BarChart.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/>.
	 * 
	 */
	
	/**
	 * Base abstract class for rendering both horizontal and vertical bar charts.
	 *
	 * @author Jean-Marc Trémeaux (jm.tremeaux at gmail.com)
	 */
	abstract class BarChart extends Chart {
		protected $bound;
		protected $axis;
		protected $hasSeveralSerie;
		
		/**
		 * Creates a new bar chart.
		 *
		 * @param integer width of the image
		 * @param integer height of the image
		 */
		protected function __construct($width, $height) {
			parent::__construct($width, $height);

			// Initialize the bounds
			$this->bound = new Bound();
			$this->bound->setLowerBound(0);
		}

		/**
		 * Compute the axis.
		 */
		protected function computeAxis() {
			$this->axis = new Axis($this->bound->getYMinValue(), $this->bound->getYMaxValue());
			$this->axis->computeBoundaries();
		}

		/**
		 * Create the image.
		 */
		protected function createImage() {
			parent::createImage();

			// Get graphical obects
			$img = $this->plot->getImg();
			$palette = $this->plot->getPalette();
			$text = $this->plot->getText();
			$primitive = $this->plot->getPrimitive();
			
			// Get the graph area
			$graphArea = $this->plot->getGraphArea();

			// Aqua-like background
			for ($i = $graphArea->y1; $i < $graphArea->y2; $i++) {
				$color = $palette->aquaColor[($i + 3) % 4];
				$primitive->line($graphArea->x1, $i, $graphArea->x2, $i, $color);
			}

			// Axis
			imagerectangle($img, $graphArea->x1 - 1, $graphArea->y1, $graphArea->x1, $graphArea->y2, $palette->axisColor[0]->getColor($img));
			imagerectangle($img, $graphArea->x1 - 1, $graphArea->y2, $graphArea->x2, $graphArea->y2 + 1, $palette->axisColor[0]->getColor($img));
		}

		/**
		 * Returns true if the data set has some data.
		 * @param minNumberOfPoint Minimum number of points (1 for bars, 2 for lines).
		 *
		 * @return true if data set empty
		 */
		protected function isEmptyDataSet($minNumberOfPoint) {
			if ($this->dataSet instanceof XYDataSet) {
				$pointList = $this->dataSet->getPointList();
				$pointCount = count($pointList);
				return $pointCount < $minNumberOfPoint;
			} else if ($this->dataSet instanceof XYSeriesDataSet) {
				$serieList = $this->dataSet->getSerieList();
				reset($serieList);
				if (count($serieList) > 0) {
					$serie = current($serieList);
					$pointList = $serie->getPointList();
					$pointCount = count($pointList);
					return $pointCount < $minNumberOfPoint;
				}
			} else {
				die("Error: unknown dataset type");
			}
		}

		/**
		 * Checks the data model before rendering the graph.
		 */
		protected function checkDataModel() {
			// Check if a dataset was defined
			if (!$this->dataSet) {
				die("Error: No dataset defined.");
			}
			
			// Bar charts accept both XYDataSet and XYSeriesDataSet
			if ($this->dataSet instanceof XYDataSet) {
				// The dataset contains only one serie
				$this->hasSeveralSerie = false;
			} else if ($this->dataSet instanceof XYSeriesDataSet) {
				// Check if each series has the same number of points
				unset($lastPointCount);
				$serieList = $this->dataSet->getSerieList();
				for ($i = 0; $i < count($serieList); $i++) {
					$serie = $serieList[$i];
					$pointCount = count($serie->getPointList());
					if (isset($lastPointCount) && $pointCount != $lastPointCount) {
						die("Error: serie <" . $i . "> doesn't have the same number of points as last serie (last one: <" . $lastPointCount. ">, this one: <" . $pointCount. ">).");
					}
					$lastPointCount = $pointCount;
				}
				
				// The dataset contains several series
				$this->hasSeveralSerie = true;
			} else {
				die("Error: Bar chart accept only XYDataSet and XYSeriesDataSet");
			}
		}

		/**
		 * Return the data as a series list (for consistency).
		 *
		 * @return List of series
		 */
		protected function getDataAsSerieList() {
			// Get the data as a series list
			$serieList = null;
			if ($this->dataSet instanceof XYSeriesDataSet) {
				$serieList = $this->dataSet->getSerieList();
			} else if ($this->dataSet instanceof XYDataSet) {
				$serieList = array();
				array_push($serieList, $this->dataSet);
			}
			
			return $serieList;
		}
		
		/**
		 * Return the first serie of the list, or the dataSet itself if there is no serie.
		 *
		 * @return XYDataSet
		 */
		protected function getFirstSerieOfList() {
			$pointList = null;
			if ($this->dataSet instanceof XYSeriesDataSet) {
				// For a series dataset, print the legend from the first serie
				$serieList = $this->dataSet->getSerieList();
				reset($serieList);
				$serie = current($serieList);
				$pointList = $serie->getPointList();
			} else if ($this->dataSet instanceof XYDataSet) {
				$pointList = $this->dataSet->getPointList();
			}
			
			return $pointList;
		}
		
		/**
		 * Retourns the bound.
		 *
		 * @return bound Bound
		 */
		public function getBound() {
			return $this->bound;
		}
	}
?>