从枢轴点旋转矩形后如何获得矩形的方向(角度) [英] How to get the direction (angle) of rectangle after rotating it from a pivot point

问题描述

当从矩形中心旋转矩形时，通常只使用setRotate(double value)和getRotate()即可.假设如果getRotate()为0且我正试图获取其方向，则矩形朝北，我只是得到getRotate()的负数，并从360中获取其余数(如果为负数，则添加360).这意味着0度的角度面向北，然后将其顺时针旋转一个角度使其变为359度(同样，将其逆时针旋转一个角度将使其变为1度).

I normally just use setRotate(double value) and getRotate() when rotating a rectangle from its center. Suppose a rectangle is facing North if the getRotate() is 0 and I'm trying to get its direction, I simply get the negative of the getRotate() and get its remainder from 360 (if it's negative, I add 360). Which means that an angle of 0 degrees faces North, and rotating it clockwise by a degree makes it 359 degrees (likewise, rotating it counter-clockwise by a degree makes it 1 degree).

    public double angle(){
        double angle = -rectangle.getRotate();
        if(angle<0){ angle += 360; }
        return angle%360;
    }

但是，我现在的问题是我需要不从矩形的中心而是从枢轴点旋转矩形.我再也不能使用setRotate(double value)和getRotate()了，所以我不得不使用getTransforms().add(new Rotate(double angle，double axisX，double shaftY)).

However, my problem now is that I need to rotate the rectangle not from its center but from a pivot point. I can't use setRotate(double value) and getRotate() anymore so I have to use getTransforms().add(new Rotate(double angle, double pivotX, double pivotY)).

现在，我的问题是我想知道矩形所面对的方向的角度，但是我不能再使用getRotate()了.即使我使用Rotate中的getAngle()，我仍然不知道如何获得其面向的方向，因为它没有从中心旋转.

Now, my problem is that I want to know the angle of the direction where the rectangle faces but I can no longer use getRotate(). And even if I use the getAngle() from the Rotate, I still don't know how to get the direction it faces because it wasn't rotated from the center.

推荐答案

考虑到矩形只有一个旋转变换，您可以从变换中获取信息:

Considering you have only one rotate transform for your rectangle you can just get info from transform:

for (Transform transform : rectangle.getTransforms()) {
    if (transform instanceof Rotate) {
        return ((Rotate)transform).getAngle();
    }
}

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