UIImageView content mode is not working

Question

I have a large image (1920*1080), and a smaller UIImageView (320*568) that scaled to full screen size in the story board.

Now I want to display this large image full screen size, but fit to the UIImageView.

I have tried all the content mode, but they are all not working. Every time it just shows the top left part of the image full screen sized.

 [self.imageView setFrame:self.view.bounds];
 [self.imageView setContentMode:UIViewContentModeScaleAspectFit] ;
 [self.imageView setImage:image] ;
 [self.view insertSubview:_imageView aboveSubview:_previewView] ;

So what might be wrong in my case? could that be a Xcode story board configuration error ?

thanks.

Answer 1

If you are seeing only the image top corner in your ImageView, then the possible reasons are: Your ImageView frame is out of screen size OR Content Mode is not set. In your code you are setting the frame as the bounds of the superview. If your are using Auto-layout, check the auto-layout are set properly. If this is ok, then try setting UIImageView ContentMode before setting the frame.

// Setting the content mode.
self.imageView.contentMode = UIViewContentModeScaleAspectFit;
// Now set the frame.
[self.imageView setFrame:self.view.bounds];

Other solution is you can downscale your image to fit your ImageView. For that you can use the following function:

- (UIImage *)scaleImage:(UIImage *)orginalImage
{
    float widthFactor = photoImageView.frame.size.width / orginalImage.size.width;
    CGSize destinationSize = CGSizeMake(orginalImage.size.width * widthFactor,orginalImage.size.height * widthFactor);
    UIGraphicsBeginImageContext(destinationSize);
    [orginalImage drawInRect:CGRectMake(0,0,destinationSize.width,destinationSize.height)];
    UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    photoImageView.image = scaledImage;
    return scaledImage;
}