linux系统之（一） 深入理解/proc文件系统

getPerimeterPoint(VertexView view, Point2D source, Point2D p)

 是获取VertexView的边框与连线之间的交叉点的方法。

 

 

源码：

 

 

/**
* Returns the intersection of the bounding rectangle and the straight line
* between the source and the specified point p. The specified point is
* expected not to intersect the bounds.
*/
public Point2D getPerimeterPoint(VertexView view, Point2D source, Point2D p) {
Rectangle2D bounds = view.getBounds();
Icon icon = GraphConstants.getIcon(view.getAllAttributes());

double x = bounds.getX();
double y = bounds.getY();
double width = bounds.getWidth();
double height = bounds.getHeight();
double xCenter = x + width / 2;
double yCenter = y + height / 2;
double dx = p.getX() - xCenter; // Compute Angle
double dy = p.getY() - yCenter;
double alpha = Math.atan2(dy, dx);
double xout = 0, yout = 0;
double pi = Math.PI;
double pi2 = Math.PI / 2.0;
double beta = pi2 - alpha;
double t = Math.atan2(height, width);
if (alpha < -pi + t || alpha > pi - t) { // Left edge
xout = x;
yout = yCenter - width * Math.tan(alpha) / 2;
} else if (alpha < -t) { // Top Edge
yout = y;
xout = xCenter - height * Math.tan(beta) / 2;
} else if (alpha < t) { // Right Edge
xout = x + width;
yout = yCenter + width * Math.tan(alpha) / 2;
} else { // Bottom Edge
yout = y + height;
xout = xCenter + height * Math.tan(beta) / 2;
}
return new Point2D.Double(xout, yout);
}

 

 

如果想在连线连接图元对象时，连接到图元的图标范围上，而不是连接到图元的边框上(有些图元设置了小图标，而显示的名称很小，连线连到图元的边框时，看上去感觉不是连接到图元上)

 

 

连接到图标上，可以修改如下：

 

 

/**
* Returns the intersection of the bounding rectangle and the straight line
* between the source and the specified point p. The specified point is
* expected not to intersect the bounds.
*/
public Point2D getPerimeterPoint(VertexView view, Point2D source, Point2D p) {
Rectangle2D bounds = view.getBounds();
//获取图标
Icon icon = GraphConstants.getIcon(view.getAllAttributes());
if (icon != null) {//图标不为空
//获取X坐标偏移的大小
double doubX = bounds.getX() + (bounds.getWidth()-icon.getIconWidth())/2;
//重新构建边框(图标的边框)
bounds = new Rectangle2D.Double(doubX, bounds.getY(), icon.getIconWidth(), icon.getIconWidth());
}

double x = bounds.getX();
double y = bounds.getY();
double width = bounds.getWidth();
double height = bounds.getHeight();
double xCenter = x + width / 2;
double yCenter = y + height / 2;
double dx = p.getX() - xCenter; // Compute Angle
double dy = p.getY() - yCenter;
double alpha = Math.atan2(dy, dx);
double xout = 0, yout = 0;
double pi = Math.PI;
double pi2 = Math.PI / 2.0;
double beta = pi2 - alpha;
double t = Math.atan2(height, width);
if (alpha < -pi + t || alpha > pi - t) { // Left edge
xout = x;
yout = yCenter - width * Math.tan(alpha) / 2;
} else if (alpha < -t) { // Top Edge
yout = y;
xout = xCenter - height * Math.tan(beta) / 2;
} else if (alpha < t) { // Right Edge
xout = x + width;
yout = yCenter + width * Math.tan(alpha) / 2;
} else { // Bottom Edge
yout = y + height;
xout = xCenter + height * Math.tan(beta) / 2;
}
return new Point2D.Double(xout, yout);
}