I believe there are commercial chart libraries you can buy which contain such a thing. For a recent project I wrote one myself - a single control descended from Canvas (via several other custom components adding functionality along the way) that basically combined an area chart with a line chart. You can then add whatever axis zooming mechanism you want. I wouldn't say it was the easiest component I wrote but it certainly wasn't the most difficult! The main trick is to get both charts using the same data provider, but restrict the axis of the top one in some way connected with your manipulation of the bottom one.