PHP的生成条形图

PHP的生成条形图
由于overwhelmning为广东的需求有关的例子，这个最重要的是产生从一个数组条形图要

求。当然，这些可以很容易地从任何来源数目，以及投入到一个数组

  // create an array of values for the chart. These values
  // could come from anywhere, POST, GET, database etc.
  $values = array(23,32,35,57,12,3,36,54,32,15,43,24,30);

  // now we get the number of values in the array. this will
  // tell us how many columns to plot
    $columns  = count($values);

  // set the height and width of the graph image

    $width = 300;
    $height = 200;

  // Set the amount of space between each column
    $padding = 5;

  // Get the width of 1 column
    $column_width = $width / $columns ;

  // set the graph color variables
    $im        = imagecreate($width,$height);
    $gray      = imagecolorallocate ($im,0xcc,0xcc,0xcc);
    $gray_lite = imagecolorallocate ($im,0xee,0xee,0xee);
    $gray_dark = imagecolorallocate ($im,0x7f,0x7f,0x7f);
    $white     = imagecolorallocate ($im,0xff,0xff,0xff);

  // set the background color of the graph
    imagefilledrectangle($im,0,0,$width,$height,$white);

  // Calculate the maximum value we are going to plot
  $max_value = max($values);

  // loop over the array of columns
    for($i=0;$i        {
    // set the column hieght for each value
        $column_height = ($height / 100) * (( $values[$i] / $max_value)

*100);
    // now the coords
        $x1 = $i*$column_width;
        $y1 = $height-$column_height;
        $x2 = (($i+1)*$column_width)-$padding;
        $y2 = $height;

        // write the columns over the background
        imagefilledrectangle($im,$x1,$y1,$x2,$y2,$gray);

        // This gives the columns a little 3d effect
        imageline($im,$x1,$y1,$x1,$y2,$gray_lite);
        imageline($im,$x1,$y2,$x2,$y2,$gray_lite);
        imageline($im,$x2,$y1,$x2,$y2,$gray_dark);
        }

   // set the correct png headers
   header ("Content-type: image/png");
  // spit the image out the other end
  imagepng($im);
?>