org.sakaiproject.gradebookng.tool.component.JFreeChartImageWithToolTip.java Source code

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Here is the source code for org.sakaiproject.gradebookng.tool.component.JFreeChartImageWithToolTip.java

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/**
 * Copyright (c) 2003-2017 The Apereo Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *             http://opensource.org/licenses/ecl2
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.sakaiproject.gradebookng.tool.component;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.html.image.NonCachingImage;
import org.apache.wicket.model.IModel;
import org.apache.wicket.request.resource.DynamicImageResource;
import org.apache.wicket.request.resource.IResource;
import org.jfree.chart.ChartRenderingInfo;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.entity.StandardEntityCollection;

/**
 * Renders a {@link NonCachingImage} via JFreeChart using the {@link JFreeChart} data supplied as the model. Attach this to an img tag
 */
public class JFreeChartImageWithToolTip extends NonCachingImage {

    private static final long serialVersionUID = 1L;
    private final String imageMapId;
    private final int width;
    private final int height;
    private final ChartRenderingInfo chartRenderingInfo = new ChartRenderingInfo(new StandardEntityCollection());

    /**
     * Build the chart
     * 
     * @param id wicket id
     * @param model data as {@link IModel} of type {@link JFreeChart}
     * @param imageMapId HTML id of the tooltip connected via the usemap attribute in the HTML tag
     * @param width width of chart
     * @param height height of chart
     */
    public JFreeChartImageWithToolTip(final String id, final IModel<JFreeChart> model, final String imageMapId,
            final int width, final int height) {
        super(id, model);
        this.imageMapId = imageMapId;
        this.width = width;
        this.height = height;

        setOutputMarkupId(true);
    }

    @Override
    protected IResource getImageResource() {
        IResource imageResource = null;
        final JFreeChart chart = (JFreeChart) getDefaultModelObject();
        imageResource = new DynamicImageResource() {
            private static final long serialVersionUID = 1L;

            @Override
            protected byte[] getImageData(final Attributes attributes) {
                final ByteArrayOutputStream stream = new ByteArrayOutputStream();
                try {
                    if (chart != null) {
                        JFreeChartImageWithToolTip.this.chartRenderingInfo.clear();
                        ChartUtilities.writeChartAsPNG(stream, chart, JFreeChartImageWithToolTip.this.width,
                                JFreeChartImageWithToolTip.this.height,
                                JFreeChartImageWithToolTip.this.chartRenderingInfo);
                    }
                } catch (final IOException ex) {
                    // TODO logging for rendering chart error
                }
                return stream.toByteArray();
            }
        };
        return imageResource;
    }

    @Override
    public void onComponentTagBody(final MarkupStream markupStream, final ComponentTag openTag) {
        final JFreeChart chart = (JFreeChart) getDefaultModelObject();
        if (chart == null) {
            return;
        }
        final ByteArrayOutputStream stream = new ByteArrayOutputStream();
        try {
            this.chartRenderingInfo.clear();
            ChartUtilities.writeChartAsPNG(stream, chart, this.width, this.height, this.chartRenderingInfo);
        } catch (final IOException ex) {
            // do something
        }
        replaceComponentTagBody(markupStream, openTag,
                ChartUtilities.getImageMap(this.imageMapId, this.chartRenderingInfo));
    }
}