《PHP编程最快明白》第七讲：php图片验证码与缩略图_

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1、《PHP编程最快明白》第七讲：php图片验证码与缩略图_这个是输出4个验证码的例子，对于汉字，需要font文件和imagettftext函数，用到的时候大家再网上搜索吧。实例22图片验证的核心代码代码如下:?php//header("content-type:image/png");$num='1234';$imagewidth=60;$imageheight=18;$numimage=imagecreate($imagewidth,$imageheight);imagecolorallocate($numimage,

2、240,240,240);for($i=0;$istrlen($num);$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;$i200;$i++){$randc

3、olor=imagecolorallocate($numimage,rand(200,255),rand(200,255),rand(200,255));imagesetpixel($numimage,rand()%70,rand()%20,$randcolor);}imagepng($numimage);imagedestroy($numimage);?这个是输出4个验证码的例子，对于汉字，需要font文件和imagettftext函数，用到的时候大家再网上搜索吧。你要产生随机数，那有mt_rand函数；你还要用到s

4、ession保存这个随机数；假如需要转成utf-8，需要iconv函数。实例23缩略图代码如下:?phpclassSimpleImage{var$image;var$image_type;functionload($filename){$image_info=getimagesize($filename);$this-image_type=$image_info[2];if($this-image_type==IMAGETYPE_JPEG){$this-image=imagecreatefromjpeg($filena

5、me);}elseif($this-image_type==IMAGETYPE_GIF){$this-image=imagecreatefromgif($filename);}elseif($this-image_type==IMAGETYPE_PNG){$this-image=imagecreatefrompng($filename);}}functionsave($filename,$image_type=IMAGETYPE_JPEG,$compression=75,$permissions=null){if($i

6、mage_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)

7、;}}functionoutput($image_type=IMAGETYPE_JPEG){if($image_type==IMAGETYPE_JPEG){imagejpeg($this-image);}elseif($image_type==IMAGETYPE_GIF){imagegif($this-image);}elseif($image_type==IMAGETYPE_PNG){imagepng($this-image);}}functiongetWidth(){returnimagesx($this-imag

8、e);}functiongetHeight(){returnimagesy($this-image);}functionresizeToHeight($height){$ratio=$height/$this-getHeight();$width=$this-getWidth()*$ratio;$this-resize($widt