从段中获取具有固定宽度的矩形坐标

Question

我想根据角度从段创建一个矩形。例如，在图片上：

C = xA + rectangleWidth

我需要找到角度CAD来旋转C并制作一个矩形

此代码可以使用70％的时间，但有些奇怪的事情发生了我不理解

case polyRectangle:

    int rectangleWidth=25;
    double vectorAngle, basicRotationAngle, rotationAngle;
    int re, im, x1rot, y1rot, x2rot, y2rot;
    double PI = Math.PI;

    //getting coordinates of the vector
    re = segment.X1()-segment.getX2();
    im = segment.Y1()-segment.getY2();

    //getting angle of the vector
    if(im==0&&re<0) {
        vectorAngle=Math.PI;
    } else { 
        vectorAngle=2*Math.atan(im/(re+Math.sqrt(re*re+im*im)));
    }

    //deducting the basic rotation angle 
    basicRotationAngle = ((PI/2)*(1+Math.floor(vectorAngle/(PI/2))))-vectorAngle;
    //changing orientation of the angle according to the segment position
    rotationAngle = (im>=0&&re>=0) || (re<=0&&im<=0) ? (2*PI-basicRotationAngle):basicRotationAngle; 
    //applying complex rotation formula z'=(z-w)e^(iθ)+w around segment extremities (with the deduced cartesian form)   
    x1rot = (int) (rectangleWidth*Math.cos(rotationAngle )+segment.getX1()+rectangleWidth);
    y1rot = (int) (rectangleWidth*Math.sin(rotationAngle )+segment.getY1());
    x2rot = (int) (rectangleWidth*Math.cos(rotationAngle )+segment.getX2()+rectangleWidth);
    y2rot = (int) (rectangleWidth*Math.sin(rotationAngle )+segment.getY2());

    p.addPoint(segment.getX2(), segment.getY2());
    p.addPoint(x2rot,y2rot);
    p.addPoint(x1rot,y1rot);
    p.addPoint(segment.getX1(), segment.getY1());

    g.fillPolygon(p);

    break;