CASDragGestureListener.java

package org.geogebra.desktop.util;

import java.awt.Color;
import java.awt.Point;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragGestureRecognizer;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.util.ArrayList;

import javax.swing.ImageIcon;

import org.geogebra.common.kernel.Kernel;
import org.geogebra.common.kernel.StringTemplate;
import org.geogebra.common.kernel.geos.GeoCasCell;
import org.geogebra.common.main.App;
import org.geogebra.desktop.cas.view.CASTableD;
import org.geogebra.desktop.gui.util.GeoGebraIconD;
import org.geogebra.desktop.main.AppD;

public class CASDragGestureListener
		implements DragGestureListener, DragSourceListener {

	private Kernel kernel;
	private App app;
	private CASTableD table;
	private DragSource ds;

	private ArrayList<String> geoLabelList;
	private DragGestureRecognizer dgr;

	public CASDragGestureListener(Kernel kern, CASTableD table) {
		super();
		kernel = kern;
		app = kernel.getApplication();
		this.table = table;
		ds = new DragSource();

	}

	/**
	 * enables Drag and Drop for this listener
	 */
	public void enableDnD() {
		if (dgr == null) {
			dgr = ds.createDefaultDragGestureRecognizer(table,
					DnDConstants.ACTION_COPY_OR_MOVE, this);
		}
	}

	@Override
	public void dragGestureRecognized(DragGestureEvent dge) {
		table.stopEditing();

		if (geoLabelList == null) {
			geoLabelList = new ArrayList<String>();
		} else {
			geoLabelList.clear();
		}

		int row = table.rowAtPoint(dge.getDragOrigin());
		GeoCasCell cell = table.getGeoCasCell(row);
		// needed for #3972
		if (cell.isError()) {
			return;
		}

		geoLabelList.add(cell.getLabel(StringTemplate.defaultTemplate));
		int cellnumber = cell.getRowNumber();
		// String tableRef = "$" + (cellnumber+1);

		String latex;
		latex = cell.getLaTeXAlgebraDescription(true,
				StringTemplate.latexTemplate);
		ImageIcon ic = GeoGebraIconD.createLatexIcon((AppD) app, latex,
				((AppD) app).getPlainFont(), Color.DARK_GRAY, null);

		TransferableCAS transferable = new TransferableCAS(geoLabelList,
				cellnumber);
		transferable.setIsAssignment(cell.isAssignmentVariableDefined());

		// start drag
		ds.startDrag(dge, DragSource.DefaultCopyDrop, ic.getImage(),
				new Point(-5, -30), transferable, this);
	}

	/**
	 * Extension of Transferable for exporting CAS selections as a list of Geo
	 * labels can transfer: algebraViewFlavor: geoLabelList (ArrayList) only
	 * with the labels of the transfered variables casTableFlavor: tableRef
	 * (int) return the reference to the specific cell number casLaTeXFlavor:
	 * latexText (String) for not dynamic functionality, return the content of
	 * the cas cell as latex string
	 */
	static class TransferableCAS implements Transferable {

		private final DataFlavor supportedFlavors[] = {
				AlgebraViewTransferHandler.algebraViewFlavor,
				CASTransferHandler.casTableFlavor, };

		private ArrayList<String> geoLabels;
		private int tableRef;
		private boolean isAssignment;

		/**
		 * @param geoLabelList
		 *            list of labels
		 * @param tableRef
		 *            table reference
		 */
		public TransferableCAS(ArrayList<String> geoLabelList, int tableRef) {
			this.geoLabels = geoLabelList;
			this.tableRef = tableRef;
			isAssignment = false;
		}

		@Override
		public DataFlavor[] getTransferDataFlavors() {
			return supportedFlavors;
		}

		@Override
		public boolean isDataFlavorSupported(DataFlavor flavor) {
			// algebraViewFlavor can only be used if the cas cell contains an
			// assignment
			if (flavor.equals(AlgebraViewTransferHandler.algebraViewFlavor)
					&& isAssignment) {
				return true;
			}
			if (flavor.equals(CASTransferHandler.casTableFlavor)) {
				return true;
			}

			return false;
		}

		@Override
		public Object getTransferData(DataFlavor flavor)
				throws UnsupportedFlavorException {
			if (flavor.equals(AlgebraViewTransferHandler.algebraViewFlavor)) {
				return geoLabels;
			}
			if (flavor.equals(CASTransferHandler.casTableFlavor)) {
				return tableRef;
			}
			throw new UnsupportedFlavorException(flavor);
		}

		/**
		 * @param ass
		 *            whether the cell contains assignment
		 */
		public void setIsAssignment(boolean ass) {
			isAssignment = ass;
		}

	}

	// =====================================================
	// Drag and Drop
	// =====================================================

	@Override
	public void dragDropEnd(DragSourceDropEvent e) {
		// do nothing
	}

	@Override
	public void dragEnter(DragSourceDragEvent e) {
		// do nothing
	}

	@Override
	public void dragExit(DragSourceEvent e) {
		// do nothing
	}

	@Override
	public void dragOver(DragSourceDragEvent e) {
		// do nothing
	}

	@Override
	public void dropActionChanged(DragSourceDragEvent e) {
		// do nothing
	}
}