trigonometry


How to get the direction (angle) of rectangle after rotating it from a pivot point


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;
}
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)).
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.
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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