Question

我必须修改一些人的项目。 getTheta是该项目中的一种方法，我不明白但help to rotate view rotate like a knob (not fully 360 but less on b/s)

 private float getTheta(float x, float y)
    {
        float sx = x - (float)getWidth() / 2.0F;
        float sy = y - (float)getHeight() / 2.0F;

        float length = (float)Math.sqrt(sx * sx + sy * sy);

        float nx = sx / length;

        float theta = 57.29578F * (float)Math.atan2(sy / length, nx);

        if (theta < 0.0F)
        {
            theta += 360F;
        }
        return theta;
    }

我发现获取theta的方法是

private float getMyTheta(float x, float y) {
    float sx = x - (getWidth() / 2.0f);
    float sy = y - (getHeight() / 2.0f);

    float length = (float) Math.sqrt(sx * sx + sy * sy);
    float nx = sx / length;
    float ny = sy / length;

    float theta = (float) Math.atan2(ny, nx);

    final float rad2deg = (float) (180.0 / Math.PI);

    float theta2 = theta * rad2deg;

    return (theta2 < 0) ? theta2 + 360.0f : theta2;
}

有人可以解释我在getTheta(float x,float y);

中做了什么

提前致谢...

像旋钮一样旋转视图

0 个答案: