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 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 * 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.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.IOException;

/**
 * @test
 * @bug 8015070
 * @summary Tests for artifacts around the edges of anti-aliased text.
 */
public class AADrawStringArtifact {
    /* Image dimensions */
    static final int TEST_IMAGE_WIDTH  = 200;
    static final int TEST_IMAGE_HEIGHT = 100;

    public AADrawStringArtifact() throws IOException {
        /* Create a Graphics2D object from a BufferedImage */
        BufferedImage testImg = new BufferedImage(TEST_IMAGE_WIDTH,
                                                  TEST_IMAGE_HEIGHT,
                                                  BufferedImage.TYPE_INT_ARGB);
        Graphics2D graphics = (Graphics2D) testImg.getGraphics();

        /* Fill the image with translucent color */
        graphics.setColor(new Color(127, 127, 127, 127));
        graphics.fillRect(0, 0, TEST_IMAGE_WIDTH, TEST_IMAGE_HEIGHT);

        /* Drawstring with Antialiasing hint */
        graphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
                                  RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
        Font font = new Font("Verdana" , Font.PLAIN, 60);
        graphics.setFont(font);
        graphics.setColor(new Color(255, 0, 0));
        graphics.drawString("Save", 30, 65);
        graphics.dispose();

        /* Check for artifacts */
        checkArtifacts(testImg);
    }

    void checkArtifacts(BufferedImage testImage) throws IOException {
        int componentMask   = 0xff;
        int colorThreshold  = 200;
        int rowIndex = 0;
        int colIndex = 0;

        /* Loop through every pixel to check for possible artifact */
        for (rowIndex = 0; rowIndex < testImage.getHeight(); rowIndex++) {
            for (colIndex = 0; colIndex < testImage.getWidth(); colIndex++) {
                /*
                 * API: getRGB(x,y) returns color in INT_ARGB color space.
                 * Extract individual color components with a simple mask.
                 */
                int colorValue = testImage.getRGB(colIndex, rowIndex);
                int colorComponent1 = colorValue & componentMask;
                int colorComponent2 = (colorValue>>8) & componentMask;
                int colorComponent3 = (colorValue>>16) & componentMask;

                /*
                 * Artifacts are predominantly a subjective decision based on
                 * the quality of the rendered image content. However, in the
                 * current use-case, the artifacts around the edges of the anti
                 * aliased text appear like spots of white pixels without any
                 * relation to the color of foreground text or the background
                 * translucent shape.
                 *
                 * To identify the artifact pixels, each color component from
                 * the testImage is compared with a constant threshold. The
                 * component threshold has been set based on observation from
                 * different experiments on mulitple Java versions.
                 */
                if (colorComponent1 >= colorThreshold
                        && colorComponent2 >= colorThreshold
                        && colorComponent3 >= colorThreshold) {
                    /* Artifact has been noticed. Report error. */
                    throw new RuntimeException("Test Failed.");
                }
            }
        }
    }

    public static void main(String[] args) throws IOException {
        /* Mere instantiating this object will suffice for automated test */
        AADrawStringArtifact artifactTest = new AADrawStringArtifact();
    }
}