com.philbeaudoin.quebec.client.scene.Callout.java Source code

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Here is the source code for com.philbeaudoin.quebec.client.scene.Callout.java

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/**
 * Copyright 2012 Philippe Beaudoin
 *
 * 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.philbeaudoin.quebec.client.scene;

import com.google.gwt.canvas.dom.client.Context2d;
import com.philbeaudoin.quebec.shared.utils.ConstantTransform;
import com.philbeaudoin.quebec.shared.utils.Vector2d;

/**
 * Scene tree node drawing a triangular callout pointing from one point to another.
 * @author Philippe Beaudoin <philippe.beaudoin@gmail.com>
 */
public class Callout extends SceneNodeImpl {
    private static final double BASE_SIZE = 0.065;

    private final Vector2d from;
    private final Vector2d to;
    private final Vector2d p1;
    private final Vector2d p3;

    /**
     * Creates a scene tree node drawing an arrow pointing from one point to another.
     * @param from The starting point of the arrow.
     * @param to The ending point of the arrow.
     */
    public Callout(Vector2d from, Vector2d to) {
        this(from, to, true);
    }

    private Callout(Vector2d from, Vector2d to, boolean visible) {
        super(new ConstantTransform(), visible);
        this.from = from;
        this.to = to;
        double px = to.getY() - from.getY();
        double py = from.getX() - to.getX();
        double factor = 0.5 * BASE_SIZE / Math.sqrt(px * px + py * py);
        px *= factor;
        py *= factor;
        p1 = new Vector2d(from.getX() + px, from.getY() + py);
        p3 = new Vector2d(from.getX() - px, from.getY() - py);
    }

    @Override
    public void drawUntransformed(double time, Context2d context) {
        context.beginPath();
        context.moveTo(p1.getX(), p1.getY());
        context.lineTo(to.getX(), to.getY());
        context.lineTo(p3.getX(), p3.getY());
        context.lineTo(p1.getX(), p1.getY());
        context.setLineWidth(0.002);
        context.setStrokeStyle("#000");
        context.stroke();
        context.setFillStyle("#aaa");
        context.fill();
    }

    @Override
    public SceneNode deepClone() {
        return new Callout(from, to, isVisible());
    }
}