Otherwise, it loads the unmodified filename and sets the scale
property to 1.0. See iOS App Programming Guide for more information on
supporting images with different scale factors.
If at all possible, you really should include both retina and non-retina images. Using higher-resolution images than necessary negatively affects memory and performance.
I have a few questions about screen resolution, that I'm not clear on. These questions assume they my app will be running on iOS 4.0 and up, and on either iPhone 3GS or iPhone 4.
Should the size of the splash image (default.png) be (960x640) or (480x320)?
Should the size of the app icon (Icon.png) be (57x57) or (114x114)?
What about other graphics that I may use in my app, such a graphic that represents a button? Should I always create these images for the higher resolution, and have the app scale them down? In other words, if I want a button image to be displayed on the 3GS that is 200x40 - should I create the image at 400x80, so that iPhone 4 can take advantage of it?
Thanks!
A good guide to this can be found here: http://mobile.tutsplus.com/tutorials/iphone/preparing-your-iphone-app-for-higher-resolutions/
In general you just create 2 sets of images. Your original and then a new one twice as big with #2x in the name. So for image.png at size 32x32 you would have one that is twice the resolution called image#2x.png at size 64x64. In your app just always use the image.png in Interface Builder and when loading in code.
There is no need to detect the device. These images will automatically be picked up by the OS and subbed in as necessary.
Provide both sizes (960x640 & 480x320) for the splash image using the #2x method described above
Provide both icons (57x57 & 114x114) using the #2x method
For our apps we use a combination of the #2x images and just Scaling the large images. (More information on this can be found in the above article) We use the #2x images for bar buttons, icons, etc. But for UIImageViews we often just use the Scaling. There can be a performance hit for doing this, but for most apps I'd say this is negligible. The savings in file size sometimes make scaling the only option.
Related Questions:
Retina/non-retina images in UIImageView
Making an app Retina Display friendly
You need to provide both if you want them to look nice. For example,
Default.png -> (480x320)
Amd
Default#2x.png -> (960x640)
I'm developing my software, all the ui is drawn based on 480x320 size screen, can my software run on iphone4 without any modification?
Yes it can run with no modification.
If you'd like to create "retina" assets you can create all of your images at the double resolution and include copies with '#2x' appended to the filename in your Application bundle. The iPhone will automatically load the correct images.
Example:
existing image - myImage.png
new up-sampled image - myImage#2x.png
Yes, but any images sized for the earlier iPhone models will look chunky compared to custom-designed iPhone 4 images.
Both the iPhone 4 and older devices are 320x480 points in size, which is the coordinate system that Core Graphics and UIKit uses. So your software will run the same.
Only the automatic scaling between your bitmaps and the display will be different. If you have bitmapped content or images, you can optionally provide #2x sized versions that will look somewhat smoother without the 2X scaling on iPhone 4 devices. This is nice, but optional.
I am trying to add art to my game for the iPhone4 resolution. The images i am using are twice the original and i have added the #2x suffix to the image names.
When i load in a sprite like this:
[CCSprite spritewithFile:#"example.png"];
where example.png is the original image and example#2x.png is the scaled up version. When running on the original iPhone it loads the low res image and when running on the iPHone4 it loads the high res image, but it doubles the size of the image. So the high res image appears the same on the iPhone4 as on the original iPhone. Each pixel on the image takes up 4 pixels on the screen.
Any idea why this might be happening? Is there something I am supposed to do to tell the app not to double the size of the art?
Are you using the latest version of cocos2d?
The entire cocos2d API was converted
to Points. Previous versions were
using Pixels.
If your using v0.99.4:
cocos2d v0.99.4 has RetinaDisplay
support, however it required you to
use two different sets of positions
depending on the device , since the
API was in Pixels. (more)
If your using >= v0.99.5-rc0
But in v0.99.5-rc0 (and newer) the only thing that you have to do is[...] (more)
Have you read the "Retina Display in cocos2d" section of the cocos2d for iPhone wiki? (It pretty much tells you all you need to know.)