iOS 宽高相等图片适配iPhone X

一张宽高相等375*375的正方形图片显示在iPhone X上需要单独处理。

Snip20190407_6.png

在其他机型上能完美适配，在iPhoneX效果中间会留白(下图绿色部分)。

Simulator Screen Shot - iPhone X - 2019-04-07 at 17.10.59.png

    self.backgroundView = [[UIView alloc] initWithFrame:CGRectMake(0, KNavgationBarHeight+kStatusBarHeight, kLScreenWidth, kLScreenHeight)];
    self.backgroundView.backgroundColor = [UIColor greenColor];
    [self.view addSubview:self.backgroundView];
    
    CGFloat width = 375*[UIScreen mainScreen].bounds.size.width/375;
    CGFloat height = 375*[UIScreen mainScreen].bounds.size.height/667;
    
    self.backImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, width, height)];
    self.backImageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.backImageView setImage:[UIImage imageNamed:@"limit_face_background"]];
    [self.backgroundView addSubview:self.backImageView];
    
    self.innerCircleImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, width, height)];
    self.innerCircleImageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.innerCircleImageView setImage:[UIImage imageNamed:@"limit_face_innercircle"]];
    [self.backgroundView addSubview:self.innerCircleImageView];
    
    self.circleImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, width, height)];
    self.circleImageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.circleImageView setImage:[UIImage imageNamed:@"limit_face_circle"]];
    [self.backgroundView addSubview:self.circleImageView];
    
    self.topAnimationView = [[UIView alloc] initWithFrame:CGRectMake(0, height, kLScreenWidth, kLScreenHeight - height)];
    self.topAnimationView.backgroundColor = [UIColor cyanColor];
    [self.backgroundView addSubview:self.topAnimationView];

其他机型的宽高比实质上是相等(1:1)的，只有iPhone X系列上面的机型宽高比不相等(375:1218*0.56 = 682)。图片是正方形UIViewContentModeScaleAspectFit，所以造成上面留白(682-562)/2=60，

机型	屏幕尺寸	比例	比例
iPhone 4	640x960	2:3	0.67
iPhone 5	640x1136	9:16	0.56
iPhone 6	750x1334	9:16	0.56
iPhone 6p	1242x2208	9:16	0.56
iPhone X	1125x2436	9:16	0.46
iPhone XM	1242x2688	9:16	0.46
iPhone XS	828x1792	9:16	0.46

消除空白:用白色将上面60填充。

        //表明有空隙
        UIView *blankView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kLScreenWidth, (height-width)/2)];
        blankView.backgroundColor = [UIColor whiteColor];
        [self.backImageView addSubview:blankView];
        UIView *blank0View = [[UIView alloc] initWithFrame:CGRectMake(0, width + (height-width)/2, kLScreenWidth, (height-width)/2)];
        blank0View.backgroundColor = [UIColor whiteColor];
        [self.backImageView addSubview:blank0View];

Simulator Screen Shot - iPhone X - 2019-04-07 at 20.02.39.png

UIViewContentModeScaleAspectFit
Description 
The option to scale the content to fit the size of the view by maintaining the aspect ratio. Any remaining area of the view’s bounds is transparent.
有效的根据屏幕大小填充视图，从屏幕边界多余的部分是透明的。