//设置某个View的宽高比 [thumbImageView mas_makeConstraints:^(MASConstraintMaker *make) { make.top.equalTo(@0); make.left.equalTo(@0); make.width.equalTo(self); make.height.equalTo(thumbImageView.mas_width).multipliedBy(0.8); }];
原文：http://www.cnblogs.com/xiongzenghui/p/4686712.html