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<?php |
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/** |
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* Copyright (C) 2013-2022 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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* Class for calculating logarithmic axis measurements |
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*/ |
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class AxisLog extends Axis { |
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|
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protected $lgmin; |
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protected $lgmax; |
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protected $base = 10; |
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protected $divisions; |
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protected $grid_space; |
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protected $grid_split = 0; |
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protected $negative = false; |
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protected $lgmul; |
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protected $int_base = true; |
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|
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public function __construct($length, $max_val, $min_val, $min_unit, |
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$min_space, $fit, $units_before, $units_after, $decimal_digits, |
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$base, $divisions, $label_callback, $values) |
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{ |
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if($min_val == 0 || $max_val == 0) |
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throw new \Exception('0 value on log axis'); |
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if($min_val < 0 && $max_val > 0) |
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throw new \Exception('-ve and +ve on log axis'); |
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if($max_val <= $min_val && $min_unit == 0) |
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throw new \Exception('Zero length axis (min >= max)'); |
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$this->length = $length; |
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$this->min_unit = $min_unit; |
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$this->min_space = $min_space; |
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$this->units_before = $units_before; |
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$this->units_after = $units_after; |
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$this->decimal_digits = $decimal_digits; |
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$this->label_callback = $label_callback; |
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$this->values = $values; |
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if(is_numeric($base) && $base > 1) { |
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$this->base = $base * 1.0; |
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$this->int_base = $this->base == floor($this->base); |
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} |
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$this->uneven = false; |
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if($min_val < 0) { |
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$this->negative = true; |
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$m = $min_val; |
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$min_val = abs($max_val); |
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$max_val = abs($m); |
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} |
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if(is_numeric($divisions)) |
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$this->divisions = $divisions; |
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|
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if($fit && $this->int_base) { |
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// X-axis, try to use values |
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$lgminf = $this->bfloor($min_val); |
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$lgmaxf = $this->bceil($max_val); |
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$this->lgmin = log($lgminf, $this->base); |
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$this->lgmax = log($lgmaxf, $this->base); |
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} else { |
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// Y-axis, allow space |
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$this->lgmin = floor(log($min_val, $this->base)); |
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$this->lgmax = ceil(log($max_val, $this->base)); |
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} |
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|
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// if all the values are the same, and a power of the base |
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if($this->lgmax <= $this->lgmin) |
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$this->lgmin -= 1.0; |
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|
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$this->lgmul = $this->length / ($this->lgmax - $this->lgmin); |
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$this->min_value = pow($this->base, $this->lgmin); |
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$this->max_value = pow($this->base, $this->lgmax); |
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} |
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|
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/** |
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* Floor to the nearest sensible number |
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*/ |
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protected function bfloor($value) |
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{ |
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$b = floor(log($value, $this->base)); |
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$bf = pow($this->base, $b); |
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$m = floor($value / $bf); |
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return $m * $bf; |
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} |
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|
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/** |
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* Ceil to the nearest sensible number |
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*/ |
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protected function bceil($value) |
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{ |
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$b = floor(log($value, $this->base)); |
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$bf = pow($this->base, $b); |
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$m = ceil($value / $bf); |
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return $m * $bf; |
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} |
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|
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/** |
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* Returns the grid points as an associative array: |
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* array($value => $position) |
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*/ |
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public function getGridPoints($start) |
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{ |
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if($start === null) |
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return; |
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|
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$pow_div = ceil($this->lgmax) - floor($this->lgmin); |
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$this->grid_space = $this->length / $pow_div; |
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|
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$this->grid_split = $this->divisions ? $this->divisions : |
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$this->findDivision($this->grid_space, $this->min_space); |
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|
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$spoints = []; |
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if($this->grid_split) { |
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for($l = $this->grid_split; $l < $this->base; $l += $this->grid_split) |
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$spoints[] = log($l, $this->base); |
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} |
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|
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$points = []; |
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$val = $this->min_value; |
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while($val <= $this->max_value) { |
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$value = $this->negative ? -$val : $val; |
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$position = $this->position($value); |
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$position = $start + ($this->direction * $position); |
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$points[] = $this->getGridPoint($position, $value); |
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|
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// inserted at start of loop, but calculated at end |
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if($val > ($this->max_value * 0.995)) |
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break; |
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|
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// find next point |
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$l = log($val, $this->base); |
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$l_floor = floor($l); |
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$l_dec = $l - $l_floor; |
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$l_next = 0; |
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foreach($spoints as $l1) { |
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if($l1 && ($l1 - $l_dec) > 0.001) { |
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$l_next = $l_floor + $l1; |
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break; |
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} |
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} |
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if(!$l_next || $l_next > $this->lgmax) { |
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// next full power or end of axis |
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$l_next = min($l_floor + 1, $this->lgmax); |
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} |
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$val = pow($this->base, $l_next); |
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} |
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|
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if($this->direction < 0) { |
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usort($points, function($a, $b) { return $b->position - $a->position; }); |
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} else { |
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usort($points, function($a, $b) { return $a->position - $b->position; }); |
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} |
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return $points; |
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} |
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|
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/** |
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* Returns the grid subdivision points as an array |
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*/ |
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public function getGridSubdivisions($min_space, $min_unit, $start, $fixed) |
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{ |
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$points = []; |
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if($this->int_base) { |
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$split = $this->findDivision($this->grid_space, $min_space, |
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$this->grid_split); |
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if($split) { |
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for($l = $this->lgmin; $l < $this->lgmax; ++$l) { |
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for($l1 = $split; $l1 < $this->base; $l1 += $split) { |
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if($this->grid_split == 0 || $l1 % $this->grid_split) { |
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$p = log($l1, $this->base); |
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$val = pow($this->base, $l + $p); |
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$position = $start + $this->position($val) * $this->direction; |
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$points[] = new GridPoint($position, '', $val); |
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} |
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} |
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} |
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} |
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} |
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return $points; |
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} |
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|
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/** |
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* Returns the distance in pixels $u takes from $pos |
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*/ |
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public function measureUnits($pos, $u) |
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{ |
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$i = Coords::parseValue($pos); |
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if(!is_numeric($i['value'])) |
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throw new \Exception("Unable to measure $u units from '{$i['value']}'"); |
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|
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$start_pos = $this->position($i['value']); |
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$end_pos = $this->position($i['value'] + $u); |
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return $end_pos - $start_pos; |
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} |
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|
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/** |
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* Returns the position of a value on the axis, or NULL if the position is |
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* not possible |
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*/ |
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public function position($index, $item = null) |
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{ |
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$value = $index; |
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if($item !== null && !$this->values->associativeKeys()) |
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$value = $item->key; |
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if($this->negative) { |
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if($value >= 0) |
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return null; |
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$abs_value = abs($value); |
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if($abs_value < $this->min_value) |
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return null; |
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return $this->length - (log($abs_value, $this->base) - $this->lgmin) * |
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$this->lgmul; |
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} |
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if($value <= 0 || $value < $this->min_value) |
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return null; |
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return (log($value, $this->base) - $this->lgmin) * $this->lgmul; |
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} |
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|
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/** |
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* Returns the position of the origin |
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*/ |
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public function origin() |
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{ |
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// not the position of 0, because that doesn't exist |
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return $this->negative ? $this->length : 0; |
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} |
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|
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/** |
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* Returns the value at a position on the axis |
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*/ |
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public function value($position) |
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{ |
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$p = pow($this->base, $this->lgmin + $position / $this->lgmul); |
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return $p; |
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} |
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|
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/** |
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* Finds an even division of the given space that is >= min_space |
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*/ |
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private function findDivision($space, $min_space, $main_division = 0) |
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{ |
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$split = 0; |
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if($this->int_base) { |
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$division = $main_division ? $main_division : $this->base; |
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$l = $this->base - 1; |
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$lgs = $space * log($l, $this->base); |
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|
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$smallest = $space - $lgs; |
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if($smallest < $min_space) { |
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$max_split = floor($division / 2); |
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for($i = 2; $smallest < $min_space && $i <= $max_split; ++$i) { |
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if($division % $i == 0) { |
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// the smallest gap is the one before the next power |
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$l = $this->base - $i; |
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$lgs = $space * log($l, $this->base); |
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$smallest = $space - $lgs; |
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$split = $i; |
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} |
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} |
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if($smallest < $min_space) |
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$split = 0; |
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} else { |
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$split = 1; |
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} |
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} |
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return $split; |
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} |
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|
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/** |
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* Not actually 0, but the position of the axis |
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*/ |
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public function zero() |
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{ |
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if($this->negative) |
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return $this->length; |
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return 0; |
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} |
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} |
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|
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|
