HTC Butterfly - Manual (Page 23)

Pinch and spread
In some apps, like Gallery, Messages, Mail,
or the web browser, spread your fingers
on the screen to zoom in when viewing a
picture or text.
Pinch the screen to zoom out of the picture or text.
Two-finger swipe
In some apps that have sorting, like Mail or People, swipe up or
down using two fingers to scroll the screen. The screen displays the
sorting order, and you can easily scroll to the information you want.
23 Your first week with your new phone