PHP生成条形图的方法

本文实例讲述了PHP生成条形图的方法。分享给大家供大家参考。具体实现方法如下：

<?php 

  // 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<$columns;$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);  

?>

运行效果如下图所示：

希望本文所述对大家的PHP程序设计有所帮助。