iOS UIImageView自适应图片大小

窗口大小获取：    

CGRect screenBounds = [ [UIScreenmainScreen]bounds];//返回的是带有状态栏的Rect

CGRect rect = [ [UIScreenmainScreen]applicationFrame];//不包含状态栏的Rect

UIImageView：

一 ：圆角以及自适应图片大小

   UIImage* image = [UIImage imageNamed:@"image.png"];

   UIImageView* imageView = [[[UIImageView alloc] initWithImage:image] autorelease];

   imageView.frame = CGRectMake(0, 0, 300, 200);

   imageView.layer.cornerRadius = 8;  
   imageView.layer.masksToBounds = YES;

    //自适应图片宽高比例
    imageView1.contentMode = UIViewContentModeScaleAspectFit;

二 图片自适应UIImageView (来源于:http://www.61ic.com/Mobile/iPhone/201103/29636.html)

- (UIImage *)rescaleImageToSize:(CGSize)size {

CGRect rect = CGRectMake(0.0, 0.0, size.width, size.height);

UIGraphicsBeginImageContext(rect.size);

[self drawInRect:rect];  // scales image to rect

UIImage *resImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return resImage;

}