日常整理PHP中简单的图形处理(经典)_PHP
1.加载GD库
GD库是一个开放的动态创建图像、源代码公开的函数库，可以从官方网站http://www.boutell.com/gd处下载。目前，GD库支持GIF、PNG、JPEG、WBMP和XBM等多种图像格式，用于对图像的处理。
GD库在PHP 5中是默认安装的，但要激活GD库，必须修改php.ini文件。将该文件中的“;extension=php_gd2.dll”选项前的分号“;”删除，保存修改后的文件并重新启动Apache服务器即可生效。
2.创建一个简单的图像
使用GD2函数库可以实现各种图形图像的处理。创建画布是使用GD2函数库来创建图像的第一步，无论创建什么样的图像，首先都需要创建一个画布，其他操作都将在这个画布上完成。在GD2函数库中创建画布，可以通过imagecreate()函数实现。
使用imagecreate（）函数创建一个宽度为200像素，高度为60像素的画布，并设置画布颜色RGB（225,66，159），最后输出一个GIF格式的图像，代码如下：
<?php $im = imagecreate(200,60); //创建一个画布 $white = imagecolorallocate($im, 225,66,159); //设置画布的背景颜色为浅绿色 imagegif($im); //输出图像 ?>
3.使用GD2函数在照片上添加文字
PHP中的GD库支持中文，但必须要以UTF-8格式的参数来进行传递，如果使用imageString()函数直接绘制中文字符串就会显示乱码，这是因为GD2对中文只能接收UTF-8编码格式，并且默认使用英文字体，所以要输出中文字符串，必须对中文字符串进行转码，并设置中文字符使用的字体。否则，输出的只能是乱码。
使用imageTTFText（）函数将文字“这是一个测试”输出到图像中，代码如下：
<?php
header("content-type:image/jpeg"); //定义输出为图像类型
$im=imagecreatefromjpeg("images/photo.jpg"); //载入照片
$textcolor=imagecolorallocate($im,56,73,136);//设置字体颜色为蓝色，值为RGB颜色值
$fnt="c:/windows/fonts/simhei.ttf"; //定义字体
$motto=iconv("gb2312","utf-8","这是一个测试"); //定义输出字体串
imageTTFText($im,220,0,480,340,$textcolor,$fnt,$motto); //写TTF文字到图中
imagejpeg($im); //建立JPEG图形
imagedestroy($im); //结束图形，释放内存空间
?>
4.PHP生成验证码
创建一个checks.php文件在文件中使用GD2函数创建一个4位的验证码，并将生成的验证码保存到session中：
<?php
session_start();
header("content-type:image/png"); //设置创建图像的格式
$image_width=70; //设置图像宽度
$image_height=18; //设置图像高度
srand(microtime()*100000); //设置随机数的种子
for($i=0;$i<4;$i++){ //循环输出一个4位的随机数
$new_number.=dechex(rand(0,15));
}
$_SESSION[check_checks]=$new_number; //将获取的随机数验证码写入到SESSION变量中
$num_image=imagecreate($image_width,$image_height); //创建一个画布
imagecolorallocate($num_image,255,255,255); //设置画布的颜色
for($i=0;$i<strlen($_SESSION[check_checks]);$i++){ //循环读取SESSION变量中的验证码
$font=mt_rand(3,5); //设置随机的字体
$x=mt_rand(1,8)+$image_width*$i/4; //设置随机字符所在位置的X坐标
$y=mt_rand(1,$image_height/4); //设置随机字符所在位置的Y坐标
$color=imagecolorallocate($num_image,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)); //设置字符的颜色
imagestring($num_image,$font,$x,$y,$_SESSION[check_checks][$i],$color); //水平输出字符
}
imagepng($num_image); //生成PNG格式的图像
imagedestroy($num_image); //释放图像资源
?>
创建一个用户登录的表单并调用checks.php在表单中输出图像的内容：
<?php
session_start();
if($_POST["Submit"]!=""){
$checks=$_POST["checks"];
if($checks==""){
echo "<script> alert('验证码不能为空');window.location.href='index.php';</script>";
}
if($checks==$_SESSION[check_checks]){
echo "<script> alert('用户登录成功!');window.location.href='index.php';</script>";
}else{
echo "<script> alert('您输入的验证码不正确!');window.location.href='index.php';</script>";
}
}
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>rand函数的应用</title>
<style type="text/css">
<!--
.STYLE1 {
font-size: 12px;
color: #FFFFFF;
font-weight: bold;
}
.style2 {font-weight: bold; font-size: 12px;}
-->
</style>
</head>
<body>
<form name="form" method="post" action="">
<table width="1003" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="168" height="169" background="images/index_01.gif"> </td>
<td width="685" background="images/index_02.gif"> </td>
<td width="150" background="images/index_03.gif"> </td>
</tr>
<tr>
<td width="168" height="311" background="images/index_04.gif"> </td>
<td background="images/index_05.gif"><table width="675" height="169" border="0" cellpadding="0" cellspacing="0">
<tr>
<td height="43" align="center" valign="baseline"> </td>
<td align="center" valign="middle"> </td>
<td align="center" valign="baseline"> </td>
</tr>
<tr>
<td width="382" height="24" align="center" valign="baseline"> </td>
<td width="207" height="24" valign="middle"><span class="style2">用户名</span><span class="STYLE1">
<input name="txt_user" id="txt_user" style="height:20px " size="10">
</span></td>
<td width="86" height="24" align="center" valign="baseline"> </td>
</tr>
<tr>
<td height="24" align="center" valign="baseline"> </td>
<td height="24" valign="middle"><span class="style2">密码</span><span class="STYLE1">
<input name="txt_pwd" type="password" id="txt_pwd" style="FONT-SIZE: 9pt; height:20px" size="10">
</span></td>
<td height="24" align="center" valign="baseline"> </td>
</tr>
<tr>
<td height="24" align="center" valign="baseline"> </td>
<td height="24" valign="middle"><span class="style2">验证码</span><span class="STYLE1">
<input name="checks" size="6" style="height:20px ">
<img src="/static/imghw/default1.png" data-src="checks.php" class="lazy" style="max-width:90%" style="max-width:90%" border="0" align="bottom" alt="日常整理PHP中简单的图形处理(经典)_PHP" ></span> </td>
<td height="24" align="center" valign="baseline"> </td>
</tr>
<tr>
<td height="40" align="center" valign="baseline"> </td>
<td align="center" valign="baseline"> <input type="submit" name="Submit" value="登录"></td>
<td align="center" valign="baseline"> </td>
</tr>
</table></td>
<td background="images/index_06.gif"> </td>
</tr>
<tr>
<td height="100"> </td>
<td> </td>
<td> </td>
</tr>
</table>
</form>
</body>
</html>以上内容是小编给大家分享的有关php中简单的图形处理，希望大家喜欢。
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