startZoom static method
Called in response to an interaction model operation that responds to an event that starts zooming.
It's used in the default callback for "mousedown" operations. Custom interaction model builders can use it to provide the default zooming behavior.
Implementation
external static void startZoom(
// the event object which led to the startZoom call
Event e,
// the dygraph on which to act
Dygraph dygraph,
// the dragging context object (with dragStartX/dragStartY/etc. properties).
// (this function modifies the context!!!)
DygraphDragContext context,
);