es.deusto.weblab.client.ui.widgets.WlStreamImage.java Source code

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Here is the source code for es.deusto.weblab.client.ui.widgets.WlStreamImage.java

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/*
* Copyright (C) 2005 onwards University of Deusto
* All rights reserved.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution.
*
* This software consists of contributions made by many individuals, 
* listed below:
*
* Author: Pablo Ordua <pablo@ordunya.com>
*
*/
package es.deusto.weblab.client.ui.widgets;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ErrorEvent;
import com.google.gwt.event.dom.client.ErrorHandler;
import com.google.gwt.event.dom.client.LoadEvent;
import com.google.gwt.event.dom.client.LoadHandler;
import com.google.gwt.json.client.JSONObject;
import com.google.gwt.json.client.JSONValue;
import com.google.gwt.user.client.Random;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.HasHorizontalAlignment;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Image;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

public class WlStreamImage extends VerticalPanel implements IWlWidget {

    public static final String DEFAULT_IMAGE_URL = GWT.getModuleBaseURL() + "/waiting_url_image.jpg";
    public static final int DEFAULT_REFRESH_TIME = 400;

    protected Image image;

    protected int time;
    protected String url;
    protected String streamingUrl;
    protected int streamingWidth;
    protected int streamingHeight;
    protected Timer timer;
    protected boolean running;
    protected final HorizontalPanel imagePanel;

    public WlStreamImage() {
        this(WlStreamImage.DEFAULT_REFRESH_TIME, WlStreamImage.DEFAULT_IMAGE_URL);
    }

    public WlStreamImage(int time) {
        this(time, WlStreamImage.DEFAULT_IMAGE_URL);
    }

    public WlStreamImage(int time, String url) {
        this(time, url, WlStreamImage.DEFAULT_IMAGE_URL);
    }

    public WlStreamImage(int time, String url, String streamingUrl) {
        this.imagePanel = new HorizontalPanel();
        this.imagePanel.setWidth("100%");
        this.imagePanel.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);
        this.time = time;
        this.url = url;
        this.streamingUrl = streamingUrl;

        this.image = new Image(this.getDifferentUrl());

        this.imagePanel.add(this.image);
        this.setWidth("100%");
        this.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);
        this.add(this.imagePanel);
    }

    public void start() {
        this.running = true;
        this.timer = new Timer() {
            @Override
            public void run() {
                WlStreamImage.this.reload();
            }
        };
        this.reload();
    }

    public void configureImageStream(JSONObject initialConfigObject) {
        final JSONValue webcamValue = initialConfigObject.get("webcam");
        if (webcamValue != null) {
            final String urlWebcam = webcamValue.isString().stringValue();
            setUrl(urlWebcam);
        }

    }

    public void stop() {
        this.running = false;
        if (this.timer != null)
            this.timer.cancel();
    }

    @Override
    public void dispose() {
        this.running = false;

        if (this.timer != null)
            this.timer.cancel();

        this.timer = null;
    }

    @Override
    public void setVisible(boolean visible) {
        super.setVisible(visible);
        this.image.setVisible(visible);
    }

    public void reload() {
        if (this.running) {
            reloadJpeg();
        }
    }

    protected void reloadJpeg() {
        this.image.setUrl(this.getDifferentUrl());
        this.image.addErrorHandler(new ErrorHandler() {

            @Override
            public void onError(ErrorEvent event) {
                if (WlStreamImage.this.timer != null)
                    WlStreamImage.this.timer.schedule(WlStreamImage.this.time);
            }
        });
        this.image.addLoadHandler(new LoadHandler() {
            @Override
            public void onLoad(LoadEvent event) {
                if (WlStreamImage.this.timer != null)
                    WlStreamImage.this.timer.schedule(WlStreamImage.this.time);
            }
        });
    }

    protected String randomStuff() {
        return "?" + Random.nextInt();
    }

    protected String getDifferentUrl() {
        return this.url + this.randomStuff();
    }

    public String getUrl() {
        return this.url;
    }

    public String getStreamingUrl() {
        return this.streamingUrl;
    }

    protected void reloadPanel() {
        reload();
    }

    public void setTime(int milliseconds) {
        this.time = milliseconds;
        if (this.running) {
            stop();
            start();
        }
    }

    /**
     * Sets the URL to obtain the webcam image from and reloads the webcam
     * so as to display that new image.
     * @param url URL of the image.
     */
    public void setUrl(String url) {
        this.url = url;
        this.reloadPanel();
    }

    /**
     * Sets the URL to obtain the webcam image in MJPEG format so it 
     * automatically shows the video stream.
     * @param url URL of the image.
     */
    public void setStreamingUrl(String streamingUrl, int width, int height) {
        this.streamingUrl = streamingUrl;
        this.streamingHeight = height;
        this.streamingWidth = width;
        this.reloadPanel();
    }

    @Override
    public Widget getWidget() {
        return this;
    }
}