com.rcharts.client.HiddenPanel.java Source code

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Here is the source code for com.rcharts.client.HiddenPanel.java

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/*
 * Copyright 2011 Saurabh Tripathi
 *
 * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0
 *
 * 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 com.rcharts.client;

import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.SimplePanel;

/**
 *   HiddenPanel is responsible for lazy loading of the charts.
 *  Its essential for Charts that they do not start the rendering process
 *  until the parent is not visible. Even when parent visible a little delay 
 *  is needed for the parent to be rendered by browser. HiddenPanel delays 
 *  the calculations and rendering process by 100 Milliseconds by default.
 * (* Its only a observation that without delay chats are rendered properly
 *   the technical reason behind this may or may not be true *)
 *   
 *  In cases like TabLayoutPanel the charts are needed to wrapped to HiddenPanel
 */
public class HiddenPanel extends SimplePanel {

    private Chart chart;
    private boolean added;

    public HiddenPanel() {

    }

    public HiddenPanel(Chart chart) {
        this.chart = chart;
    }

    /**
     * @return the chart
     */
    public Chart getChart() {
        return chart;
    }

    /**
     * @param chart the chart to set
     */
    public void setChart(Chart chart) {
        added = false;
        this.chart = chart;
    }

    @Override
    public void setVisible(boolean visible) {
        if (visible) {
            Timer timer = new Timer() {

                @Override
                public void run() {
                    if (!added) {
                        add(chart);
                        added = true;
                    }
                }
            };
            timer.schedule(100);
        }
    }
}