HTC One M9 - Manual (Page 28)

Get Started 15
Pinch and Spread
“Pinch” the screen using your thumb and forefinger to zoom out or “spread” the screen to zoom in
when viewing a picture or a Web page. (Move fingers inward to zoom out and outward to zoom in.)
Slide two fingers together to zoom out of the picture or text.
Two-finger Swipe
Swipe down from the status bar using two fingers to access Quick Settings.