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<?php |
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/** |
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* Copyright (C) 2019-2022 Graham Breach |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU Lesser General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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/** |
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* For more information, please contact <graham@goat1000.com> |
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*/ |
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|
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namespace Goat1000\SVGGraph; |
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|
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/** |
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* Colour range for HSL values |
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*/ |
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class ColourRangeHSL extends ColourRange { |
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|
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private $h1, $s1, $l1; |
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private $hdiff, $sdiff, $ldiff; |
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|
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/** |
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* HSL range |
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*/ |
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public function __construct($h1, $s1, $l1, $h2, $s2, $l2) |
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{ |
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$this->h1 = $this->clamp($h1, 0, 360); |
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$this->s1 = $this->clamp($s1, 0, 1); |
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$this->l1 = $this->clamp($l1, 0, 1); |
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|
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$hdiff = $this->clamp($h2, 0, 360) - $this->h1; |
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if(abs($hdiff) > 180) |
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$hdiff += $hdiff < 0 ? 360 : -360; |
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$this->hdiff = $hdiff; |
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$this->sdiff = $this->clamp($s2, 0, 1) - $this->s1; |
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$this->ldiff = $this->clamp($l2, 0, 1) - $this->l1; |
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} |
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|
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/** |
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* Reverse direction of colour cycle |
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*/ |
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public function reverse() |
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{ |
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$this->hdiff += $this->hdiff < 0 ? 360 : -360; |
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} |
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|
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/** |
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* Return the colour from the range |
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*/ |
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#[\ReturnTypeWillChange] |
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public function offsetGet($offset) |
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{ |
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$c = max($this->count - 1, 1); |
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$offset = $this->clamp($offset, 0, $c); |
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$h = fmod(360 + $this->h1 + $offset * $this->hdiff / $c, 360); |
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$s = $this->s1 + $offset * $this->sdiff / $c; |
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$l = $this->l1 + $offset * $this->ldiff / $c; |
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|
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list($r, $g, $b) = $this->hslToRgb($h, $s, $l); |
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return sprintf('#%02x%02x%02x', $r, $g, $b); |
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} |
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|
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/** |
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* Factory method creates an instance from RGB values |
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*/ |
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public static function fromRgb($r1, $g1, $b1, $r2, $g2, $b2) |
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{ |
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list($h1, $s1, $l1) = ColourRangeHSL::rgbToHsl($r1, $g1, $b1); |
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list($h2, $s2, $l2) = ColourRangeHSL::rgbToHsl($r2, $g2, $b2); |
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return new ColourRangeHSL($h1, $s1, $l1, $h2, $s2, $l2); |
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} |
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|
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/** |
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* Convert RGB to HSL (0-360, 0-1, 0-1) |
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*/ |
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public static function rgbToHsl($r, $g, $b) |
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{ |
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$r1 = ColourRangeHSL::clamp($r, 0, 255) / 255; |
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$g1 = ColourRangeHSL::clamp($g, 0, 255) / 255; |
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$b1 = ColourRangeHSL::clamp($b, 0, 255) / 255; |
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$cmax = max($r1, $g1, $b1); |
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$cmin = min($r1, $g1, $b1); |
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$delta = $cmax - $cmin; |
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|
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$l = ($cmax + $cmin) / 2; |
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if($delta == 0) { |
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$h = $s = 0; |
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} else { |
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if($cmax == $r1) { |
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$h = fmod(($g1 - $b1) / $delta, 6); |
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} elseif($cmax == $g1) { |
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$h = 2 + ($b1 - $r1) / $delta; |
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} else { |
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$h = 4 + ($r1 - $g1) / $delta; |
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} |
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$h = fmod(360 + ($h * 60), 360); |
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$s = $delta / (1 - abs(2 * $l - 1)); |
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} |
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return [$h, $s, $l]; |
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} |
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|
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/** |
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* Convert HSL to RGB |
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*/ |
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public static function hslToRgb($h, $s, $l) |
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{ |
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$h1 = ColourRangeHSL::clamp($h, 0, 360); |
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$s1 = ColourRangeHSL::clamp($s, 0, 1); |
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$l1 = ColourRangeHSL::clamp($l, 0, 1); |
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|
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$c = (1 - abs(2 * $l1 - 1)) * $s1; |
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$x = $c * (1 - abs(fmod($h1 / 60, 2) - 1)); |
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$m = $l1 - $c / 2; |
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|
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$c = 255 * ($c + $m); |
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$x = 255 * ($x + $m); |
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$m *= 255; |
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switch(floor($h1 / 60)) { |
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case 0 : $rgb = [$c, $x, $m]; break; |
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case 1 : $rgb = [$x, $c, $m]; break; |
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case 2 : $rgb = [$m, $c, $x]; break; |
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case 3 : $rgb = [$m, $x, $c]; break; |
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case 4 : $rgb = [$x, $m, $c]; break; |
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case 5 : $rgb = [$c, $m, $x]; break; |
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} |
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|
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return $rgb; |
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} |
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} |
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