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<?php |
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/** |
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* Copyright (C) 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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* A class for drawing arrows |
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*/ |
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class Arrow { |
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|
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protected $a; |
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protected $b; |
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protected $head_size = 7; |
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protected $head_colour = '#000'; |
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|
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public function __construct(Point $a, Point $b) |
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{ |
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$this->a = $a; |
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$this->b = $b; |
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} |
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|
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/** |
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* Sets the arrow head size (min 2 pixels) |
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*/ |
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public function setHeadSize($size) |
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{ |
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$this->head_size = max(2, $size); |
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} |
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|
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public function setHeadColour($colour) |
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{ |
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$this->head_colour = $colour; |
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} |
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|
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/** |
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* Returns the arrow head as the ID of a <marker> element |
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*/ |
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protected function getArrowHead($graph) |
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{ |
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$sz = new Number($this->head_size); |
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$point = 75; // sharpness of arrow |
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$marker = [ |
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'viewBox' => "0 0 {$point} 100", |
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'markerWidth' => $sz, |
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'markerHeight' => $sz, |
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'refX' => $point, |
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'refY' => 50, |
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'orient' => 'auto', |
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]; |
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$pd = new PathData('M', 0, 0, 'L', $point, 50, 'L', 0, 100, 'z'); |
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$path = [ |
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'd' => $pd, |
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'stroke' => $this->head_colour, |
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'fill' => $this->head_colour, |
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]; |
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$marker_content = $graph->element('path', $path); |
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return $graph->defs->addElement('marker', $marker, $marker_content); |
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} |
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|
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/** |
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* Returns the PathData for an arrow line |
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*/ |
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protected function getArrowPath() |
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{ |
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return new PathData('M', $this->a, $this->b); |
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} |
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|
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/** |
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* Returns the arrow element |
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*/ |
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public function draw($graph, $style = null) |
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{ |
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$head_id = $this->getArrowHead($graph); |
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$p = $this->getArrowPath(); |
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|
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$path = [ |
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'd' => $p, |
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'marker-end' => 'url(#' . $head_id . ')', |
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'fill' => 'none', |
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]; |
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if(is_array($style)) |
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$path = array_merge($style, $path); |
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return $graph->element('path', $path); |
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} |
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} |
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|
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|
