You've correctly set the delegate property on the chart, so the method you have defined should be being called. Does the chart render as expected? If you're adding chart3 as a subview of chart3View, then I'd expect it to look a little weird because you have created the chart with the same frame as its container view. This might make more sense:
UIView *chart3View = [[UIView alloc] initWithFrame: CGRectMake (128, 638, 866, 128)];
chart3 = [[ShinobiChart alloc] initWithFrame:chart3View.bounds];
You also haven't actually added chart3 as a subview of anything, but I expect that that is because you have just given a sample of the code.
Some things that might be worth trying:
- Do any of the delegate methods get called?
- Does the zooming delegate method get called for any of the other charts?
- Do any other delegte methods get called for other charts?
- Do you also need to implement the equivalent delegate method for panning?
Sorry I can't be more specific. If you still can't get it to work as expected it might be worth posting a simple project which demonstrates your problem, or contacting the Shinobi support team, with your project file.