zoom in zoom out at levels in shinobicharts ios - ios

Question

I am using ShinobiCharts in my iOS app to plot a line chart. This requires a feature where in the default view will be in Days. When i pinch zoom, i will be getting Weeks data, and more pinch zooming will give me Months data. Same applies for zoom out in reverse order.
I am not able to find a way to show this data at different zoom levels.
Please help me with this.
Im using following delegate method to check zoom level
- (void)sChartIsZooming:(ShinobiChart *)chart withChartMovementInformation:
(const SChartMovementInformation *)information;
but i dont find any way to check zoom levels.

Answer 1

One way of checking this is to determine the number of days currently displayed within the axis' visible range.
First off you'll need a way to record the current granularity of data on display in the chart:
typedef NS_ENUM(NSUInteger, DataView)
{
DataViewDaily,
DataViewWeekly,
DataViewMonthly,
};
The initial view will be DataViewDaily and is assigned within viewDidLoad to the property currentDataView.
Then within sChartIsZooming:withChartMovementInformation: you could do:
- (void)sChartIsZooming:(ShinobiChart *)chart withChartMovementInformation:(const SChartMovementInformation *)information
{
// Assuming x is our independent axis
CGFloat span = [_chart.xAxis.axisRange.span doubleValue];
static NSUInteger dayInterval = 60 * 60 * 24;
NSUInteger numberOfDaysDisplayed = span / dayInterval;
DataView previousDataView = _currentDataView;
if (numberOfDaysDisplayed <= 7)
{
// Show daily data
_currentDataView = DataViewDaily;
}
else if (numberOfDaysDisplayed <= 30)
{
// Show weekly data
_currentDataView = DataViewWeekly;
}
else
{
// Show monthly data
_currentDataView = DataViewMonthly;
}
// Only reload if the granularity has changed
if (previousDataView != _currentDataView)
{
// Reload and redraw chart to show new data
[_chart reloadData];
[_chart redrawChart];
}
}
Now within your datasource method sChart:dataPointAtIndex:forSeriesAtIndex: you can return the appropriate data points by switching on the value of _currentDataView.
Note that you may need to also update sChart:numberOfDataPointsForSeriesAtIndex to return the number of points to display at the current view level.