ios 图片缩放 失真

失真用红色代码起作用：

        UIImageView *_lockImage = (UIImageView *)[cell.contentView
viewWithTag:lockTag];

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

        CGSize size=image.size;     

         //UIGraphicsBeginImageContext(size);  如果用这个就失真

        
UIGraphicsBeginImageContextWithOptions(size,
NO, 0.0);

        [image drawInRect:CGRectMake(0,
0, size.width/1.5, size.height/1.5)];//缩放比例

        

        UIImage* scaledImage =
UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

  

        _lockImage.image=scaledImage;

      // _lockImage.contentMode = UIViewContentModeScaleAspectFit; //不起作用