1. Field of the Invention
The present invention relates to a method and controller for identifying double tap gestures, especially referring to a method and controller for identifying double tap gestures on touch device. When the touch device identifies the double tap gesture, simulate a double tap signal that represent a series of consecutive double clicking of the mouse button (usually the default is the left button).
2. Brief Description of Related Art
Graphical User Interface, GUI, accompanying by the pointing device (such as a mouse) was the first program operation interface released by the PARC research group. The user can easily accomplish the executed action by just using the visual type of pointer through the movement and clicking of the mouse, this solves the inconvenience created by the input of complex instruction during the text mode. Therefore, GUI is commonly used by Apple computers and Microsoft and it becomes a mainstream interface of all the operating systems. In the electronic devices that utilize GUI, such as desktop computer, portable computer, tablets, personal digital assistant and so on, pointing device has become a basic accessory.
Currently, the pointing device includes external mouse, track-ball and touch pad built-in on the portable computers, the touch panel incorporated with the monitor and so on. The mouse is the pointing device that is released the earliest. Using the mouse as an example to illustrate the functionality of the pointing device, the mouse is able to control the pointer on the monitor screen, which means that the pointer will follow to anywhere the mouse moves to and when clicking of the control button is performed at the to be executed target on the monitor, then the instruction will be executed to the electronic device. However, the current trend of the electronic equipment is heading towards small and light, for example, the portable computers are gradually replacing the export of the desktop computers and this results the small-sized touch device (e.g. touch pad) to be slowly become the mainstream of pointing device.
Presently, the touch device technology includes capacitor type, resistive type, magnetic type, pressure type, inductance type, surface sonar type, supersonic type, and optical type and so on. When an object such as a finger moves on the touch device, it can control the pointer to move in the direction of the movement of the object. Moreover, the pointing device besides controlling the pointer, it also has the function to execute instruction. Using the mouse as an example, when the pointer moves over the target (e.g. program, document) to be started, double clicking the mouse button (default to be left button in most system) will select the target and opens it. However, for touch device such as touch pad, currently two control buttons have been installed below to replace the left and right buttons of the mouse or by defining certain gesture on the touch device to generate signal corresponding to the simulated double clicking.
Currently, the touch device opens the selected target by tapping the touch device consecutively twice gesture (known as double tap gesture in the following text), which replaces the double clicking action of the mouse. Thus, a conventional method of identifying double tap gesture is described in U.S. Pat. No. 6,414,671. Referring to FIG. 1 (corresponding to FIG. 15F in U.S. Pat. No. 6,414,671 specification), first of all, compare the first appearing time duration t19 of the object on the touch device (refers to the time of stay of the object first appeared on the touch device) with the first reference time, if the first appearing time duration t19 is smaller than the first reference time value, then produce a first signal 11; after that, if second appearance is not detected within the time of the second reference time, terminates the first signal, in other words, the time span between the two appearing time duration t20 has to be smaller than the second reference time value; next, compare the second appearing time duration t21 with the third reference time value, if the second appearing time duration t21 is shorter than the third reference time value, then terminates the first signal and produce a second signal 12, therefore it can output two signals 11 and 12 to simulate the signal of double clicking of the mouse button.
Even though the conventional method can achieve the objective of identifying the double tap gesture, however in the conventional method, it makes the determination to be more complex by comparing the first appearing time duration t19, time span between two appearing time duration t20, and the second appearing time duration t21 with the respective reference time values. Additionally, since the user differs from one another, therefore, when each person perform the double tap gesture on the touch device will have different length of time in each step of the action or even for the same user to perform the every double tap gesture on the touch device will vary in time for each action, thus resulting in the situation where a misinterpretation has occurred. Also, during the operation of the touch device, it can be easily touched by mistake, or due to the noise of the touch device itself, or interference by the noise from the surrounding environment will all produce short spike of the first and second appearance phenomenon. The conventional method does not have minimum time restriction on the first and second appearing time duration and the time span between the two appearing time durations; therefore, the interference signal produced due to noise will cause inappropriate determination and easily allow the situation of misinterpretation to happen. Moreover, as the tap and drag gesture also taps on the touch device twice where during the drag of the second tap, the conventional method did not take into the consideration of the accumulated displacement of the second appearing duration, it will easily cause the misinterpretation of the double tap gesture with the tap and drag gesture.