I'm making a spritekit game. I understand how to size my images in an SKScene because it's 750x1334 points across all devices, but the main page of the app uses UIKit/a collection view controller, so I'm not sure how to size my images. I want to have the images take up 1/3 of the screen width and then have the image height equal the image width.
iPhone SE is 320x568 points
iPhone 7 is 375x667 points
iPad Pro 10.5 inch is 1112x834 points
Do I just make images that are 1/3 of the largest possible device width (1112 points) and then let smaller devices scale the images down? i.e. 1112 points divided by 3 is 370 points, so make images that are 370 points wide and high (740.6px#2x and 1112px#3x)?
I want to have the images take up 1/3 of the screen width and then have the image height equal the image width. Do I just make images that are 1/3 of the largest possible device width (1112 points) and then let smaller devices scale the images down?
No. When you "let smaller devices scale the images down", you are still loading the full-sized image and thus wasting memory. Plus, letting the runtime scale the image down automatically (e.g. because you use an image view with an aspect fit or aspect fill content mode) wastes time and processing power, often at a critical moment when the app is trying to launch.
The correct procedure is:
In your app bundle, you should include just one size for the image, possibly in three resolutions, and this should be the smallest size that is acceptable on the largest screen you'll be showing on.
In your code, you should figure out the size at which the image will actually be displayed for the screen of the device we are running on, and load a thumbnail of the image sized down to that size.
In this way, no memory is wasted; the image held in memory is the image as displayed.
In Storyboard, you can use the below steps,
Put equal width and equal height between image view and your actual view
Select the equal width constraint and change the multiplier from 1 to 1:3
Select the equal height constraint and change the multiplier from 1 to 1:3
The image view should occupy 1:3 of your screen size now.
Screenshots are attached for iPhone and iPad designs,
Hope it helps.
I have a question about using images for universal apps on IOS.
I've created a universal app that works on all iphone devices and ipads. I've placed all the content via storyboard. On a View I have two buttons one on the top space area that is 40 points high and as wide as the view, one on the bottom area also 40 points high and as wide as the view and an image that is a square (A x A) in the middle of the view, the image is constrained by horizontal and vertical (For it to stay always aligned in the middle of the view).
(I understand that if I use an image that is 100 points by 100 points image at 1x, I need to create two other images at 200 points by 200 points for 2x and 300 by 300 for 3x.)
1) So if I constrain the UIImage container by height and width equal to 100 by 100, it will be 100 by 100 points in all devices. But I want it to use as much space as possible. That would mean that on iphone 5 - 6s+ it would always be 100 by 100, it would look smaller on every growing screen. It would also mean that I would need to make it bigger for Ipad (Storyboard changing to regular regular to change UIImage container size for ipad, ex. increase it to 300 x 300). Put once I make it bigger, the image I have will be to small for that size therefore turn blurry or pixelated.
Right?
2) If I would like to be able to use as much space as possible I thought of using the following method. Constraining the UIImage to be equal width as the view but reducing its multiplier to 0.9 or 0.8 (Therefore making it smaller then the view width) and placing an aspect ratio of 1:1(To maintain it square). That way taking advantage of most of the view space that is free, and In all the devices it would always seem filling the same space. However the problem would be that the image would have to be different sizes. (Ex. iphone 5 = 150 x 150, on iphone 6 = 250 x 250, on iphone 6+ = 320 x 320 ans on ipad 600 x 600).
so If I make an image that in 2x that is 150 x 150, when its used on the iphone 6 it would be distorted or pixelated and the same for for the rest.
So can someone help me understand what I should do? or link a tutorial?
Please help!!
I've found that the best way to solve this problem would be to make a much larger image and let the constraints resize it. That way, you've covered your bases if new resolutions are developed, or with the current varying sizes. A much larger image would not look bad if it was compressed into a smaller space, but you might lose some details.
I have a simple view with a text and an Image. I ran this app on iPhone6Plus and iPhone5. Then I made a screenshot of both and enlarged the iPhone5 screenshot such that it matches the size of the screenshot from iPhone6Plus. Here is the result:
As you can se the size of the text the size of the image and there positions are not identical but they should be to look the same on different screen sized.
Here is an example of a weather app running on different screens:
As you can see the sizes and the positions of text and image are identical.
The image is loaded from asset catalog:
imageView.image = UIImage(named: "shower3")
self.view.addSubView(imageView)
imageView.center = self.view.center
I have only created a 128x128 image and put it into the #1x version in the asset cataloge.
Let me rephrase this. I run the wether app on iPhone5 make ascreenshot and iPhone6 make a screenshot. Then I resize both screenshots to the same size. Then I see that both fontsize as well as images dimension are exactly equal on both screenshots. This means that on each device font and image must have different dimensions. How can I do that?
How can I achieve that text and image have identical proportions on different screen sizes? How does the Weather App do it?
Images
I am the creator and one of the developers of the Swift Weather app. The app doesn't use three versions of images because I didn't make those images and it was a Pull Request from another developer. I don't have the origin images.
As #Daniil Korotin mentioned, iOS uses points to calculate image and font sizes. iOS uses let screenScale = UIScreen.mainScreen().scale to retrieve the screen scale and pick up the proper size (1x, 2x or 3x) of the image. If we don't provide the proper size of the image, for example, in SwiftWeather app, we have only 1x version of the image (as the screenshot below), iOS will upscale the image to render on retina devices. On iPhone 6 Plus, it actually does downsampling for 3x assets. Please have a look at iPhone 6 Screens Demystified. In some case, if you don't provide 2x or 3x images, on retina devices, the image upscaled from 1x may looks blurry. We should always provide 1x, 2x and 3x images if possible.
Fonts
iOS renders fonts according to the specified points. It will automatically convert the points to certain pixel based on the devices' screen scale (as mentioned above).
How can I achieve that text and image have identical proportions on different screen sizes? How does the Weather App do it?
The answer is Auto Layout
You can see we set constraints for the image view (used for the weather icon) as below.
The width and height are always 150 points, please notice it is points nor pixels. It will render the same size (for look and feel, not for exactly pixels) for different devices. For your first image (iPhone 6 Plus vs. iPhone 5), it looks different because maybe your simulators have different scale. A better way to check how auto layout elements lay on the screen is to use Preview in Interface Builder.
Open the main storyboard, and click on Assistant Editor. On the right hand side, select Preview (on the top left). And click the plus sign ( on the bottom left) to add different devices. You can see they are identical proportions on different screen sizes.
If you have any questions, please let me know.
Something maybe off topic
If I design the images/assets, I would like to use some vector base tool like Sketch to design the assets and export them to three different sizes. Please have a look my another project iOSAnimationSample. It has a Sketch file for the design.
Sketch design
Export assets to different sizes
In that case, iOS can pick up the proper assets for different devices.
The app you are referring to does not correctly support multiple screen sizes. The interface is scaled up to run on the 6 and 6 plus, which is why everything appears the same size.
Look at the screenshots from your app - the status bar is much smaller on the 6 plus. This is because it is supposed to take up less room on the screen. It's 20 points high on all devices.
Now look at the screenshot from the weather app - the status bars are the same size. Because the weather app does not support multiple screen sizes, iOS simply takes the smaller interface and scales it up to fill the screen.
If you want to achieve the same effect (which you shouldn't) then remove the LaunchScreen.xib file and use a launch image instead. But people don't buy larger phoned screens because they want to have the same content, but bigger. That would be achieved more cheaply by simply holding the phone closer to one's face.
You're supposed to take advantage of larger displays by allowing more content to be shown at once on the screen - more rows of data in a table, more text from a book, more images from a photo library.
In the case of a weather app the extra space should be used to display more rows of an hourly forecast or something, not just a larger version of a fairly useless icon depicting the type of weather.
I suspect it is only game support that means supporting larger screens properly is not already a requirement for app store submission. Supporting the 4 inch screen became mandatory quite quickly, you should expect a similar rule to be introduced for the 6 and 6 plus before too long.
If you want a specific element to always take up 50% of the width of the screen, or a label to always be the same size as an image, then you use autolayout constraints with multipliers. An autolayout constraint is of the basic structure:
attribute of A = (attribute of B * multiplier) + constant
Most of the time the multiplier is left as one, so you're just saying that this is 20 points to the left of that, or whatever, but you can use the multiplier as well, and say that A is the width of B, multiplied by 2 or 0.5 or whatever you like.
iOS uses points to calculate image and font sizes. On non-retina screen 1 point equals 1 pixel, on retina screens — 2 pixels, and for iPhone 6 Plus it is equal to 3 pixels (some downscaling is applied, though). If you want to scale the image and font based on the actual pixel size of the screen, you can get the number of pixel per point like this:
CGFloat screenScale = [[UIScreen mainScreen] scale];
The iPhone 5, 6 and 6 Plus screen aspect ratios are the same, while resolutions differ. If you want to simply keep proportions, then you have to pick a 'base' screen width or height (say, the iPhone 5 screen width, which is 320.0 points) and then calculate the proportion by dividing the actual device screen width (say, iPhone 6 Plus screen width, which is 414.0 points) by that 'base' width (414.0 / 320.0 = 1.29375). You can get the screen size like this:
CGRect screenBounds = [[UIScreen mainScreen] bounds];
Dividing screenBounds's width by base width gives you the proportion. Then you just multiply all the sizes and margins with that proportion (1.29375 in our case for iPhone 6 Plus). Hope you get the idea.
P.S. A good guide to resolutions is here.
P.P.S. And in your case, as skorolkov mentioned below, the app just upscales everything for bigger screens (add/remove splash screens to enable/disable this upscaling).
UPD: Ok, now I see what confuses you. Here's the thing: when Apple initially released iPhone 6 and 6 Plus many apps didn't support their larger screens and bigger resolutions. So they decided that if an app lacks splash screens specifically made for those phones, it should use the iPhone 5 resolution.
That's why you get the exact same pictures after manually resizing screenshots: the system does that too. It simply takes iPhone 5 'picture' and stretches it so that it fits larger screens. The drawback is clear (and visible, especially on iPhone 6 Plus): the fonts and images are blurry and upscaled (system interface elements, like status bar, get upscaled too). So basically you get the iPhone 5 picture on all larger-screened devices (you can check that by taking a screenshot on an iPhone 5, resizing it manually to fit iPhone 6/6 Plus resolution and comparing the actual iPhone 6/6 Plus screenshot to it).
To be clear: that's the behavior you currently get, but it's not good. To keep everything properly scaled using the devices' native resolution, use the method I described above (manual multiplication) or autolayouts with equal height/width set to desired ratios for interface elements.
Weather App is using upscale mode to run on iPhone 6+. You can enable it by removing launch screens for 6/6+.
Go to asset catalog, select your launch image and unset 'iOS 8 or Later' checkbox in Attributes Inspector.
Screenshot - your app has this set
Screenshot from WeatherApp
in programatically (X and Y) we pre define the values in constant :
#define XScale [[UIScreen mainScreen] bounds].size.width / 320.0f
#define YScale [[UIScreen mainScreen] bounds].size.height / 568.0f
Then create UIImageView programatically
var imageView : UIImageView
imageView = UIImageView(frame:CGRectMake(XScale *someValue, YScale * someValue, XScale *someValue, YScale *someValue));
imageView.image = UIImage(named:"image.jpg")
self.view.addSubview(imageView)
based on your screen size we need to set Constant values. We use for iPhone5 and 4s screen.
You need to set Layout constraint to all the views to make them look at same places and sizes in all screens sizes provided that the aspect ratio of screens are same.
Have you tried to remove autoResizingfunctionality from view?
Click on inner arrow to remove autoResize view as per superview
First turn off auto layout, auto resizing and size classes in storyboard.
Click on Images.xcassets icon and select all your graphics. In attribute inspector set Devices property to "Device Specific" and set the checkbox checked against "iPhone" and "Retina 4-inch"
Place all your graphics in 2x image set. You may place a higher resolution image set for better results with iPhone 6/6+.
Design your view for a reference device say iPhone 5 (320x568 portrait).
In your viewDidLoad method paste the following code
self.view.transform=CGAffineTransformScale(CGAffineTransformIdentity,self.view.frame.size.width/320, self.view.frame.size.height/568);
And you will have same result on iPhone 5/5s, iPhone 6/6+.
The photo taken using the UIImagePickerController is of 4:3 aspect ratio. However, the full screen aspect ratio is 3:2. So the gallery app is doing some magic to show the photo as 3:2 aspect ratio. When you zoom out in the full screen view, the photo appears in 4:3 aspect ratio. Can anyone shed light on how it could be done? I've been breaking my head for the past two weeks on this.
Really appreciate the help!!
To fit a 4:3 image into a 3:2 space you can either match the height or match the width.
If you were to match the height then you'd turn the 3 in 4:3 into the 2 in 3:2. So you'd scale the entire image by 2/3. Since you'd be scaling width and height by the same amount, the effective height after scaling would be the 4 from 4:3 scaled by 2/3, to give 8/3 — a bit less than three. You'd therefore not quite fill the screen.
Conversely, if you were to match the width then you'd turn the 4 in 4:3 into the 3 in 3:2. So you'd scale the entire image by 3/4. Since you'd be scaling width and height by the same amount, the effective height at the end would be the 3 from 4:3 scaled by 3/4, to give 9/4 — a bit more than two. You'll therefore slightly more than fill the screen.
So that the photos app does is display pictures with an initial zoom so as to fit the width of the stored image to the width of the display. If the stored image is 3264x2448 (which I think it is on the iPhone 4S and the 5) then on an iPhone 4s — using points rather than pixels — it's scaled by a ratio of 480/3264. If you work that out, it gives the image a final height of very close to 360pt, 40pt wider than the screen.
In terms of UIKit, that probably means putting a UIImage inside a UIScrollView and setting the initial value of zoomScale to 480/3264 (ie, approximately 0.15). The scroll view can help you with zooming in and out though there's still some manual work to be done — see e.g. this tutorial. By setting a minimumZoomScale of 320/2448 (ie, approximately 0.13) you'll automatically get the behaviour where zooming out as far as you can go ends up showing the entire 4:3 image on screen.
not sure how you obtain your image, but you might have gotten one of the representations of the image. One of those representations is specifically for getting a quick fullScreen CGImage, an other will return the FullResolution. FullScreen will be whatever is needed for the device (640x960 on iPhone4), Full resolution would be the 8MP picture.