datasource.m

- (void)sChartRenderFinished:(ShinobiChart *)chart
{
    if (YES == self.firstChartRender) {
        self.firstChartRender = NO;

        [chart removeAllAnnotations];

        SChartCategoryAxis *categoryAxis = (SChartCategoryAxis *)chart.xAxis;

        for (NSDictionary *resultDictionary in self.leftBreastData) {
            NSNumber *referenceDate = resultDictionary[TBDEventAttributes.groupingDateSinceReferenceDate];

            __block NSInteger xIndex = NSNotFound;

            [categoryAxis.categories enumerateObjectsUsingBlock:^(NSNumber *obj, NSUInteger idx, BOOL *stop) {
                if (obj.doubleValue == referenceDate.doubleValue) {
                    xIndex = idx;
                    *stop = YES;
                }
            }];

            if (NSNotFound == xIndex) {
                continue;
            }

            NSNumber *duration = resultDictionary[@"result"];

            SChartAnnotation *newAnnotation = [SChartAnnotation annotationWithText:[NSString stringWithFormat:@"%.1f", [duration doubleValue] / 60.0 / 60.0] // Hours
                                                                           andFont:[UIFont systemFontOfSize:10.f]
                                                                         withXAxis:chart.xAxis
                                                                          andYAxis:chart.yAxis
                                                                       atXPosition:@(xIndex)
                                                                      andYPosition:duration
                                                                     withTextColor:[UIColor blackColor]
                                                               withBackgroundColor:[UIColor clearColor]];

            newAnnotation.position = SChartAnnotationAboveData;
            [chart addAnnotation:newAnnotation];
            newAnnotation.transform = CGAffineTransformMakeTranslation(-14.f, -6.f);
        }

        for (NSDictionary *resultDictionary in self.rightBreastData) {
            NSNumber *referenceDate = resultDictionary[TBDEventAttributes.groupingDateSinceReferenceDate];

            __block NSInteger xIndex = NSNotFound;

            [categoryAxis.categories enumerateObjectsUsingBlock:^(NSNumber *obj, NSUInteger idx, BOOL *stop) {
                if (obj.doubleValue == referenceDate.doubleValue) {
                    xIndex = idx;
                    *stop = YES;
                }
            }];

            if (NSNotFound == xIndex) {
                continue;
            }

            NSNumber *duration = resultDictionary[@"result"];

            SChartAnnotation *newAnnotation = [SChartAnnotation annotationWithText:[NSString stringWithFormat:@"%.1f", [duration doubleValue] / 60.0 / 60.0] // Hours
                                                                           andFont:[UIFont systemFontOfSize:10.f]
                                                                         withXAxis:chart.xAxis
                                                                          andYAxis:chart.yAxis
                                                                       atXPosition:@(xIndex)
                                                                      andYPosition:duration
                                                                     withTextColor:[UIColor blackColor]
                                                               withBackgroundColor:[UIColor clearColor]];

            newAnnotation.position = SChartAnnotationAboveData;
            [chart addAnnotation:newAnnotation];
            newAnnotation.transform = CGAffineTransformMakeTranslation(14.f, -6.f);
        }
    }
}