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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 11:46:43 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 11:46:43 +0000
commit3e02d5aff85babc3ffbfcf52313f2108e313aa23 (patch)
treeb01f3923360c20a6a504aff42d45670c58af3ec5 /library/Icinga/Chart/Unit/LogarithmicUnit.php
parentInitial commit. (diff)
downloadicingaweb2-upstream.tar.xz
icingaweb2-upstream.zip
Adding upstream version 2.12.1.upstream/2.12.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/Icinga/Chart/Unit/LogarithmicUnit.php')
-rw-r--r--library/Icinga/Chart/Unit/LogarithmicUnit.php263
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diff --git a/library/Icinga/Chart/Unit/LogarithmicUnit.php b/library/Icinga/Chart/Unit/LogarithmicUnit.php
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+<?php
+/* Icinga Web 2 | (c) 2013 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Chart\Unit;
+
+/**
+ * Logarithmic tick distribution over the axis
+ *
+ * This class does not use the actual logarithm, but a slightly altered version called the
+ * Log-Modulo transformation. This is necessary, since a regular logarithmic scale is not able to display negative
+ * values and zero-points. See <a href="http://blogs.sas.com/content/iml/2014/07/14/log-transformation-of-pos-neg>
+ * this article </a> for a more detailed description.
+ */
+class LogarithmicUnit implements AxisUnit
+{
+ /**
+ * @var int
+ */
+ protected $base;
+
+ /**
+ * @var
+ */
+ protected $currentTick;
+
+ /**
+ * @var
+ */
+ protected $minExp;
+
+ /**
+ * @var
+ */
+ protected $maxExp;
+
+ /**
+ * True when the minimum value is static and isn't affected by the data set
+ *
+ * @var bool
+ */
+ protected $staticMin = false;
+
+ /**
+ * True when the maximum value is static and isn't affected by the data set
+ *
+ * @var bool
+ */
+ protected $staticMax = false;
+
+ /**
+ * Create and initialize this AxisUnit
+ *
+ * @param int $nrOfTicks The number of ticks to use
+ */
+ public function __construct($base = 10)
+ {
+ $this->base = $base;
+ $this->minExp = PHP_INT_MAX;
+ $this->maxExp = ~PHP_INT_MAX;
+ }
+
+ /**
+ * Add a dataset and calculate the minimum and maximum value for this AxisUnit
+ *
+ * @param array $dataset The dataset to add
+ * @param int $idx The idx (0 for x, 1 for y)
+ *
+ * @return $this Fluent interface
+ */
+ public function addValues(array $dataset, $idx = 0)
+ {
+ $datapoints = array();
+
+ foreach ($dataset['data'] as $points) {
+ $datapoints[] = $points[$idx];
+ }
+ if (empty($datapoints)) {
+ return $this;
+ }
+ sort($datapoints);
+ if (!$this->staticMax) {
+ $this->maxExp = max($this->maxExp, $this->logCeil($datapoints[count($datapoints) - 1]));
+ }
+ if (!$this->staticMin) {
+ $this->minExp = min($this->minExp, $this->logFloor($datapoints[0]));
+ }
+ $this->currentTick = 0;
+
+ return $this;
+ }
+
+ /**
+ * Transform the absolute value to an axis relative value
+ *
+ * @param int $value The absolute coordinate from the data set
+ * @return float|int The axis relative coordinate (between 0 and 100)
+ */
+ public function transform($value)
+ {
+ if ($value < $this->pow($this->minExp)) {
+ return 0;
+ } elseif ($value > $this->pow($this->maxExp)) {
+ return 100;
+ } else {
+ return 100 * ($this->log($value) - $this->minExp) / $this->getTicks();
+ }
+ }
+
+ /**
+ * Return the position of the current tick
+ *
+ * @return int
+ */
+ public function current(): int
+ {
+ return $this->currentTick * (100 / $this->getTicks());
+ }
+
+ /**
+ * Calculate the next tick and tick value
+ */
+ public function next(): void
+ {
+ ++ $this->currentTick;
+ }
+
+ /**
+ * Return the label for the current tick
+ *
+ * @return string The label for the current tick
+ */
+ public function key(): string
+ {
+ $currentBase = $this->currentTick + $this->minExp;
+ if (abs($currentBase) > 4) {
+ return $this->base . 'E' . $currentBase;
+ }
+ return (string) intval($this->pow($currentBase));
+ }
+
+ /**
+ * True when we're at a valid tick (iterator interface)
+ *
+ * @return bool
+ */
+ public function valid(): bool
+ {
+ return $this->currentTick >= 0 && $this->currentTick < $this->getTicks();
+ }
+
+ /**
+ * Reset the current tick and label value
+ */
+ public function rewind(): void
+ {
+ $this->currentTick = 0;
+ }
+
+ /**
+ * Perform a log-modulo transformation
+ *
+ * @param $value The value to transform
+ *
+ * @return double The transformed value
+ */
+ protected function log($value)
+ {
+ $sign = $value > 0 ? 1 : -1;
+ return $sign * log1p($sign * $value) / log($this->base);
+ }
+
+ /**
+ * Calculate the biggest exponent necessary to display the given data point
+ *
+ * @param $value
+ *
+ * @return float
+ */
+ protected function logCeil($value)
+ {
+ return ceil($this->log($value)) + 1;
+ }
+
+ /**
+ * Calculate the smallest exponent necessary to display the given data point
+ *
+ * @param $value
+ *
+ * @return float
+ */
+ protected function logFloor($value)
+ {
+ return floor($this->log($value));
+ }
+
+ /**
+ * Inverse function to the log-modulo transformation
+ *
+ * @param $value
+ *
+ * @return double
+ */
+ protected function pow($value)
+ {
+ if ($value == 0) {
+ return 0;
+ }
+ $sign = $value > 0 ? 1 : -1;
+ return $sign * (pow($this->base, $sign * $value));
+ }
+
+ /**
+ * Set the axis minimum value to a fixed value
+ *
+ * @param int $min The new minimum value
+ */
+ public function setMin($min)
+ {
+ $this->minExp = $this->logFloor($min);
+ $this->staticMin = true;
+ }
+
+ /**
+ * Set the axis maximum value to a fixed value
+ *
+ * @param int $max The new maximum value
+ */
+ public function setMax($max)
+ {
+ $this->maxExp = $this->logCeil($max);
+ $this->staticMax = true;
+ }
+
+ /**
+ * Return the current minimum value of the axis
+ *
+ * @return int The minimum set for this axis
+ */
+ public function getMin()
+ {
+ return $this->pow($this->minExp);
+ }
+
+ /**
+ * Return the current maximum value of the axis
+ *
+ * @return int The maximum set for this axis
+ */
+ public function getMax()
+ {
+ return $this->pow($this->maxExp);
+ }
+
+ /**
+ * Get the amount of ticks necessary to display this AxisUnit
+ *
+ * @return int
+ */
+ public function getTicks()
+ {
+ return $this->maxExp - $this->minExp;
+ }
+}