PHP中的绘图技术画比例圆

<?php
/*
燕十八 公益PHP培训    课堂地址:YY频道88354001   学习社区:www.zixue.it 原型图测试文件
*/
	header('content-type:text/html;charset=utf-8');
	//POST接受数据
	$smaller = $_POST['smaller']+0;
	$middle = $_POST['middle']+0;
	$college = $_POST['college']+0;
	$doctor = $_POST['doctor']+0;
	$all = $smaller+$middle+$college+$doctor;
	$one = ($smaller/$all)*360;
	$two = ($middle/$all)*360;
	$three = ($college/$all)*360;
	$four = ($doctor/$all)*360;
	//画布
	$im = imagecreatetruecolor(300,200);
	//颜料
	$color = imagecolorallocate($im,255,255,255);
	$color1 = imagecolorallocate($im,0,50,40);
	$color2 = imagecolorallocate($im,0,50,255);
	$color3 = imagecolorallocate($im,0,250,0);
	$color4 = imagecolorallocate($im,50,50,30);
	$color5 = imagecolorallocate($im,255,255,255);
	$color6 = imagecolorallocate($im,255,255,51);
	$color7 = imagecolorallocate($im,255,27,255);
	$color8 = imagecolorallocate($im,25,27,255);
	$color9 = imagecolorallocate($im,25,27,55);
	//填充
	imagefill($im,0,0,$color);
	//画图

	imagefilledarc($im,102,102,105,105,0,360,$color7,4);
	imagefilledarc($im,100,100,100,100,0,$one,$color1,0);
	//画矩形
	imagefilledrectangle($im,5,5,30,30,$color1);
	imagefttext($im,5,0,7,20,$color5,'simhei.ttf','小学生');

	imagefilledarc($im,100,100,100,100,$one,$one+$two,$color2,0);
	//画矩形
	imagefilledrectangle($im,35,5,60,30,$color2);
	imagefttext($im,5,0,37,20,$color5,'simhei.ttf','中学生');

	imagefilledarc($im,100,100,100,100,$one+$two,$one+$two+$three,$color3,0);
	//画矩形
	imagefilledrectangle($im,65,5,90,30,$color3);
	imagefttext($im,5,0,67,20,$color5,'simhei.ttf','大学生');
	
	imagefilledarc($im,100,100,100,100,$one+$two+$three,$one+$two+$three+$four,$color4,0);
	//画矩形
	imagefilledrectangle($im,95,5,120,30,$color4);
	imagefttext($im,5,0,97,20,$color5,'simhei.ttf','博士生');

	header('content-type:image/jpeg');
	imagejpeg($im);
	imagedestroy($im);