Package diva.canvas.interactor

Source Code of diva.canvas.interactor.SelectionDragger

/*
Copyright (c) 1998-2005 The Regents of the University of California
All rights reserved.
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*
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package diva.canvas.interactor;

import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;

import diva.canvas.Figure;
import diva.canvas.FigureDecorator;
import diva.canvas.FigureLayer;
import diva.canvas.GeometricSet;
import diva.canvas.GraphicsPane;
import diva.canvas.OverlayLayer;
import diva.canvas.event.EventLayer;
import diva.canvas.event.LayerEvent;
import diva.canvas.event.MouseFilter;
import diva.util.CompoundIterator;

/** A class that implements rubber-banding on a canvas. It contains
* references to one or more instances of SelectionInteractor, which it
* notifies whenever dragging on the canvas covers or uncovers items.
* The SelectionDragger requires three layers: an Event Layer,
* which it listens to perform drag-selection, an OutlineLayer, on
* which it draws the drag-selection box, and a FigureLayer, which it
* selects figures on. It can also accept a GraphicsPane in its
* constructor, in which case it will use the background event layer,
* outline layer, and foreground event layer from that pane.
*
* @version $Id: SelectionDragger.java,v 1.17 2005/07/08 19:54:55 cxh Exp $
* @author John Reekie
*/
public class SelectionDragger extends DragInteractor {
    /* The overlay layer
     */
    private OverlayLayer _overlayLayer;

    /* The event layer
     */
    private EventLayer _eventLayer;

    /* The figure layer
     */
    private FigureLayer _figureLayer;

    /* The rubber-band
     */
    private Rectangle2D _rubberBand = null;

    /* The set of figures covered by the rubber-band
     */
    private GeometricSet _intersectedFigures;

    /** A hash-set containing those figures
     */
    private HashSet _currentFigures;

    /** A hash-set containing figures that overlap the rubber-band
     * but are not "hit"
     */
    private HashSet _holdovers;

    /* The origin points
     */
    private double _originX;

    private double _originY;

    /** The list of selection models selected by this dragger.
     */
    private List _selectionModels = new ArrayList();

    /** The mouse filter for selecting items
     */
    private MouseFilter _selectionFilter = MouseFilter.selectionFilter;

    /** The mouse filter for toggling items
     */
    private MouseFilter _toggleFilter = MouseFilter.alternateSelectionFilter;

    /** The selection mode flags
     */
    private boolean _isSelecting;

    private boolean _isToggling;

    ///////////////////////////////////////////////////////////////////
    ////                         constructors                      ////

    /**
     * Create a new SelectionDragger
     */
    public SelectionDragger() {
        super();
    }

    /**
     * Create a new SelectionDragger attached to the given graphics
     * pane.
     */
    public SelectionDragger(GraphicsPane gpane) {
        super();
        setOverlayLayer(gpane.getOverlayLayer());
        setEventLayer(gpane.getBackgroundEventLayer());
        setFigureLayer(gpane.getForegroundLayer());
    }

    ///////////////////////////////////////////////////////////////////
    //// public methods

    /**
     * Add the given selection model to the set of selection models
     * selected by this dragger.  When drag-selecting, only figures
     * that have a selection interactor with a selection model in this
     * list are added to the selection model.
     */
    public void addSelectionModel(SelectionModel model) {
        if (!(_selectionModels.contains(model))) {
            _selectionModels.add(model);
        }
    }

    /**
     * Add the selection model of the given selection interactor to the
     * set of selection models selected by this dragger.  When
     * drag-selecting, only figures that have a selection interactor
     * with a selection model in this list are added to the selection
     * model.
     */
    public void addSelectionInteractor(SelectionInteractor interactor) {
        if (!(_selectionModels.contains(interactor.getSelectionModel()))) {
            _selectionModels.add(interactor.getSelectionModel());
        }
    }

    /**
     * Clear the selection in all the relevant selection interactors.
     */
    public void clearSelection() {
        Iterator models = _selectionModels.iterator();

        while (models.hasNext()) {
            SelectionModel model = (SelectionModel) models.next();
            model.clearSelection();
        }
    }

    /**
     * Contract the selection by removing an item from it and
     * removing highlight rendering. If the figure is not in
     * the selection, do nothing.
     */
    public void contractSelection(SelectionInteractor i, Figure figure) {
        if (i.getSelectionModel().containsSelection(figure)) {
            i.getSelectionModel().removeSelection(figure);
        }
    }

    /**
     * Expand the selection by adding an item to it and adding
     * highlight rendering to it. If the
     * figure is already in the selection, do nothing.
     */
    public void expandSelection(SelectionInteractor i, Figure figure) {
        if (!(i.getSelectionModel().containsSelection(figure))) {
            i.getSelectionModel().addSelection(figure);
        }
    }

    /**
     * Get the layer that drag rectangles are drawn on
     */
    public OverlayLayer getOverlayLayer() {
        return _overlayLayer;
    }

    /**
     * Get the layer that drag events are listened on
     */
    public EventLayer getEventLayer() {
        return _eventLayer;
    }

    /**
     * Get the layer that figures are selected on
     */
    public FigureLayer getFigureLayer() {
        return _figureLayer;
    }

    /**
     * Get the mouse filter that controls when this selection
     * filter is activated.
     */
    public MouseFilter getSelectionFilter() {
        return _selectionFilter;
    }

    /**
     * Get the mouse filter that controls the toggling of
     * selections
     */
    public MouseFilter getToggleFilter() {
        return _toggleFilter;
    }

    /** Reshape the rubber-band, swapping coordinates if necessary.
     * Any figures that are newly included or excluded from
     * the drag region are added to or removed from the appropriate
     * selection.
     */
    public void mouseDragged(LayerEvent event) {
        if (!isEnabled()) {
            return;
        }

        if (!_isToggling && !_isSelecting) {
            return;
        }

        if (_rubberBand == null) {
            // This should never happen, but it does.
            return;
        }

        double x = event.getLayerX();
        double y = event.getLayerY();
        double w;
        double h;

        // Figure out the coordinates of the rubber band
        _overlayLayer.repaint(_rubberBand);

        if (x < _originX) {
            w = _originX - x;
        } else {
            w = x - _originX;
            x = _originX;
        }

        if (y < _originY) {
            h = _originY - y;
        } else {
            h = y - _originY;
            y = _originY;
        }

        _rubberBand.setFrame(x, y, w, h);
        _overlayLayer.repaint(_rubberBand);

        // Update the intersected figure set
        _intersectedFigures.setGeometry(_rubberBand);

        HashSet freshFigures = new HashSet();

        for (Iterator i = _intersectedFigures.figures(); i.hasNext();) {
            Figure f = (Figure) i.next();

            if (f instanceof FigureDecorator) {
                f = ((FigureDecorator) f).getDecoratedFigure();
            }

            if (f.hit(_rubberBand)) {
                freshFigures.add(f);
            } else {
                _holdovers.add(f);
            }
        }

        for (Iterator i = ((HashSet) _holdovers.clone()).iterator(); i
                .hasNext();) {
            Figure f = (Figure) i.next();

            if (f.hit(_rubberBand)) {
                freshFigures.add(f);
                _holdovers.remove(f);
            }
        }

        // stale = current-fresh;
        HashSet staleFigures = (HashSet) _currentFigures.clone();
        staleFigures.removeAll(freshFigures);

        // current = fresh-current
        HashSet temp = (HashSet) freshFigures.clone();
        freshFigures.removeAll(_currentFigures);
        _currentFigures = temp;

        // If in selection mode, add and remove figures
        if (_isSelecting) {
            // Add figures to the selection
            Iterator i = freshFigures.iterator();

            while (i.hasNext()) {
                Figure f = (Figure) i.next();
                Interactor r = f.getInteractor();

                if ((r != null) && r instanceof SelectionInteractor) {
                    SelectionInteractor interactor = (SelectionInteractor) r;

                    if (_selectionModels.contains(interactor
                            .getSelectionModel())) {
                        expandSelection((SelectionInteractor) r, f);
                    }
                }
            }

            // Remove figures from the selection
            i = staleFigures.iterator();

            while (i.hasNext()) {
                Figure f = (Figure) i.next();
                Interactor r = f.getInteractor();

                if ((r != null) && r instanceof SelectionInteractor) {
                    SelectionInteractor interactor = (SelectionInteractor) r;

                    if (_selectionModels.contains(interactor
                            .getSelectionModel())) {
                        contractSelection((SelectionInteractor) r, f);
                    }
                }
            }
        } else {
            // Toggle figures into and out of the selection
            Iterator i = new CompoundIterator(freshFigures.iterator(),
                    staleFigures.iterator());

            while (i.hasNext()) {
                Figure f = (Figure) i.next();
                Interactor r = f.getInteractor();

                if ((r != null) && r instanceof SelectionInteractor) {
                    SelectionInteractor interactor = (SelectionInteractor) r;

                    if (_selectionModels.contains(interactor
                            .getSelectionModel())) {
                        if (interactor.getSelectionModel().containsSelection(f)) {
                            contractSelection(interactor, f);
                        } else {
                            expandSelection(interactor, f);
                        }
                    }
                }
            }
        }

        // Consume the event
        if (isConsuming()) {
            event.consume();
        }
    }

    /** Clear the selection, and create the rubber-band
     */
    public void mousePressed(LayerEvent event) {
        if (!isEnabled()) {
            return;
        }

        // Check mouse event, set flags, etc
        _isSelecting = _selectionFilter.accept(event);
        _isToggling = _toggleFilter.accept(event);

        if (!_isToggling && !_isSelecting) {
            return;
        }

        // Do it
        _originX = event.getLayerX();
        _originY = event.getLayerY();
        _rubberBand = new Rectangle2D.Double(_originX, _originY, 0.0, 0.0);

        _overlayLayer.add(_rubberBand);
        _overlayLayer.repaint(_rubberBand);

        _intersectedFigures = _figureLayer.getFigures().getIntersectedFigures(
                _rubberBand);
        _currentFigures = new HashSet();
        _holdovers = new HashSet();

        // Clear all selections
        if (_isSelecting) {
            clearSelection();
        }

        // Consume the event
        if (isConsuming()) {
            event.consume();
        }
    }

    /** Delete the rubber-band
     */
    public void mouseReleased(LayerEvent event) {
        if (!isEnabled()) {
            return;
        }

        if (_rubberBand == null) {
            // This should never happen, but it does.
            return;
        }

        terminateDragSelection();

        // Consume the event
        if (isConsuming()) {
            event.consume();
        }
    }

    /**
     * Remove a selection model from the list of models selected by
     * this dragger.
     */
    public void removeSelectionModel(SelectionModel model) {
        if (_selectionModels.contains(model)) {
            _selectionModels.remove(model);
        }
    }

    /**
     * Get the selection interactors
     */
    public Iterator selectionModels() {
        return _selectionModels.iterator();
    }

    /**
     * Set the layer that drag rectangles are drawn on
     */
    public void setOverlayLayer(OverlayLayer l) {
        _overlayLayer = l;
    }

    /**
     * Set the layer that drag events are listened on
     */
    public void setEventLayer(EventLayer l) {
        if (_eventLayer != null) {
            _eventLayer.removeLayerListener(this);
        }

        _eventLayer = l;
        _eventLayer.addLayerListener(this);
    }

    /**
     * Set the layer that figures are selected on
     */
    public void setFigureLayer(FigureLayer l) {
        _figureLayer = l;
    }

    /**
     * Set the mouse filter that controls when this selection
     * filter is activated.
     */
    public void setSelectionFilter(MouseFilter f) {
        _selectionFilter = f;
    }

    /**
     * Set the mouse filter that controls the toggling of
     * selections.
     */
    public void setToggleFilter(MouseFilter f) {
        _toggleFilter = f;
    }

    /** Terminate drag-selection operation. This must only be called
     * from events that are triggered during a drag operation.
     */
    public void terminateDragSelection() {
        if (!_isToggling && !_isSelecting) {
            return;
        }

        _overlayLayer.repaint(_rubberBand);
        _overlayLayer.remove(_rubberBand);
        _rubberBand = null;
        _currentFigures = null;
        _holdovers = null;
    }
}
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