I followed the PaintCode tutorials on StyleKit and I've successfully exported icons into a Swift project (code only - MyStyleKit.swift file). I'm trying to understand the relationship between the UIImage generated in code and the image sizes expected for different iOS devices.
I wired up the MyStyleKit object in the storyboards to the image for the Tab bar icon. Works great but I can't tell if the resolution of the image is adjusting depending on the device. Apple's HIG suggests the tab bar icon size in pixels should be
75 x 75 px for #3x images (iphone6+)
50 x 50 px for #2x retina image
25 x 25 px for non-retina
Firstly what canvas size should I be choosing in PaintCode initially? I guessed at putting the canvas size as 25 x 25, reasoning that I should map to the UI points size.
When I rig up the icon in Storyboards does it automatically adjust to whether it needs #3x, #2x or #1x?
Should I be setting the canvas size to the UI points size?
Any help would be greatly appreciated.
Yes, set the canvas size to 25×25 points. You can then preview the canvas at #1x, #2x or #3x (or infinite) scale.
When you ask the StyleKit for image of this canvas, the returned UIImage will have the size of 25×25 points, but scale of the current screen. That means 25×25, 50×50 or 75×75 pixels.
Related
I'm having a hard time putting all the information on image sizes for #1x, #2x, and #3x together. I've been using the scene editor in XCode with the scene size being 1334x750 (pixel dimensions of the screen of the iPhone 6). So when I size an image for a sprite in that scene, is that the size I should use for the #2x?
From what I've read in the documentation CGSize uses points, not pixels, so if I have an image that is CGSize(width: 50, height: 50), is this independent of my scene size in the scene editor?
Bottom line question: How does the CGSize dimensions translate to how I export my images for #1x, #2x, and #3x in pixels and what should the PPI be when I export?
Xcode can handle vector images, so you can forget about #2X and #3X images if you are able to export your images as PDF e.g. in Sketches export panel one of the options for export format is PDF, so create your artwork #1X and export as PDF, then in Xcode when you add the image to Assets.xcassets, you can set the images Scales attribute to Single Scale. Xcode will generate the required #2X and #3X images from your vector PDF at build time.
The concept is simple. The size in Storyboard or Interface Builder should be the size of you asset in #1x format.
The retina display ( or the iPhone 6+ #3x size ) does not mean than you have much space than before, it means that you can draw 2 ( or 3 ) pixels where you draw 1 before.
So for a 50x50 px Image View, cou should have 3 assets :
- Image#1x.png ( 50x50 px)
- Image#2x.png ( 100x100 px)
- Image#3x.png ( 150x150 px)
Suppose you have created an image in your assets library consisting of 3 sets of same image, #1x.png having size 50x50 pixels, #2x.png of size 100x100 pixels and #3x.png size 150x150 pixels.
you don't needs to worry about which one to use in your storyboard(because storyboard automatically using #1x.png), and which one to use for the targeted device like as iPhone6, or iphone7, or iPad(because by default programing all hardware finds out their pixels relative required image among those #1x.png, #2x.png and #3x.png)
for further instructions you needs to study Auto layout Programing Guide
you can also view their apple's tutorial videos regarding Auto layout.
mysteries of auto layout part1
mysteries of auto layout part2
#1x and #2x used to relate to the retina graphics change when iPhone 4 came out.
iPhone 3GS was 320x480, iPhone 4 was 640x960. This meant that the points per inch were literally the same, but the ppi was doubled, hence the #2x. When the iPhone 5 came out, the only thing that changed was the height, so the ppi was the same for the width, no problems here.
Then we hit the 6 and 6+. At this point, apple said screw it, try to keep ppi that correlate to previous iPhones without having keep the previous iphones usable area, or provide bigger screen pixels for bigger devices. Now #2x has lost its original meaning
But, to really throw us off, they made the iPhone SE, which went back to the ppi screen size of the iPhone 5, so #2x makes sense again.
Basically, when thinking of the #2x graphics, think about the 1st iPhone resolution size.
Now, you have a choice to make. You can give your apps more/less usable area, you can black box the extra usable area, or you can scale and take some kind of quality loss due to game pixels not being 1:1 with the screen pixels anymore.
I've got a problem here and it's easy to explain:
I'm using image assets for a new project being built in Swift 2.0 and Xcode 7.1.
I have a bunch of buttons with images set. The buttons are much larger than the images and so they center (as expected) just fine on any #1x or #2x screens.
However, as soon as I build to the 6+ with its #3x resolution, the button instead uses the dimensions larger than the #1x image and the image in the center of the button becomes larger.
So I have an image that's 20x20, 40x40 (for #2x), and 60x60 (#3x).
If I build to an iPhone 6, the image dimensions are indeed 20x20 and the #2x image is used for the double resolution. But if I build to the 6+, the image dimensions are made larger. I don't know exactly how much larger but it's larger than 20x20. This is only happening with UIButton.
Any help is appreciated.
Turns out it was because I was rendering the images at 4x instead of 3x.
I need a few icons for my navigation and tab bars on Xcode 6, so I downloaded a few icons from:
https://icons8.com/web-app/new-icons/all
Yet once I download them and open the file, every size seems pixelated and not as clear cut and sharp as it looks on the actual website.
Why is that? What would be a method to download it just as how it looks and resize it to use it for iOS mobile application? Any insight or help would be appreciated.
Try placing them in the 2x or 3x size in your .xcassets
The 1x size is equal to the amount points on your screen (not pixels). The iPhone 3GS has 320 points in the width so the amount pixels are also 320. The iPhone 4 which has a Retina display also has 320 points, but the actual pixels are 640. So retina needs 2x and the image file needs to be 2 times larger than you expect them in points on your screen. Same for 3x.
I usually work with vectors, you can use them in Xcode as .pdf file, you can scale them as you like without getting blurried images.
The designers on a project I am responsible for developing (one of my first iOS projects) designed the app using a Photoshop canvas set at 1242x2208 pixels, which is the number of pixels that the iPhone 6+ uses. I've scoured the internet and am just getting more and more confused by all the conversions for 1x, 2x, 3x and to further the confusion, apple downsizes to 1080x1920.
Anyways, how do I cut the assets correctly for #1x, #2x, #3x? When I crop the element I want, I save it out at 3x. But what do I divide by to get the 2x and 1x versions?
Here's secondary question and a hypothetical situation: There is a button that is designed to be the full width of the screen in portrait, so the designer made it 1242x100. If I save it out at 3x, then scale it down for 2 and 1x, will this button fit all the different screen sizes all the way down to iPhone 4/4s, which has a smaller pixel dimension and different aspect ratio?
Confused, any help appreciated!
Example:
If you original artwork is 960px by 1704px, just save you image including "#3x"
image#3x.png // (960 x 1704)
Then you have to resize it to 640x1136 and save including "2x"
image#2x.png // (640x1136)
And then you have to resize it to 320x568 and save as 1x
image.png // (320x568)
Indeed the Retina sizes are confusing, but this is what auto resize is used for in Xcode.
But The API which Apple give us, chooses the #3, #2 and 1 sizes by itself. There isn't anything that the developer/designer needs to do but provide all three images. An example is:
ObjC:
+ (NSImage *)imageNamed:(NSString *)name]
Swift:
init?(named name: String) -> NSImage
Would just use the name of the image without the # etc... So, myImageName#3x.png myImageName#2x.png myImageName.png would just be referred to as "myImageName"
The API handles the rest :)
I have had the same problem. What I did was, after cutting all images for iPhone 6+(#3x), I just resized the PSD to iPhone 5's width which is 640px, (height would be 1138 px if you keep aspect ratio) and cut #2x images. For the 1x images, again resized to 320px width.
Just, iPhone 6+, iPhone 6 and iPhone 5 have almost same aspect ratio.
Good Luck!
I need to implement some photo uploading function, but I'm a little bit confused because of the pixel/size dimension of the images. I need to display a square cropped image which size in IB is 320 x 320.
I've made a little research, but couldn't find an exact answer. I've checked Instagram, and it uses 640 x 640 pixel images everywhere. How is that possible? The iPhone 6 Plus's screen resolution is bigger then the Full Hd, the width of the screen is 1136 px while an Instagram image is 640 px wide (and doesn't pixelated) . I don't think that they save images for every devices separately.
So UIImageView can display non-retina images on retina screens like this? Or what's the reason why the 640 px is enough?
UIImageView can scale the image you pass to it. So if you were to pass a 640x640 pixel image into a UIImageView that was displayed larger on screen, it would be scaled to fit appropriately. It would scale up and you would lose quality when displayed that way.
As for the IB size being 320x320 points, that doesn't directly translate to pixels. Older devices worked that way, but newer (retina) devices scaled at 2x (including the iPhone 6). So a 320x320 pt UIImageView in IB would actually render at 640x640 pixels. The 6 Plus renders at 3x, so 960x960 pixels.
I'm not sure how you concluded that Instagram was using 640x640 on all devices, but if that is the case, the 6 Plus is scaling images to 960x960 pixels and losing quality. It's possible that the loss isn't noticeable in most cases, but I would guess they request larger images for the larger screen.
http://www.paintcodeapp.com/news/ultimate-guide-to-iphone-resolutions