Please see screen shot of flower setup below. The flower image has been correctly loaded from an asset catalog and when the app is run on various simulators the correct pixel resolution is assigned to each device. My problem is how to get the flower image to be scaled (equally sized to fit) the same on each device ??
I have learnt how to position the image to different positions using constraints and frames but the image never scales correctly - please see first pic
The following image is a mock up of what I want to be able to do (flower image scaled correctly on each device)
Judging by your mockups, it looks like you want the image to fill half the width, and keep its square aspect ratio to determine its height. One way to approach this would be to use AutoLayout to make a left UIImageView and a right placeholder (blank) view. Pin the left view to the left edge of the parent, the right view to the right edge, and then set them to be 0 pixels from each other. Then set an equal widths constraint on them. Finally, control drag the image view to itself and you can select aspect ratio -- and assuming that in IB, the width and height is the same, it will keep it square. Adding an equal heights constraint will give the other view the height it needs to be equal in case you need that.
This gives you a left image view that is 50% and with your mode set to Aspect Fit or Aspect Fill, it should give you the results in your mockups. In case you have an image that isn't square, make sure to check Clip Subviews for your UIImageView to prevent showing the overflow.
The real problem is that your goals are not well defined. Scaled with respect to what? The screen has a height and a width. You can't scale with respect to both, because that would distort the image (because different devices have different overall aspect ratios). Thus you have to pick one dimension that you will scale to.
Judging from your mockup, I'm going to guess that what you want is to scale with respect to height. If so, then give the image view a height constraint that is a fixed fraction of its superview's height. It looks to be about 0.25 in your mockups but you will have to eyeball what you think is a good fraction.
Now, if the content mode of the image view is Aspect Fit (or Aspect Fill), the image will change its height along with the image view without distorting the aspect ratio.
However, it would be best if you would make the other dimension (here, the width) of the image view a fixed fraction of the height, such as to make the aspect ratio of the image view the same as the aspect ratio of the image. The reason is that otherwise the image might end up centered in the image view in such a way that it doesn't touch the top or left any more, even though the image view itself does.
CGFloat screen_width = [[UIScreen mainScreen] bounds].size.width;
your_imageview.frame = CGRectMake(0, 0, screen_width/2, screen_width/2);
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I expect there's a simple answer here. If so, sorry and thanks.
I'm trying to make my launch screen for all the different iPad and iPhone sizes. On the launch storyboard I have two UIViews, one full size for the background (backView) and one in the shape of a square (squareView). I'm trying to keep the square from stretching (i.e. I'm trying to maintain a 1:1 aspect ratio) and make it 0.75 the width of whatever device the app runs on. I know that there will be varying amounts of space below, but how can I keep the square from distorting when I switch devices?
I've been researching the constraints and diddling with them for hours. I expect someone will tell me it's easy, just do ... what?
First, I've centered my rect horizontally and vertically
Then I've set the rect's width to x0.75 of his superview
For the final step I'm setting his ratio to 1:1
That's it! Final result:
I'm trying to build a simple tableview with a tableView showing a list of images people posted and comments their friends added.
This is a subclass of TableViewCell, and I used stack views to lay it out. The problem is that I want to show the photos without stretching them - I want them to keep their original aspect ratio, but people can upload images of any dimensions. You see in the screenshot that the image is squished.
What I noticed is that the larger the uploaded .jpeg file, the taller the cells grew (I'm guessing the image size is dictating the intrinsic height?), but since the width can't change, each image is squished differently. A huge picture will show up super tall but with the same width.
I tried setting the image to Aspect Fit, but only the visible image itself does what I want: fit to width and not warp the aspect ratio. However, the UIImageView itself is still super tall and pushing all other UI elements out of the way.
I must be missing something here... It shouldn't be so hard, should it?
To constraint the image as aspect ratio , first give it width of screen , then give it a static height in IB and hook that constraint as IBOutlet
and set it inside cellForRow
cell.imageHeightcon.constant = imageRealHeight*imageWidthInIB/imageRealWidth
You should fix the size of the image view for whatever you want. Then you should use aspect to fill instead of aspect to fit and select the option clip to bounds in the attribute inspection
How could I use UIImageView with aspectFill and alignment to the top? Auto-layout or programmatically don't mind.
It can be done, but you are talking about quite a bit of coding. Let's start with a detailed description of what you are asking for.
We'll start with an iPhone6s in portrait mode with a screen size of 667x375 points, or a regular height by compressed width in size classes.
(Keep in mind, on any iPad you'll also need to work with slide-over and split screen too.)
But for now we'll go with 667x375. Into that we'll add our imageView as a square size of 375x375. Along the top of the screen when in portrait mode.
(Keep in mind that with AutoLayout you'll also have it pinned, and without putting some code in to determine if it's in landscape or portrait, otherwise, that 375x375 will shrink in landscape if you have other views underneath it.)
So now, stripped out to the most minimum (for now), we are talking about how to pin "an image" to the top of a UIImageView that is 375x375 in size and with a contentMode of aspectFill.
We need to find the size of the image next, based on both the largest dimension (height or width) AND how that dimension compares to the size of the imageView, calculate how the imageView will normally render it. The key figure you want is the height it will render it as
For instance, how will a 480x1020 (HxW) image fit into it? The 1020 width will be taken down to 375, so the height will be 480/(1020375) or 176.4705 points.
Always do the math for both dimensions - if your imageView isn't square or if the height isn't the "bounded" dimension, you'll be off.
Once you've calculated what the "Aspect Filled" height will be, check it against the dimensions of the imageView, and adjust the height of it as needed.
Here's where the real work comes in. If you are using AutoLayout, you can do a heightAnchor adjustment, but depending on how you pinned those other views things may be laid out really bad after you do. If you are using frames and CGRects be aware that you have to take into account iPad slide-out and split screen, etc.
Finally, if you want your app to load a different image in that imageView after it was loaded, you will have to "reset" the height back to what it originally was, at least in your calculations.
My recommendation is to find an alternative to what you are asking. For instance, put a small border around the image view to let the user know the true dimensions of that view.
I place an image view (content size: aspect fit) on my base layout. I create the trailing, leading and bottom constraints and set their constants to 0.
This doesn't happen when the image is smaller than the view:
Though, the image isn't positioned properly on the iPhone - it appears almost centered - while it is on the iPad. Perhaps its intrinsic content size is too big? Why is this happening?
As you haven't set a top, aspect ratio, or height constraint on your image view, iOS falls back to the intrinsic content size (the actual size of the image) for the height only (the width is set by the leading/trailing constraints). If the image is wider than the screen, it will result in an image view that is as tall as the original image, but with the with set to the screen width.
Then, as you have the content mode set to Aspect Fit, iOS places your resized image inside the image view, and leaves lots of blank space around it.
One option to resolve this is to add an aspect ratio contraint on the image view, matching the aspect ratio of the image inside it. This will result in a correct height for the image view.
beyowulf was correct i believe. You should try changing the background color of imageview. If you change the imageview background color, you will realise that imageview always obeys your auto-layout constraint.
Now why not image??
Its because you asked it not to :) aspect fit will try to resize the image still maintaining the aspect ratio :) when the size of the image is too large i.e greater than the size of imageview frame, image covers the full frame of imageview and maintains the aspect ratio as well. Meaning if width is greater than screen width, image will cover the imageview frame width and takes a corresponding height for that width.
Thats why in first case your image covers full imageview frame where as in second where image size is small covers only space required :)
If on the other hand you want image to cover imageview frame always either fall back to scale to fill or aspect fill based on your requirement.
Happy coding :)
I am having trouble figuring out how to set up the constraints on an image view.
I have an imageView of size 155*155. I want the view to remain a square shape but scale up if the iPhone screen size increases to 6 or 6+. I can constrain the distance to the bottom of the container and the sides of the imageView to the sides of the main view. This should stretch the width but is there a way to make the height increase by the same amount? Any pointers would be really appreciated. Thanks
You can use an aspect ratio constraint by ctrl + dragging from your image INTO your image.
This basically tells that you want to maintain the current aspect ratio as your other constraints force a change in the width or in the height.