Scrolling to a component

Question

I have a JPanel that contained withn a JScrollPane (called flowchartPane). The JPane contains other JPanels that are arranged with a grid layout.
These JPanels contain graphics and when put together in various combinations make a flowchart.
The actual size of the JPane is larger than the viewport of the JScrollPane. So there are times when I want to scroll to a perticular component that is out of the bounds of the view port rectangle.
I am aware of the scrollRectToVisible method and have been utilising it in my method. However my method seems to be unreliable.
What the method attempts to do is, if a component (comp) has its left, right, top or bottom edge outside the bounds of the viewport scroll the viewport so the component is in view.
However this method is not reliable and does not allways do what is expected. Can anyone think of anyway I can improve it, see what I am doing wrong or help in the writing of a scroll to component method.
Kind regards
Andrew Scott.
   public void scrollToComponent( Component comp)
       int x = comp.getLocation().x;//get x location of  the component
       int y = comp.getLocation().y;//get the y location of the component
       int h = comp.getHeight();//get the height of the component;
       int w = comp.getWidth();//get the width of the component
      Rectangle vr = flowchartPane.getViewport().getViewRect();
      int newY = vr.x;
      int newX = vr.y;
      //if outside the bounds of the viewport
      if (  ((x+w) > (vr.x + vr.width)) |  (x < vr.x) |
      ((y+h) > (vr.y + vr.height)) | (y <  (vr.y))) 
        //Do not attempt to scroll to an posision zero or less on the X axis
        if (x-w > 0)
          newX = x;// - w ;
        else
          newX = x;
        //Do not attempt to sctoll to a position zero or less on the Y axis
        if (y - (h/2) > 0)
         newY = y;// - (h/2);
        else
          newY = y;
        flowchartPane.getViewport().scrollRectToVisible(new Rectangle(newX,newY,vr.width,vr.height));
      }//end if
   }//End Scroll to Component

Answer 1

Stanislav,
Close, but no cigar. I will say that is the best solution yet, but its far from perfect.
It does not want to scroll upwards or to the left. It will only scroll to the right or down.
Why is that??
From your ideas Stanislav I developed this method:
public void scrollToComponent( Component comp)
     Rectangle vr = flowchartPane.getViewport().getViewRect();
     int centerX=comp.getBounds().x + comp.getBounds().width/2;
     int centerY=comp.getBounds().y + comp.getBounds().height/2;
     int newX=centerX-vr.width/2;
     int newY=centerY-vr.height/2;
    flowchartPane.getViewport().scrollRectToVisible(new Rectangle(newX,newY,vr.width,vr.height));
}//end scroll to componentKind Regards.
Andrew.
Message was edited by:
scottie_uk