I have a userViewfunction that is set by
mdlView_setFunction (UPDATE_POST, myViewFunction);
When user pans a view myViewFunction is called as expected. But how do I know whether myViewFunction was called by user zooming out in a particular view? That is, the view extents may have changed but the view centre is unchanged.
To rephrase the question, is this the right way to detect a user zoom out?
I don't think that an unchanged centerpoint alone is enough to be sure you have a zoom function. As soon as you define a tentative point before scrolling, or use the zoom in function instead of scrolling, you have different extends and a different viewcenter. So while an unchanged center point will show a zoom, not every zoom has an unchanged center point ;).
Edit: You asked for 'zoom out', which has little to do with 'zoom in', but for tentative+scroll there is still a different center.