UIImageView content mode

问题:

The blue line is the imageview's bounds. UIImageView's contentMode is UIViewContentModeScaleAspectFit, And I want keep the original picture's scale. How can I make the picture's left edge is on the UIImageView's left edge? But not like UIViewContentModeTopLeft mode. Keep the scale and no blank in the left. My english is not good, hope you guys could understand what I'm saying. Thank you very much.

回答1:

 yourimageView.contentMode = UIViewContentModeCenter;
if ( yourimageView.bounds.size.width > yourimageView.size.width && yourimageView.bounds.size.height > yourimageView.size.height) {
   yourimageView.contentMode = UIViewContentModeScaleAspectFit;
}

Swift3

yourimageView.contentMode = .center
if yourimageView.bounds.size.width > yourimageView.size.width && yourimageView.bounds.size.height > yourimageView.size.height {
yourimageView.contentMode = .scaleAspectFit
}

you can change your mode as

typedef NS_ENUM(NSInteger, UIViewContentMode) {
UIViewContentModeScaleToFill,
UIViewContentModeScaleAspectFit,      // contents scaled to fit with fixed aspect. remainder is transparent
UIViewContentModeScaleAspectFill,     // contents scaled to fill with fixed aspect. some portion of content may be clipped.
UIViewContentModeRedraw,              // redraw on bounds change (calls -setNeedsDisplay)
UIViewContentModeCenter,              // contents remain same size. positioned adjusted.
UIViewContentModeTop,
UIViewContentModeBottom,
UIViewContentModeLeft,
UIViewContentModeRight,
UIViewContentModeTopLeft,
UIViewContentModeTopRight,
UIViewContentModeBottomLeft,
UIViewContentModeBottomRight,
};

回答2:

the moment i saw your situation,i thought about this:

_imageView.contentMode = UIViewContentModeLeft | UIViewContentModeScaleAspectFit;

and i tried it, but it makes things worse

so i think you may resize your imageView`s bound to fit the size you want with this code

/// resize image to fit in show area without changing image ratio
+ (CGSize)resizeImageViewFromImageSize:(CGSize)imageSize toFitShowSize:(CGSize)showSize {
CGFloat ratioW = imageSize.width / showSize.width;
CGFloat ratioH = imageSize.height / showSize.height;

CGFloat ratio = imageSize.width / imageSize.height;

if (ratioW > 1 && ratioH > 1) { 

    if (ratioW > ratioH) { 
        imageSize.width = showSize.width;
        imageSize.height = imageSize.width / ratio;
    } else {
        imageSize.height = showSize.height;
        imageSize.width = imageSize.height * ratio;
    }

} else if (ratioW > 1) {

    imageSize.width = showSize.width;
    imageSize.height = imageSize.width / ratio;

} else if (ratioH > 1) {

    imageSize.height = showSize.height;
    imageSize.width = imageSize.height * ratio;

} else {

    if (ratioW > ratioH) { 

        if (showSize.width / imageSize.width <= 2) {   
            imageSize.width = showSize.width;
            imageSize.height = imageSize.width / ratio;
        }

    } else {

        if (showSize.height / imageSize.height <= 2) {
            imageSize.height = showSize.height;
            imageSize.width = imageSize.height * ratio;
        }

    }

}

return imageSize;
}

then put your imageView align to left of the screen

回答3:

just like this

imageView.contentMode = UIViewContentModeCenter;
if (imageView.bounds.size.width > imageView.size.width && imageView.bounds.size.height > imageView.size.height) {
   imageView.contentMode = UIViewContentModeScaleAspectFit;
}

回答4:

Swift

import UIKit
import AVFoundation



let originalsize = CGSizeMake(500, 500)
let rect = CGRectMake(0, 0, 320, 480)


var result = AVMakeRectWithAspectRatioInsideRect(originalsize, rect)

print(result)