PhpSpreadsheet/tests/data/Style/ColorChangeBrightness.php

<?php

return [
    [['FFAABBCC', 0.1], 'FFB2C1D1'], //  RGBA
    [['FFAABBCC', -0.1], 'FF99A8B7'], //  RGBA
    [['AABBCC', 0.1], 'B2C1D1'], //  RGB
    [['AABBCC', -0.1], '99A8B7'],
    [['FF0000', 0.1], 'FF1919'],
    [['FF0000', -0.1], 'E50000'],
    [['FF8080', 0.1], 'FF8C8C'],
    [['FF8080', -0.1], 'E57373'],
    [['FF0000', 0.15], 'FF2626'],
    [['FF0000', -0.15], 'D80000'],
    [['FF8080', 0.15], 'FF9393'],
    [['FF8080', -0.15], 'D86C6C'],
    [['FFF008', 0.5], 'FFF783'],
    [['FFF008', -0.5], '7F7804'],
];