Using an openlayers 3 map. I want to do drag zoom to in-between resolutions rather than to the nearest integer zoom. I can see that pinchzoom has a constrainResolution but there doesn't seem to be anything on dragzoom. Openlayers 2 seemed to have a fractionalzoom that did what I want, can I get the same effect in openlayers 3?
If you upgrade to OpenLayers >= v3.20.0, pinch and wheel zoom use fractional target zoom levels by default. Integer zoom level are only being enforced for +/- and drag zooming.
For drag zooming, it should now be easy to implement a
constrainResolution option, but it has not been done. Creating a feature request ticket on https://github.com/openlayers/openlayers might help.