The implementation of `class CCBPGraph`
| Chapter 35. Creating Critical chain buffer penetration charts |

## The implementation of `class CCBPGraph`

The entire implementation is included below and is also available en the "`Example/`" directory of the distribution as "`ccbpgraph.class.php`". There are also two example scripts using this utility class "`ccbp_ex1.php`" and "`ccbp_ex2.php`"

Example 35.2. (`ccbpgraph.class.php`)

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    <?php // content="text/plain; charset=utf-8"
    /**
    * Class CCBPGraph
    * Utility class to create Critical Chain Buffer penetration charts
    */
    class CCBPGraph {
        const TickStep = 25;
        const YTitle = '% Buffer used';
        const XTitle = '% CC Completed';
        const NColorMaps = 2;
        private $graph=null;
        private $iWidth,$iHeight;
        private $iPlots=array();
        private $iXMin=-50, $iXMax = 100;
        private $iYMin=-50, $iYMax = 150;
        private $iColorInd = array(
            array(5,75),   /* Green */
            array(25,85),  /* Yellow */
            array(50,100));/* Red */
        private $iColorMap = 0;
        private $iColorSpec = array(
                    array('darkgreen:1.0','yellow:1.4','red:0.8','darkred:0.85'),
                    array('#c6e9af','#ffeeaa','#ffaaaa','#de8787'));
        private $iMarginColor = array('darkgreen@0.7','darkgreen@0.9');
        private $iSubTitle='',$iTitle = 'CC Buffer penetration';
        /**
        * Construct a new instance of CCBPGraph
        *
        * @param int $aWidth
        * @param int $aHeight
        * @return CCBPGraph
        */
        public function __construct($aWidth, $aHeight) {
            $this->iWidth = $aWidth;
            $this->iHeight = $aHeight;
        }
        /**
        * Set the title and subtitle for the graph
        *
        * @param string $aTitle
        * @param string $aSubTitle
        */
        public function SetTitle($aTitle, $aSubTitle) {
            $this->iTitle = $aTitle;
            $this->iSubTitle = $aSubTitle;
        }
        /**
        * Set the x-axis min and max values
        *
        * @param int $aMin
        * @param int $aMax
        */
        public function SetXMinMax($aMin, $aMax) {
            $this->iXMin = floor($aMin/CCBPGraph::TickStep)*CCBPGraph::TickStep;
            $this->iXMax = ceil($aMax/CCBPGraph::TickStep)*CCBPGraph::TickStep;
        }
        /**
        * Specify what color map to use
        *
        * @param int $aMap
        */
        public function SetColorMap($aMap) {
            $this->iColorMap = $aMap % CCBPGraph::NColorMaps;
        }
        /**
        * Set the y-axis min and max values
        *
        * @param int $aMin
        * @param int $aMax
        */
        public function SetYMinMax($aMin,$aMax) {
            $this->iYMin = floor($aMin/CCBPGraph::TickStep)*CCBPGraph::TickStep;
            $this->iYMax = ceil($aMax/CCBPGraph::TickStep)*CCBPGraph::TickStep;
        }
        /**
        * Set the specification of the color backgrounds and also the
        * optional exact colors to be used
        *
        * @param mixed $aSpec  An array of 3 1x2 arrays. Each array specify the
        * color indication value at x=0 and x=max x in order to determine the slope
        * @param mixed $aColors  An array with four elements specifying the colors
        * of each color indicator
        */
        public function SetColorIndication(array $aSpec,array $aColors=null) {
            if( count($aSpec) !== 3 ) {
                JpgraphError::Raise('Specification of scale values for background indicators must be an array with three elements.');
            }
            $this->iColorInd = $aSpec;
            if( $aColors !== null ) {
                if( is_array($aColors) && count($aColors) == 4 ) {
                    $this->iColorSpec = $aColors;
                }
                else {
                    JpGraphError::Raise('Color specification for background indication must have four colors.');
                }
            }
        }
        /**
        * Construct the graph
        *
        */
        private function Init() {

            // Setup limits for color indications
            $lowx = $this->iXMin; $highx= $this->iXMax;
            $lowy = $this->iYMin; $highy = $this->iYMax;
             $width=$this->iWidth; $height=$this->iHeight;

            // Margins
            $lm=50; $rm=40;
            $tm=60; $bm=40;

            if( $width <= 300 || $height <= 250 ) {
                $labelsize = 8;
                $lm=25; $rm=25;
                $tm=45; $bm=25;
            }
            elseif( $width <= 450 || $height <= 300 ) {
                $labelsize = 8;
                $lm=30; $rm=30;
                $tm=50; $bm=30;
            }
            elseif( $width <= 600 || $height <= 400 ) {
                $labelsize = 9;
            }
            else {
                $labelsize = 11;
            }

            if( $this->iSubTitle == '' ) {
                $tm -= $labelsize+4;
            }

            $graph = new Graph($width,$height);
            $graph->SetScale('intint',$lowy,$highy,$lowx,$highx);
            $graph->SetMargin($lm,$rm,$tm,$bm);
            $graph->SetMarginColor($this->iMarginColor[$this->iColorMap]);
            $graph->SetClipping();

            $graph->title->Set($this->iTitle);
            $graph->subtitle->Set($this->iSubTitle);

            $graph->title->SetFont(FF_ARIAL,FS_BOLD,$labelsize+4);
            $graph->subtitle->SetFont(FF_ARIAL,FS_BOLD,$labelsize+1);

            $graph->SetBox(true,'black@0.3');

            $graph->xaxis->SetFont(FF_ARIAL,FS_BOLD,$labelsize);
            $graph->yaxis->SetFont(FF_ARIAL,FS_BOLD,$labelsize);

            $graph->xaxis->scale->ticks->Set(CCBPGraph::TickStep,CCBPGraph::TickStep);
            $graph->yaxis->scale->ticks->Set(CCBPGraph::TickStep,CCBPGraph::TickStep);

            $graph->xaxis->HideZeroLabel();
            $graph->yaxis->HideZeroLabel();

            $graph->xaxis->SetLabelFormatString('%d%%');
            $graph->yaxis->SetLabelFormatString('%d%%');

            // For the x-axis we adjust the color so labels on the left of the Y-axis are in black
            $n1 = floor(abs($this->iXMin/25))+1;
            $n2 = floor($this->iXMax/25);
            if( $this->iColorMap == 0 ) {
                $xlcolors=array();
                for( $i = 0; $i < $n1; ++$i ) {
                    $xlcolors[$i] = 'black';
                }
                for( $i = 0; $i < $n2; ++$i ) {
                    $xlcolors[$n1+$i] = 'lightgray:1.5';
                }
                $graph->xaxis->SetColor('gray',$xlcolors);
                $graph->yaxis->SetColor('gray','lightgray:1.5');
            }
            else {
                $graph->xaxis->SetColor('darkgray','darkgray:0.8');
                $graph->yaxis->SetColor('darkgray','darkgray:0.8');
            }
            $graph->SetGridDepth(DEPTH_FRONT);
            $graph->ygrid->SetColor('gray@0.6');
            $graph->ygrid->SetLineStyle('dotted');

            $graph->ygrid->Show();

            $graph->xaxis->SetWeight(1);
            $graph->yaxis->SetWeight(1);

            $ytitle = new Text(CCBPGraph::YTitle,floor($lm*.75),($height-$tm-$bm)/2+$tm);
            #$ytitle->SetFont(FF_VERA,FS_BOLD,$labelsize+1);
            $ytitle->SetAlign('right','center');
            $ytitle->SetAngle(90);
            $graph->Add($ytitle);

            $xtitle = new Text(CCBPGraph::XTitle,($width-$lm-$rm)/2+$lm,$height - 10);
            #$xtitle->SetFont(FF_VERA,FS_BOLD,$labelsize);
            $xtitle->SetAlign('center','bottom');
            $graph->Add($xtitle);

            $df = 'D j:S M, Y';
            if( $width < 400 ) {
                $df = 'D j:S M';
            }

            $time = new Text(date($df),$width-10,$height-10);
            $time->SetAlign('right','bottom');
            #$time->SetFont(FF_VERA,FS_NORMAL,$labelsize-1);
            $time->SetColor('darkgray');
            $graph->Add($time);

            // Use an accumulated fille line graph to create the colored bands

            $n = 3;
            for( $i=0; $i < $n; ++$i ) {
                $b = $this->iColorInd[$i][0];
                $k = ($this->iColorInd[$i][1] - $this->iColorInd[$i][0])/$this->iXMax;
                $colarea[$i] = array( array($lowx,$lowx*$k+$b), array($highx,$highx*$k+$b) );
            }
            $colarea[3] = array( array($lowx,$highy), array($highx,$highy) );

            $cb = array();
            for( $i=0; $i < 4; ++$i ) {
                $cb[$i] = new LinePlot(array($colarea[$i][0][1],$colarea[$i][1][1]),
                                       array($colarea[$i][0][0],$colarea[$i][1][0]));
                $cb[$i]->SetFillColor($this->iColorSpec[$this->iColorMap][$i]);
                $cb[$i]->SetFillFromYMin();
            }

            $graph->Add(array_slice(array_reverse($cb),0,4));
            $this->graph = $graph;
        }
        /**
        * Add a line or scatter plot to the graph
        *
        * @param mixed $aPlots
        */
        public function Add($aPlots) {
            if( is_array($aPlots) ) {
                $this->iPlots = array_merge($this->iPlots,$aPlots);
            }
            else {
                $this->iPlots[] = $aPlots;
            }
        }
        /**
        * Stroke the graph back to the client or to a file
        *
        * @param mixed $aFile
        */
        public function Stroke($aFile='') {
            $this->Init();
            if( count($this->iPlots) > 0 )  {
                $this->graph->Add($this->iPlots);
            }
            $this->graph->Stroke($aFile);
        }
    }
    ?>

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