Windows 8 Touch
In Windows 8 touch system, you can browse online newspapers, flick through photo albums, and shuffle files and folders—using nothing but your fingers. New hardware and Application Programming Interface (API) elements in the Windows 8 operating system provide applications the ability to receive input from multiple contacts. This gives such applications the ability to detect and respond to multiple simultaneous touch points on the application's visible surface. The function of Windows 8 touch is provided by a new message that reports and tracks touches. And this message can report the action, position and an identifier for touch points. Some of the functionalities of Windows Touch are built into the core of Windows 8. This functionality is available to users without the need for developers to explicitly enable support.
Today, our priority task is to tell you how to operate your windows 8 with two fingers. As long as you owna touch device, you can also able to operate Windows 8 with two fingers on the touch screen. It is possible to enlarge, narrow, flip over and other special efficiencies, etc in Windows 8.
Two commonly used gestures
1. Narrowing and enlargement gesture
Narrowing and enlargement gestures are often used to enlarge or narrow interface pictures and articles when you are browsing. If you want to enlarge a picture, you should close your two fingers together at first, then upward one finger while slide the other one to the opposite side. And if you also want to know how to narrow a picture, just do that in the contrary way.
If you want to be recognized by the program, you’d better follow the below steps: the first step is to make sure the screen has got information of your hands. The second step, calculate the distance according to the coordinates of two fingers, then compare the distance of two fingers based on an empirical value. The third step is to calculate the direction and velocity, according to a timer which can real-timely capture the finger points coordinates, so that you can further judge the two fingers in backward sliding or opposite sliding.
2. Parallel gesture
Parallel gesture often used for navigation. For example, in an image viewer, you just need to shift left if you want to navigate to the previous picture. And shift right to next picture. In order to distinguish whether the users want to change the location of the picture or flip, we have to learn something about acceleration.
In a timer, we can real-timely capture the finger points coordinates to calculate the velocity and acceleration. Compare an empirical value with the acceleration, we can get a conclusion that it is a flip when the acceleration is relatively large and on the contrary it is dragging. Of course, this is not enough to determine whether it is a flip. When you are dragging, you also need to further judge whether the program has reached the border, if it has reached, it is a flip. Back to previous page can be realized by fast moving or reaching left border.
Tips: The easiest way to let the program support multi-touch is to use windows 8 gesture recognition function, which is mainly used the following API.
GetSystemMetrics, used to check whether the multi-touch hardware exists and is ready.
GetGestureInfo, used to obtain gesture type and relevant data.