php生成雪花背景验证码程序代码

<?php
session_start();
session_register("login_check_number");
//昨晚看到了chianren上的验证码效果，就考虑了一下，用PHP的GD库完成了类似功能
//先成生背景，再把生成的验证码放上去
$img_height=120;    //先定义图片的长、宽
$img_width=40;
if($HTTP_GET_VARS["act"]== "init"){
    //srand(microtime() * 100000);//PHP420后，srand不是必须的
    for($Tmpa=0;$Tmpa<4;$Tmpa++){
        $nmsg.=dechex(rand(0,15));
    }//by sports98

    $HTTP_SESSION_VARS[login_check_number] = $nmsg;

    //$HTTP_SESSION_VARS[login_check_number] = strval(mt_rand("1111","9999"));    //生成4位的随机数，放入session中
    //谁能做下补充，可以同时生成字母和数字啊？？----由sports98完成了

    $aimg = imageCreate($img_height,$img_width);    //生成图片
    ImageColorAllocate($aimg, 255,255,255);            //图片底色，ImageColorAllocate第1次定义颜色PHP就认为是底色了
    $black = ImageColorAllocate($aimg, 0,0,0);        //定义需要的黑色
    ImageRectangle($aimg,0,0,$img_height-1,$img_width-1,$black);//先成一黑色的矩形把图片包围

    //下面该生成雪花背景了，其实就是在图片上生成一些符号
    for ($i=1; $i<=100; $i++) {    //先用100个做测试
        imageString($aimg,1,mt_rand(1,$img_height),mt_rand(1,$img_width),"*",imageColorAllocate($aimg,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)));
        //哈，看到了吧，其实也不是雪花，就是生成＊号而已。为了使它们看起来"杂乱无章、5颜6色"，就得在1个1个生成它们的时候，让它们的位置、颜色，甚至大小都用随机数，rand()或mt_rand都可以完成。
    }

    //上面生成了背景，现在就该把已经生成的随机数放上来了。道理和上面差不多，随机数1个1个地放，同时让他们的位置、大小、颜色都用成随机数~~
    //为了区别于背景，这里的颜色不超过200，上面的不小于200
    for ($i=0;$i<strlen($HTTP_SESSION_VARS[login_check_number]);$i++){
        imageString($aimg, mt_rand(3,5),$i*$img_height/4+mt_rand(1,10),mt_rand(1,$img_width/2), $HTTP_SESSION_VARS[login_check_number][$i],imageColorAllocate($aimg,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)));
    }
    Header("Content-type: image/png");    //告诉浏览器，下面的数据是图片，而不要按文字显示
    ImagePng($aimg);                    //生成png格式。
    ImageDestroy($aimg);
}
?>

<?session_start();?>
<FORM METHOD=POST ACTION="">
<input type=text name=number maxlength=4><img src="YanZhengMa.php?act=init">
<INPUT TYPE="submit" name="sub">
</FORM>
<?
//检验校验码
if(isset($HTTP_POST_VARS["sub"])):
if($HTTP_POST_VARS["number"] != $HTTP_SESSION_VARS[login_check_number] || empty($HTTP_POST_VARS["number"])){
    echo "校验码不正确!" ;
}else{
    echo"验证码通过！";
}
endif;
show_source('test.php');
//以上本页的源码

//以下是生成验证码的源码
show_source('YanZhengMa.php');
?>

<?php
header("Content-type: image/jpeg");

//原始图像
$dst = "images/flower_1.jpg";

//得到原始图片信息
$dst_im = imagecreatefromjpeg($dst);
$dst_info = getimagesize($dst);

//水印图像
$src = "images/logo.gif";
$src_im = imagecreatefromgif($src);
$src_info = getimagesize($src);

//水印透明度
$alpha = 30;

//合并水印图片
imagecopymerge($dst_im,$src_im,$dst_info[0]-$src_info[0],$dst_info[1]-$src_info[1],0,0,$src_info[0],
$src_info[1],$alpha);

//输出合并后水印图片
imagejpeg($dst_im);
imagedestroy($dst_im);
imagedestroy($src_im);
?>

新版本之后imagecopymerge函数几乎不使用了，我们可直接使用imagecopy来生成水印两个函数的功能是完全一样的。

//增加水印
$watermark   =1;
$watertype   =2;
$waterstring =''; 
$waterimg="z.png";    //水印图片
$sFilePath ='aa.jpg';
if($watermark==1)
{
 $image_size = getimagesize($sFilePath); //上传的图片
 $water_size = getimagesize($waterimg);  //水印图片
 $iinfo=getimagesize($sFilePath,$iinfo);
 $nimage=imagecreatetruecolor($image_size[0],$image_size[1]);
 $white=imagecolorallocate($nimage,255,255,255);
 $black=imagecolorallocate($nimage,0,0,0);
 $red=imagecolorallocate($nimage,255,0,0);
 imagefill($nimage,0,0,$white);
 switch ($iinfo[2])
 {
  case 1:
   $simage =imagecreatefromgif($sFilePath);
   break;
  case 2:
   $simage =imagecreatefromjpeg($sFilePath);
   break;
  case 3:
   $simage =imagecreatefrompng($sFilePath);
   break;
//            case 6:
//            $simage =imagecreatefromwbmp($sFilePath);
//            break;
  default:
   die("不支持的文件类型");
   exit;
 }
 
 imagecopy($nimage,$simage,0,0,0,0,$image_size[0],$image_size[1]);
 
 switch($watertype)
 {
  case 1:   //加水印字符串
   imagestring($nimage,2,3,$image_size[1]-15,$waterstring,$black);
   break;
  case 2:   //加水印图片
   $simage1 =imagecreatefrompng($waterimg);     
   $x= $image_size[0]-$water_size[0];
   $y= $image_size[1]-$water_size[1];
   imagecopy($nimage,$simage1,$x,$y,0,0,240,65);
   imagedestroy($simage1);
   break;
 }
    
 switch ($iinfo[2])
 {
  case 1:
   imagegif($nimage, $sFilePath);
//            imagejpeg($nimage, $sFilePath);
   break;
  case 2:
   imagejpeg($nimage, $sFilePath);
   break;
  case 3:
   imagepng($nimage, $sFilePath);
   break;
//            case 6:
//            imagewbmp($nimage, $sFilePath);
//            //imagejpeg($nimage, $sFilePath);
//            break;
 }
 
 //覆盖原上传文件
 imagedestroy($nimage);
 imagedestroy($simage);
}

class ImageTool { 
    // imageInfo 分析图片的信息 
    // return array() 
    public static function imageInfo($image) { 
        // 判断图片是否存在 
        if (!file_exists($image)) { 
            return false; 
        } 
 
        $info = getimagesize($image); 
 
        if ($info == false) { 
            return false; 
        } 
 
        // 此时info分析出来,是一个数组 
        $img['width'] = $info[0]; 
        $img['height'] = $info[1]; 
        $img['ext'] = substr($info['mime'], strpos($info['mime'], '/') + 1); 
 
        return $img; 
    } 
 
    /*
     加水印功能
     parm String $dst 等操作图片
     parm String $water 水印小图
     parm String $save,不填则默认替换原始图
     */ 
    public static function water($dst, $water, $save = NULL, $pos = 2, $alpha = 50) { 
        // 先保证2个图片存在 
        if (!file_exists($dst) || !file_exists($water)) { 
            return false; 
        } 
 
        // 首先保证水印不能比待操作图片还大 
        $dinfo = self::imageInfo($dst); 
        $winfo = self::imageInfo($water); 
 
        if ($winfo['height'] > $dinfo['height'] || $winfo['width'] > $dinfo['width']) { 
            return false; 
        } 
 
        // 两张图,读到画布上! 但是图片可能是png,可能是jpeg,用什么函数读? 
        $dfunc = 'imagecreatefrom' . $dinfo['ext']; 
        $wfunc = 'imagecreatefrom' . $winfo['ext']; 
 
        if (!function_exists($dfunc) || !function_exists($wfunc)) { 
            return false; 
        } 
 
        // 动态加载函数来创建画布 
        $dim = $dfunc($dst); 
        // 创建待操作的画布 
        $wim = $wfunc($water); 
        // 创建水印画布 
 
        // 根据水印的位置 计算粘贴的坐标 
        switch($pos) { 
            case 0 : 
                // 左上角 
                $posx = 0; 
                $posy = 0; 
                break; 
 
            case 1 : 
                // 右上角 
                $posx = $dinfo['width'] - $winfo['width']; 
                $posy = 0; 
                break; 
 
            case 3 : 
                // 左下角 
                $posx = 0; 
                $posy = $dinfo['height'] - $winfo['height']; 
                break; 
 
            default : 
                $posx = $dinfo['width'] - $winfo['width']; 
                $posy = $dinfo['height'] - $winfo['height']; 
        } 
 
        // 加水印 
        imagecopymerge($dim, $wim, $posx, $posy, 0, 0, $winfo['width'], $winfo['height'], $alpha); 
 
        // 保存 
        if (!$save) { 
            $save = $dst; 
            unlink($dst); 
            // 删除原图 
        } 
 
        $createfunc = 'image' . $dinfo['ext']; 
        $createfunc($dim, $save); 
 
        imagedestroy($dim); 
        imagedestroy($wim); 
 
        return true; 
    } 
 
    /**
     thumb 生成缩略图
     等比例缩放,两边留白
     **/ 
    public static function thumb($dst, $save = NULL, $width = 200, $height = 200) { 
        // 首先判断待处理的图片存不存在 
        $dinfo = self::imageInfo($dst); 
        if ($dinfo == false) { 
            return false; 
        } 
 
        // 计算缩放比例 
        $calc = min($width / $dinfo['width'], $height / $dinfo['height']); 
 
        // 创建原始图的画布 
        $dfunc = 'imagecreatefrom' . $dinfo['ext']; 
        $dim = $dfunc($dst); 
 
        // 创建缩略画布 
        $tim = imagecreatetruecolor($width, $height); 
 
        // 创建白色填充缩略画布 
        $white = imagecolorallocate($tim, 255, 255, 255); 
 
        // 填充缩略画布 
        imagefill($tim, 0, 0, $white); 
 
        // 复制并缩略 
        $dwidth = (int)$dinfo['width'] * $calc; 
        $dheight = (int)$dinfo['height'] * $calc; 
 
        $paddingx = (int)($width - $dwidth) / 2; 
        $paddingy = (int)($height - $dheight) / 2; 
 
        imagecopyresampled($tim, $dim, $paddingx, $paddingy, 0, 0, $dwidth, $dheight, $dinfo['width'],

$dinfo['height']); 
 
        // 保存图片 
        if (!$save) { 
            $save = $dst; 
            unlink($dst); 
        } 
 
        $createfunc = 'image' . $dinfo['ext']; 
        $createfunc($tim, $save); 
 
        imagedestroy($dim); 
        imagedestroy($tim); 
 
        return true; 
 
    } 
 
} 

//首先开启session
session_start();
//定义前台显示验证码长&宽
$image_width = 120;
$image_height = 40;
$characters_on_image = 6;
$font = './monofont.ttf';

//The characters that can be used in the CAPTCHA code.
//avoid confusing characters (l 1 and i for example)
$possible_letters = '23456789bcdfghjkmnpqrstvwxyz';
$random_dots = 10;
$random_lines = 30;
$captcha_text_color="0x142864";
$captcha_noice_color = "0x142864";
//定义要生成验证码的字符串
$code = '';

$i = 0;
while ($i < $characters_on_image) {
$code .= substr($possible_letters, mt_rand(0, strlen($possible_letters)-1), 1);
$i++;
}

$font_size = $image_height * 0.75;
$image = @imagecreate($image_width, $image_height);

/* setting the background, text and noise colours here */
$background_color = imagecolorallocate($image, 255, 255, 255);

$arr_text_color = hexrgb($captcha_text_color);
$text_color = imagecolorallocate($image, $arr_text_color['red'],
        $arr_text_color['green'], $arr_text_color['blue']);

$arr_noice_color = hexrgb($captcha_noice_color);
$image_noise_color = imagecolorallocate($image, $arr_noice_color['red'],
        $arr_noice_color['green'], $arr_noice_color['blue']);

/* generating the dots randomly in background */
for( $i=0; $i<$random_dots; $i++ ) {
imagefilledellipse($image, mt_rand(0,$image_width),
 mt_rand(0,$image_height), 2, 3, $image_noise_color);
}

/* generating lines randomly in background of image */
for( $i=0; $i<$random_lines; $i++ ) {
imageline($image, mt_rand(0,$image_width), mt_rand(0,$image_height),
 mt_rand(0,$image_width), mt_rand(0,$image_height), $image_noise_color);
}

/* create a text box and add 6 letters code in it */
$textbox = imagettfbbox($font_size, 0, $font, $code);
$x = ($image_width - $textbox[4])/2;
$y = ($image_height - $textbox[5])/2;
imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code);

/* Show captcha image in the page html page */
header('Content-Type: image/jpeg');// defining the image type to be shown in browser widow
imagejpeg($image);//showing the image
imagedestroy($image);//destroying the image instance
//设置session，做验证
$_SESSION['6_letters_code'] = $code;

function hexrgb ($hexstr)
{
  $int = hexdec($hexstr);

  return array("red" => 0xFF & ($int >> 0x10),
               "green" => 0xFF & ($int >> 0x8),
               "blue" => 0xFF & $int);
}

<?php
session_start();
if(isset($_REQUEST['Submit'])){
    // code for check server side validation
    if(empty($_SESSION['6_letters_code'] ) ||
        strcasecmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0)
    { 
        $msg="您输入的验证码有误，请重新输入!";
    }else{
        echo "您输入的是正确的!";
        // Captcha verification is Correct. Final Code Execute here!
    }
}   
 ?>

<style type="text/css">
.table{
    font-family:Arial, Helvetica, sans-serif;
    font-size:12px;
    color:#333;
    background-color:#E4E4E4;   
}
.table td{
    background-color:#F8F8F8;   
}
</style>

<form action="" method="post" name="form1" id="form1" >
  <table width="400" border="0" align="center" cellpadding="5" cellspacing="1">
<?php if(isset($msg)){?>
    <tr>
      <td colspan="2" align="center" valign="top"><?php echo $msg;?></td>
    </tr>
<?php } ?>
    <tr>
      <td align="right" valign="top"> 验证码Demo:</td>
      <td><img src="captcha_code_file.php?rand=<?php echo rand(0,20);?>" id='captchaimg'  onclick="refreshCaptcha();" ><br>
        <label for='message'>请输入验证码:</label>
        <br>
        <input id="6_letters_code" name="6_letters_code" type="text">
        <br>
        如果看不到，请 <a href='javascript: refreshCaptcha();'>点我</a> 刷新一下!
        </p></td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td><input name="Submit" type="submit" onclick="return validate();" value="Submit"></td>
    </tr>
  </table>
</form>
<script type='text/javascript'>
//定义的刷新请求
function refreshCaptcha()
{
    var img = document.images['captchaimg'];
    img.src = img.src.substring(0,img.src.lastIndexOf("?"))+"?rand="+Math.random()*1000;
}
</script>

<?php
function _UPLOADPIC($upfile, $maxsize, $updir, $newname = 'date') {

if ($newname == 'date')

$newname = date ( "Ymdhis" ); //使用日期做文件名 

$name = $upfile ["name"];

$type = $upfile ["type"];

$size = $upfile ["size"];

$tmp_name = $upfile ["tmp_name"];

switch ($type) {

case 'image/pjpeg' :

case 'image/jpeg' :

$extend = ".jpg";

break;

case 'image/gif' :

$extend = ".gif";

break;

case 'image/png' :

$extend = ".png";

break;

}

if (emptyempty ( $extend )) {

echo ( "警告！只能上传图片类型：GIF JPG PNG" );

exit ();

}

if ($size > $maxsize) {

$maxpr = $maxsize / 1000;

echo ( "警告！上传图片大小不能超过" . $maxpr . "K!" );

exit ();

}

if (move_uploaded_file ( $tmp_name, $updir . $newname . $extend )) {

return $updir . $newname . $extend;

}

}

function show_pic_scal($width, $height, $picpath) {

$imginfo = GetImageSize ( $picpath );

$imgw = $imginfo [0];

$imgh = $imginfo [1];

$ra = number_format ( ($imgw / $imgh), 1 ); //宽高比

$ra2 = number_format ( ($imgh / $imgw), 1 ); //高宽比

if ($imgw > $width or $imgh > $height) {

if ($imgw > $imgh) {

$newWidth = $width;

$newHeight = round ( $newWidth / $ra );

} elseif ($imgw < $imgh) {

$newHeight = $height;

$newWidth = round ( $newHeight / $ra2 );

} else {

$newWidth = $width;

$newHeight = round ( $newWidth / $ra );

}

} else {

$newHeight = $imgh;

$newWidth = $imgw;

}

$newsize [0] = $newWidth;

$newsize [1] = $newHeight;

return $newsize;

}

function getImageInfo($src)

{

return getimagesize($src);

}

/**

* 创建图片，返回资源类型

* @param string $src 图片路径

* @return resource $im 返回资源类型 

* **/ 

function create($src)

{

$info=getImageInfo($src);

switch ($info[2])

{

case 1:

$im=imagecreatefromgif($src);

break;

case 2:

$im=imagecreatefromjpeg($src);

break;

case 3:

$im=imagecreatefrompng($src);

break;

}

return $im;

}

/**

* 缩略图主函数

* @param string $src 图片路径

* @param int $w 缩略图宽度

* @param int $h 缩略图高度

* @return mixed 返回缩略图路径

* **/ 

function resize($src,$w,$h)

{

$temp=pathinfo($src);

$name=$temp["basename"];//文件名

$dir=$temp["dirname"];//文件所在的文件夹

$extension=$temp["extension"];//文件扩展名

$savepath="{$dir}/{$name}";//缩略图保存路径,新的文件名为*.thumb.jpg

//获取图片的基本信息

$info=getImageInfo($src);

$width=$info[0];//获取图片宽度

$height=$info[1];//获取图片高度

$per1=round($width/$height,2);//计算原图长宽比

$per2=round($w/$h,2);//计算缩略图长宽比

//计算缩放比例

if($per1>$per2||$per1==$per2)

{

//原图长宽比大于或者等于缩略图长宽比，则按照宽度优先

$per=$w/$width;

}

if($per1<$per2)

{

//原图长宽比小于缩略图长宽比，则按照高度优先

$per=$h/$height;

}

$temp_w=intval($width*$per);//计算原图缩放后的宽度

$temp_h=intval($height*$per);//计算原图缩放后的高度

$temp_img=imagecreatetruecolor($temp_w,$temp_h);//创建画布

$im=create($src);

imagecopyresampled($temp_img,$im,0,0,0,0,$temp_w,$temp_h,$width,$height);

if($per1>$per2)

{

imagejpeg($temp_img,$savepath, 100);

imagedestroy($im);

return addBg($savepath,$w,$h,"w");

//宽度优先，在缩放之后高度不足的情况下补上背景

}

if($per1==$per2)

{

imagejpeg($temp_img,$savepath, 100);

imagedestroy($im);

return $savepath;

//等比缩放

}

if($per1<$per2)

{

imagejpeg($temp_img,$savepath, 100);

imagedestroy($im);

return addBg($savepath,$w,$h,"h");

//高度优先，在缩放之后宽度不足的情况下补上背景

}

}

/**

* 添加背景

* @param string $src 图片路径

* @param int $w 背景图像宽度

* @param int $h 背景图像高度

* @param String $first 决定图像最终位置的，w 宽度优先 h 高度优先 wh:等比

* @return 返回加上背景的图片

* **/ 

function addBg($src,$w,$h,$fisrt="w")

{

$bg=imagecreatetruecolor($w,$h);

$white = imagecolorallocate($bg,255,255,255);

imagefill($bg,0,0,$white);//填充背景

//获取目标图片信息

$info=getImageInfo($src);

$width=$info[0];//目标图片宽度

$height=$info[1];//目标图片高度

$img=create($src);

if($fisrt=="wh")

{

//等比缩放

return $src;

}

else 

{

if($fisrt=="w")

{

$x=0;

$y=($h-$height)/2;//垂直居中

}

if($fisrt=="h")

{

$x=($w-$width)/2;//水平居中

$y=0;

}

imagecopymerge($bg,$img,$x,$y,0,0,$width,$height,100);

imagejpeg($bg,$src,100);

imagedestroy($bg);

imagedestroy($img);

return $src;

}
}
?> 

使用方法： 

$filename=(_UPLOADPIC($_FILES["upload"],$maxsize,$updir,$newname='date'));
$show_pic_scal=show_pic_scal(230, 230, $filename);
resize($filename,$show_pic_scal[0],$show_pic_scal[1]);

<?php
class resizeimage
{
    //图片类型
    var $type;
    //实际宽度
    var $width;
    //实际高度
    var $height;
    //改变后的宽度
    var $resize_width;
    //改变后的高度
    var $resize_height;
    //是否裁图
    var $cut;
    //源图象
    var $srcimg;
    //目标图象地址
    var $dstimg;
    //临时创建的图象
    var $im;

    function resizeimage($img, $wid, $hei,$c,$dstpath)
    {
        $this->srcimg = $img;
        $this->resize_width = $wid;
        $this->resize_height = $hei;
        $this->cut = $c;
        //图片的类型
  
$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));

        //初始化图象
        $this->initi_img();
        //目标图象地址
        $this -> dst_img($dstpath);
        //--
        $this->width = imagesx($this->im);
        $this->height = imagesy($this->im);
        //生成图象
        $this->newimg();
        ImageDestroy ($this->im);
    }
    function newimg()
    {
        //改变后的图象的比例
        $resize_ratio = ($this->resize_width)/($this->resize_height);
        //实际图象的比例
        $ratio = ($this->width)/($this->height);
        if(($this->cut)=="1")
        //裁图
        {
            if($ratio>=$resize_ratio)
            //高度优先
            {
                $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this-

>resize_height, (($this->height)*$resize_ratio), $this->height);
                ImageJpeg ($newimg,$this->dstimg);
            }
            if($ratio<$resize_ratio)
            //宽度优先
            {
                $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this-

>resize_height, $this->width, (($this->width)/$resize_ratio));
                ImageJpeg ($newimg,$this->dstimg);
            }
        }
        else
        //不裁图
        {
            if($ratio>=$resize_ratio)
            {
                $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this-

>resize_width)/$ratio, $this->width, $this->height);
                ImageJpeg ($newimg,$this->dstimg);
            }
            if($ratio<$resize_ratio)
            {
                $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio,

$this->resize_height, $this->width, $this->height);
                ImageJpeg ($newimg,$this->dstimg);
            }
        }
    }
    //初始化图象
    function initi_img()
    {
        if($this->type=="jpg")
        {
            $this->im = imagecreatefromjpeg($this->srcimg);
        }
        if($this->type=="gif")
        {
            $this->im = imagecreatefromgif($this->srcimg);
        }
        if($this->type=="png")
        {
            $this->im = imagecreatefrompng($this->srcimg);
        }
    }
    //图象目标地址
    function dst_img($dstpath)
    {
        $full_length  = strlen($this->srcimg);

        $type_length  = strlen($this->type);
        $name_length  = $full_length-$type_length;

        $name         = substr($this->srcimg,0,$name_length-1);
        $this->dstimg = $dstpath;

//echo $this->dstimg;
    }
}
?>

类的调用方法

$resizeimage = new resizeimage("图片源文件地址", "200", "100", "0","缩略图地址");

<?php
error_reporting( E_ALL );

// 测试
imagezoom('1.jpg', '2.jpg', 400, 300, '#FFFFFF');

/*
    php缩略图函数：
        等比例无损压缩，可填充补充色 author: 华仔
    主持格式：
        bmp 、jpg 、gif、png
    param:
        @srcimage : 要缩小的图片
        @dstimage : 要保存的图片
        @dst_width: 缩小宽
        @dst_height: 缩小高
        @backgroundcolor: 补充色  如：#FFFFFF  支持 6位  不支持3位
*/
function imagezoom( $srcimage, $dstimage,  $dst_width, $dst_height, $backgroundcolor ) {
       
        // 中文件名乱码
        if ( PHP_OS == 'WINNT' ) {
                $srcimage = iconv('UTF-8', 'GBK', $srcimage);
                $dstimage = iconv('UTF-8', 'GBK', $dstimage);
        }
   
    $dstimg = imagecreatetruecolor( $dst_width, $dst_height );
    $color = imagecolorallocate($dstimg
        , hexdec(substr($backgroundcolor, 1, 2))
        , hexdec(substr($backgroundcolor, 3, 2))
        , hexdec(substr($backgroundcolor, 5, 2))
    );
    imagefill($dstimg, 0, 0, $color);
   
    if ( !$arr=getimagesize($srcimage) ) {
                echo "要生成缩略图的文件不存在";
                exit;
        }
       
    $src_width = $arr[0];
    $src_height = $arr[1];
    $srcimg = null;
    $method = getcreatemethod( $srcimage );
    if ( $method ) {
        eval( '$srcimg = ' . $method . ';' );
    }
   
    $dst_x = 0;
    $dst_y = 0;
    $dst_w = $dst_width;
    $dst_h = $dst_height;
    if ( ($dst_width / $dst_height - $src_width / $src_height) > 0 ) {
        $dst_w = $src_width * ( $dst_height / $src_height );
        $dst_x = ( $dst_width - $dst_w ) / 2;
    } elseif ( ($dst_width / $dst_height - $src_width / $src_height) < 0 ) {
        $dst_h = $src_height * ( $dst_width / $src_width );
        $dst_y = ( $dst_height - $dst_h ) / 2;
    }

    imagecopyresampled($dstimg, $srcimg, $dst_x
        , $dst_y, 0, 0, $dst_w, $dst_h, $src_width, $src_height);
   
    // 保存格式
    $arr = array(
        'jpg' => 'imagejpeg'
        , 'jpeg' => 'imagejpeg'
        , 'png' => 'imagepng'
        , 'gif' => 'imagegif'
        , 'bmp' => 'imagebmp'
    );
    $suffix = strtolower( array_pop(explode('.', $dstimage ) ) );
    if (!in_array($suffix, array_keys($arr)) ) {
        echo "保存的文件名错误";
        exit;
    } else {
        eval( $arr[$suffix] . '($dstimg, "'.$dstimage.'");' );
    }
   
    imagejpeg($dstimg, $dstimage);
   
    imagedestroy($dstimg);
    imagedestroy($srcimg);
   
}

function getcreatemethod( $file ) {
        $arr = array(
                '474946' => "imagecreatefromgif('$file')"
                , 'FFD8FF' => "imagecreatefromjpeg('$file')"
                , '424D' => "imagecreatefrombmp('$file')"
                , '89504E' => "imagecreatefrompng('$file')"
        );
        $fd = fopen( $file, "rb" );
        $data = fread( $fd, 3 );
       
        $data = str2hex( $data );
       
        if ( array_key_exists( $data, $arr ) ) {
                return $arr[$data];
        } elseif ( array_key_exists( substr($data, 0, 4), $arr ) ) {
                return $arr[substr($data, 0, 4)];
        } else {
                return false;
        }
}

function str2hex( $str ) {
        $ret = "";
       
        for( $i = 0; $i < strlen( $str ) ; $i++ ) {
                $ret .= ord($str[$i]) >= 16 ? strval( dechex( ord($str[$i]) ) )
                        : '0'. strval( dechex( ord($str[$i]) ) );
        }
       
        return strtoupper( $ret );
}

// BMP 创建函数  php本身无
function imagecreatefrombmp($filename)
{
   if (! $f1 = fopen($filename,"rb")) return FALSE;

   $FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1,14));
   if ($FILE['file_type'] != 19778) return FALSE;

   $BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel'.
                 '/Vcompression/Vsize_bitmap/Vhoriz_resolution'.
                 '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1,40));
   $BMP['colors'] = pow(2,$BMP['bits_per_pixel']);
   if ($BMP['size_bitmap'] == 0) $BMP['size_bitmap'] = $FILE['file_size'] - $FILE['bitmap_offset'];
   $BMP['bytes_per_pixel'] = $BMP['bits_per_pixel']/8;
   $BMP['bytes_per_pixel2'] = ceil($BMP['bytes_per_pixel']);
   $BMP['decal'] = ($BMP['width']*$BMP['bytes_per_pixel']/4);
   $BMP['decal'] -= floor($BMP['width']*$BMP['bytes_per_pixel']/4);
   $BMP['decal'] = 4-(4*$BMP['decal']);
   if ($BMP['decal'] == 4) $BMP['decal'] = 0;
  
   $PALETTE = array();
   if ($BMP['colors'] < 16777216)
   {
    $PALETTE = unpack('V'.$BMP['colors'], fread($f1,$BMP['colors']*4));
   }
  
   $IMG = fread($f1,$BMP['size_bitmap']);
   $VIDE = chr(0);

   $res = imagecreatetruecolor($BMP['width'],$BMP['height']);
   $P = 0;
   $Y = $BMP['height']-1;
   while ($Y >= 0)
   {
        $X=0;
        while ($X < $BMP['width'])
        {
         if ($BMP['bits_per_pixel'] == 24)
            $COLOR = unpack("V",substr($IMG,$P,3).$VIDE);
         elseif ($BMP['bits_per_pixel'] == 16)
         { 
            $COLOR = unpack("n",substr($IMG,$P,2));
            $COLOR[1] = $PALETTE[$COLOR[1]+1];
         }
         elseif ($BMP['bits_per_pixel'] == 8)
         { 
            $COLOR = unpack("n",$VIDE.substr($IMG,$P,1));
            $COLOR[1] = $PALETTE[$COLOR[1]+1];
         }
         elseif ($BMP['bits_per_pixel'] == 4)
         {
            $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
            if (($P*2)%2 == 0) $COLOR[1] = ($COLOR[1] >> 4) ; else $COLOR[1] = ($COLOR[1] & 0x0F);
            $COLOR[1] = $PALETTE[$COLOR[1]+1];
         }
         elseif ($BMP['bits_per_pixel'] == 1)
         {
            $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
            if     (($P*8)%8 == 0) $COLOR[1] =  $COLOR[1]        >>7;
            elseif (($P*8)%8 == 1) $COLOR[1] = ($COLOR[1] & 0x40)>>6;
            elseif (($P*8)%8 == 2) $COLOR[1] = ($COLOR[1] & 0x20)>>5;
            elseif (($P*8)%8 == 3) $COLOR[1] = ($COLOR[1] & 0x10)>>4;
            elseif (($P*8)%8 == 4) $COLOR[1] = ($COLOR[1] & 0x8)>>3;
            elseif (($P*8)%8 == 5) $COLOR[1] = ($COLOR[1] & 0x4)>>2;
            elseif (($P*8)%8 == 6) $COLOR[1] = ($COLOR[1] & 0x2)>>1;
            elseif (($P*8)%8 == 7) $COLOR[1] = ($COLOR[1] & 0x1);
            $COLOR[1] = $PALETTE[$COLOR[1]+1];
         }
         else
            return FALSE;
         imagesetpixel($res,$X,$Y,$COLOR[1]);
         $X++;
         $P += $BMP['bytes_per_pixel'];
        }
        $Y--;
        $P+=$BMP['decal'];
   }
   fclose($f1);

return $res;
}
// BMP 保存函数，php本身无
function imagebmp ($im, $fn = false)
{
    if (!$im) return false;
           
    if ($fn === false) $fn = 'php://output';
    $f = fopen ($fn, "w");
    if (!$f) return false;
           
    $biWidth = imagesx ($im);
    $biHeight = imagesy ($im);
    $biBPLine = $biWidth * 3;
    $biStride = ($biBPLine + 3) & ~3;
    $biSizeImage = $biStride * $biHeight;
    $bfOffBits = 54;
    $bfSize = $bfOffBits + $biSizeImage;
           
    fwrite ($f, 'BM', 2);
    fwrite ($f, pack ('VvvV', $bfSize, 0, 0, $bfOffBits));
           
    fwrite ($f, pack ('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));
           
    $numpad = $biStride - $biBPLine;
    for ($y = $biHeight - 1; $y >= 0; --$y)
    {
        for ($x = 0; $x < $biWidth; ++$x)
        {
            $col = imagecolorat ($im, $x, $y);
            fwrite ($f, pack ('V', $col), 3);
        }
        for ($i = 0; $i < $numpad; ++$i)
            fwrite ($f, pack ('C', 0));
    }
    fclose ($f);
    return true;
}

?>