PHP 柱状图实现代码

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效果图：

<?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); 
?>