ZoomListener.java

package com.baselet.standalone.gui;

import java.awt.AWTEvent;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;

import javax.swing.JComboBox;

import com.baselet.diagram.CurrentDiagram;
import com.baselet.gui.CurrentGui;

public class ZoomListener implements ActionListener, MouseWheelListener {

	@Override
	public void actionPerformed(ActionEvent e) {
		handleEvent(e);
	}

	@Override
	public void mouseWheelMoved(MouseWheelEvent e) {
		handleEvent(e);
	}

	private void handleEvent(AWTEvent e) {
		if (CurrentGui.getInstance().getGui() instanceof StandaloneGUI && CurrentDiagram.getInstance().getDiagramHandler() != null) {
			// The offset is -1 (wheel up) or +1 (wheel down) or 0 (no wheel used)
			int offset = 0;
			if (e instanceof MouseWheelEvent) {
				offset = ((MouseWheelEvent) e).getWheelRotation();
			}

			String zoomFactor = ((JComboBox) e.getSource()).getSelectedItem().toString();
			zoomFactor = zoomFactor.substring(0, zoomFactor.length() - 2); // Cut the zoomvalue eg: "120%" to "12"
			int newZoomFactor = Integer.parseInt(zoomFactor) + offset;

			if (newZoomFactor > 0 && newZoomFactor < 21) {
				CurrentDiagram.getInstance().getDiagramHandler().setGridAndZoom(newZoomFactor);
			}
		}
	}
}