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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import static java.awt.image.BufferedImage.TYPE_INT_ARGB;

/**
 * @test
 * @key headful
 * @bug 8167310
 * @summary The clip should be correct if the scale is fractional
 */
public final class IncorrectFractionalClip {

    private static final int SIZE = 128;

    public static final Color RED = new Color(255, 0, 0, 100);

    public static final Color GREEN = new Color(0, 255, 0, 100);

    public static final Color WHITE = new Color(0, 0, 0, 0);

    private static final double[] SCALES = {
            0.1, 0.25, 0.4, 0.5, 0.6, 1, 1.4, 1.5, 1.6, 2.0, 2.4, 2.5, 2.6, 4
    };

    static BufferedImage bi;

    static BufferedImage redI;

    static BufferedImage greenI;

    public static void main(final String[] args) throws Exception {
        bi = new BufferedImage(SIZE, SIZE, TYPE_INT_ARGB);
        redI = createImage(RED);
        greenI = createImage(GREEN);

        System.out.println("Will test fillRect");
        test(0, true);
        test(0, false);
        System.out.println("Will test DrawImage");
        test(1, true);
        test(1, false);
        System.out.println("Will test drawLine");
        test(2, true);
        test(2, false);
    }

    /**
     * This method draw/fills a number of rectangle, images and lines. Each of
     * them are painted one after anothere without gaps. Each time the clip is
     * set as one vertical/horizontal line. The resulted image should not
     * have any overlapping of different colors. The gaps are possible only in
     * case of Lines.
     */
    private static void test(final int testId, final boolean horiz)
            throws Exception {
        for (final double scale : SCALES) {
            // Initialize the main image
            Graphics2D g = bi.createGraphics();
            g.setComposite(AlphaComposite.Src);
            g.setColor(WHITE);
            g.fillRect(0, 0, bi.getWidth(), bi.getHeight());
            g.setComposite(AlphaComposite.SrcOver);

            // set the scale in one direction
            if (horiz) {
                g.scale(scale, 1);
            } else {
                g.scale(1, scale);
            }
            // cover all units in the user space to touch all pixels in the
            // image after transform
            for (int step = 0; step < SIZE / scale; ++step) {
                if (horiz) {
                    g.setClip(step, 0, 1, SIZE);
                } else {
                    g.setClip(0, step, SIZE, 1);
                }
                switch (testId) {
                    case 0:
                        g.setColor(step % 2 == 0 ? RED : GREEN);
                        g.fillRect(0, 0, Integer.MAX_VALUE, Integer.MAX_VALUE);
                        break;
                    case 1:
                        g.drawImage(step % 2 == 0 ? redI : greenI, 0, 0,
                                    Integer.MAX_VALUE, Integer.MAX_VALUE, null);
                        break;
                    case 2:
                        g.setColor(step % 2 == 0 ? RED : GREEN);
                        if (horiz) {
                            g.drawLine(step, 0, step, SIZE);
                        } else {
                            g.drawLine(0, step, SIZE, step);
                        }
                        break;
                    default:
                        throw new RuntimeException();
                }
            }
            g.dispose();
            validate(bi, testId);
        }
    }

    private static void validate(final BufferedImage bi, final int testID)
            throws Exception {
        for (int x = 0; x < SIZE; ++x) {
            for (int y = 0; y < SIZE; ++y) {
                int rgb = bi.getRGB(x, y);
                if (rgb != GREEN.getRGB() && rgb != RED.getRGB()) {
                    if (testID == 2) {
                        // The drawLine should not overlap lines but it is
                        // possible to have gaps between lines.
                        if (rgb == WHITE.getRGB()) {
                            continue;
                        }
                        ImageIO.write(bi, "png", new File("image.png"));
                        throw new RuntimeException("Test failed.");
                    }
                }
            }
        }
    }

    private static BufferedImage createImage(final Color color) {
        BufferedImage bi = new BufferedImage(SIZE, SIZE, TYPE_INT_ARGB);
        Graphics2D g = bi.createGraphics();
        g.setComposite(AlphaComposite.Src);
        g.setColor(color);
        g.fillRect(0, 0, bi.getWidth(), bi.getHeight());
        g.dispose();
        return bi;
    }
}