StartCallback (Charba - J2CL and GWT charts library based on CHART.JS)

```
public interface StartCallback
```
Callback interface of ZoomPlugin.ID plugin that is called when pan or zoom is about to start.
If this callback returns false, pan or zoom is aborted and RejectedCallback is invoked.

Author:

Andrea "Stock" Stocchero

- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  boolean onStart(ZoomContext context)
  Method called when pan or zoom is about to start.

- Method Detail
  - onStart
```
boolean onStart(ZoomContext context)
```
    Method called when pan or zoom is about to start.
    
    Parameters:
    
    context - ZoomPlugin.ID plugin context instance
    
    Returns:
    
    if this callback returns false, pan or zoom is aborted and RejectedCallback is invoked.