UIImageView aspect fit and center - ios

Question

I have an image view, declared programmatically, and I am setting its image, also programmatically.
However, I find myself unable to set the image to both fit the aspect and align centre to the image view.
In other words, I want the image to:
Scale down to fit the aspect, if the image is large.
Centre but not scale up, if the image is small.
How do I get that?

Answer 1

Just pasting the solution:
Just like #manohar said
imageView.contentMode = UIViewContentModeCenter;
if (imageView.bounds.size.width > ((UIImage*)imagesArray[i]).size.width && imageView.bounds.size.height > ((UIImage*)imagesArray[i]).size.height) {
imageView.contentMode = UIViewContentModeScaleAspectFit;
}
solved my problem

Answer 2

In swift language we can set content mode of UIImage view like following as:
let newImgThumb = UIImageView(frame: CGRect(x: 10, y: 10, width: 100, height: 100))
newImgThumb.contentMode = .scaleAspectFit

Answer 3

Swift
yourImageView.contentMode = .center
You can use the following options to position your image:
scaleToFill
scaleAspectFit // contents scaled to fit with fixed
aspect. remainder is transparent
redraw // redraw on bounds change (calls -setNeedsDisplay)
center // contents remain same size. positioned adjusted.
top
bottom
left
right
topLeft
topRight
bottomLeft
bottomRight

Answer 4

Updated answer
When I originally answered this question in 2014, there was no requirement to not scale the image up in the case of a small image. (The question was edited in 2015.) If you have such a requirement, you will indeed need to compare the image's size to that of the imageView and use either UIViewContentModeCenter (in the case of an image smaller than the imageView) or UIViewContentModeScaleAspectFit in all other cases.
Original answer
Setting the imageView's contentMode to UIViewContentModeScaleAspectFit was enough for me. It seems to center the images as well. I'm not sure why others are using logic based on the image. See also this question: iOS aspect fit and center

Answer 5

I solved this problem like this.
setImage to UIImageView (with UIViewContentModeScaleAspectFit)
get imageSize (CGSize imageSize = imageView.image.size)
UIImageView resize. [imageView sizeThatFits:imageSize]
move position where you want.
I wanted to put UIView on the top center of UICollectionViewCell.
so, I used this function.
- (void)setImageToCenter:(UIImageView *)imageView
{
CGSize imageSize = imageView.image.size;
[imageView sizeThatFits:imageSize];
CGPoint imageViewCenter = imageView.center;
imageViewCenter.x = CGRectGetMidX(self.contentView.frame);
[imageView setCenter:imageViewCenter];
}
It works for me.

Answer 6

You can achieve this by setting content mode of image view to UIViewContentModeScaleAspectFill.
Then use following method method to get the resized uiimage object.
- (UIImage*)setProfileImage:(UIImage *)imageToResize onImageView:(UIImageView *)imageView
{
CGFloat width = imageToResize.size.width;
CGFloat height = imageToResize.size.height;
float scaleFactor;
if(width > height)
{
scaleFactor = imageView.frame.size.height / height;
}
else
{
scaleFactor = imageView.frame.size.width / width;
}
UIGraphicsBeginImageContextWithOptions(CGSizeMake(width * scaleFactor, height * scaleFactor), NO, 0.0);
[imageToResize drawInRect:CGRectMake(0, 0, width * scaleFactor, height * scaleFactor)];
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resizedImage;
}
Edited Here (Swift Version)
func setProfileImage(imageToResize: UIImage, onImageView: UIImageView) -> UIImage
{
let width = imageToResize.size.width
let height = imageToResize.size.height
var scaleFactor: CGFloat
if(width > height)
{
scaleFactor = onImageView.frame.size.height / height;
}
else
{
scaleFactor = onImageView.frame.size.width / width;
}
UIGraphicsBeginImageContextWithOptions(CGSizeMake(width * scaleFactor, height * scaleFactor), false, 0.0)
imageToResize.drawInRect(CGRectMake(0, 0, width * scaleFactor, height * scaleFactor))
let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resizedImage;
}

Answer 7

This subclass uses center if the image is not larger than the view, otherwise it scales down. I found this useful for a UIImageView that changes the size.
The image it displays is smaller than the view for large sizes, but larger than the view for small sizes. I want it only to scale down, but not up.
class CenterScaleToFitImageView: UIImageView {
override var bounds: CGRect {
didSet {
adjustContentMode()
}
}
override var image: UIImage? {
didSet {
adjustContentMode()
}
}
func adjustContentMode() {
guard let image = image else {
return
}
if image.size.width > bounds.size.width ||
image.size.height > bounds.size.height {
contentMode = .ScaleAspectFit
} else {
contentMode = .Center
}
}
}

Answer 8

let bannerImageView = UIImageView();
bannerImageView.contentMode = .ScaleAspectFit;
bannerImageView.frame = CGRectMake(cftX, cftY, ViewWidth, scrollHeight);

Answer 9

[your_imageview setContentMode:UIViewContentModeCenter];

Answer 10

For people looking for UIImage resizing,
#implementation UIImage (Resize)
- (UIImage *)scaledToSize:(CGSize)size
{
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);
[self drawInRect:CGRectMake(0.0f, 0.0f, size.width, size.height)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
- (UIImage *)aspectFitToSize:(CGSize)size
{
CGFloat aspect = self.size.width / self.size.height;
if (size.width / aspect <= size.height)
{
return [self scaledToSize:CGSizeMake(size.width, size.width / aspect)];
} else {
return [self scaledToSize:CGSizeMake(size.height * aspect, size.height)];
}
}
- (UIImage *)aspectFillToSize:(CGSize)size
{
CGFloat imgAspect = self.size.width / self.size.height;
CGFloat sizeAspect = size.width/size.height;
CGSize scaledSize;
if (sizeAspect > imgAspect) { // increase width, crop height
scaledSize = CGSizeMake(size.width, size.width / imgAspect);
} else { // increase height, crop width
scaledSize = CGSizeMake(size.height * imgAspect, size.height);
}
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClipToRect(context, CGRectMake(0, 0, size.width, size.height));
[self drawInRect:CGRectMake(0.0f, 0.0f, scaledSize.width, scaledSize.height)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
#end