php 复杂生成验证码图片

function image3($length=4,$type='png',$width=180,$height=60,$fontface='fpnf.ttf',$verifyName='verify') {
        $code = $this->rand_string($length,4);
        $width = ($length*25)>$width?$length*25:$width;
        $authCode = new Zend_Session_Namespace('Auth_Code');
        $authCode->imagecode = $randval;
       
        $im=imagecreatetruecolor($width,$height);
        $borderColor = imagecolorallocate($im, 100, 100, 100);                    //边框色
        $bkcolor=imagecolorallocate($im,250,250,250);
        imagefill($im,0,0,$bkcolor);
        @imagerectangle($im, 0, 0, $width-1, $height-1, $borderColor);
        // 干扰
        for($i=0;$i<15;$i++){
            $fontcolor=imagecolorallocate($im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
            imagearc($im,mt_rand(-10,$width),mt_rand(-10,$height),mt_rand(30,300),mt_rand(20,200),55,44,$fontcolor);
        }
        for($i=0;$i<255;$i++){
            $fontcolor=imagecolorallocate($im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
            imagesetpixel($im,mt_rand(0,$width),mt_rand(0,$height),$fontcolor);
        }
        if(!is_file($fontface)) {
            $fontface = dirname(__FILE__)."/".$fontface;
        }
        for($i=0;$i<$length;$i++){
            $fontcolor=imagecolorallocate($im,mt_rand(0,120),mt_rand(0,120),mt_rand(0,120)); //这样保证随机出来的颜色较深。
            $codex= substr($code,$i,1);
            imagettftext($im,mt_rand(16,20),mt_rand(-60,60),40*$i+20,mt_rand(30,35),$fontcolor,$fontface,$codex);
        }
        $this->output($im,$type);
    }
   
    function output($im,$type='png')
    {
        header("Content-type: image/".$type);
        $ImageFun='Image'.$type;
        $ImageFun($im);
        imagedestroy($im);
    }

<?php
$height = 300;
$width = 300;
//创建背景图
$im = ImageCreateTrueColor($width, $height);
//分配颜色
$white = ImageColorAllocate ($im, 255, 255, 255);
$blue = ImageColorAllocate ($im, 0, 0, 64);
//绘制颜色至图像中
ImageFill($im, 0, 0, $blue);
//绘制字符串：Hello,PHP
ImageString($im, 10, 100, 120, 'Hello,PHP', $white);
//输出图像，定义头
Header ('Content-type: image/png');
//将图像发送至浏览器
ImagePng($im);
//清除资源
ImageDestroy($im);
?>

<?php教程
 
class My_Lib_simpleimage {
 var $image;
 var $image_type;
 function load($filename) { 
    //$filename 文件的临时文件名 $_FILES['name']['tmp_name']
  $image_info = getimagesize($filename);
  $this->image_type = $image_info[2];
  if( $this->image_type == IMAGETYPE_JPEG ) {
  $this->image = imagecreatefromjpeg($filename);
  } elseif( $this->image_type == IMAGETYPE_GIF ) {
  $this->image = imagecreatefromgif($filename);
  } elseif( $this->image_type == IMAGETYPE_PNG ) {
  $this->image = imagecreatefrompng($filename);
  }
 }
 
 function save($filename, $image_type=IMAGETYPE_JPEG, $compression=75, $permissions=null) {
  if( $image_type == IMAGETYPE_JPEG ) {
  imagejpeg($this->image,$filename,$compression);
  } elseif( $image_type == IMAGETYPE_GIF ) {
  imagegif($this->image,$filename);
  } elseif( $image_type == IMAGETYPE_PNG ) {
  imagepng($this->image,$filename);
  }
  if( $permissions != null) {
  chmod($filename,$permissions);
  }
 }
 function output($image_type=IMAGETYPE_JPEG) {
  if( $image_type == IMAGETYPE_JPEG ) {
  imagejpeg($this->image);
  } elseif( $image_type == IMAGETYPE_GIF ) {
  imagegif($this->image);
  } elseif( $image_type == IMAGETYPE_PNG ) {
  imagepng($this->image);
  }
 }
 function getWidth() {
  return imagesx($this->image);
 }
 function getHeight() {
  return imagesy($this->image);
 }
 
 #设置缩略图片高度
 function resizeToHeight($height) {
  $ratio = $height / $this->getHeight();
  $width = $this->getWidth() * $ratio;
  $this->resize($width,$height);
 }
 #设置缩略图片宽度
 function resizeToWidth($width) {
  $ratio = $width / $this->getWidth();
  $height = $this->getheight() * $ratio;
  $this->resize($width,$height);
 }
 function scale($scale) {
  $width = $this->getWidth() * $scale/100;
  $height = $this->getheight() * $scale/100;
  $this->resize($width,$height);
 }
 function resize($width,$height) {
  $new_image = imagecreatetruecolor($width, $height);
  imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
  $this->image = $new_image;
 }
}
?>

php imagecreatefromgif创建 gif图片

imagecreatefromgif（$filename）
imagecreatefromgif（）返回一个图像标识符代表从给定的文件名获得的图像

$filename是gif图片名称哦。

来看个实例

<?php
function LoadGif($imgname)
{
    /* Attempt to open */
    $im = @imagecreatefromgif($imgname);

    /* See if it failed */
    if(!$im)
    {
        /* Create a blank image */
        $im = imagecreatetruecolor (150, 30);
        $bgc = imagecolorallocate ($im, 255, 255, 255);
        $tc = imagecolorallocate ($im, 0, 0, 0);

        imagefilledrectangle ($im, 0, 0, 150, 30, $bgc);

        /* Output an error message */
        imagestring ($im, 1, 5, 5, 'Error loading ' . $imgname, $tc);
    }

    return $im;
}

header('Content-Type: image/gif');

$img = LoadGif('bogus.image');

imagegif($img);
imagedestroy($img);
?>

php imagecreate实例教程

描述
资源imagecreate（$width，$height）
imagecreate（）返回一个图像标识符代表了指定大小的空白图像。

我们建议使用imagecreatetruecolor（）。

看个
<?php
header("Content-type: image/png");
$im = @imagecreate(110, 20)
    or die("Cannot Initialize new GD image stream");
$background_color = imagecolorallocate($im, 0, 0, 0);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5,  "A Simple Text String", $text_color);
imagepng($im);
imagedestroy($im);
?>

如果您可以访问gd.h（很少在一个共享的主机），您可以修改GD_RESOLUTION并给它所需的价值。

该解决方案，我发现直接操纵的JPEG头字节。
我希望此示例代码将帮助别人，因为我花了5挖掘推测离开系统I小时，没有其他选择。

<?php
header('Content-Disposition: attachment; filename="myimg.jpg"');
header('Cache-Control: private');
$dst    = imagecreatetruecolor(300, 300); /*this creates a 300x300 pixels image*/
ob_start(); /*don't send the output to the browser since we'll need to manipulate it*/
ImageJpeg($dst);
$img = ob_get_contents();
ob_end_clean();

//byte #14 in jpeg sets the resolution type: 0=none, 1=pixels per inch, 2=pixels per cm
//bytes 15-16 sets X resolution
//bytes 17-18 sets Y resolution
$img = substr_replace($img, pack('cnn',1,300,300),13,5);

echo $img;

?>

文件在其文件类型，并返回假的负载如果失败
<?php
function imagecreatefromfile($path, $user_functions = false)
{
    $info = @getimagesize($path);
   
    if(!$info)
    {
        return false;
    }
   
    $functions = array(
        IMAGETYPE_GIF => 'imagecreatefromgif',
        IMAGETYPE_JPEG => 'imagecreatefromjpeg',
        IMAGETYPE_PNG => 'imagecreatefrompng',
        IMAGETYPE_WBMP => 'imagecreatefromwbmp',
        IMAGETYPE_XBM => 'imagecreatefromwxbm',
        );
   
    if($user_functions)
    {
        $functions[IMAGETYPE_BMP] = 'imagecreatefrombmp';
    }
   
    if(!$functions[$info[2]])
    {
        return false;
    }
   
    if(!function_exists($functions[$info[2]]))
    {
        return false;
    }
   
    return $functions[$info[2]]($path);
}
?>