iOS几款实用的工具类demo

- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect {
    
    NSArray *arr = [self getCopyOfAttributes:[super layoutAttributesForElementsInRect:rect]];
    //屏幕中线
    CGFloat centerX = self.collectionView.contentOffset.x + self.collectionView.bounds.size.width/2.0f;
    //刷新cell缩放
    for (UICollectionViewLayoutAttributes *attributes in arr) {
        CGFloat distance = fabs(attributes.center.x - centerX);
        //移动的距离和屏幕宽度的的比例
        CGFloat apartScale = distance/self.collectionView.bounds.size.width;
        //把卡片移动范围固定到 -π/4到 +π/4这一个范围内
        CGFloat scale = fabs(cos(apartScale * M_PI/4));
        //设置cell的缩放 按照余弦函数曲线 越居中越趋近于1
        attributes.transform = CGAffineTransformMakeScale(1.0, scale);
    }
    return arr;
}

 设置  [[RCIM sharedRCIM] setUserInfoDataSource:self];
- (void)getUserInfoWithUserId:(NSString *)userId completion:(void(^)(RCUserInfo* userInfo))completion
{}

  //识别图片
            [[AipOcrService shardService] detectWebImageFromImage:self.showImage
                                                      withOptions:nil
                                                   successHandler:_successHandler
                                                      failHandler:_failHandler];

//5.视频输出
    self.outputURL = [NSURL fileURLWithPath: self.outPutPath];
    AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:self.mixComposition presetName:self.presetName];
    
    exporter.outputURL = self.outputURL;
    exporter.videoComposition = self.videoComposition;
    exporter.outputFileType = [self transOutPutFileType:fileType];
    exporter.shouldOptimizeForNetworkUse = self.shouldOptimizeForNetworkUse;
    [exporter exportAsynchronouslyWithCompletionHandler:^{
        
        dispatch_async(dispatch_get_main_queue(), ^{
            if (exporter.status == AVAssetExportSessionStatusCompleted) {
                if (successBlock) {
                    successBlock(self.outputURL);
                }
            }else{
                NSLog(@"exporter %@",exporter.error);
                if (failureBlock) {
                    failureBlock(exporter.error);
                }
                
            }
        });
    }];