Back button for Zoom - one solution

["K. B. Udaya" <ubk@kogalur-shear.com>]

*************************************************
Message from the sgt mail list.
*************************************************

An implementation of the solution is as follows:

Define a zoom history buffer:  
  private Domain[] zoomHistory;

Define backward and forward buttons with listeners.

Define a zoom listener:
  class ZoomL implements PropertyChangeListener {
    public void propertyChange(PropertyChangeEvent pce) {
        addZoomHistory();
      }
    }
  }

Populate the zoom buffer accordingly: 
  private void addZoomHistory() {
    Domain zoomElement = graph.getRange();
    // Is the zoom history buffer full ?
    if (currentZoomPtr == (MAX_ZOOM_HISTORY - 1)) {
      // Drop the first element in the buffer.
      for (int i=1; i < MAX_ZOOM_HISTORY; i++) {
        zoomHistory[i-1] = zoomHistory[i];
      }
      // Add the current zoom element to the end of the buffer.
      zoomHistory[MAX_ZOOM_HISTORY - 1] = zoomElement;
    }
    else {
      currentZoomPtr++;
      zoomHistory[currentZoomPtr] = zoomElement;
      maxZoomPtr = currentZoomPtr;
    }
    backZoom.setEnabled(true);
    forwardZoom.setEnabled(false);
  }

ubk

> -----Original Message-----
> From: K. B. Udaya [mailto:ubk@kogalur-shear.com]
> Sent: Saturday, March 25, 2006 11:25 AM
> To: sgt@noaa.gov
> Subject: Back button for Zoom
> 
> 
> *************************************************
> Message from the sgt mail list.
> *************************************************
> 
> Has anyone implemented a "back" button for zoom functionality that would
> allow the user to restore the previous state of a screen after a 
> zoom?  This
> is in contrast to sgt.swing.JPlotLayout.resetZoom() that restores the
> original plot with all the data being displayed.
> 
> I suppose I'll have to get the shovel out and start digging into 
> the source
> code again ...
> 
> ubk
> 
> K. B. Udaya, Ph.D.
> Kogalur Shear Corporation
> ubk@kogalur-shear.com
> 
> 
> 
> *************************************************
> To remove yourself from this mailing list,
> send mail to <epic-majordomo@noaa.gov> with
> "unsubscribe sgt" in the message body.
> ==========


*************************************************
To remove yourself from this mailing list,
send mail to <epic-majordomo@noaa.gov> with
"unsubscribe sgt" in the message body.
==========