transformations.py 文件源码

def getInscribedRectangle(self, angle, rectSz):
        """
        From https://stackoverflow.com/questions/5789239/calculate-largest-rectangle-in-a-rotated-rectangle
        :param angle: angle in radians
        :param rectSz: rectangle size
        :return:
        """

        imgSzw = rectSz[0]
        imgSzh = rectSz[1]

        quadrant = int(numpy.floor(angle / (numpy.pi / 2.))) & 3
        sign_alpha = angle if (quadrant & 1) == 0 else numpy.pi - angle
        alpha = (sign_alpha % numpy.pi + numpy.pi) % numpy.pi

        bbw = imgSzw * numpy.cos(alpha) + imgSzh * numpy.sin(alpha)
        bbh = imgSzw * numpy.sin(alpha) + imgSzh * numpy.cos(alpha)

        gamma = numpy.arctan2(bbw, bbh) if imgSzw < imgSzh else numpy.arctan2(bbh, bbw)
        delta = numpy.pi - alpha - gamma

        length = imgSzh if imgSzw < imgSzh else imgSzw
        d = length * numpy.cos(alpha)
        a = d * numpy.sin(alpha) / numpy.sin(delta)

        y = a * numpy.cos(gamma)
        x = y * numpy.tan(gamma)

        return (int(x), int(y), int(x + bbw - 2*x), int(y + bbh - 2*y))