SRTTransform.py 文件源码

def setFromQTransform(self, tr):
        p1 = Point(tr.map(0., 0.))
        p2 = Point(tr.map(1., 0.))
        p3 = Point(tr.map(0., 1.))

        dp2 = Point(p2-p1)
        dp3 = Point(p3-p1)

        ## detect flipped axes
        if dp2.angle(dp3) > 0:
            #da = 180
            da = 0
            sy = -1.0
        else:
            da = 0
            sy = 1.0

        self._state = {
            'pos': Point(p1),
            'scale': Point(dp2.length(), dp3.length() * sy),
            'angle': (np.arctan2(dp2[1], dp2[0]) * 180. / np.pi) + da
        }
        self.update()