Bound.php

<?php
	/* Libchart - PHP chart library
	 * Copyright (C) 2005-2008 Jean-Marc Trémeaux (jm.tremeaux at gmail.com)
	 * 
	 * This program is free software: you can redistribute it and/or modify
	 * it under the terms of the GNU 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 General Public License for more details.
	 *
	 * You should have received a copy of the GNU General Public License
	 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
	 * 
	 */
	
	/**
	 * Object representing the bounds of a dataset (its minimal and maximal values) on its vertical axis.
	 * The bounds are automatically calculated from a XYDataSet or XYSeriesDataSet.
	 * Default (calculated) bounds can be overriden using the setLowerBound() and setUpperBound() methods.
	 *
	 * @author Jean-Marc Trémeaux (jm.tremeaux at gmail.com)
	 * Created on 25 july 2007
	 */
	 class Bound {
		/**
		 * Manually set lower bound, overrides the value calculated by computeBound().
		 */
		private $lowerBound = null;

		/**
		 * Manually set upper bound, overrides the value calculated by computeBound().
		 */
		private $upperBound = null;
		
		/**
		 * Computed min bound.
		 */
		private $yMinValue = null;
		
		/**
		 * Computed max bound.
		 */
		private $yMaxValue = null;
		
		/**
		 * Compute the boundaries on the axis.
		 *
		 * @param dataSet The data set
		 */
		public function computeBound($dataSet) {
			// Check if the data set is empty
			$dataSetEmpty = true;
			$serieList = null;
			if ($dataSet instanceof XYDataSet) {
				$pointList = $dataSet->getPointList();
				$dataSetEmpty = count($pointList) == 0;
				
				if (!$dataSetEmpty) {
					// Process it as a serie
					$serieList = array();
					array_push($serieList, $dataSet);
				}
			} else if ($dataSet instanceof XYSeriesDataSet) {
				$serieList = $dataSet->getSerieList();
				if (count($serieList) > 0) {
					$serie = current($serieList);
					$dataSetEmpty = count($serie) == 0;
				}
			} else {
				die("Error: unknown dataset type");
			}
			
			// If the dataset is empty, default some bounds
			$yMin = 0;
			$yMax = 1;
			if (!$dataSetEmpty) {
				// Compute lower and upper bound on the value axis
				unset($yMin);
				unset($yMax);

				foreach ($serieList as $serie) {
					foreach ($serie->getPointList() as $point) {
						$y = $point->getY();
						
						if (!isset($yMin)) {
							$yMin = $y;
							$yMax = $y;
						} else {
							if ($y < $yMin) {
								$yMin = $y;
							}
			
							if ($y > $yMax) {
								$yMax = $y;
							}
						}
					}
				}
			}

			// If user specified bounds and they are actually greater than computer bounds, override computed bounds
			if (isset($this->lowerBound) && $this->lowerBound < $yMin) {
				$this->yMinValue = $this->lowerBound;
			} else {
				$this->yMinValue = $yMin;
			}

			if (isset($this->upperBound) && $this->upperBound > $yMax) {
				$this->yMaxValue = $this->upperBound;
			} else {
				$this->yMaxValue = $yMax;
			}
		}

		/**
		 * Getter of yMinValue.
		 *
		 * @return min bound
		 */
		public function getYMinValue() {
			return $this->yMinValue;
		}

		/**
		 * Getter of yMaxValue.
		 *
		 * @return max bound
		 */
		public function getYMaxValue() {
			return $this->yMaxValue;
		}

		/**
		 * Set manually the lower boundary value (overrides the automatic formatting).
		 * Typical usage is to set the bars starting from zero.
		 *
		 * @param double lower boundary value
		 */
		public function setLowerBound($lowerBound) {
			$this->lowerBound = $lowerBound;
		}

		/**
		 * Set manually the upper boundary value (overrides the automatic formatting).
		 *
		 * @param double upper boundary value
		 */
		public function setUpperBound($upperBound) {
			$this->upperBound = $upperBound;
		}
	 }
?>