UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"图片"]];
- Fil(填充)
- Fit, (适应)
- Scale(比例)
- Aspect(方向)
UIViewContentModeScaleToFill,
UIViewContentModeScaleAspectFit,
UIViewContentModeScaleAspectFill,
imgView.contentMode = UIViewContentModeScaleAspectFit;