PHP 柱状图实现代码

<?php
function createImage($data,$twidth,$tspace,$height){
header("Content-Type:image/jpeg");
$dataname = array();
$datavalue = array();//data里面的值
$i = 0;
$j = 0;
$k = 0;
$num = sizeof($data);

foreach($data as $key => $val){
$dataname[] = $key;
$datavalue[] = $val;
}

$width = $num * ($twidth + $tspace) + 20 ;//获取图像的宽度
$im = imagecreate($width,$height);//创建图像

$bgcolor = imagecolorallocate($im,255,255,255);//背景色
$jcolor = imagecolorallocate($im,255,255,0);//矩形的背景色
$acolor = imagecolorallocate($im,0,0,0);//线的颜色

imageline($im,25,$height-20,$width-5,$height -20,$acolor);//X轴
imageline($im,25,$height-20,25,2,$acolor);//Y轴
while($i< $num){
imagefilledrectangle($im,$i*($tspace+$twidth)+40,$height-$datavalue[$i]-20,$i*($twidth+$tspace)+$tspace+40,$height-20,$jcolor);//画矩形
imagestring($im,3,$i*($tspace+$twidth)+40+$twidth/2,$height-$datavalue[$i]-35,$datavalue[$i],$acolor);//在柱子上面写出值
imagestring($im,3,$i*($tspace+$twidth)+40+$twidth/2,$height-15,$dataname[$i],$acolor);//在柱子下面写出值
$i ++;

}
while($j < 400/10){
imageline($im,25,($height-20)-$j*8,28,($height-20)-$j*8,$acolor);//画出刻度
imagestring($im,2,5,($height-30)-$j*8,$j*10,$acolor);//标出刻度值
$j = $j +10;
}
imagejpeg($im);
}
$data =array("1"=>25,"2"=>30,"3" =>21 );
createImage($data,40,40,300);

?>