/*
 * Moonlight|3D Copyright (C) 2005 The Moonlight|3D team
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 * 
 * Created on Nov 13, 2005
 */
package eu.moonlight3d.graph;

import com.trolltech.qt.core.Qt;
import com.trolltech.qt.gui.QGraphicsView;
import com.trolltech.qt.gui.QKeyEvent;
import com.trolltech.qt.gui.QMouseEvent;
import com.trolltech.qt.gui.QPainter;
import com.trolltech.qt.gui.QWheelEvent;
import com.trolltech.qt.gui.QWidget;

/**
 * The graph rendering Qt widget. It takes its data from a populated GraphModel
 * class and renders it.
 * 
 * This widget itself is derived from a QScrollArea and provides automatic scrolling
 * if the graph becomes too large for the widget. The graph itself is rendered into a
 * child widget.
 *
 * @author gregor
 */
public class GraphView extends QGraphicsView {
	/**
	 * The GraphModel instance from which all structural data on the graph is taken. 
	 */
	private GraphModel graphModel;

	/**
	 * A typical Qt widget constructor taking the parent widget as argument.
	 * 
	 * @param parent the intended parent of this widget.
	 */
	public GraphView(QWidget parent) {
		super(parent);

		this.graphModel=null;
		setDragMode(QGraphicsView.DragMode.ScrollHandDrag);
		setRenderHint(QPainter.RenderHint.Antialiasing);
	}
	
	/**
	 * Set the graph model which represents the graph data that is to be displayed.
	 * 
	 * @param graphModel the graph model that should be rendered
	 */
	public void setGraphModel(GraphModel graphModel) {
		if(this.graphModel!=null) {
			this.graphModel.unregisterGraphView(this);
		}
		this.graphModel=graphModel;
		graphModel.registerGraphView(this);
		setScene(graphModel);
	}
	
	@Override
	public void wheelEvent(QWheelEvent event) {
		if(event.delta()>0) {
			for(int i=0;i<event.delta()/32;i++) {
				scale(1.1,1.1);
			}
		} else if(event.delta()<0) {
			for(int i=0;i>event.delta()/32;i--) {
				scale(1/1.1,1/1.1);
			}			
		}
	}
	
	@Override
	public void keyPressEvent(QKeyEvent event) {
		if(event.modifiers().isSet(Qt.KeyboardModifier.ShiftModifier)) {
			setDragMode(QGraphicsView.DragMode.RubberBandDrag);			
		}
		super.keyPressEvent(event);
	}

	@Override
	public void keyReleaseEvent(QKeyEvent event) {
		if(!event.modifiers().isSet(Qt.KeyboardModifier.ShiftModifier)) {
			setDragMode(QGraphicsView.DragMode.ScrollHandDrag);			
		}
		super.keyReleaseEvent(event);
	}

	@Override
	public void disposed() {
		setScene(null);
		if(graphModel!=null) {
			graphModel.unregisterGraphView(this);
		}
	}
}