Touch, Multitouch, and Gestures

Whenever you see a demonstration of Windows 7, touch, multitouch, and gestures are likely the most prominent features in the demonstration. Since Microsoft first demonstrated the Surface platform, interest in applications and scenarios that allow the user to touch the screen in multiple places to interact with user interfaces has reached an all-time high! Windows 7 fully supports touch interfaces, and it's flexible enough to handle many different touch types. You might be familiar with building applications for touch with Tablet PCs using the inking subsystem, but that's just the beginning.

Because of the importance and popularity of these features, we spend a lot of time in these tutorials talking about the new multitouch APIs. We first go into detail about how the underlying system works and how the operating system manages the vastly diverse touch hardware. In the past, the only touch hardware was either a Tablet PC containing a single input via a pen or specialized hardware having specialized drivers that a developer would have to learn. With Windows 7, hardware vendors can now build screens or external devices and hook them up to the new touch driver system, and you as a developer can take advantage of this.

A gesture is a fixed action that can happen in a multitouch environment. To understand this, think about how you would interact with a photograph in a multitouch environment. Typically, a photograph is rendered as a rectangle oriented vertically. You can zoom in and out usually with a mouse wheel or a slider. But what about when you can touch the screen? Wouldn't it be nice if you could put your thumb on one corner and your index finger on the opposite corner and then bring your fingers together to make the picture get smaller as the corners follow your fingers? In a similar vein, you can make the picture bigger by moving your fingers apart, rotate it by twisting your wrist, or move it to another part of the screen by moving your hand and having the picture follow it. These are the concepts in Windows 7 that are called gestures.