Enable spring for zooming with touch gesture

Is there any way to enable spring when zooming by pinching (touch gesture)?

From what I have come across it seems to be a deliberate choice that spring is only enabled when dragging and not when zooming. I would like the zoom to be a bit smoother, as it is when scrolling with the mouse.

Furthermore I think this can alleviate issues I have with the image jumping when trying to zoom further in our out than the minZoomLevel or maxZoomLevel while having constrainDuringPan enabled. This jumping only happens when zooming with the pinch gesture and not when scrolling, leading me to believe that enabling the spring will fix it.

Best regards

[iangilman]

It appears we don’t expose a flag for turning on animations for pinch. Here’s the code:

https://github.com/openseadragon/openseadragon/blob/master/src/viewer.js#L2956

That true at the end of the line means “immediately”, i.e. no animation.

You might try changing it to false and building a fresh OSD to see if your hunch is correct.

There also doesn’t appear to be any zoom version of constrainDuringPan, and zoom doesn’t honor constrainDuringPan. Maybe what we need is a new constrainDuringZoom to help with this situation?

[iangilman]

@thatcher A good place to start is the various gestureSettings entries in http://openseadragon.github.io/docs/OpenSeadragon.html#.Options. We could definitely use some examples on the site though!