边框不适应Aspect Fit？

Question

我以编程方式设置带边框的imageview.我将imageView的内容模式设置为Aspect Fit,它可以工作,但边框仍然是原始方块.

码:

CGRect imageViewRect = CGRectMake(left, top, 158, 119); 
        UIImageView *imageView = [[UIImageView alloc] initWithFrame:imageViewRect];
        [imageView setContentMode:UIViewContentModeScaleAspectFit];
        [imageView setImage:image];
        [imageView.layer setBorderColor:[[UIColor blackColor] CGColor]];
        [imageView.layer setBorderWidth:3.0];

显然,我希望黑色边框可以根据纵横比调整,并在所有面上环绕图像.相反它保留在原始框架中,看起来像这样:

Answer 1

使用从弗兰克施密特在稍微修改的方法此篇,可以添加的方法制定出显示缩放到方面的图像所需的帧:

- (CGRect)getFrameSizeForImage:(UIImage *)image inImageView:(UIImageView *)imageView {

    float hfactor = image.size.width / imageView.frame.size.width;
    float vfactor = image.size.height / imageView.frame.size.height;

    float factor = fmax(hfactor, vfactor);

    // Divide the size by the greater of the vertical or horizontal shrinkage factor
    float newWidth = image.size.width / factor;
    float newHeight = image.size.height / factor;

    // Then figure out if you need to offset it to center vertically or horizontally
    float leftOffset = (imageView.frame.size.width - newWidth) / 2;
    float topOffset = (imageView.frame.size.height - newHeight) / 2;

    return CGRectMake(leftOffset, topOffset, newWidth, newHeight);
}

然后,您可以在设置UIImageView图像后调用它:

CGRect frame = [self getFrameSizeForImage:imageView.image inImageView:imageView]; 

最后,使用此框架设置UIImageView的框架,偏移位置以适应宽度/高度的任何变化:

CGRect imageViewFrame = CGRectMake(imageView.frame.origin.x + frame.origin.x, imageView.frame.origin.y + frame.origin.y, frame.size.width, frame.size.height);
imageView.frame = imageViewFrame;