Contact :
malaiac // AT // gmail.com

Goog Chart Class

• Thanks to Google for a nice, fast, and easy-to-use API : Google Chart API
• There are some limitations to it (who said "labels positions" ? :) ) but it's worth most of the commercial classes anyway.
  
• I am not Google officiel or whatsoever, just a freelance developer and SEO
• This class is officially in eternal beta : no garanties (it works, though), no cashback (it's free anyway), no extensive support (but the doc is simple)
• I expect Google to update his API in the next few months, so stay tuned

Terms of Use

• This class is free for you to use, and all Google Chart API terms applies (whatever they are)
• A feedback about your usage, and some cool graphs are most welcome
• A link back to this page is appreciated, somewhere on your site
• The link should be something like : <a href="http://www.malaiac.com/GphpChart/">Google Chart PHP Class by Malaiac</a>

Why use GphpChart class ?

• Easy to use within your PHP backend or website
• Cache images: don't break the API limit ( 50 000 calls a day ) by requesting the same image twice.
• Example usage: http://chart.apis.google.com/chart?cht=lc&chd=t:8.3,16.7,25,33.3,41.7,50,58.3,66.7,75,83.3,91.7,100|69.2,20,81.7,1.7,45,72.5,81.7,54.2,72.5,45,45,72.5&chtt=My+pretty+chart&chs=300x200
• You set :

  $lc1 = $array;
  $GphpChart = new GphpChart("lc");
  $GphpChart->title = "My chart";
  $GphpChart->add_data($lc1);
  echo $GphpChart->get_Image_String();

• Which shows the image on the right
• Emulates 95 % of the API functions

Download GphpChart Class

Content :

• GphpChart.class.php (class file, 12kb)
• index.php (this file, 28kb)

Download   (tgz)(release 2007.12.18, 11kb)

Download   (zip)(release 2007.12.18, 11kb)

Install

• Decompress in a GphpChart/ folder on your server
• Include the GphpChart.class.php
• Call a new graph with : $graph = new GphpChart('type','encoding'); // encoding is text encoding if not specified

GphpChart documentation

• Basic usage

  From PHP array to line chart.

  // daily visitors
  $data = array('01/12' => 1245,'02/12' => 895, '03/12' => 956, '04/12' => 1356,'05/12' => 1542,'06/12' => 1423);
  $GphpChart = new GphpChart('lc'); // 'lc' stands for a line chart
  $GphpChart->title = 'Daily Visitors'; // this title will be on the chart image
  $GphpChart->add_data(array_values($data)); // adding values
  $GphpChart->add_labels('x',array_keys($data)); // adding x labels (bottom axis)
  $GphpChart->add_labels('y',array(0,500,1000,1500)); // adding y labels (left axis)
  echo $GphpChart->get_Image_String();
  
  
  

• Types and encodings

  Types are based on API types : "lc","lxy","bhs","bvs","bhg","bvg","p","p3","v","s"
  Encodings are based on API encodings : 's' (simple encoding), 't' (text encoding, default), 'e' (extended encoding)

  $GphpChart = new GphpChart('{type}','{encoding?}');
  // if not specified, encoding will be text encoding (float, up to 100)

  According to the encoding, datas are normalized to fit in range.

• Image Cache

  Charts can be cached on your server. This prevents from calling the same graph again and again, and reaching the API limit ( 50,000 calls a day)

  
  $GphpChart = new GphpChart('lc');
  $GphpChart->filename = 'cache/{ a unique filename here}.png';
  AND / OR
  $GphpChart->title = 'my chart'; // filename will 'my+chart.png'
  
  if(file_exists($GphpChart->filename)) echo $GphpChart->get_Image_String();
  else
  {
  $GphpChart->add_data(/*....*/'); // add data, labels, etc.
  echo $GphpChart->get_Image_String();
  $GphpChart->save_Image(); // mandatory
  }

• Add labels

  You can add array_keys as labels, but an array may have empty values.
  If you want to add a full range of (integer) labels to your chart, from 0 to 10 on the bottom axis :

  $GphpChart->add_labels('x',array('values_type' => 'discret','min' => 0,'max' => 10));

• Area Fill

  $goo_chart->fill('(bg|c)','(s|lg|ls)','<params>')
    bg|c = Background or chart area
    s|lg|ls = solid, linear gradient or linear stripes
    Params :
    s : color (RRGGBB format hexadecimal number)
    lg : <angle>,<color 1>,<offset 1>,<color n>,<offset n>
    ls : <angle>,<color 1>,<width 1>,<color n>,<width n>
    http://code.google.com/apis/chart/#chart_or_background_fill

• Adding Style

  $goo_chart->add_styles(<string>)
    <data set 1 line thickness>,<length of line segment>,<length of blank segment>
    http://code.google.com/apis/chart/#line_styles

• Adding Grid

  $goo_chart->add_grid(<string>)
    <x axis step size>,
    <y axis step size>,
    <length of line segment>,
    <length of blank segment>
    http://code.google.com/apis/chart/#grid

• Adding Markers

  $goo_chart->add_marker(<string>)
    MARKER = <marker type>,<color>,<data set index>,<data point>,<size>
    <a href="http://code.google.com/apis/chart/#shape_markers">http://code.google.com/apis/chart/#shape_markers</a>
    RANGE = <r or R>,<color>,<any value>,<start point>,<end point>
    <a href="http://code.google.com/apis/chart/#hor_line_marker">http://code.google.com/apis/chart/#hor_line_marker</a>
    FILL AREA = b,<color>,<start line index>,<end line index>,<any value>
    http://code.google.com/apis/chart/#fill_area_marker

• Not supported

  LXY charts : 'chd=t:-1|5,33,50,55,7'
  "Provide a single undefined value to evenly space the data points along the x-axis."
  Not supported. You have to specify the evenly spaced x-axis points.