我有一张动态UIImage和一个宽度固定为280.0像素的UIImageView,我正在使用自动布局。在UIImage视图上,我设置了宽度和高度约束,并降低了高度约束的优先级。我选择了“aspect fit”,并将内容抱紧和压缩优先级提高到1000。
在这种情况下,UIImageView被重新调整大小以保持比例,但高度比我想要的大。纵横比保持不变,因为UIImageView上下有空白区域。我想去掉这些空白区域,自动调整高度以完美地适应UIImage图片。
像这样的东西...
(这段话需要翻译吗?)UIImage *image = ...;
UIImageView *imageView = ...;
imageView.image = image;
float ar = image.size.width/image.size.height;
NSLayoutConstraint* aspectConstraint = [NSLayoutConstraint constraintWithItem: imageView
attribute: NSLayoutAttributeWidth
relatedBy: NSLayoutRelationEqual
toItem: imageView
attribute: NSLayoutAttributeHeight
multiplier: ar
constant: 0];
[parentView addConstraint: aspectConstraint];
-(CGFloat) scaleImageAutoLayout:(UIImageView *)imageView withWidth:(CGFloat)width
{
CGFloat scale = width/imageView.image.size.width;
CGFloat height = imageView.image.size.height * scale;
NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(imageView);
[imageView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"V:[imageView(%f)]",ceilf(height)]
options:0 metrics:nil views:viewsDictionary]];
return height;
}