org.geomajas.gwt2.client.widget.legend.DynamicVectorServerLayerLegend.java Source code

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Here is the source code for org.geomajas.gwt2.client.widget.legend.DynamicVectorServerLayerLegend.java

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/*
 * This is part of Geomajas, a GIS framework, http://www.geomajas.org/.
 *
 * Copyright 2008-2014 Geosparc nv, http://www.geosparc.com/, Belgium.
 *
 * The program is available in open source according to the GNU Affero
 * General Public License. All contributions in this program are covered
 * by the Geomajas Contributors License Agreement. For full licensing
 * details, see LICENSE.txt in the project root.
 */

package org.geomajas.gwt2.client.widget.legend;

import java.util.ArrayList;
import java.util.List;

import org.geomajas.annotation.Api;
import org.geomajas.configuration.NamedStyleInfo;
import org.geomajas.gwt2.client.GeomajasServerExtension;
import org.geomajas.gwt2.client.event.LayerStyleChangedEvent;
import org.geomajas.gwt2.client.event.LayerStyleChangedHandler;
import org.geomajas.gwt2.client.event.ViewPortChangedEvent;
import org.geomajas.gwt2.client.event.ViewPortChangedHandler;
import org.geomajas.gwt2.client.map.MapEventBus;
import org.geomajas.gwt2.client.map.ViewPort;
import org.geomajas.gwt2.client.map.layer.VectorServerLayer;
import org.geomajas.sld.FeatureTypeStyleInfo;
import org.geomajas.sld.RuleInfo;

import com.google.gwt.http.client.URL;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * Widget that represents the legend for a {@link VectorServerLayer}. This legend will only display the currently
 * visible styles and update automatically. For example, every style rule may have a minimum and/or maximum scale range.
 * Should the map be out of that range, the corresponding style will be made invisible.<br/>
 * This legend will also react to {@link LayerStyleChangedEvent}s to update automatically.
 * 
 * 
 * @author Pieter De Graef
 * @since 2.0.0
 */
@Api(allMethods = true)
public class DynamicVectorServerLayerLegend implements IsWidget {

    private final List<ServerLayerStyleWidget> ruleWidgets = new ArrayList<ServerLayerStyleWidget>();

    private final ViewPort viewPort;

    private final VectorServerLayer layer;

    private VerticalPanel layout;

    /**
     * Create a new legend widget.
     * 
     * @param eventBus
     *            The map eventbus. Used to react to the correct events to update the legend content.
     * @param viewPort
     *            The viewport.
     * @param layer
     *            The layer for which to build a legend.
     */
    protected DynamicVectorServerLayerLegend(MapEventBus eventBus, ViewPort viewPort, VectorServerLayer layer) {
        this.viewPort = viewPort;
        this.layer = layer;

        // Zooming in or out may cause some styles to become visible/invisible:
        eventBus.addViewPortChangedHandler(new ViewPortChangedHandler() {

            public void onViewPortChanged(ViewPortChangedEvent event) {
                updateVisibility();
            }
        });

        // Update the legend widget when the style on this layer changes:
        eventBus.addLayerStyleChangedHandler(new LayerStyleChangedHandler() {

            @Override
            public void onLayerStyleChanged(LayerStyleChangedEvent event) {
                layout.clear();
                buildLegend(layout);
            }
        }, layer);
    }

    @Override
    public Widget asWidget() {
        if (layout == null) {
            layout = new VerticalPanel();
            buildLegend(layout);
        }
        return layout;
    }

    /**
     * Get the layer for this legend.
     * 
     * @return The layer.s
     */
    public VectorServerLayer getLayer() {
        return layer;
    }

    // ------------------------------------------------------------------------
    // Private methods:
    // ------------------------------------------------------------------------

    private void buildLegend(VerticalPanel layout) {
        NamedStyleInfo styleInfo = layer.getLayerInfo().getNamedStyleInfo();
        int i = 0;
        for (FeatureTypeStyleInfo sfi : styleInfo.getUserStyle().getFeatureTypeStyleList()) {
            for (RuleInfo rInfo : sfi.getRuleList()) {
                String url = GeomajasServerExtension.getInstance().getEndPointService().getLegendServiceUrl();
                ServerLayerStyleWidget.addPath(url, layer.getServerLayerId());
                ServerLayerStyleWidget.addPath(url, styleInfo.getName());
                ServerLayerStyleWidget.addPath(url, i + ".png");
                ServerLayerStyleWidget widget = new ServerLayerStyleWidget(URL.encode(url), rInfo.getName(), rInfo);
                ruleWidgets.add(widget);
                layout.add(widget);
                i++;
            }
        }
    }

    private void updateVisibility() {
        for (ServerLayerStyleWidget ruleWidget : ruleWidgets) {
            ruleWidget.asWidget().setVisible(isVisible(ruleWidget.getRule(), viewPort));
        }
    }

    /** TODO This method might be interesting as a static method in some SLD utility class. */
    private boolean isVisible(RuleInfo rule, ViewPort viewPort) {
        if (rule == null) {
            return true;
        }
        double minScale = Double.MAX_VALUE;
        double maxScale = Double.MIN_VALUE;

        if (rule.getMinScaleDenominator() != null && rule.getMinScaleDenominator().getMinScaleDenominator() != 0) {
            minScale = viewPort.toScale(rule.getMinScaleDenominator().getMinScaleDenominator());
        }

        if (rule.getMaxScaleDenominator() != null && rule.getMaxScaleDenominator().getMaxScaleDenominator() != 0) {
            maxScale = viewPort.toScale(rule.getMaxScaleDenominator().getMaxScaleDenominator());
        }

        return (maxScale <= viewPort.getScale() && viewPort.getScale() < minScale);
    }
}