@jshantaram,
Handling adding and removing viewportMinimum and viewportMaximum to viewportMinStack and viewportMaxStack properly should work fine in your case.
As of now, Zoom Out in steps is not available out of the box. However, you can workaround using viewportMinimum and viewportMaximum on the rangeChanged event by adding an extra button.
Considering this as the duplicate of https://canvasjs.com/forums/topic/zoom-out-functionality/ and hence, closing the thread.
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Priyanka M S
Team CanvasJS
