UIImage 按照指定宽度等比例裁切

//使用
UIImage *portraitImg = [info objectForKey:UIImagePickerControllerOriginalImage];
    portraitImg = [Util reSizeImage:portraitImg WithWidth:1242];

 //代码
//对image按照width缩放剪裁
+ (UIImage *)reSizeImage:(UIImage *)originImage WithWidth:(float)width{

    float   scaleSize = width/originImage.size.width;
    
    if (scaleSize < 1) {

        UIGraphicsBeginImageContext(CGSizeMake(originImage.size.width * scaleSize, originImage.size.height * scaleSize));
        [originImage drawInRect:CGRectMake(0, 0, originImage.size.width * scaleSize, originImage.size.height * scaleSize)];
        UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
        
        UIGraphicsEndImageContext();
        return scaledImage;
        
    }
    return originImage;
}