org.primaresearch.web.gwt.client.ui.page.renderer.PolygonRendererHelper.java Source code

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Here is the source code for org.primaresearch.web.gwt.client.ui.page.renderer.PolygonRendererHelper.java

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/*
 * Copyright 2014 PRImA Research Lab, University of Salford, United Kingdom
 *
 * 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 org.primaresearch.web.gwt.client.ui.page.renderer;

import org.primaresearch.maths.geometry.Polygon;
import org.primaresearch.web.gwt.client.ui.RenderStyles.RenderStyle;

import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.canvas.dom.client.CssColor;

/**
 * Simple static helper class to draw a polygon on a canvas.
 * 
 * @author Christian Clausner
 *
 */
public abstract class PolygonRendererHelper {

    private static void setFillColor(Context2d context, RenderStyle style) {
        if (style != null)
            context.setFillStyle(style.getFillColor());
        else
            context.setFillStyle(CssColor.make("rgba(128, 128, 128, 0.2)"));
    }

    private static void setLineColor(Context2d context, RenderStyle style) {
        if (style != null)
            context.setStrokeStyle(style.getLineColor());
        else
            context.setStrokeStyle(CssColor.make("rgb(128, 128, 128)"));
    }

    /**
     * Draws a polygon
     * @param context Canvas
     * @param polygon List of points
     * @param style Colours and line width
     * @param zoomFactor Current zoom
     * @param outline Set to <code>true</code> to draw the polygon outline
     * @param fill Set to <code>true</code> to fill the polygon
     */
    public static void drawPolygon(Context2d context, Polygon polygon, RenderStyle style, double zoomFactor,
            boolean outline, boolean fill) {
        setLineColor(context, style);
        setFillColor(context, style);
        context.setLineWidth(style.getLineWidth() / zoomFactor);
        drawPolygon(context, polygon, outline, fill);
    }

    private static void drawPolygon(Context2d context, Polygon polygon, boolean outline, boolean fill) {
        if (polygon == null || polygon.getSize() < 3 || (!outline && !fill))
            return;

        context.beginPath();
        context.moveTo(polygon.getPoint(0).x, polygon.getPoint(0).y);
        for (int i = 1; i < polygon.getSize(); i++)
            context.lineTo(polygon.getPoint(i).x, polygon.getPoint(i).y);
        context.lineTo(polygon.getPoint(0).x, polygon.getPoint(0).y);
        if (fill)
            context.fill();
        if (outline)
            context.stroke();
    }

}