iphone图片等比缩放

iphone图片等比缩放

UIImage *img = imgView.p_w_picpath;

 

int h = img.size.height;

int w = img.size.width;

if(h <= 320 && w <= 480)

{

imgView.p_w_picpath = img;

}

else 

{

float b = (float)320/w < (float)480/h ? (float)320/w : (float)480/h;

CGSize itemSize = CGSizeMake(b*w, b*h);

UIGraphicsBeginImageContext(itemSize);

CGRect p_w_picpathRect = CGRectMake(0, 0, b*w, b*h);

[img drawInRect:p_w_picpathRect];

imgView.p_w_picpath = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

}