Proyectos de Subversion Moodle

<?php

namespace PhpOffice\PhpSpreadsheet\Style;

/**

 * Class to handle tint applied to color.

 * Code borrows heavily from some Python projects.

 *

 * @see https://docs.python.org/3/library/colorsys.html

 * @see https://gist.github.com/Mike-Honey/b36e651e9a7f1d2e1d60ce1c63b9b633

 */

class RgbTint

{

    private const ONE_THIRD = 1.0 / 3.0;

    private const ONE_SIXTH = 1.0 / 6.0;

    private const TWO_THIRD = 2.0 / 3.0;

    private const RGBMAX = 255.0;

    /**

     * MS excel's tint function expects that HLS is base 240.

     *

     * @see https://social.msdn.microsoft.com/Forums/en-US/e9d8c136-6d62-4098-9b1b-dac786149f43/excel-color-tint-algorithm-incorrect?forum=os_binaryfile#d3c2ac95-52e0-476b-86f1-e2a697f24969

     */

    private const HLSMAX = 240.0;

    /**

     * Convert red/green/blue to hue/luminance/saturation.

     *

     * @param float $red 0.0 through 1.0

     * @param float $green 0.0 through 1.0

     * @param float $blue 0.0 through 1.0

     *

     * @return float[]

     */

    private static function rgbToHls(float $red, float $green, float $blue): array

    {

        $maxc = max($red, $green, $blue);

        $minc = min($red, $green, $blue);

        $luminance = ($minc + $maxc) / 2.0;

        if ($minc === $maxc) {

            return [0.0, $luminance, 0.0];

        }

        $maxMinusMin = $maxc - $minc;

        if ($luminance <= 0.5) {

            $s = $maxMinusMin / ($maxc + $minc);

        } else {

            $s = $maxMinusMin / (2.0 - $maxc - $minc);

        }

        $rc = ($maxc - $red) / $maxMinusMin;

        $gc = ($maxc - $green) / $maxMinusMin;

        $bc = ($maxc - $blue) / $maxMinusMin;

        if ($red === $maxc) {

            $h = $bc - $gc;

        } elseif ($green === $maxc) {

            $h = 2.0 + $rc - $bc;

        } else {

            $h = 4.0 + $gc - $rc;

        }

        $h = self::positiveDecimalPart($h / 6.0);

        return [$h, $luminance, $s];

    }

    /**

     * Convert hue/luminance/saturation to red/green/blue.

     *

     * @param float $hue 0.0 through 1.0

     * @param float $luminance 0.0 through 1.0

     * @param float $saturation 0.0 through 1.0

     *

     * @return float[]

     */

    private static function hlsToRgb(float $hue, float $luminance, float $saturation): array

    {

        if ($saturation === 0.0) {

            return [$luminance, $luminance, $luminance];

        }

        if ($luminance <= 0.5) {

            $m2 = $luminance * (1.0 + $saturation);

        } else {

            $m2 = $luminance + $saturation - ($luminance * $saturation);

        }

        $m1 = 2.0 * $luminance - $m2;

        return [

            self::vFunction($m1, $m2, $hue + self::ONE_THIRD),

            self::vFunction($m1, $m2, $hue),

            self::vFunction($m1, $m2, $hue - self::ONE_THIRD),

        ];

    }

    private static function vFunction(float $m1, float $m2, float $hue): float

    {

        $hue = self::positiveDecimalPart($hue);

        if ($hue < self::ONE_SIXTH) {

            return $m1 + ($m2 - $m1) * $hue * 6.0;

        }

        if ($hue < 0.5) {

            return $m2;

        }

        if ($hue < self::TWO_THIRD) {

            return $m1 + ($m2 - $m1) * (self::TWO_THIRD - $hue) * 6.0;

        }

        return $m1;

    }

    private static function positiveDecimalPart(float $hue): float

    {

        $hue = fmod($hue, 1.0);

        return ($hue >= 0.0) ? $hue : (1.0 + $hue);

    }

    /**

     * Convert red/green/blue to HLSMAX-based hue/luminance/saturation.

     *

     * @return int[]

     */

    private static function rgbToMsHls(int $red, int $green, int $blue): array

    {

        $red01 = $red / self::RGBMAX;

        $green01 = $green / self::RGBMAX;

        $blue01 = $blue / self::RGBMAX;

        [$hue, $luminance, $saturation] = self::rgbToHls($red01, $green01, $blue01);

        return [

            (int) round($hue * self::HLSMAX),

            (int) round($luminance * self::HLSMAX),

            (int) round($saturation * self::HLSMAX),

        ];

    }

    /**

     * Converts HLSMAX based HLS values to rgb values in the range (0,1).

     *

     * @return float[]

     */

    private static function msHlsToRgb(int $hue, int $lightness, int $saturation): array

    {

        return self::hlsToRgb($hue / self::HLSMAX, $lightness / self::HLSMAX, $saturation / self::HLSMAX);

    }

    /**

     * Tints HLSMAX based luminance.

     *

     * @see http://ciintelligence.blogspot.co.uk/2012/02/converting-excel-theme-color-and-tint.html

     */

    private static function tintLuminance(float $tint, float $luminance): int

    {

        if ($tint < 0) {

            return (int) round($luminance * (1.0 + $tint));

        }

        return (int) round($luminance * (1.0 - $tint) + (self::HLSMAX - self::HLSMAX * (1.0 - $tint)));

    }

    /**

     * Return result of tinting supplied rgb as 6 hex digits.

     */

    public static function rgbAndTintToRgb(int $red, int $green, int $blue, float $tint): string

    {

        [$hue, $luminance, $saturation] = self::rgbToMsHls($red, $green, $blue);

        [$red, $green, $blue] = self::msHlsToRgb($hue, self::tintLuminance($tint, $luminance), $saturation);

        return sprintf(

            '%02X%02X%02X',

            (int) round($red * self::RGBMAX),

            (int) round($green * self::RGBMAX),

            (int) round($blue * self::RGBMAX)

        );

    }

}