PHP生成条形图的方法

发布:smiling　来源: PHP粉丝网　添加日期：2021-05-03 15:07:51　浏览: 评论：0　

这篇文章主要介绍了PHP生成条形图的方法,可实现生成柱状的条形图,适用于一些类似柱状图显示报表的场合,具有一定的实用价值,需要的朋友可以参考下

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);

?>