对齐UIImageView与纵横匹配 [英] Alignment UIImageView with Aspect Fit

问题描述

解决方案

对于我的UIImageView我选择了Aspect Fit（InterfaceBuilder），但是如何改变垂直对齐？这个代码是一个有点发霉从2011年，所有，但我成立@ ArtOfWarefare的mods]

你不能这样做/ UIImageView。我创建了一个简单的UIView子类 MyImageView ，其中包含一个UIImageView。

  // MyImageView.h 
 #import< UIKit / UIKit.h> 
 
 @interface MyImageView：UIView {
 UIImageView * _imageView; 
} 
 
 @property（nonatomic，assign）UIImage * image; 
 
 @end 
  

和

  // MyImageView.m 
 
 #importMyImageView.h
 
 @implementation MyImageView 
 
 @dynamic image; 
 
  - （id）initWithCoder：（NSCoder *）coder 
 {
 self = [super initWithCoder：coder]; 
 if（self）{
 self.clipsToBounds = YES; 
 _imageView = [[UIImageView alloc] initWithFrame：self.bounds]; 
 _imageView.contentMode = UIViewContentModeScaleAspectFill; 
 [self addSubview：_imageView]; 
} 
 return self; 
} 
 
  - （id）initWithFrame：（CGRect）frame 
 {
 self = [super initWithFrame：frame]; 
 if（self）{
 self.clipsToBounds = YES; 
 _imageView = [[UIImageView alloc] initWithFrame：self.bounds]; 
 _imageView.contentMode = UIViewContentModeScaleAspectFill; 
 [self addSubview：_imageView]; 
} 
 return self; 
} 
 
  - （id）initWithImage：（UIImage *）anImage 
 {
 self = [self initWithFrame：CGRectZero]; 
 if（self）{
 _imageView.image = anImage; 
 [_imageView sizeToFit]; 
 
 //初始化框架与imageView的大小相同
 self.frame = _imageView.bounds; 
} 
 return self; 
} 
 
 //如果使用ARC，删除此函数
  - （void）dealloc 
 {
 [_imageView release]; 
 [super dealloc]; 
} 
 
  - （UIImage *）image 
 {
 return _imageView.image; 
} 
 
  - （void）setImage：（UIImage *）anImage 
 {
 _imageView.image = anImage; 
 [self setNeedsLayout]; 
} 
 
  - （void）layoutSubviews 
 {
 if（！self.image）return; 
 
 //计算imageView的缩放因子
 CGFloat widthScaleFactor = CGRectGetWidth（self.bounds）/ self.image.size.width; 
 CGFloat heightScaleFactor = CGRectGetHeight（self.bounds）/ self.image.size.height; 
 
 CGFloat imageViewXOrigin = 0; 
 CGFloat imageViewYOrigin = 0; 
 CGFloat imageViewWidth; 
 CGFloat imageViewHeight; 
 
 
 //如果图像窄和高，缩放到宽度并垂直对齐顶部
 if（widthScaleFactor> heightScaleFactor）{
 imageViewWidth = self。 image.size.width * widthScaleFactor; 
 imageViewHeight = self.image.size.height * widthScaleFactor; 
} 
 
 //如果图像宽和短，缩放到高度，水平对齐
 else {
 imageViewWidth = self.image.size.width * heightScaleFactor; 
 imageViewHeight = self.image.size.height * heightScaleFactor; 
 imageViewXOrigin =  - （imageViewWidth  -  CGRectGetWidth（self.bounds））/ 2; 
} 
 
 _imageView.frame = CGRectMake（imageViewXOrigin，
 imageViewYOrigin，
 imageViewWidth，
 imageViewHeight）; 
} 
 
  - （void）setFrame：（CGRect）frame 
 {
 [super setFrame：frame]; 
 [self setNeedsLayout]; 
} 
 
 @end 
  

for my UIImageView I choose Aspect Fit (InterfaceBuilder) but how can I change the vertical alignment?

解决方案

[EDIT - this code is a bit moldy being from 2011 and all but I incorporated @ArtOfWarefare's mods]

You can't do this w/ UIImageView. I created a simple UIView subclass MyImageView that contains a UIImageView. Code below.

// MyImageView.h
#import <UIKit/UIKit.h>

@interface MyImageView : UIView {
    UIImageView *_imageView;
}

@property (nonatomic, assign) UIImage *image;

@end

and

// MyImageView.m

#import "MyImageView.h"

@implementation MyImageView

@dynamic image;

- (id)initWithCoder:(NSCoder*)coder
{
    self = [super initWithCoder:coder];
    if (self) {
        self.clipsToBounds = YES;
        _imageView = [[UIImageView alloc] initWithFrame:self.bounds];
        _imageView.contentMode = UIViewContentModeScaleAspectFill;
        [self addSubview:_imageView];
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.clipsToBounds = YES;
        _imageView = [[UIImageView alloc] initWithFrame:self.bounds];
        _imageView.contentMode = UIViewContentModeScaleAspectFill;
        [self addSubview:_imageView];
    }
    return self;
}

- (id)initWithImage:(UIImage *)anImage
{
    self = [self initWithFrame:CGRectZero];
    if (self) {
        _imageView.image = anImage;
        [_imageView sizeToFit];

        // initialize frame to be same size as imageView
        self.frame = _imageView.bounds;        
    }
    return self;
}

// Delete this function if you're using ARC
- (void)dealloc
{
    [_imageView release];
    [super dealloc];
}

- (UIImage *)image
{
    return _imageView.image;
}

- (void)setImage:(UIImage *)anImage
{
    _imageView.image = anImage;
    [self setNeedsLayout];
}

- (void)layoutSubviews
{
    if (!self.image) return;

    // compute scale factor for imageView
    CGFloat widthScaleFactor = CGRectGetWidth(self.bounds) / self.image.size.width;
    CGFloat heightScaleFactor = CGRectGetHeight(self.bounds) / self.image.size.height;

    CGFloat imageViewXOrigin = 0;
    CGFloat imageViewYOrigin = 0;
    CGFloat imageViewWidth;
    CGFloat imageViewHeight;


    // if image is narrow and tall, scale to width and align vertically to the top
    if (widthScaleFactor > heightScaleFactor) {
        imageViewWidth = self.image.size.width * widthScaleFactor;
        imageViewHeight = self.image.size.height * widthScaleFactor;
    }

    // else if image is wide and short, scale to height and align horizontally centered
    else {
        imageViewWidth = self.image.size.width * heightScaleFactor;
        imageViewHeight = self.image.size.height * heightScaleFactor;
        imageViewXOrigin = - (imageViewWidth - CGRectGetWidth(self.bounds))/2;
    }

    _imageView.frame = CGRectMake(imageViewXOrigin,
                                  imageViewYOrigin,
                                  imageViewWidth,
                                  imageViewHeight);
}

- (void)setFrame:(CGRect)frame
{
    [super setFrame:frame];
    [self setNeedsLayout];
}

@end

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