I cannot find a way to make showValues: '1' show the data plot values in a zoomline graphic with Fusion Charts.
You see and try it in this fiddle: http://jsfiddle.net/60oeahc1/4/
¿Is there a way to make it work for zoomline charts?
The thing is that with a line chart is working: http://jsfiddle.net/z0xutjhL/
As per your query, since zoomline features large data , using showValue would overlap the data value text which in turn will result in poor visualization. Hence, It will not be possible to use showValue here.