{
//scopeRect：限制的扫描区域范围
_metadataOutput.rectOfInterest = [self rectOfInterestByScanViewRect:scopeRect];
}
- (CGRect)rectOfInterestByScanViewRect:(CGRect)rect {
CGFloat width = SCREEN_WIDTH;
CGFloat height = SCREEN_HEIGHT;
CGFloat x = rect.origin.y/ height;
CGFloat y = rect.origin.x/ width;
CGFloat w = CGRectGetHeight(rect) / height;
CGFloat h = CGRectGetWidth(rect) / width;
return CGRectMake(x, y, w, h);
}