cursorlens.java

JPowerGraph is a Java library for creating directed graphs for SWT. It supports graph movement, sele

package net.sourceforge.jpowergraph.lens;

import java.awt.geom.Point2D;
import java.util.Iterator;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.widgets.Display;

import net.sourceforge.jpowergraph.pane.JGraphPane;

public class CursorLens extends AbstractLens {
    
    protected boolean moveGraph;

    private static Cursor arrow;
    public static Cursor hand;
    private static Cursor cross;
    public static Cursor stop;

    private Cursor overRideCursor;

    private boolean disposed = false;
    
    public CursorLens(Display theDisplay) {
        arrow = new Cursor(theDisplay, SWT.CURSOR_ARROW);
        hand = new Cursor(theDisplay, SWT.CURSOR_HAND);
        cross = theDisplay.getSystemCursor(SWT.CURSOR_CROSS);
        stop = theDisplay.getSystemCursor(SWT.CURSOR_NO);
        setMoveGraph(true);
    }

    public boolean isMoveGraph() {
        return moveGraph;
    }

    public boolean isCreateEdge() {
        return !moveGraph;
    }

    public void setMoveGraph(boolean theMoveGraph) {
        moveGraph = theMoveGraph;
        fireLensUpdated();
    }

    public void setCreateEdge(boolean theCreateEdge) {
        moveGraph = !theCreateEdge;
        fireLensUpdated();
    }
    
    public void setCursor(Cursor theCursor){
        overRideCursor = theCursor;
        fireLensUpdated();
    }

    public void applyLens(JGraphPane theJGraphPane, Point2D point) {
        if (overRideCursor != null && !overRideCursor.isDisposed()){
            theJGraphPane.setCursor(overRideCursor);
        }
        else if (moveGraph){
            if (!arrow.isDisposed()){
                theJGraphPane.setCursor(arrow);
            }
        }
        else {
            if (!cross.isDisposed()){
                theJGraphPane.setCursor(cross);
            }
        }
    }

    public void undoLens(JGraphPane theJGraphPane, Point2D point) {
        if (overRideCursor != null && !overRideCursor.isDisposed()){
            theJGraphPane.setCursor(overRideCursor);
        }
        else if (moveGraph){
            if (!arrow.isDisposed()){
                theJGraphPane.setCursor(arrow);
            }
        }
        else {
            if (!cross.isDisposed()){
                theJGraphPane.setCursor(cross);
            }
        }
    }
    
    public void dispose(){
        if (!arrow.isDisposed()){
            arrow.dispose();
        }
        if (!hand.isDisposed()){
            hand.dispose();
        }
        if (!cross.isDisposed()){
            cross.dispose();
        }
        if (!stop.isDisposed()){
            stop.dispose();
        }
        if (overRideCursor != null && !overRideCursor.isDisposed()){
            overRideCursor.dispose();
        }        
        disposed = true;
    }
    
    public boolean isDisposed(){
        return disposed ;
    }
}