PHP生成等比缩略图类和自定义函数分享

共有两种等比例缩略图方法可以借鉴
一、为类文件，实例化之后即可使用
二、为自定义方法，比较轻巧

类文件

$resizeimage = new resizeimage("./shawn.jpg", "200", "100", "0","../pic/shawnsun.jpg");

//实例化下面的类,就能生成缩略图

//其中,源文件和缩略图地址可以相同,200,100分别代表宽和高，第四个参数为可选 0不截图，1为截图

<?php

class resizeimage{

 

    //图片类型

    public $type;

    //实际宽度

    public $width;

    //实际高度

    public $height;

    //改变后的宽度

    public $resize_width;

    //改变后的高度

    public $resize_height;

    //是否裁图

    public $cut;

    //源图象

    public $srcimg;

    //目标图象地址

    public $dstimg;

    //临时创建的图象

    public $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);

          //W & H

          $this->width  = imagesx($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;

    }

}

 

?>

自定义方法

thumbs('shawn.jpg','shawnsun.jpg',100,100);

//参数属性类似于方法一

<?php

 

function thumbs($FileName,$SaveTo,$SetW,$SetH){

    $IMGInfo= getimagesize($FileName);

    if(!$IMGInfo) return false;

         

    if($IMGInfo['mime']== "image/pjpeg" || $IMGInfo['mime']=="image/jpeg"){

        $ThisPhoto= imagecreatefromjpeg($FileName);

    }elseif($IMGInfo['mime']== "image/x-png" || $IMGInfo['mime']== "image/png"){

        $ThisPhoto= imagecreatefrompng($FileName);   

    }elseif($IMGInfo['mime']== "image/gif"){

        $ThisPhoto=imagecreatefromgif($FileName); 

    } 

     

    $width=$IMGInfo[0];

    $height=$IMGInfo[1];   

    $scalc = max($width/$SetW,$height/$SetH);

    $nw = intval($width/$scalc);

    $nh = intval($height/$scalc);

    echo "缩略大小：w$nw,h$nh <br /-->";

     

    if($SetW-$nw == 1){$nw = $SetW;}

    if($SetH-$nh == 1){$nh = $SetH;}

    echo "+修正1像素： w$nw,h$nh<br>";

     

    //补宽

    if($SetW-$nw > 0){

        $nh = $nh +(($nh/$nw) * ($SetW-$nw));

        echo "*需补宽".($SetW-$nw).",陪补高".(($nh/$nw) * ($SetW-$nw))."  <br>";  

        $nw = $SetW;

    }

    //补高

    if($SetH-$nh > 0){

        $nw = $nw + (($nw/$nh) * ($SetH-$nh));

        echo "*需补高".($SetH-$nh).",陪补宽". (($nw/$nh) * ($SetH-$nh)) ."<br>";

        $nh = $SetH;

    }

    $nw = intval($nw);

    $nh = intval($nh);

    echo "+修正大小：w$nw,h$nh<br>";

     

    $px = ($SetW - $nw)/2;

    $py = ($SetH - $nh)/2;

    echo "窗口大小：w$SetW,h$SetH <br>";

    echo "+偏移修正：x$px,y$py <br>";

     

    $NewPhoto=imagecreatetruecolor($SetW,$SetH);

    imagecopyresized($NewPhoto,$ThisPhoto,$px,$py,0,0,$nw,$nh,$width,$height);

    ImageJpeg ($NewPhoto,$SaveTo);

    return true;

}

     

?>