<?php
/**
* Copyright (C) 2020-2023 Graham Breach
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* For more information, please contact <[email protected]>
*/
namespace Goat1000\SVGGraph;
/**
* Class for drawing best-fit lines
*/
class BestFit {
protected $graph;
protected $bbox;
protected $lines_below = [];
protected $lines_above = [];
public function __construct(Graph &$graph, BoundingBox $bbox)
{
$this->graph =& $graph;
$this->bbox = $bbox;
}
/**
* Adds a line
*/
public function add($dataset, $points)
{
$type = $this->graph->getOption(['best_fit', $dataset]);
if($type !== 'straight' && $type !== 'curve')
return;
// range and projection
$r_start = $r_end = $p_start = $p_end = null;
list($start, $end) = $this->getRange($dataset);
if($start !== null || $end !== null) {
if($start !== null)
$r_start = $this->graph->unitsX($start);
if($end !== null)
$r_end = $this->graph->unitsX($end);
$project = $this->graph->getOption(['best_fit_project', $dataset]);
$p_start = $project == 'start' || $project == 'both';
$p_end = $project == 'end' || $project == 'both';
$project = $p_start || $p_end;
$points = $this->filterPoints($points, $r_start, $r_end);
}
$class = '\\Goat1000\\SVGGraph\\' . ($type === 'straight' ? 'BestFitLine' : 'BestFitCurve');
$subtypes = $this->graph->getOption(['best_fit_type', $dataset]);
$best_fit = new $class($this->graph, $points, $subtypes);
$best_fit->calculate($this->bbox, $r_start, $r_end, $p_start, $p_end);
if($this->graph->getOption(['best_fit_above', $dataset]))
$this->lines_above[$dataset] = $best_fit;
else
$this->lines_below[$dataset] = $best_fit;
}
/**
* Returns the start and end of selection range
*/
protected function getRange($dataset)
{
$range = $this->graph->getOption(['best_fit_range', $dataset]);
if(!is_array($range))
$range = $this->graph->getOption('best_fit_range');
if(!is_array($range))
return [null, null];
if(count($range) !== 2)
throw new \Exception('Best fit range must contain start and end values');
if($range[0] !== null && !is_numeric($range[0]))
throw new \Exception('Best fit range start not numeric or NULL');
if($range[1] !== null && !is_numeric($range[1]))
throw new \Exception('Best fit range end not numeric or NULL');
if($range[0] !== null && $range[1] !== null && $range[1] <= $range[0])
throw new \Exception('Best fit range start >= end');
return $range;
}
/**
* Filters out points outside the range
*/
protected function filterPoints($points, $start, $end)
{
if($start === null && $end === null)
return $points;
if($start === null)
$callback = function($p) use ($end) { return $p->x <= $end; };
elseif($end === null)
$callback = function($p) use ($start) { return $p->x >= $start; };
else
$callback = function($p) use ($start, $end) { return $p->x <= $end && $p->x >= $start; };
return array_filter($points, $callback);
}
/**
* Returns the lines that go above the graph
*/
public function getAbove()
{
return $this->getLines('lines_above');
}
/**
* Returns the lines below the graph
*/
public function getBelow()
{
return $this->getLines('lines_below');
}
/**
* Creates the markup for a group of lines
*/
private function getLines($which_lines)
{
$lines = '';
foreach($this->{$which_lines} as $dataset => $best_fit) {
$line_path = $best_fit->getLine();
if($line_path->isEmpty())
continue;
$proj_path = $best_fit->getProjection();
$lines .= $this->getLinePath($dataset, $line_path, $proj_path);
}
if($lines == '')
return $lines;
if($this->graph->getOption('semantic_classes')) {
$cls = ['class' => 'bestfit'];
$lines = $this->graph->element('g', $cls, null, $lines);
}
return $lines;
}
/**
* Wraps up the PathData with SVG
*/
protected function getLinePath($dataset, $line_path, $proj_path)
{
// use ColourGroup to support fill and fillColour
$cg = new ColourGroup($this->graph, null, 0, $dataset, 'best_fit_colour');
$colour = $cg->stroke();
$stroke_width = $this->graph->getOption(['best_fit_width', $dataset]);
$dash = $this->graph->getOption(['best_fit_dash', $dataset]);
$opacity = $this->graph->getOption(['best_fit_opacity', $dataset]);
$above = $this->graph->getOption(['best_fit_above', $dataset]);
$type = $this->graph->getOption(['best_fit', $dataset]);
$path = [
'd' => $line_path,
'stroke' => $colour->isNone() ? '#000' : $colour,
];
if($stroke_width != 1 && $stroke_width > 0)
$path['stroke-width'] = $stroke_width;
if(!empty($dash))
$path['stroke-dasharray'] = $dash;
if($opacity != 1)
$path['opacity'] = $opacity;
if($type != 'straight')
$path['fill'] = 'none'; // don't fill curves
$line = $this->graph->element('path', $path);
if($proj_path->isEmpty())
return $line;
// append the projection path
$path['d'] = $proj_path;
$cg = new ColourGroup($this->graph, null, 0, $dataset, 'best_fit_project_colour');
$colour = $cg->stroke();
$stroke_width = $this->graph->getOption(['best_fit_project_width', $dataset]);
$dash = $this->graph->getOption(['best_fit_project_dash', $dataset]);
$opacity = $this->graph->getOption(['best_fit_project_opacity', $dataset]);
if(!$colour->isNone())
$path['stroke'] = $colour;
if($stroke_width > 0)
$path['stroke-width'] = $stroke_width;
if(!empty($dash))
$path['stroke-dasharray'] = $dash;
if($opacity > 0)
$path['opacity'] = $opacity;
$line .= $this->graph->element('path', $path);
return $line;
}
}
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