<?
/*
** $Id: piechart.phl,v 1.2 1998/02/03 16:55:06 borud Exp $
**
** PHP Class for creating pie charts using the GD library functions.
**
** There is a bug in the GD library somewhere that seems to kick in
** when you try to return images that are larger than 4K.  We probably
** need a workaround for this...
**
** Pie charts look a bit shabby.  There seems to be one or more
** roundoff errors lurking about making life hard for us.  To fix this
** we should perhaps investigate how the Arc-drawing thingey works and
** try to find out how it gets the endpoints.  Also the flood-filler
** doesn't quite cope with filling the pieces very well.
**
** Authors: Bjørn Borud, Guardian Networks AS, <borud@guardian.no>
*/

// Modified by Jeff Schmitt
// Save graph in file rather than just display it


/* {{{ piechart */

/*
**  This is a class for creating pie charts.  Generally you just have
**  to instantiate it, and then make a call to the "init" method to
**  set the size and transfer the data.
**
**  The data is an array of arrays that consist the following data:
**    o numeric value
**    o value legend
**    o red  \
**    o green > the RGB values for the color of the slice/legend
**    o blue /
**
*/

class piechart {
/* {{{ attributes */

  var $im;
  var $width, $height;

  var $data;
  var $colors;
  var $angles;

  var $left=10;
  var $right=200;
  var $top=100;
  var $bottom=10;
  var $head_top=10;
  var $head_space=5;

  var $legend_left=20;

  var $center_x;
  var $center_y;
  var $diameter;

  /* sum of values */
  var $sum;

  /* font sizes */
  var $fx, $fy;

  var $legend_num = "";

/* }}} */
/* {{{ constants */

  var $PI = 3.1415926535897931; 

/* }}} */
/* {{{ roundoff */

  /* 
  ** PHP has no function for rounding off doubles to the nearest
  ** integer so we have to roll our own.
  */
  function roundoff ($v) {
    if ( $v - floor($v) >= 0.5) {
      return(ceil($v));
    } else {
      return(floor($v));
    }
  }

/* }}} */
/* {{{ deg2rad */

  /*
  ** The built-in trig functions use radians and there's no
  ** function in PHP to convert between degrees and radians
  */

  function deg2rad ($degrees) {
    return (($this->PI * $degrees) / doubleval(180));
  }

/* }}} */
/* {{{ get_xy_factors */

  /*
  ** Calculate the directional vector for the sides of the
  ** piece of pie.
  */

  function get_xy_factors ($degrees) {
    $x = cos($this->deg2rad($degrees));
    $y = sin($this->deg2rad($degrees));
    return (array($x, $y));
  }

/* }}} */
/* {{{ init */

  /*
  ** Initialize the object and draw the pie.  This would be the
  ** constructor in an ordinary OO scenario -- just that we haven't
  ** got constructors in PHP, now do we? ;-)
  */

  function init ($w, $h, $d) {
    $this->im    = ImageCreate($w, $h);
    $this->width  = $w;
    $this->height = $h;

    $this->data = $d;

    $this->da_width = ($this->width - $this->left - $this->right);
    $this->da_height = ($this->height - $this->top - $this->bottom);

    $this->center_x = intval($this->left + ($this->da_width / 2));
    $this->center_y = intval($this->top  + ($this->da_height / 2));


    /* font sizes */
    $this->fx = array(0, 5,6,7,8,9);
    $this->fy = array(0, 7,8,10,14,11);

    /* decide the diameter of the pie */

    if ($this->da_height > $this->da_width) {
      $this->diameter = $this->da_width;
    } else {
      $this->diameter = $this->da_height;
    }

    $this->white = ImageColorAllocate($this->im, 255, 255, 255);
    $this->black = ImageColorAllocate($this->im,   0,   0,   0);

    $n = count($this->data);
    for ($i = 0; $i < $n; $i++) {
      $this->colors[$i] = ImageColorAllocate($this->im, $this->data[$i][2],   
                                       $this->data[$i][3],
                                       $this->data[$i][4]);
      $this->sum += $this->data[$i][0];
    }

    $from = 0;    $to = 0;

    for ($i = 0; $i < $n; $i++) {

      $this->angles[$i] = $this->roundoff(($this->data[$i][0] * 360) 
                                          / doubleval($this->sum));
      $to = $from + $this->angles[$i];
      $col = $this->colors[$i];
      
      $foo = $this->angles[$i];
      $this->draw_slice($this->center_x, 
                        $this->center_y, 
                        $from, 
                        $to, 
                        $this->colors[$i]);
      $from += $this->angles[$i];
    }
  }

/* }}} */
/* {{{ set_legend_percent */

/* utility function to set an attribute so we display percentages */  
  function set_legend_percent () {
    $this->legend_num = "p";
  }

/* }}} */
/* {{{ set_legend_value */

  /* utility function to set an attribute so we display values */  
  function set_legend_value () {
    $this->legend_num = "v";
  }

/* }}} */
/* {{{ draw_point */

  /*
  ** This function is just here for debugging purposes.  It is
  ** sometimes very useful to be able to draw an X to check
  ** coordinates.
  */
  function draw_point($x, $y) {
    ImageLine($this->im, $x-4, $y-4, $x+4, $y+4, $this->black);
    ImageLine($this->im, $x-4, $y+4, $x+4, $y-4, $this->black);
  }

/* }}} */
/* {{{ draw_margins */

  /*
  ** Also a debugging function to show where the margins are at
  */
  function draw_margins () {

    ImageLine($this->im, 0, $this->top, $this->width, 
              $this->top, 
              $this->black);    

    ImageLine($this->im, 0, $this->height - $this->bottom, 
              $this->width, $this->height - $this->bottom, 
              $this->black);

    ImageLine($this->im, $this->left, 0, $this->left, 
              $this->height, $this->black);

    ImageLine($this->im, $this->width - $this->right, 
              0, $this->width - $this->right, 
              $this->height, $this->black);
  }

/* }}} */
/* {{{ draw_legends */

  /*
  ** Draw legends at the right side of the pie chart.  This function
  ** accepts a fontsize and gathers all the other information from
  ** the multilevel data array
  */
  function draw_legends ($fontsize) {
    $n = count($this->data);

    $x1 = $this->width - $this->right + $this->legend_left;
    $x2 = $x1 + $this->fy[$fontsize];;

    for ($i = 0; $i < $n; $i++) {

      /* determine Y coordinates */
      $y1 = ($i * $this->fy[$fontsize] * 1.5) + $this->top;
      $y2 = $y1 + $this->fy[$fontsize];

      /* draw the legend color rectangle */
      ImageFilledRectangle($this->im, $x1, $y1, $x2, $y2, $this->colors[$i]);
      ImageRectangle($this->im, $x1, $y1, $x2, $y2, $this->black);

      $legend = $this->data[$i][1];

      /* decide what to show after legend */
      switch ($this->legend_num) {
      case "v":
        $legend .= sprintf(" (%.2f)", $this->data[$i][0]);
        break;
      case "p":
        $legend .= sprintf(" (%.2f%%)", 
                           ($this->data[$i][0] 
                            * 100 / doubleval($this->sum)));
        break;
      }

      ImageString($this->im, $fontsize, $x2 + 5, $y1, 
                  $legend, $this->black);
    }
  }

/* }}} */
/* {{{ draw_heading */

  /*
  ** This function accepts an array of arrays containing (in order):
  **  o The text of the heading as a string
  **  o The fontsize as an integer
  **  o The justification ("c"=center)
  **
  */
  function draw_heading($head_data) {
    $n = count($head_data);

    $y = $this->head_top;
    for ($i = 0; $i < $n; $i++) {
      
      switch($head_data[$i][2]) {
      case "c":
        $x = ($this->width - $this->fx[$head_data[$i][1]] 
              * strlen($head_data[$i][0])) / 2;
        break;

      case "r": /* uses left margin here... */
        $x = $this->width - $this->left -
          ($this->fx[$head_data[$i][1]] * strlen($head_data[$i][0]));
        break;

      default:
        $x = $this->left;
        break;


      }

      ImageString($this->im, $head_data[$i][1], $x, $y, $head_data[$i][0],
                  $this->black);

      $y += ($this->fy[$head_data[$i][1]] + $this->head_space);      
    }
  }

/* }}} */
/* {{{ draw_slice */

  /*
  ** This function draws a piece of pie centered at x,y starting at
  ** "from" degrees and ending at "to" degrees using the specified color.
  */
  function draw_slice ($x, $y, $from, $to, $color) {

    # Awful Kludge!!!
    if ($to > 360) {
      $to = 360;
    }

    ImageArc($this->im, $this->center_x, $this->center_y,
             $this->diameter, $this->diameter, $from, $to, $color);

    /* First line */
    $axy2 = $this->get_xy_factors($from);
    $ax2 = floor($this->center_x + ($axy2[0] * ($this->diameter /2)));
    $ay2 = floor($this->center_y + ($axy2[1] * ($this->diameter /2)));
    ImageLine($this->im, $this->center_x, $this->center_y, $ax2, $ay2, $color);

    /* Second line */
    $bxy2 = $this->get_xy_factors($to);
    $bx2 = ceil($this->center_x + ($bxy2[0] * ($this->diameter /2)));
    $by2 = ceil($this->center_y + ($bxy2[1] * ($this->diameter /2)));
    ImageLine($this->im, $this->center_x, $this->center_y, $bx2, $by2, $color);


    /* decide where to start filling, then fill */
    $xy2 = $this->get_xy_factors((($to - $from) / 2) + $from);
    $x2 = floor($this->center_x + ($xy2[0] * ($this->diameter /3)));
    $y2 = floor($this->center_y + ($xy2[1] * ($this->diameter /3)));
    ImageFillToBorder($this->im, $x2, $y2, $color, $color);
  }

/* }}} */
/* {{{ display */

  /*
  ** Make sure the legends are drawn, then output the image to the
  ** client
  */
  function display($filename) {

    $this->draw_legends(2);
#    $this->draw_margins();

     if ($filename) {
        ImageGif($this->im, $filename);

     } else {
        ImageGif($this->im, "/tmp/pie.gif");
        Header("Content-type: image/gif");
        ImageGif($this->im);
     }
  }

/* }}} */
};
?>