tablepress / libraries / vendor / PhpSpreadsheet / Style / RgbTint.php

RgbTint.php in TablePress – Tables in WordPress made easy 3.4, at libraries/vendor/PhpSpreadsheet/Style/RgbTint.php

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1	<?php
2
3	namespace TablePress\PhpOffice\PhpSpreadsheet\Style;
4
5	/**
6	* Class to handle tint applied to color.
7	* Code borrows heavily from some Python projects.
8	*
9	* @see https://docs.python.org/3/library/colorsys.html
10	* @see https://gist.github.com/Mike-Honey/b36e651e9a7f1d2e1d60ce1c63b9b633
11	*/
12	class RgbTint
13	{
14	private const ONE_THIRD = 1.0 / 3.0;
15	private const ONE_SIXTH = 1.0 / 6.0;
16	private const TWO_THIRD = 2.0 / 3.0;
17	private const RGBMAX = 255.0;
18	/**
19	* MS Excel's tint function expects that HLS is base 240.
20	*
21	* @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
22	*/
23	private const HLSMAX = 240.0;
24
25	/**
26	* Convert red/green/blue to hue/luminance/saturation.
27	*
28	* @param float $red 0.0 through 1.0
29	* @param float $green 0.0 through 1.0
30	* @param float $blue 0.0 through 1.0
31	*
32	* @return float[]
33	*/
34	private static function rgbToHls(float $red, float $green, float $blue): array
35	{
36	$maxc = max($red, $green, $blue);
37	$minc = min($red, $green, $blue);
38	$luminance = ($minc + $maxc) / 2.0;
39	if ($minc === $maxc) {
40	return [0.0, $luminance, 0.0];
41	}
42	$maxMinusMin = $maxc - $minc;
43	if ($luminance <= 0.5) {
44	$s = $maxMinusMin / ($maxc + $minc);
45	} else {
46	$s = $maxMinusMin / (2.0 - $maxc - $minc);
47	}
48	$rc = ($maxc - $red) / $maxMinusMin;
49	$gc = ($maxc - $green) / $maxMinusMin;
50	$bc = ($maxc - $blue) / $maxMinusMin;
51	if ($red === $maxc) {
52	$h = $bc - $gc;
53	} elseif ($green === $maxc) {
54	$h = 2.0 + $rc - $bc;
55	} else {
56	$h = 4.0 + $gc - $rc;
57	}
58	$h = self::positiveDecimalPart($h / 6.0);
59
60	return [$h, $luminance, $s];
61	}
62
63	/**
64	* Convert hue/luminance/saturation to red/green/blue.
65	*
66	* @param float $hue 0.0 through 1.0
67	* @param float $luminance 0.0 through 1.0
68	* @param float $saturation 0.0 through 1.0
69	*
70	* @return float[]
71	*/
72	private static function hlsToRgb(float $hue, float $luminance, float $saturation): array
73	{
74	if ($saturation === 0.0) {
75	return [$luminance, $luminance, $luminance];
76	}
77	if ($luminance <= 0.5) {
78	$m2 = $luminance * (1.0 + $saturation);
79	} else {
80	$m2 = $luminance + $saturation - ($luminance * $saturation);
81	}
82	$m1 = 2.0 * $luminance - $m2;
83
84	return [
85	self::vFunction($m1, $m2, $hue + self::ONE_THIRD),
86	self::vFunction($m1, $m2, $hue),
87	self::vFunction($m1, $m2, $hue - self::ONE_THIRD),
88	];
89	}
90
91	private static function vFunction(float $m1, float $m2, float $hue): float
92	{
93	$hue = self::positiveDecimalPart($hue);
94	if ($hue < self::ONE_SIXTH) {
95	return $m1 + ($m2 - $m1) * $hue * 6.0;
96	}
97	if ($hue < 0.5) {
98	return $m2;
99	}
100	if ($hue < self::TWO_THIRD) {
101	return $m1 + ($m2 - $m1) * (self::TWO_THIRD - $hue) * 6.0;
102	}
103
104	return $m1;
105	}
106
107	private static function positiveDecimalPart(float $hue): float
108	{
109	$hue = fmod($hue, 1.0);
110
111	return ($hue >= 0.0) ? $hue : (1.0 + $hue);
112	}
113
114	/**
115	* Convert red/green/blue to HLSMAX-based hue/luminance/saturation.
116	*
117	* @return int[]
118	*/
119	private static function rgbToMsHls(int $red, int $green, int $blue): array
120	{
121	$red01 = $red / self::RGBMAX;
122	$green01 = $green / self::RGBMAX;
123	$blue01 = $blue / self::RGBMAX;
124	[$hue, $luminance, $saturation] = self::rgbToHls($red01, $green01, $blue01);
125
126	return [
127	(int) round($hue * self::HLSMAX),
128	(int) round($luminance * self::HLSMAX),
129	(int) round($saturation * self::HLSMAX),
130	];
131	}
132
133	/**
134	* Converts HLSMAX based HLS values to rgb values in the range (0,1).
135	*
136	* @return float[]
137	*/
138	private static function msHlsToRgb(int $hue, int $lightness, int $saturation): array
139	{
140	return self::hlsToRgb($hue / self::HLSMAX, $lightness / self::HLSMAX, $saturation / self::HLSMAX);
141	}
142
143	/**
144	* Tints HLSMAX based luminance.
145	*
146	* @see http://ciintelligence.blogspot.co.uk/2012/02/converting-excel-theme-color-and-tint.html
147	*/
148	private static function tintLuminance(float $tint, float $luminance): int
149	{
150	if ($tint < 0) {
151	return (int) round($luminance * (1.0 + $tint));
152	}
153
154	return (int) round($luminance * (1.0 - $tint) + (self::HLSMAX - self::HLSMAX * (1.0 - $tint)));
155	}
156
157	/**
158	* Return result of tinting supplied rgb as 6 hex digits.
159	*/
160	public static function rgbAndTintToRgb(int $red, int $green, int $blue, float $tint): string
161	{
162	[$hue, $luminance, $saturation] = self::rgbToMsHls($red, $green, $blue);
163	[$red, $green, $blue] = self::msHlsToRgb($hue, self::tintLuminance($tint, $luminance), $saturation);
164
165	return sprintf(
166	'%02X%02X%02X',
167	(int) round($red * self::RGBMAX),
168	(int) round($green * self::RGBMAX),
169	(int) round($blue * self::RGBMAX)
170	);
171	}
172	}
173