I'm using an image that fills the screen (like a background) to my app. The image is already in retina dimensions, but I scaled it to fit the simulator screen. Because it's already in retina dimensions, do I still need to add a copy of it with the #2x extension?
It's better to use separate images, normal & normal#2x. if you only use single image, small images will be distorted while bigger image will look squeezed.
don't forget the iphone 5 for background images for example.
3 images are required : Background-568h.png Background.png Background#2x.png
if ([UIScreen mainScreen].bounds.size.height > 480.0f) {
// for the iPhone 5
self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"Background-568h.png"]];
} else {
// for iphone 3.5 inch retina /non retina.
self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"Background.png"]];
}
the naming notation is required for compiler to detect your retina images.if you write image.png the compiler looks for image#2x.png and then image.png and if it can not find it(for retina displays).
So name all your images xxx#2x.png and provide also xxx.png for non retina devices.
On the other hand i would use exact image sizes for non-strechable images in you app.Resizing means extra time and naturally extra computation.On the other hand fractional image resolutions ends up with blurry images.
For iphone 5 images you should for instance include Iphone5BackgorundIamge#2x.png but call Iphone5BackgorundIamge.png in your code.
Iphone dont have to do with image dimension but it uses image name for checking whether it is to be used as ratina or normal image.You have to keep a normal size image with it's name like "image1.png" for normal display and ratina size image as "image1#2x.png" for ratina display.If your used image is already of ratina display then keep it with #2x format and put one half size image with normal name.
Related
I know that 2x images are for retina display.
But i want to know that how can we identify that my device is using 1x image or 2x image?
and one more thing
I have one image name stackOverflow.png of size 50x50 and its 2x with name stackOverflow#2x.png of size 100x98.
My question is that device will select retina image with name or size???
To check which one has been loaded, you can use this code:
UIImage *image = [UIImage imageNamed:#"image"];
NSLog(#"scale: %f", image.scale); //this will be 2.0 for retina image
Or just simply use two different images, as #MidhunMP suggested in comments.
It's usually not hard to tell just by looking at them-- especially in the iOS simulator. Set the simulator to retina mode and take a look. Non-retina images will be visibly blurry compared to retina images.
As for the image size, if your 2x image is not actually 2x the size of the original image, you are doing it wrong. Fix one image or the other, or both. Retina images are selected by name. If the size is wrong, the image will be stretched to fit. That will ruin the high-resolution retina effect you're trying to get with a 2x image.
I have 3 images:
test.png
test#2x.png
test-568#2x.png
In IBOutlet, a UIImageView is set to display test.png.
On iPhone 3.5in without retina, it's displaying test.png
On iPhone 3.5in with retina, it's displaying test#2x.png
But on iPhone 4in with retina, it's displaying test#2x.png!!!
What's going on?
Thanks!
The -568#2x suffix only applies to the Default.png launch images. There is no special suffix used by UIImage imageNamed: (or the other UIImage methods). If you need a special image on the 4" screen, you need to add code to get the desired image yourself.
The following works for the iPhone. For the iPad, you would need additional images.
For the three versions of the background image, use the following names:
background-480h.png (320x480)
background-480h#2x.png (640x960)
background-568h#2x.png (640x1136)
(You don't need a "-568h.png" image because there's no 320x568 iPhone screen.)
When you set the background image, simply append the screen height to the image name:
NSString* imageName = [NSString stringWithFormat: #"background-%ih", (int)[[UIScreen mainScreen] bounds].size.height];
[view setBackgroundColor: [UIColor colorWithPatternImage: [UIImage imageNamed: imageName]]];
iOS automtically appends the "#2x" if applicable.
You could omit the "h" after the height in the image names, but I think it's nice to emulate the iOS convention for the default image.
I know it's an old thread but I was having trouble with the new screen sizes for iPhone 6/6+.
What I did is to use this naming convention for different image files:
none if #1x small old phones
#2x for iPhone 4
-568h#2x for iPhone 5
-667h#2x for iPhone 6
#3x for iPhone 6 Plus
And then to automatically generate (full size) images just by including the code from this Gist in the project:
https://gist.github.com/kevindelord/fe2e691d06ab745fbb00
You have nothing else to do. When you instantiate an image in your code:
[UIImage imageNamed:#"background.png”];
The categorised class from the Gist will automatically create an image corresponding to the current device.
There is a Pod for it UIImage+Autoresize documented on CocoaDocs.
I'm doing a book in which I display text with images in order to get the exact text layout I want.
The problem is that the text is crispy on non-retina display if I use retina images (image with *2 resolution). For the moment, I've added pages for retina and non-retina display but this means my application is bigger.
Is there a way to use only retina ressources and to have a nice text even on non-retina display ?
No, you can't,:( since the non retina display is having less resolution screen compared to retina display thats why the concept of normal image and #2x image was introduced.
If you use UIImage's imageNamed property with your image it will automatically renders respective images wrt the devices,
ex:- if your image name is background.png and for retina display background#2x.png then once you write
backgroundImgView.image = [UIImage imageNamed:#"background"];
it will automatically assigns normal & #2x image to non-retina & retina display.
For testing not/retina display I've created an UIView with size 100x100.
I've create 2 images:
- normal size (100x100)
- retina size (200x200)
I have two situations:
1) Non-Retina display + Normal Size image in background
2) Retina display + Retina Size image in background
The 1st scenario is ok.
In the 2nd scenario the image is double size and in my UIView I can see only 1/4 of the total image.
The same happens when I try to assign a background image to my UIViewController navigation bar as following:
if (IS_RETINA()) {
[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:IMG_NAVIGATION_BAR_BACKGROUND_RETINA] forBarMetrics:UIBarMetricsDefault];
}
else {
[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:IMG_NAVIGATION_BAR_BACKGROUND] forBarMetrics:UIBarMetricsDefault];
}
There's a much easier way to do this. Give the retina version of the image the same name as the non-retina version, except with a "#2x" at the end. For example, if your regular image was named foo.png, then the retina version should be named foo#2x.png.
Then, just refer to the regular version of the filename (e.g., foo.png) at all times. When your app is running on non-retina hardware the regular image will be used, but whenever you're on retina hardware the higher-resolution image will be used automatically. It's easier than having to write an if statement for every image you use, plus it'll actually work.
You don't need to code the IS_RETINA test, just add the #2x suffix to the name of the file containing the image you want to use for the retina display, and iOS will automagically use that in preference.
Bundle 2 image files, prettyNavBarBackground.png and prettyNavBarBackground#2x.png
#define IMG_NAVIGATION_BAR_BACKGROUND prettyNavBarBackground
Then you can just use this single call, and iOS will select the appropriate option
[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:IMG_NAVIGATION_BAR_BACKGROUND] forBarMetrics:UIBarMetricsDefault];
U don't have to write any sought of code to distinguish between retina and normal hardware. U just need to add a "#2x" image . This will work fine as perfect.
U don't have to call these images individually, but just write the filename.
I am showing a high resolution image in iphone 4 and i set the image view frame size as below :
imageFrameNormal.size.width = 470;
imageFrameNormal.size.height = 625;
but it showing full screen instead of this size. so plz can any one suggest how i show image in right size.
i am trying to check it in simulator.
Thx
You have to use the same sizes on retina and normal displays. For example, you have image view with size 100x100. On retina device you should use the same size 100x100 (no changes in your code). However you'd better use high-res image (2x size). For this you need to name it properly:
image.png - normal size image
image#2x.png - 2x size image.
When you call
UIImage* img = [UIImage imageNamed: #"image.png"];
image.png would be used on normal display and image#2x.png on retina (iOS does it automatically).
The retina display's coordinate system is not in pixels, but in "points". The iPhone display, whether retina or legacy will always be 320x480 points. When interacting with any parameters such as the frame, size, origin, etc., you will need to remember to use points instead of pixels. The OS will handle the "conversion" between points and pixels for you.
For a much more detailed explanation, see Points vs. Pixels in the Drawing and Printing Guide for iOS.