org.eclipse.swt.examples.graphics.StarPolyTab.java Source code

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Here is the source code for org.eclipse.swt.examples.graphics.StarPolyTab.java

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/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.examples.graphics;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;

public class StarPolyTab extends GraphicsTab {
    int[] radial;
    static final int POINTS = 11;

    Combo fillRuleCb;

    public StarPolyTab(GraphicsExample example) {
        super(example);
        radial = new int[POINTS * 2];
    }

    @Override
    public void createControlPanel(Composite parent) {
        new Label(parent, SWT.NONE).setText(GraphicsExample.getResourceString("FillRule")); //$NON-NLS-1$
        fillRuleCb = new Combo(parent, SWT.DROP_DOWN);
        fillRuleCb.add("FILL_EVEN_ODD");
        fillRuleCb.add("FILL_WINDING");
        fillRuleCb.select(0);
        fillRuleCb.addListener(SWT.Selection, event -> example.redraw());
    }

    @Override
    public String getCategory() {
        return GraphicsExample.getResourceString("Polygons"); //$NON-NLS-1$
    }

    @Override
    public String getText() {
        return GraphicsExample.getResourceString("StarPolygon"); //$NON-NLS-1$
    }

    @Override
    public String getDescription() {
        return GraphicsExample.getResourceString("StarPolygonDescription"); //$NON-NLS-1$
    }

    @Override
    public void paint(GC gc, int width, int height) {
        int centerX = width / 2;
        int centerY = height / 2;
        int pos = 0;
        for (int i = 0; i < POINTS; ++i) {
            double r = Math.PI * 2 * pos / POINTS;
            radial[i * 2] = (int) ((1 + Math.cos(r)) * centerX);
            radial[i * 2 + 1] = (int) ((1 + Math.sin(r)) * centerY);
            pos = (pos + POINTS / 2) % POINTS;
        }
        gc.setFillRule(fillRuleCb.getSelectionIndex() != 0 ? SWT.FILL_WINDING : SWT.FILL_EVEN_ODD);
        gc.setBackground(gc.getDevice().getSystemColor(SWT.COLOR_YELLOW));
        gc.fillPolygon(radial);
        gc.drawPolygon(radial);
    }
}