<?php
  /*=======================================================================
  // File:        JPGRAPH_CONTOUR.PHP
  // Description: Contour plot
  // Created:     2009-03-08
  // Ver:         $Id: jpgraph_contour.php 1870 2009-09-29 04:24:18Z ljp $
  //
  // Copyright (c) Asial Corporation. All rights reserved.
  //========================================================================
  */
  require_once('jpgraph_meshinterpolate.inc.php');
  define('HORIZ_EDGE',0);
  define('VERT_EDGE',1);
  
  /**
   * This class encapsulates the core contour plot algorithm. It will find the path
   * of the specified isobars in the data matrix specified. It is assumed that the
   * data matrix models an equspaced X-Y mesh of datavalues corresponding to the Z
   * values.
   *
   */
  class Contour {
  
      private $dataPoints = array();
      private $nbrCols=0,$nbrRows=0;
      private $horizEdges = array(), $vertEdges=array();
      private $isobarValues = array();
      private $stack = null;
      private $isobarCoord = array();
      private $nbrIsobars = 10, $isobarColors = array();
      private $invert = true;
      private $highcontrast = false, $highcontrastbw = false;
  
      /**
       * Create a new contour level "algorithm machine".
       * @param $aMatrix    The values to find the contour from
       * @param $aIsobars Mixed. If integer it determines the number of isobars to be used. The levels are determined
       * automatically as equdistance between the min and max value of the matrice.
       * If $aIsobars is an array then this is interpretated as an array of values to be used as isobars in the
       * contour plot.
       * @return an instance of the contour algorithm
       */
      function __construct($aMatrix,$aIsobars=10, $aColors=null) {
  
          $this->nbrRows = count($aMatrix);
          $this->nbrCols = count($aMatrix[0]);
          $this->dataPoints = $aMatrix;
  
          if( is_array($aIsobars) ) {
              // use the isobar values supplied
              $this->nbrIsobars = count($aIsobars);
              $this->isobarValues = $aIsobars;
          }
          else {
              // Determine the isobar values automatically
              $this->nbrIsobars = $aIsobars;
              list($min,$max) = $this->getMinMaxVal();
              $stepSize = ($max-$min) / $aIsobars ;
              $isobar = $min+$stepSize/2;
              for ($i = 0; $i < $aIsobars; $i++) {
                  $this->isobarValues[$i] = $isobar;
                  $isobar += $stepSize;
              }
          }
  
          if( $aColors !== null && count($aColors) > 0 ) {
  
              if( !is_array($aColors) ) {
                  JpGraphError::RaiseL(28001);
                  //'Third argument to Contour must be an array of colors.'
              }
  
              if( count($aColors) != count($this->isobarValues) ) {
                  JpGraphError::RaiseL(28002);
                  //'Number of colors must equal the number of isobar lines specified';
              }
  
              $this->isobarColors = $aColors;
          }
      }
  
      /**
       * Flip the plot around the Y-coordinate. This has the same affect as flipping the input
       * data matrice
       *
       * @param $aFlg If true the the vertice in input data matrice position (0,0) corresponds to the top left
       * corner of teh plot otherwise it will correspond to the bottom left corner (a horizontal flip)
       */
      function SetInvert($aFlg=true) {
          $this->invert = $aFlg;
      }
  
      /**
       * Find the min and max values in the data matrice
       *
       * @return array(min_value,max_value)
       */
      function getMinMaxVal() {
          $min = $this->dataPoints[0][0];
          $max = $this->dataPoints[0][0];
          for ($i = 0; $i < $this->nbrRows; $i++) {
              if( ($mi=min($this->dataPoints[$i])) < $min )  $min = $mi;
              if( ($ma=max($this->dataPoints[$i])) > $max )  $max = $ma;
          }
          return array($min,$max);
      }
  
      /**
       * Reset the two matrices that keeps track on where the isobars crosses the
       * horizontal and vertical edges
       */
      function resetEdgeMatrices() {
          for ($k = 0; $k < 2; $k++) {
              for ($i = 0; $i <= $this->nbrRows; $i++) {
                  for ($j = 0; $j <= $this->nbrCols; $j++) {
                      $this->edges[$k][$i][$j] = false;
                  }
              }
          }
      }
  
      /**
       * Determine if the specified isobar crosses the horizontal edge specified by its row and column
       *
       * @param $aRow Row index of edge to be checked
       * @param $aCol Col index of edge to be checked
       * @param $aIsobar Isobar value
       * @return true if the isobar is crossing this edge
       */
      function isobarHCrossing($aRow,$aCol,$aIsobar) {
  
          if( $aCol >= $this->nbrCols-1 ) {
              JpGraphError::RaiseL(28003,$aCol);
              //'ContourPlot Internal Error: isobarHCrossing: Coloumn index too large (%d)'
          }
          if( $aRow >= $this->nbrRows ) {
              JpGraphError::RaiseL(28004,$aRow);
              //'ContourPlot Internal Error: isobarHCrossing: Row index too large (%d)'
          }
  
          $v1 = $this->dataPoints[$aRow][$aCol];
          $v2 = $this->dataPoints[$aRow][$aCol+1];
  
          return ($aIsobar-$v1)*($aIsobar-$v2) < 0 ;
  
      }
  
      /**
       * Determine if the specified isobar crosses the vertical edge specified by its row and column
       *
       * @param $aRow Row index of edge to be checked
       * @param $aCol Col index of edge to be checked
       * @param $aIsobar Isobar value
       * @return true if the isobar is crossing this edge
       */
      function isobarVCrossing($aRow,$aCol,$aIsobar) {
  
          if( $aRow >= $this->nbrRows-1) {
              JpGraphError::RaiseL(28005,$aRow);
              //'isobarVCrossing: Row index too large
          }
          if( $aCol >= $this->nbrCols ) {
              JpGraphError::RaiseL(28006,$aCol);
              //'isobarVCrossing: Col index too large
          }
  
          $v1 = $this->dataPoints[$aRow][$aCol];
          $v2 = $this->dataPoints[$aRow+1][$aCol];
  
          return ($aIsobar-$v1)*($aIsobar-$v2) < 0 ;
  
      }
  
      /**
       * Determine all edges, horizontal and vertical that the specified isobar crosses. The crossings
       * are recorded in the two edge matrices.
       *
       * @param $aIsobar The value of the isobar to be checked
       */
      function determineIsobarEdgeCrossings($aIsobar) {
  
          $ib = $this->isobarValues[$aIsobar];
  
          for ($i = 0; $i < $this->nbrRows-1; $i++) {
              for ($j = 0; $j < $this->nbrCols-1; $j++) {
                  $this->edges[HORIZ_EDGE][$i][$j] = $this->isobarHCrossing($i,$j,$ib);
                  $this->edges[VERT_EDGE][$i][$j] = $this->isobarVCrossing($i,$j,$ib);
              }
          }
  
          // We now have the bottom and rightmost edges unsearched
          for ($i = 0; $i < $this->nbrRows-1; $i++) {
              $this->edges[VERT_EDGE][$i][$j] = $this->isobarVCrossing($i,$this->nbrCols-1,$ib);
          }
          for ($j = 0; $j < $this->nbrCols-1; $j++) {
              $this->edges[HORIZ_EDGE][$i][$j] = $this->isobarHCrossing($this->nbrRows-1,$j,$ib);
          }
  
      }
  
      /**
       * Return the normalized coordinates for the crossing of the specified edge with the specified
       * isobar- The crossing is simpy detrmined with a linear interpolation between the two vertices
       * on each side of the edge and the value of the isobar
       *
       * @param $aRow Row of edge
       * @param $aCol Column of edge
       * @param $aEdgeDir Determine if this is a horizontal or vertical edge
       * @param $ib The isobar value
       * @return unknown_type
       */
      function getCrossingCoord($aRow,$aCol,$aEdgeDir,$aIsobarVal) {
  
          // In order to avoid numerical problem when two vertices are very close
          // we have to check and avoid dividing by close to zero denumerator.
          if( $aEdgeDir == HORIZ_EDGE ) {
              $d = abs($this->dataPoints[$aRow][$aCol] - $this->dataPoints[$aRow][$aCol+1]);
              if( $d > 0.001 ) {
                  $xcoord = $aCol + abs($aIsobarVal - $this->dataPoints[$aRow][$aCol]) / $d;
              }
              else {
                  $xcoord = $aCol;
              }
              $ycoord = $aRow;
          }
          else {
              $d = abs($this->dataPoints[$aRow][$aCol] - $this->dataPoints[$aRow+1][$aCol]);
              if( $d > 0.001 ) {
                  $ycoord = $aRow + abs($aIsobarVal - $this->dataPoints[$aRow][$aCol]) / $d;
              }
              else {
                  $ycoord = $aRow;
              }
              $xcoord = $aCol;
          }
          if( $this->invert ) {
              $ycoord = $this->nbrRows-1 - $ycoord;
          }
          return array($xcoord,$ycoord);
  
      }
  
      /**
       * In order to avoid all kinds of unpleasent extra checks and complex boundary
       * controls for the degenerated case where the contour levels exactly crosses
       * one of the vertices we add a very small delta (0.1%) to the data point value.
       * This has no visible affect but it makes the code sooooo much cleaner.
       *
       */
      function adjustDataPointValues() {
  
          $ni = count($this->isobarValues);
          for ($k = 0; $k < $ni; $k++) {
              $ib = $this->isobarValues[$k];
              for ($row = 0 ; $row < $this->nbrRows-1; ++$row) {
                  for ($col = 0 ; $col < $this->nbrCols-1; ++$col ) {
                      if( abs($this->dataPoints[$row][$col] - $ib) < 0.0001 ) {
                          $this->dataPoints[$row][$col] += $this->dataPoints[$row][$col]*0.001;
                      }
                  }
              }
          }
  
      }
  
      /**
       * @param $aFlg
       * @param $aBW
       * @return unknown_type
       */
      function UseHighContrastColor($aFlg=true,$aBW=false) {
          $this->highcontrast = $aFlg;
          $this->highcontrastbw = $aBW;
      }
  
      /**
       * Calculate suitable colors for each defined isobar
       *
       */
      function CalculateColors() {
          if ( $this->highcontrast ) {
              if ( $this->highcontrastbw ) {
                  for ($ib = 0; $ib < $this->nbrIsobars; $ib++) {
                      $this->isobarColors[$ib] = 'black';
                  }
              }
              else {
                  // Use only blue/red scale
                  $step = round(255/($this->nbrIsobars-1));
                  for ($ib = 0; $ib < $this->nbrIsobars; $ib++) {
                      $this->isobarColors[$ib] = array($ib*$step, 50, 255-$ib*$step);
                  }
              }
          }
          else {
              $n = $this->nbrIsobars;
              $v = 0; $step = 1 / ($this->nbrIsobars-1);
              for ($ib = 0; $ib < $this->nbrIsobars; $ib++) {
                  $this->isobarColors[$ib] = RGB::GetSpectrum($v);
                  $v += $step;
              }
          }
      }
  
      /**
       * This is where the main work is done. For each isobar the crossing of the edges are determined
       * and then each cell is analyzed to find the 0, 2 or 4 crossings. Then the normalized coordinate
       * for the crossings are determined and pushed on to the isobar stack. When the method is finished
       * the $isobarCoord will hold one arrayfor each isobar where all the line segments that makes
       * up the contour plot are stored.
       *
       * @return array( $isobarCoord, $isobarValues, $isobarColors )
       */
      function getIsobars() {
  
          $this->adjustDataPointValues();
  
          for ($isobar = 0; $isobar < $this->nbrIsobars; $isobar++) {
  
              $ib = $this->isobarValues[$isobar];
              $this->resetEdgeMatrices();
              $this->determineIsobarEdgeCrossings($isobar);
              $this->isobarCoord[$isobar] = array();
  
              $ncoord = 0;
  
              for ($row = 0 ; $row < $this->nbrRows-1; ++$row) {
                  for ($col = 0 ; $col < $this->nbrCols-1; ++$col ) {
  
                      // Find out how many crossings around the edges
                      $n = 0;
                      if ( $this->edges[HORIZ_EDGE][$row][$col] )   $neigh[$n++] = array($row,  $col,  HORIZ_EDGE);
                      if ( $this->edges[HORIZ_EDGE][$row+1][$col] ) $neigh[$n++] = array($row+1,$col,  HORIZ_EDGE);
                      if ( $this->edges[VERT_EDGE][$row][$col] )    $neigh[$n++] = array($row,  $col,  VERT_EDGE);
                      if ( $this->edges[VERT_EDGE][$row][$col+1] )  $neigh[$n++] = array($row,  $col+1,VERT_EDGE);
  
                      if ( $n == 2 ) {
                          $n1=0; $n2=1;
                          $this->isobarCoord[$isobar][$ncoord++] = array(
                          $this->getCrossingCoord($neigh[$n1][0],$neigh[$n1][1],$neigh[$n1][2],$ib),
                          $this->getCrossingCoord($neigh[$n2][0],$neigh[$n2][1],$neigh[$n2][2],$ib) );
                      }
                      elseif ( $n == 4 ) {
                          // We must determine how to connect the edges either northwest->southeast or
                          // northeast->southwest. We do that by calculating the imaginary middle value of
                          // the cell by averaging the for corners. This will compared with the value of the
                          // top left corner will help determine the orientation of the ridge/creek
                          $midval = ($this->dataPoints[$row][$col]+$this->dataPoints[$row][$col+1]+$this->dataPoints[$row+1][$col]+$this->dataPoints[$row+1][$col+1])/4;
                          $v = $this->dataPoints[$row][$col];
                          if( $midval == $ib ) {
                              // Orientation "+"
                              $n1=0; $n2=1; $n3=2; $n4=3;
                          } elseif ( ($midval > $ib && $v > $ib) ||  ($midval < $ib && $v < $ib) ) {
                              // Orientation of ridge/valley = "\"
                              $n1=0; $n2=3; $n3=2; $n4=1;
                          } elseif ( ($midval > $ib && $v < $ib) ||  ($midval < $ib && $v > $ib) ) {
                              // Orientation of ridge/valley = "/"
                              $n1=0; $n2=2; $n3=3; $n4=1;
                          }
  
                          $this->isobarCoord[$isobar][$ncoord++] = array(
                          $this->getCrossingCoord($neigh[$n1][0],$neigh[$n1][1],$neigh[$n1][2],$ib),
                          $this->getCrossingCoord($neigh[$n2][0],$neigh[$n2][1],$neigh[$n2][2],$ib) );
  
                          $this->isobarCoord[$isobar][$ncoord++] = array(
                          $this->getCrossingCoord($neigh[$n3][0],$neigh[$n3][1],$neigh[$n3][2],$ib),
                          $this->getCrossingCoord($neigh[$n4][0],$neigh[$n4][1],$neigh[$n4][2],$ib) );
  
                      }
                  }
              }
          }
  
          if( count($this->isobarColors) == 0 ) {
              // No manually specified colors. Calculate them automatically.
              $this->CalculateColors();
          }
          return array( $this->isobarCoord, $this->isobarValues, $this->isobarColors );
      }
  }
  
  
  /**
   * This class represent a plotting of a contour outline of data given as a X-Y matrice
   *
   */
  class ContourPlot extends Plot {
  
      private $contour, $contourCoord, $contourVal, $contourColor;
      private $nbrCountours = 0 ;
      private $dataMatrix = array();
      private $invertLegend = false;
      private $interpFactor = 1;
      private $flipData = false;
      private $isobar = 10;
      private $showLegend = false;
      private $highcontrast = false, $highcontrastbw = false;
      private $manualIsobarColors = array();
  
      /**
       * Construct a contour plotting algorithm. The end result of the algorithm is a sequence of
       * line segments for each isobar given as two vertices.
       *
       * @param $aDataMatrix    The Z-data to be used
       * @param $aIsobar A mixed variable, if it is an integer then this specified the number of isobars to use.
       * The values of the isobars are automatically detrmined to be equ-spaced between the min/max value of the
       * data. If it is an array then it explicetely gives the isobar values
       * @param $aInvert By default the matrice with row index 0 corresponds to Y-value 0, i.e. in the bottom of
       * the plot. If this argument is true then the row with the highest index in the matrice corresponds  to
       * Y-value 0. In affect flipping the matrice around an imaginary horizontal axis.
       * @param $aHighContrast Use high contrast colors (blue/red:ish)
       * @param $aHighContrastBW Use only black colors for contours
       * @return an instance of the contour plot algorithm
       */
      function __construct($aDataMatrix, $aIsobar=10, $aFactor=1, $aInvert=false, $aIsobarColors=array()) {
  
          $this->dataMatrix = $aDataMatrix;
          $this->flipData = $aInvert;
          $this->isobar = $aIsobar;
          $this->interpFactor = $aFactor;
  
          if ( $this->interpFactor > 1 ) {
  
              if( $this->interpFactor > 5 ) {
                  JpGraphError::RaiseL(28007);// ContourPlot interpolation factor is too large (>5)
              }
  
              $ip = new MeshInterpolate();
              $this->dataMatrix = $ip->Linear($this->dataMatrix, $this->interpFactor);
          }
  
          $this->contour = new Contour($this->dataMatrix,$this->isobar,$aIsobarColors);
  
          if( is_array($aIsobar) )
              $this->nbrContours = count($aIsobar);
          else
              $this->nbrContours = $aIsobar;
      }
  
  
      /**
       * Flipe the data around the center
       *
       * @param $aFlg
       *
       */
      function SetInvert($aFlg=true) {
          $this->flipData = $aFlg;
      }
  
      /**
       * Set the colors for the isobar lines
       *
       * @param $aColorArray
       *
       */
      function SetIsobarColors($aColorArray) {
          $this->manualIsobarColors = $aColorArray;
      }
  
      /**
       * Show the legend
       *
       * @param $aFlg true if the legend should be shown
       *
       */
      function ShowLegend($aFlg=true) {
          $this->showLegend = $aFlg;
      }
  
  
      /**
       * @param $aFlg true if the legend should start with the lowest isobar on top
       * @return unknown_type
       */
      function Invertlegend($aFlg=true) {
          $this->invertLegend = $aFlg;
      }
  
      /* Internal method. Give the min value to be used for the scaling
       *
       */
      function Min() {
          return array(0,0);
      }
  
      /* Internal method. Give the max value to be used for the scaling
       *
       */
      function Max() {
          return array(count($this->dataMatrix[0])-1,count($this->dataMatrix)-1);
      }
  
      /**
       * Internal ramewrok method to setup the legend to be used for this plot.
       * @param $aGraph The parent graph class
       */
      function Legend($aGraph) {
  
          if( ! $this->showLegend )
              return;
  
          if( $this->invertLegend ) {
              for ($i = 0; $i < $this->nbrContours; $i++) {
                  $aGraph->legend->Add(sprintf('%.1f',$this->contourVal[$i]), $this->contourColor[$i]);
              }
          }
          else {
              for ($i = $this->nbrContours-1; $i >= 0 ; $i--) {
                  $aGraph->legend->Add(sprintf('%.1f',$this->contourVal[$i]), $this->contourColor[$i]);
              }
          }
      }
  
  
      /**
       *  Framework function which gets called before the Stroke() method is called
       *
       *  @see Plot#PreScaleSetup($aGraph)
       *
       */
      function PreScaleSetup($aGraph) {
          $xn = count($this->dataMatrix[0])-1;
          $yn = count($this->dataMatrix)-1;
  
          $aGraph->xaxis->scale->Update($aGraph->img,0,$xn);
          $aGraph->yaxis->scale->Update($aGraph->img,0,$yn);
  
          $this->contour->SetInvert($this->flipData);
          list($this->contourCoord,$this->contourVal,$this->contourColor) = $this->contour->getIsobars();
      }
  
      /**
       * Use high contrast color schema
       *
       * @param $aFlg True, to use high contrast color
       * @param $aBW True, Use only black and white color schema
       */
      function UseHighContrastColor($aFlg=true,$aBW=false) {
          $this->highcontrast = $aFlg;
          $this->highcontrastbw = $aBW;
          $this->contour->UseHighContrastColor($this->highcontrast,$this->highcontrastbw);
      }
  
      /**
       * Internal method. Stroke the contour plot to the graph
       *
       * @param $img Image handler
       * @param $xscale Instance of the xscale to use
       * @param $yscale Instance of the yscale to use
       */
      function Stroke($img,$xscale,$yscale) {
  
          if( count($this->manualIsobarColors) > 0 ) {
              $this->contourColor = $this->manualIsobarColors;
              if( count($this->manualIsobarColors) != $this->nbrContours ) {
                  JpGraphError::RaiseL(28002);
              }
          }
  
          $img->SetLineWeight($this->line_weight);
  
          for ($c = 0; $c < $this->nbrContours; $c++) {
  
              $img->SetColor( $this->contourColor[$c] );
  
              $n = count($this->contourCoord[$c]);
              $i = 0;
              while ( $i < $n ) {
                  list($x1,$y1) = $this->contourCoord[$c][$i][0];
                  $x1t = $xscale->Translate($x1);
                  $y1t = $yscale->Translate($y1);
  
                  list($x2,$y2) = $this->contourCoord[$c][$i++][1];
                  $x2t = $xscale->Translate($x2);
                  $y2t = $yscale->Translate($y2);
  
                  $img->Line($x1t,$y1t,$x2t,$y2t);
              }
  
          }
      }
  
  }
  
  // EOF
  ?>