GraphLine.php

   1 <?php
   2 /*=====================================================================*
   3 || ###################################################################
   4 || # Blue Static ISSO Framework
   5 || # Copyright ©2002-[#]year[#] Blue Static
   6 || #
   7 || # This program is free software; you can redistribute it and/or modify
   8 || # it under the terms of the GNU General Public License as published by
   9 || # the Free Software Foundation; version [#]gpl[#] of the License.
  10 || #
  11 || # This program is distributed in the hope that it will be useful, but
  12 || # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13 || # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  14 || # more details.
  15 || #
  16 || # You should have received a copy of the GNU General Public License along
  17 || # with this program; if not, write to the Free Software Foundation, Inc.,
  18 || # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  19 || ###################################################################
  20 \*=====================================================================*/
  21
  22 /**
  23 * Graphing System: Line Graph (GraphLine.php)
  24 *
  25 * @package      ISSO
  26 */
  27
  28 require_once('ISSO/Graph.php');
  29
  30 /**
  31 * Graphing System: Line Graph
  32 *
  33 * This creates a line graph from a set of data; each point requires
  34 * a line name (because this supports multi-line graphing), an x-value,
  35 * and a y-value. It creates PNG images.
  36 *
  37 * @author               Blue Static
  38 * @copyright    Copyright (c)2002 - [#]year[#], Blue Static
  39 * @version              $Revision$
  40 * @package              ISSO
  41 *
  42 */
  43 class BSGraphLine extends BSGraph
  44 {
  45         /**
  46         * Graphing dataset; 4D array
  47         * array(array(name, array(array(xval, yval))), color)
  48         * @var string
  49         */
  50         protected $dataset = array();
  51
  52         /**
  53         * Array of data points that are used to calculate the standard deviation
  54         * @var array
  55         */
  56         private $piles = array(0 => array(), 1 => array());
  57
  58         /**
  59         * The names of the axes
  60         * @var array
  61         */
  62         private $axis = array(0 => 'X Axis', 1 => 'Y Axis');
  63
  64         // ###################################################################
  65         /**
  66         * Does the actual graphing and returns a byte stream of a PNG image
  67         *
  68         * @return       string  Byte stream
  69         */
  70         public function graph()
  71         {
  72                 // calculates the standard deviation of the two piles to determine the x and y intervals
  73                 $xint = $this->_standardDeviation($this->piles[0]);
  74                 $yint = $this->_standardDeviation($this->piles[1]);
  75
  76                 $xmin = min($this->piles[0]);
  77                 $xmin = ($xmin - $xint < 0 ? 0 : $xmin - $xint);
  78                 $xmax = max($this->piles[0]) + $xint;
  79
  80                 $ymin = min($this->piles[1]);
  81                 $ymin = ($ymin - $yint < 0 ? 0 : $ymin - $yint);
  82                 $ymax = max($this->piles[1]) + $yint;
  83
  84                 $colors = $this->_primeColors();
  85                 $this->_paintCanvas();
  86
  87                 // draw the axes
  88                 $originx = self::PADDING + imagefontwidth(1) + self::SPACING + imagefontwidth(3) + self::PADDING;
  89                 $originy = $this->dimensions['height'] - (self::PADDING + imagefontheight(1) + self::SPACING + imagefontheight(3) + self::SPACING);
  90                 $endx = $this->dimensions['width'] - self::PADDING - 150 - self::PADDING;
  91                 $endy = 40;
  92                 $length = $endx - $originx;
  93                 $height = $originy - $endy;
  94                 imageline($this->image, $originx, $originy, $endx, $originy, $colors['grey']);
  95                 imageline($this->image, $originx, $originy, $originx, $endy, $colors['grey']);
  96                 imageline($this->image, $endx, $originy, $endx, $endy, $colors['grey']);
  97
  98                 // label the axes
  99                 imagestring($this->image, 3, $length / 2, $this->dimensions['height'] - self::SPACING - imagefontheight(3), $this->axis[0], $colors['black']);
 100                 imagestringup($this->image, 3, self::SPACING, $height / 2 + $endy, $this->axis[1], $colors['black']);
 101
 102                 // score the axes
 103                 $count = 0;
 104                 for ($i = $originx; $i <= $endx; $i += ($length / $xint))
 105                 {
 106                         imageline($this->image, $i - self::SPACING, $originy + self::SPACING, $i + self::SPACING, $originy - self::SPACING, $colors['grey']);
 107                         imagestring($this->image, 1, $i, $originy + self::PADDING, round($count), $colors['black']);
 108                         $count += $xint;
 109                 }
 110                 $count = 0;
 111                 for ($i = $originy; $i >= $endy; $i -= ($height / $yint))
 112                 {
 113                         imageline($this->image, $originx, $i, $endx, $i, $colors['grey']);
 114                         imagestring($this->image, 1, self::SPACING +  self::PADDING, $i, round($count), $colors['black']);
 115                         $count += $yint;
 116                 }
 117
 118                 header("Content-Type: image/png");
 119                 imagepng($this->image);
 120         }
 121
 122         // ###################################################################
 123         /**
 124         * Adds a "line" with a given name and a set of datapoints in the form
 125         * array(x, y)
 126         *
 127         * @param        string  The line's name
 128         * @param        array   Array of array(x,y) as data points
 129         */
 130         public function addDataSet($name, $points)
 131         {
 132                 $this->_addPoints($points);
 133                 $this->_sortPoints($points);
 134                 $this->dataset[] = array($name, $points, $this->_fetchColor());
 135         }
 136
 137         // ###################################################################
 138         /**
 139         * This does the same thing as addDataSet(), except the client code
 140         * can specify the color in the form of array(R, G, B)
 141         *
 142         * @param        string  The line's name
 143         * @param        array   Array of array(x,y) as data points
 144         * @param        array   A color in the form of 3 RGB points
 145         */
 146         public function addDataSetColor($name, $points, $color)
 147         {
 148                 $this->_addPoints($points);
 149                 $this->_sortPoints($points);
 150                 $this->dataset[] = array($name, $points, imagecolorallocate($this->image, $color[0], $color[1], $color[2]));
 151         }
 152
 153         // ###################################################################
 154         /**
 155         * Adds a set of points to the piles and ensures that they are all valid
 156         *
 157         * @param        array   Points to add
 158         */
 159         private function _addPoints($points)
 160         {
 161                 $xpairs = array();
 162                 foreach ($points AS $point)
 163                 {
 164                         if (isset($xpairs["$point[0]"]))
 165                         {
 166                                 trigger_error('You cannot have more than one of the same x-values for a given data set');
 167                         }
 168                         $xpairs["$point[0]"] = $point[0];
 169                         $this->piles[0][] = $point[0];
 170                         $this->piles[1][] = $point[1];
 171                 }
 172         }
 173
 174         // ###################################################################
 175         /**
 176         * Sorts an array of points using quick sort so they're in x-increasing
 177         * order
 178         *
 179         * @param        array   Array of points
 180         */
 181         private function _sortPoints(&$points)
 182         {
 183                 $this->_quickSortPoints($points, 0, sizeof($points) - 1);
 184         }
 185
 186         // ###################################################################
 187         /**
 188         * Quicksort function for sorting function
 189         *
 190         * @param        array   Array of points
 191         * @param        integer Lower bound
 192         * @param        integer Upper bound
 193         */
 194         private function _quickSortPoints(&$points, $low, $high)
 195         {
 196                 if (($high - $low) > 1)
 197                 {
 198                         $partition = $this->_partitionPoints($points, $low, $high);
 199                         $this->_quickSortPoints($points, $low, $partition);
 200                         $this->_quickSortPoints($points, $partition + 1, $high);
 201                 }
 202         }
 203
 204         // ###################################################################
 205         /**
 206         * Quicksort partitioner: returns the index of the pivot element where
 207         * all x-coords on the left side of pivot are less than or equal to
 208         * pivot, and all x-coords are higher to the right
 209         *
 210         * @param        array   Array of points
 211         * @param        integer Lower bound
 212         * @param        integer Upper bound
 213         *
 214         * @return       integer Pivot index
 215         */
 216         private function _partitionPoints(&$points, $low, $high)
 217         {
 218                 $pivot = $low;
 219                 for ($unsorted = $low + 1; $unsorted <= $high; $unsorted++)
 220                 {
 221                         if ($points[$unsorted][0] < $points[$pivot][0])
 222                         {
 223                                 $temp = $points[$pivot];
 224                                 $points[$pivot] = $points[$unsorted];
 225                                 $points[$unsorted] = $points[$pivot + 1];
 226                                 $points[$pivot + 1] = $temp;
 227                                 $pivot++;
 228                         }
 229                 }
 230                 return $pivot;
 231         }
 232
 233         // ###################################################################
 234         /**
 235         * Returns the unbiased statistical standard deviation of an array of
 236         * values
 237         *
 238         * @param        array   Array of values
 239         *
 240         * @return       float   Standard deviation (unbiased)
 241         */
 242         private function _standardDeviation($vals)
 243         {
 244                 $average = $this->_arrayAverage($vals);
 245                 $popVariance = array();
 246
 247                 foreach ($vals AS $val)
 248                 {
 249                         $popVariance[] = pow($val - $average, 2);
 250                 }
 251
 252                 return sqrt($this->_arrayAverage($popVariance));
 253         }
 254
 255         // ###################################################################
 256         /**
 257         * Returns the stastical mean of an array of values
 258         *
 259         * @param        array   Array of values
 260         *
 261         * @return       float   Statistical mean
 262         */
 263         private function _arrayAverage($vals)
 264         {
 265                 return array_sum($vals) / count($vals);
 266         }
 267
 268         // ###################################################################
 269         /**
 270         * Sets the titles of the two axes
 271         *
 272         * @param        string  X-axis name
 273         * @param        string  Y-axis name
 274         */
 275         public function setAxes($xaxis, $yaxis)
 276         {
 277                 $this->axis[0] = $xaxis;
 278                 $this->axis[1] = $yaxis;
 279         }
 280 }
 281
 282 /*=====================================================================*
 283 || ###################################################################
 284 || # $HeadURL$
 285 || # $Id$
 286 || ###################################################################
 287 \*=====================================================================*/
 288 ?>