IOS-图片裁剪

根据自己给定的frame对图片进行裁剪

scale 图片的缩放比例
rect 要裁剪的frame 不能超出原图
返回裁剪后的图片

• (UIImage )ct_imageFromImage:(UIImage )image inRect:(CGRect)rect {
  CGFloat scale = 1 ;
  
  CGRect rect2 = CGRectMake(rect.origin.x * scale, rect.origin.y * scale, scale rect.size.width, scale rect.size.height);
  
  CGImageRef cgImg = CGImageCreateWithImageInRect(image.CGImage, rect2);
  
  UIImage *clippedImg = [UIImage imageWithCGImage:cgImg];
  
  CGImageRelease(cgImg);
  return clippedImg;
  }