Same image slicing displays very different on 8 and 8 PLUS - ios

Here's the Sample Project
Problem
I want to make an image to have a fixed top half part and a stretched bottom half part which to make it properly resized in any height.
And I use image slicing in Assets.xcassets to achieve that. The image can be resized properly, however, it displays slightly different in different sizes.
The Original Image
Image Slicing
Just simply slice the image from the vertical center.
Storyboard
Content Mode is set to Scale to Fill
Height constraint is equal to its width constraint multiplied by 0.8
Result
I think it should display nearly the same images in different devices. Because everything is the same except for the image assets(2x, 3x).
However, the result is not what I expect. The image seems a bit squashed on iPhone 8 PLUS.
At Last
I'm using Mojave with Xcode 10.1 (10B61).
Anyone knows what is the cause. And how to make the image vertically stretched properly?

The reason it looks "squashed" is because the image is being stretched horizontally.
Your slicing allows the top portion to remain a constant height, but not a constant (or proportional) width.
Here, I use your original image without any slicing... each image view is the same height (201-pts), so you know it's not scaling vertically, but different widths so you can see the result of horizontal stretching:
What you may want to try is clipping your original image to only the top portion. Setup the constraints on that image view to stay proportional, and then use a solid color image view (or just a UIView with matching background color), as the lower "vertical stretch" section.

Related

Framing an image in iOS

I'm working on an app using XCode 6 and I'm trying to frame an image. I have one image that will change dynamically depending on the selection in the prior screen. I have another image behind it that is literally an image of a frame. The idea is to have the actual image look like it is surrounded by the frame itself. Here's the trick. I want the actual image to be a certain width to fill most of the horizontal size of the screen (say 85% if you want a number). I want the image to resize to this width based on the width of the screen (based on iPhone 4 vs iPhone 6, for example; so the width sets based on the screen, and the height sets based on the width to maintain its original aspect ratio). The frame should be about 10 pixels wider and 10 pixels taller, leaving 5 pixels around each edge, and the pictures should be centered at the same point.
I've seen a few programmatic fixes for resizing things based on the original aspect ratio of the image. However, I've been primarily using just Storyboard and was hoping to get an answer along those lines. Thanks so much!
Use auto layout and add constraints to the left and right of the frame to the superview. Then add constraints to the image inside the frame to be 10 pixels on top, bottom, left, and right to the edges of the frame. The left and right constraints of the frame should leave everything centered on the screen. Do you have any experience with Auto Layout? It can be a bit of a difficult learning curve, but for your purposes its a perfect solution.

How to work with Ipad images? Xcode

I am creating an Ipad app and no matter what height I set my ImageView to be it is always too big.
For example I have an ImageView that's about 20 pixels tall and has all of the constraints that I need to keep it where I want it to be. When I play this 20 pixel tall ImageView on the Ipad simulator the ImageView covers about half of the Ipad screen.
How can I work with Ipad images if even a 1x1 pixel image view takes up a signifiant amount of the screen? (Yes, I made the 1x1 image just to see if it would still be insanely large)
Under Auto Layout, if you don't set the size of the image view absolutely, it will size itself to match the size of the image assigned to it. That is probably what is happening to you.

iOS Image Resizing / Dealing With Blank Space

I have simply dragged UIImageView into storyboard and made it square. I added a pink background to show the effects of the leftover space in the ImageView. In each case I added either a taller image (1st image) and a wider image (2nd image), as well as a text label. Here are my results.
So the obvious question is....how can I get rid of this extra (pink) space and keep the integrity of the photo (that is, to not have to stretch or lose part of the image)? If I wanted to be able to scroll through photos, it would be nice to have them all the same width to the edge so they look neat and orderly (if they were portrait), and if I wanted to have text under each, I'd want the text to be closer to it, rather than have all the blank (pink) space in between if it were landscape. And obviously different size images will give different sizes of blank space.
So I'm thinking what I could do is before displaying the image, get the size of it, then just have a designated distance from either the label or the edge of screen, depending on the orientation of the picture, and then creating/changing the size of the UIImageView with a bit of math and using the image dimensions before inserting the picture into the ImageView. Is this possible? Is there another method I can't quite figure out?
Just look at any decent photo app and they are nice and neatly organized/displayed despite being different sizes, orientations, etc and I'm wondering how to pull this off. I obviously haven't gotten too deep into using images past simply showing them in a pre-determined ImageView.
Thanks for the help/suggestions!
Try this... set your UIImageView to AspectFit (not AspectFill since that will lose some of the image) and using constraints do the following:
centre the UIImageView in the container both horizontally and vertically
set the UILabel to float below the UIImageView by whatever distance you desire ("standard" is usually good)
set the left, right, and top constraints on the UIImageView to be >= whatever distance you desire
set the bottom constraint on the UILabel to be (once again) >= whatever distance you desire
The effect of this should be that the UIImageView will properly resize itself to its intrinsic size and the constraints should properly position it and the label.

iOS Aspect Fill Image Resizing with Content Aligned to Left/Top Edge

I am developing a universal app for iOS-7. this particular question is specific to iPad only. I want to place an image as background of root view of a View Controller i.e. the image should fill the whole screen. The 1x image has size:768x1024. This works for Portrait orientations as non-retina resolution of iPad is also 768x1024 in portrait. In Landscape however the image does not fit. I have tried using ScaleToFit but since aspect ratio of image is not preserved I can not use ScaleToFit(their are things in image which look odd when not scaled proportionally in both axis). AspectFill resizing seems most suitable for my need, but their is a small problem. As defined in Apple Documentation "The content is resized to completely fill the bounds rectangle, while still preserving the aspect of the content. The content is centered in the axis it exceeds.". I do not want the content to be centered in axis in which it exceeds, I want it to be aligned to top/left edge.
So basically I want two things:
Aspect Fill
The content remains aligned on the Left/Top edge.
Is it possible to achieve this. Any code-snippet will be great.
Thanks
You will have to subclass the View Controller's view and manually scale and align.
Look at the code snippets in THIS answer.
Adjust imageViewXOrigin and imageViewYOrigin to align however you want.
Really the only way to get around the content fill mode is to have two different images, one for each orientation. I'd suggest changing the image in the view controllers willAnimateToOrientation: method so that you can put the image changes inside UIKit's animation block.

Xcode 5 Image Slicing

I'm trying to slice an image in assets Xcode 5. I don't know if what I'm trying to do is possible with slicing.
The image looks like this:
I need to change the width and the height of the image, although not at the same time. The closest I've got is when I use Horizontal for the height and Vertical for the width. The problem is when I change the width, the left side of the image starts as a straight line and the skews and change to the original shape.
I'm about to give up on the idea of slicing and just create three images, left, center and right. Is that the only way to go?
This is how my current slice looks like:
Is there any way to change it so it works at least for the width?
UPDATE
Instead of slicing the image I used a mask and moved the mask.
Slicing works by taking the center section, and stretching it to fill the required space and then putting on the image end caps.
Because your button has a continuous diagonal line you will not be able to slice it. It will stretch the image out like so:
In fact even if you make a centre section and end caps you will still have the same issue as this image can only be scaled.
If you only need a finite set of heights then you should create individual assets for each height that can be sliced horizontally. If you need N heights then you should look into using core graphics to draw your shape in code in a -drawRect: method for arbitrary dimensions.
P.S. if you want to horizontally slice so you can grow the width its most optimal to have only 1 pixel width of image that will be stretched out so your button image resources would look a bit like this:
Aha. TIL: You can change the slicing options from the attributes inspector in the right hand pane in Xcode. To make your slicing work choose only "Horizontal"

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