annis.gui.widgets.gwt.client.ui.VSimpleCanvas.java Source code

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Here is the source code for annis.gui.widgets.gwt.client.ui.VSimpleCanvas.java

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/*
 * Copyright 2011 Corpuslinguistic working group Humboldt University Berlin.
 *
 * 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 annis.gui.widgets.gwt.client.ui;

import com.google.gwt.canvas.client.Canvas;
import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.Label;
import com.vaadin.client.ApplicationConnection;
import com.vaadin.client.Paintable;
import com.vaadin.client.UIDL;
import java.util.Iterator;

/**
 *
 * @author thomas
 */
public class VSimpleCanvas extends Composite implements Paintable {

    /** Set the CSS class name to allow styling. */
    public static final String CLASSNAME = "v-simplecanvas";
    /** The client side widget identifier */
    //protected String paintableId;
    /** Reference to the server connection object. */
    //ApplicationConnection gClient;

    static final int height = 2000;
    static final int width = 2000;

    Canvas canvas;
    Context2d context;

    /**
     * The constructor should first call super() to initialize the component and
     * then handle any initialization relevant to Vaadin.
     */
    public VSimpleCanvas() {
        super();

        canvas = Canvas.createIfSupported();

        if (canvas == null) {
            Label lblErrorMessage = new Label("Your browser does not support the Canvas element.");
            initWidget(lblErrorMessage);
        } else {
            initWidget(canvas);

            canvas.setHeight("" + height + "px");
            canvas.setWidth("" + width + "px");
            canvas.setCoordinateSpaceHeight(height);
            canvas.setCoordinateSpaceWidth(width);

            context = canvas.getContext2d();
        }

        // This method call of the Paintable interface sets the component
        // style name in DOM tree
        setStyleName(CLASSNAME);

    }

    /**
     * Called whenever an update is received from the server 
     */
    @Override
    public void updateFromUIDL(UIDL uidl, ApplicationConnection client) {

        // This call should be made first. 
        // It handles sizes, captions, tooltips, etc. automatically.
        if (client.updateComponent(this, uidl, true)) {
            // If client.updateComponent returns true there has been no changes and we
            // do not need to update anything.
            return;
        }

        // Save reference to server connection object to be able to send
        // user interaction later
        //this.gClient = client;

        // Save the client side identifier (paintable id) for the widget
        //paintableId = uidl.getId();

        if (context != null) {
            Iterator<Object> it = uidl.getChildIterator();
            while (it.hasNext()) {
                UIDL child = (UIDL) it.next();

                if ("clear".equals(child.getTag())) {
                    context.clearRect(0, 0, context.getCanvas().getWidth(), context.getCanvas().getHeight());
                } else if ("line".equals(child.getTag())) {
                    context.setGlobalAlpha(1.0);
                    context.setLineWidth(1.0);
                    context.setStrokeStyle("black");
                    context.beginPath();
                    context.moveTo(child.getIntAttribute("from_x"), child.getIntAttribute("from_y"));
                    context.lineTo(child.getIntAttribute("to_x"), child.getIntAttribute("to_y"));
                    context.closePath();
                    context.stroke();
                }
                // todo: more commands :)
            }

        }
    }
}