In different modes, the pinch gesture will do different things.
Mode 1: Viewing / Editing
horizontal pinching will increase / decrease text size
vertical pinching will increase / decrease line height
Mode 2: Version History
When viewing version history (and thus using the filmstrip UI) pinching out will minimize the full page so that the timelapse effect can be visible. You'll be able to see the page grow and expand and change over time. Zooming in will not be available in this mode. This miniaturized view will inherit the text properties from above.
Device support
Multi-touch devices like Tablet and Mobile
Multi-touch trackpad-enabled devices
