《PHP编程最快明白》第七讲：php图片验证码与缩略图

<?php
//header("content-type:image/png");
$num ='1234';
$imagewidth=60;
$imageheight=18;

$numimage = imagecreate($imagewidth,$imageheight);
imagecolorallocate($numimage,240,240,240);
for($i=0;$i<strlen($num);$i++){
$x = mt_rand(1,8)+$imagewidth*$i/4;
$y = mt_rand(1,$imageheight/4);
$color=imagecolorallocate($numimage,mt_rand(0,150),mt_rand(0,150),mt_rand(0,150));
imagestring($numimage,5,$x,$y,$num[$i],$color);
}

for($i=0;$i<200;$i++){
$randcolor=imagecolorallocate($numimage,rand(200,255),rand(200,255),rand(200,255));
imagesetpixel($numimage,rand()%70,rand()%20,$randcolor);
}
imagepng($numimage);
imagedestroy($numimage);
?>

<?php
class simpleimage {
var $image;
var $image_type;
function load($filename) {
$image_info = getimagesize($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);
}
function resizetoheight($height) {
$ratio = $height / $this->getheight();
$width = $this->getwidth() * $ratio;
$this->resize($width,$height);
}
function resizetowidth($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;
}
}

$newfile = upload_dir."/icons/".md5($_session['user']->email).".jpg";//上传文件保存的目录
$image = new simpleimage();
$image->load($_files['icons']['tmp_name']);//上传的临时文件名
$image->resizetowidth(80);设置宽度
$image->save($newfile);
?>