This library automatically generates UIImage objects fitting the current device's orientation, size and scale. Working on iPhones and iPads on portrait and landscape modes, it will add, if needed, a suffix to the given image filename in order to find and display the correct asset.
The suffixes are described as requirements.
With Xcode, at the moment, it is pretty hard to use the xcassets logic to deal with image backgrounds for all your devices supporting all interface orientation. You could maybe achieve such thing with Size Class and the customized assets (if so please, contact me).
But the easiest solution so far, is still to link one picture to one interface-oriented-screen-size.
This library is here for you!
UIImage+Autoresize is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod "UIImage+Autoresize"
And finally import the header file:
#import "UIImage+Autoresize.h"
This pod is also documented on CocoaDocs
Through the categorised class UIImage+Autoresize, a naming convention is applied to deal with different image files.
The following suffixes are expected:
| Vertical | Horizontal | Devices |
|---|---|---|
| none | -l | 3GS and earlier |
| @2x | -l@2x | iPhone 4, 4S |
| -568h@2x | -320h-l@2x | iPhone 5, 5C, 5S |
| -667h@2x | -375h-l@2x | iPhone 6 |
| @3x | -l@3x | iPhone 6 Plus |
| -512h | -384h-l | iPad Mini, iPad 2, iPad 1 |
| -1024h@2x | -768h-l@2x | iPad Mini 3, iPad Mini 2, iPad Air, iPad Air 2 |
When this class is integrated into your project, you have nothing else to do. You can instantiate an image in your code as you used to like this:
[UIImage imageNamed: @"background.png" ];
The code will automatically load an image corresponding to the current device.
You do NOT need to specify any custom file extension. If you do, the library will ignore its own methods and only load the file you are asking for.
When dealing with multiple interface orientations, an application might need different backgrounds. One for the portrait mode and another one for the landscape.
With UIImage+Autoresize and its naming convention you could even use the same asset name in the code.
The displayed picture will simply change by implementing the folloying methods in your view controller:
On iOS 8:
- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
[super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
self.imageView.image = [UIImage imageNamed:@"bg.png" withTransitionSize:size];
}
On iOS 7:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
[super didRotateFromInterfaceOrientation:fromInterfaceOrientation];
self.imageView.image = [UIImage imageNamed:@"bg.png" ];
}
If you are implementing a multi interface orientations app, it would be good to do the first initialization of your UIImageView in the viewWillAppear. This way, you should have less problems when the orientation change while a child view controller is presented. When the user pops back, the previous background will look as it should.
The library works with Swift as smooth as it does in Obj-C. Nothing to worry about :)
To run the example project, clone the repo, and open the UIImage+Autoresize.xcodeproj file.
- Make it work with Storyboard
Dennis Rieth for the assets, dennis@ieth.de
kevindelord, delord.kevin@gmail.com
UIImage+Autoresize is available under the MIT license. See the LICENSE file for more info.