LuminanceToGrayTest.java

/*
 * Copyright (c) 2021, Harald Kuhr
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package com.twelvemonkeys.imageio.plugins.jpeg;


import java.awt.image.DataBuffer;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.util.Arrays;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;

public class LuminanceToGrayTest {
    @Test
    public void testConvertByteYcc() {
        LuminanceToGray convert = new LuminanceToGray();

        WritableRaster input = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, 1, 1, 3, null);
        WritableRaster result = null;

        byte[] pixel = null;
        for (int i = 0; i < 255; i++) {
            input.setDataElements(0, 0, new byte[] {(byte) i, (byte) (255 - i), (byte) (127 + i)});
            result = convert.filter(input, result);
            pixel = (byte[]) result.getDataElements(0, 0, pixel);

            assertNotNull(pixel);
            assertEquals(1, pixel.length);
            byte[] expected = {(byte) i};
            assertArrayEquals(expected, pixel, String.format("Was: %s, expected: %s", Arrays.toString(pixel), Arrays.toString(expected)));
        }
    }

    @Test
    public void testConvertByteYccK() {
        LuminanceToGray convert = new LuminanceToGray();

        WritableRaster input = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, 1, 1, 4, null);
        WritableRaster result = null;

        byte[] pixel = null;
        for (int i = 0; i < 255; i++) {
            input.setDataElements(0, 0, new byte[] {(byte) i, (byte) (255 - i), (byte) (127 + i), (byte) 255});
            result = convert.filter(input, result);
            pixel = (byte[]) result.getDataElements(0, 0, pixel);

            assertNotNull(pixel);
            assertEquals(1, pixel.length);
            byte[] expected = {(byte) i};
            assertArrayEquals(expected, pixel, String.format("Was: %s, expected: %s", Arrays.toString(pixel), Arrays.toString(expected)));
        }
    }

    @Test
    public void testConvertByteYccA() {
        LuminanceToGray convert = new LuminanceToGray();

        WritableRaster input = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, 1, 1, 4, null);
        WritableRaster result = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, 1, 1, 2, null);

        byte[] pixel = null;
        for (int i = 0; i < 255; i++) {
            input.setDataElements(0, 0, new byte[] {(byte) i, (byte) 255, (byte) (127 + i), (byte) (255 - i)});
            result = convert.filter(input, result);
            pixel = (byte[]) result.getDataElements(0, 0, pixel);

            assertNotNull(pixel);
            assertEquals(2, pixel.length);
            byte[] expected = {(byte) i, (byte) (255 - i)};
            assertArrayEquals(expected, pixel, String.format("Was: %s, expected: %s", Arrays.toString(pixel), Arrays.toString(expected)));
        }
    }
}