| 摘要 |
PROBLEM TO BE SOLVED: To input the control data (displacement amount) of the location and attitude of a displayed graphic by a general coordinate indicator such as a mouse, SOLUTION: Based on the coordinate values of the three continuous points Pn , Pn+1 and Pn+2 inputted from a coordinate indicator such as a mouse, the central angle <Pn On Pn+2 for the circular arc Pn Pn+1 Pn+2 in a circle On which is circumscribed about these three points is determined at first. In the calculation of the angle <Pn On Pn+2 , a cosine theorem is used. Next, based on the angle <Pn On Pn+2 , the central angle <θn for the circular arc Pn Pn+1 , is determined. The <θn is determined by a ccmparatively easy geometrical calculation. A logic circuit or a host program which waits for the input of dial rotation amount as control data adopts the central angle <θn obtained by the inputs of the coordinate values of two continuous points Pn and Pn+1 and rotates the graphic model on a screen in a designated axial direction by the angle <θn (S400). Thus, the circular arc corresponding to desired dial rotation amount can be drawn by a general coordinate indicator such as a mouse, etc.
|
