Does anyone know how Apple does this? Here's the problem I have. I have some images that are very high-res. When I create a button and set the background image to one of these images the resolution is crystal clear.
Then if I take that same image and using (and believe I've tried a lot of suggestions) and I reduce the dimensions the image always come out blurry. And the images are all 354 x 354 that I"m downsizing to 40x40.
So if you know what method Apple uses to get crystal clear smaller versions or thumbnails please let me know.
Thanks!
All the iOS devices right now have retina screens. That means that your 40 x 40 image is actually an 80 x 80 image (or even different with the new iPhone 6(+)). When you size the button, the dimensions are in points but when you resize using Photoshop, you're going all the way down to 40 x 40.
Related
In my iPhone app, I have a control that takes on quite different sizes on different screens. For example, (in the iOS point coordinates)
3.5 inch devices (iPhone 4S): 242x295
4 inch devices (iPhone 5 series, SE): 242x383
4.7 inch devices (iPhone 6 series): 297x482
5.5 inch devices (iPhone 6 Plus series): 336x551
As you can see, these control sizes are not proportional.
The problem
This control has an image as its background. That particular image is important for brand identity and the custom appearance that my company's designer wants to go with. The image gives the appearance of a material and has a texture. It also has shadows within itself. I would like to apply this image on to controls of different screen sizes (my control sizes are determined at runtime according to available space, as Apple may come up with new screen sizes anytime).
My current solution
The designer makes separate PNGs for me for each screen size and I hard code it with onto my control using an if-else for screen size (after determining the size mathematically before hand). As you can probably tell, this is a horrible approach for robustness. I'm also looking to expand to iPad and having a better scaling system will certainly help.
An idea
I take an image that's the smallest unit of the repeating texture and apply it to my control with the scaling option that repeats it throughout to obtain a final image.
HOWEVER, I lose my shadows and rounded edges this way. (I tried simply using the largest image as well and the disproportionate scaling makes the rounded edges horrible)
I tried looking for solutions and most resources do not deal with such images. I simply cannot lose any part of this image and it should be fully applied to the control, shadows and corners included.
I apologize if any or all of this is naive or if I didn't look for answers using the correct words. This is my first time posting here at Stack Overflow, and I'm looking forward to hearing from you guys.
Thanks!
p
Edit:
This is applied to a custom UIButton based control to give the appearance of a card.
Edit 2: Wain seems to have suggested a perfect answer. I will try it and let everyone know the results.
I'd use tiling as you describe, and I'd combine that with changing the view layer corner radius and applying a shadow offset. In this way you can separate the important part of the image and make it nicely reusable and you can leverage the capability of CALayer.
Note that when you set the shadowOffset of the layer you should also look at the shadowColor, shadowRadius and shadowOpacity.
You can used Assets.xcassets for managing images in ios. you can make image in 1x,2x and 3x scale.
For example you want an icon of size 50x50 pixel then 1x should be 50x50,
2x should be 100x100 and 3x should be 150x150. then ios automatically take appropriate image from this set.
Hope this will help :)
The aspect ration of iPhone 5, iPhone 6 and iPhone 6P are almost same. however the aspect ration of iPhone 4 is different.
Here is the steps which helps you.
So you need one image which image is suitable for iPhone 5 and its
#2x, and #3x image and iPhone 4 and its #2x image,
i.e if you have image with 242x383 for iPhone 5 then you need images
with its #2x, and #3x images. and you need image which is compatible
with iPhone 4 size.
You need to set UIImageView's contentMode as aspectFit.
So the idea is, make iPhone 5's image and its #2x, #3x images and iPhone 4's image differently. or you can put all things in UIScrollView and for iPhone 4 set contentSize of scrollView is 568. and make different image for iPad.
Taking help from here, I know that the resolution of iPhone 6 is 1334x750 and the density or the pixels per inch is 326 ppi. So, would I be adding an image with those measures to make it appear as is or maybe even the sharpest it could on the iPhone 5?
Some cases:
What happens if I add an image with a resolution of 1334x750 but with a density of , say, 100?
What happens if I add an image with a density of 326 ppi but with a resolution of , let's say, 1900x1500?
I have picked these values at random. I know the quality of the image would be affected a lot in these cases but I'm just curious how is the image being processed to be viewed on the phone.
Thanks in advance.
P.S. Feel free to edit the tags, I just added what I felt was appropriate.
The apple guides haven't helped me too much with this but I am starting to get serious about IOS development and was taken aback when I saw images go from #1x to #3x.
One source I found said they were based on sizes. For example:
If you are working on an inferred VC size and your image is 30x30 and you run that on a iPhone6 then your image should be 30x30 for #3x, 20x20 for #2x, and 10x10 for #1x.
Another source I said mentioned that it was based off the images resolution and not the size of the image.
Could someone clear this up for me and explain how to make sure my images look professional for all screens?
Thanks in advance!
When the first iPhone (and SDK) came out, all images were 1x (1 pixel of the image = 1 pixel of the screen), because that's all we had to care about. On that phone there were 166 horizontal or vertical pixels per inch (dpi). So to display an image that stretched from the left edge to the right edge, our image would need to be 320 wide (because that's what Apple told us - we didn't have to count pixels) by whatever height we wanted. Let's say 100 pixels tall. We'd name that image MyPhoto.png (because Apple told us the iPhone OS worked best with PNG images) and we'd display it.
When the iPhone 4 came out with the retina display, its retina display had 2 times the horizontal and 2 times the vertical resolution of the older phones. So now we needed higher resolution images to get the best looking interface. We were still displaying just a 2" wide image, but it would need twice the number of horizontal pixels and twice the number of vertical pixels (4 times the total number of pixels) to fill the same space. So now our image needs to be 640 pixels by 200 pixels. Since our app would still need to support the older phones as well as the new phones, we didn't want to just replace the old image with the new one. We needed a way to support both. So the old images kept the same name they had before (we didn't append "#1x") and the new images got the "#2x" filename extension to indicate they were twice the resolution. So we'd name this larger image MyPhoto#2x.png.
A common question is why not use just the higher resolution images on both old and new phones? With scaling, both appear to work great. The problem primarily is that the iPhone, especially the older phones, had very limited memory to work with. Using images that are 4 times larger than they need to be is really hard on that limited memory. That's why we had to have both 1x and 2x images in our apps.
For our sanity, we would still just use 1x while designing the interfaces. So screens remained 320 pixels wide in our code, even if we were going to display them on a retina display that was 640 pixels wide. If we wanted to draw a 1 pixel wide line on the retinal display, we'd make it half a pixel wide in our code.
With the larger screen of the iPhone 6 Plus, Apple had to pack even more pixels on the screen to maintain the high resolution customers came to expect. So now we're into 3x images. However, the iPhone 6 Plus doesn't really have three times the number of horizontal or vertical pixels. But again Apple has kept us sane by just asking us to supply "#3x" images, and it worries about scaling them down a bit on the device. As before, we still need to support smaller screen resolutions too, so we still include "#2x" and the 1x images in our apps.
So, to continue our example, the #3x image would need to be three times the width and height of the 1x image. So now we need a 960 wide by 300 pixel tall image. We'd name it MyPhoto#3x.png.
Notice that although I mentioned earlier something about a 166 dpi display, that's not really important when creating these images. In your photo editing app you don't really care if the image is 166 or 72 dpi or anything else. The only important part is the number of pixels in width and height of the final image we export.
So to answer your question (hopefully), you'll want to include all three of these images in your iPhone compatible apps. You can skip the #3x image for iPad-only apps, because there's no 3x screen yet for the iPad. But continue to think only in the 1x size when working in Interface Builder and code.
For example, now to display a 1 pixel wide line on the iPhone 6 Plus, you'd draw a 0.33 wide line rather than a 1 point line. Of course, you still want to support all of the other screen resolutions too, so you'd use code like this to set your line width:
let lineWidth = 1.0 / UIScreen.mainScreen().scale
This will give you 1.0 for the non-retinal iPhones, 0.5 for the iPhone 4, 5 & 6, and 0.33 for the iPhone 6 Plus.
We are currently working with a design who is supplying Retina images to us with odd dimensions i.e. 28 x 15 px which I believe is incorrect as when you divide it you get an odd number like 14 x 7.5 px.
This is a rule I have always worked on but the designer is not getting the point and I thought I should double check what the exact rules are.
I've had add look on the web but cannot seem to find any references on this so it would be great to hear what everyone thinks on this matter.
Thanks
Yes you can, but NOT recommend.
For example, if you have an #2x image with 28 x 15px , your normal image will be 14 x 8px.
If you look close into the normal image, the pixels are not aligned well.
It is always recommended to use even number of pixel in dimension.
The #2x image needs to be exactly twice the width and twice the height of the standard image, or the automatic loading of it won't happen - your app will load and pixel-double the non-Retina image.
The standard image file will as a matter of course be a whole number of pixels wide and high, so you'll need the #2x to be even in its dimensions.
Tell your designer to catch on ;)
It's not possible because in Xcode you design your application with classic resolution pictures, and you can't use a float for width or height. So, you will have a one pixel gap difference between your classic and retina design. Maybe the easiest way to solve your problem is to add a transparent line of pixels in your high resolution picture.
My current resolution of all the pictures (all of png format) in my app is 300, which I realized is too high,
I heard that 72 ppi will be enough, but however I just wanna make the best vision effect of these pictures,
so what is the best resolution of pictures for IOS app? both Retina and former screens.
And one more question, I tried to save my pictures in photoShop to 72 ppi,
but after I drag that picture to my XCode project, XCode tells that the resolution is 71 pixels/inch,
would it be a problem?
THanks a lot!
The answers to your questions can be found here.
But in short, 72 dpi is what you want. Retina screen imagery is termed 'High Definition' but is simply twice the size as non Retina imagery, i.e. your app icon is nominally 57x57 pixels but your retina variant of the same icon is 114x114 pixels (both images being 72dpi).
Re: your photoshop query. I have no idea about photoshop itself but in this instance I can't imagine why an image less than 72dpi would cause too great an issue. Photoshop gurus will be able to tell you why this is happening.