<?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 extends stdClass {

    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
?>
