package ac.essex.graphing.swing; 
 
import ac.essex.graphing.plotting.PlotSettings; 
 
import java.awt.event.*; 
 
/** 
 * <p> 
 * An improvement to the graph panel, which allows the user to 
 * interactively drag the panel around to explore the graph 
 * easily. 
 * </p> 
 * 
 * <p> 
 * Easy to replace the standard Graph panel, just make sure your 
 * GUI implements SettingsUpdateListener (called after the graph panel updates) 
 * This allows your GUI to be informed when the plotSettings object changes its values. 
 * </p> 
 * 
 * @author Olly Oechsle, University of Essex, Date: 20-Nov-2007 
 * @version 1.0 
 */ 
public class InteractiveGraphPanel extends GraphPanel { 
 
    protected int mouseDownX, mouseDownY; 
    protected double minX, maxX, minY, maxY; 
    protected boolean mouseDown; 
 
    public InteractiveGraphPanel(final SettingsUpdateListener listener) { 
 
        addMouseListener(new MouseAdapter() { 
 
            public void mousePressed(MouseEvent e) { 
                if (graph != null) { 
                    PlotSettings p = graph.plotSettings; 
                    mouseDownX = e.getX(); 
                    mouseDownY = e.getY(); 
                    minX = p.getMinX(); 
                    minY = p.getMinY(); 
                    maxX = p.getMaxX(); 
                    maxY = p.getMaxY(); 
                } 
                mouseDown = true; 
            } 
 
            public void mouseReleased(MouseEvent e) { 
                mouseDown = false; 
                listener.graphUpdated(graph.plotSettings); 
            } 
 
        }); 
 
        addMouseMotionListener(new MouseMotionAdapter() { 
 
            public void mouseDragged(MouseEvent e) { 
 
                if (graph != null) { 
 
                    PlotSettings p = graph.plotSettings; 
 
                    double movementX = graph.getPlotWidth(e.getX() - mouseDownX); 
                    double movementY = graph.getPlotHeight(e.getY() - mouseDownY); 
 
                    p.setMinX(minX-movementX); 
                    p.setMaxX(maxX-movementX); 
                    p.setMinY(minY+movementY); 
                    p.setMaxY(maxY+movementY); 
                    
                    repaint(); 
 
                } 
 
            } 
 
        }); 
 
        addMouseWheelListener(new MouseWheelListener() { 
 
            public void mouseWheelMoved(MouseWheelEvent e) { 
                if (graph != null && !mouseDown)  { 
 
                    PlotSettings p = graph.plotSettings; 
 
                    double multiplier; 
 
                    if (e.getWheelRotation() < 0)  { 
                        // zoom in 
                        multiplier = 0.1; 
                    } else { 
                        // zoom out 
                        multiplier = -0.1; 
                    } 
 
                    double xDiff = p.getRangeX() * multiplier; 
                    double yDiff = p.getRangeY() * multiplier; 
 
                    p.setMinX(p.getMinX() + xDiff); 
                    p.setMaxX(p.getMaxX() - xDiff); 
 
                    p.setMinY(p.getMinY() + yDiff); 
                    p.setMaxY(p.getMaxY() - yDiff); 
 
                    listener.graphUpdated(graph.plotSettings); 
                    repaint(); 
                     
                } 
            } 
 
        }); 
 
    } 
 
}