The Google Charts API
is quite powerful and via googleVis
you can access it from R. Here is an example that demonstrates how you can zoom into your chart.
In the example below I set the maximum zoom level to 5% of the chart. Drag and pan with a left mouse button to zoom in; use a right mouse click to zoom out again. The functionality is available in other core charts as well, such as line, column and bar charts. For more configuration options of the explorer settings visit the Google documentation