这篇文章主要介绍了PHP生成等比缩略图类和自定义函数分享,分别封装成了一个类和自定义函数,需要的朋友可以参考下。

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

类文件代码如下:

1. $resizeimage = new resizeimage("./shawn.jpg", "200", "100", "0","../pic/shawnsun.jpg");
2. //实例化下面的类,就能生成缩略图
3. //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
5. <?php
6. class resizeimage{
8.     //图片类型
9.     public $type;
10.     //实际宽度
11.     public $width;
12.     //实际高度
13.     public $height;
14.     //改变后的宽度
15.     public $resize_width;
16.     //改变后的高度
17.     public $resize_height;
18.     //是否裁图
19.     public $cut;
20.     //源图象
21.     public $srcimg;
22.     //目标图象地址
23.     public $dstimg;
24.     //临时创建的图象
25.     public $im;
27.     function resizeimage($img, $wid, $hei,$c,$dstpath){
29.           $this--->srcimg = $img;
30.           $this->resize_width = $wid;
31.           $this->resize_height = $hei;
32.           $this->cut = $c;
34.           //图片的类型
35.           $this->type = strtolower(substr(strrchr($this->srcimg,"."),1));
36.           //初始化图象
37.           $this->initi_img();
38.           //目标图象地址
39.           $this->dst_img($dstpath);
40.           //W & H
41.           $this->width  = imagesx($this->im);
42.           $this->height = imagesy($this->im);
43.           //生成图象
44.           $this->newimg();
45.           ImageDestroy ($this->im);
46.      }
48.     function newimg(){
50.         //改变后的图象的比例
51.         $resize_ratio = ($this->resize_width)/($this->resize_height);
52.         //实际图象的比例
53.         $ratio = ($this->width)/($this->height);
55.         if(($this->cut)=="1")
56.         //裁图
57.         {
58.             if($ratio>=$resize_ratio)
59.             //高度优先
60.             {
61.                 $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
62.                 imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,
63.                                    $this->resize_height, (($this->height)*$resize_ratio),
64.                                    $this->height
65.                 );
66.                 ImageJpeg ($newimg,$this->dstimg);
67.             }
68.             if($ratio<$resize_ratio)
69.             //宽度优先
70.             {
71.                 $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
72.                 imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,
73.                                    $this->resize_height, $this->width,
74.                                    (($this->width)/$resize_ratio)
75.                 );
76.                 ImageJpeg ($newimg,$this->dstimg);
77.             }
78.               }
79.         else
80.         //不裁图
81.         {
82.             if($ratio>=$resize_ratio)
83.             {
84.                 $newimg = imagecreatetruecolor($this->resize_width,
85.                                                ($this->resize_width)/$ratio
86.                 );
87.                 imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,
88.                                    ($this->resize_width)/$ratio, $this->width,
89.                                    $this->height
90.                 );
91.                 ImageJpeg ($newimg,$this->dstimg);
92.             }
93.             if($ratio<$resize_ratio)
94.             {
95.                 $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,
96.                                                 $this->resize_height
97.                 );
98.                 imagecopyresampled($newimg, $this->im, 0, 0, 0, 0,
99.                                    ($this->resize_height)*$ratio,
100.                                    $this->resize_height, $this->width,
101.                                    $this->height
102.                 );
103.                 ImageJpeg ($newimg,$this->dstimg);
104.             }
105.         }
106.    }
108.     //初始化图象
109.     function initi_img(){
111.         if($this->type=="jpg")
112.         {
113.             $this->im = imagecreatefromjpeg($this->srcimg);
114.         }
115.         if($this->type=="gif")
116.         {
117.             $this->im = imagecreatefromgif($this->srcimg);
118.         }
119.         if($this->type=="png")
120.         {
121.             $this->im = imagecreatefrompng($this->srcimg);
122.         }
123.     }
124.     //图象目标地址
125.     function dst_img($dstpath){
127.         $full_length  = strlen($this->srcimg);
128.         $type_length  = strlen($this->type);
129.         $name_length  = $full_length-$type_length;
131.         $name = substr($this->srcimg,0,$name_length-1);
132.         $this->dstimg = $dstpath;
134.         //echo $this->dstimg;
135.     }
136. }
138. ?>

自定义方法，代码如下:

1. thumbs('shawn.jpg','shawnsun.jpg',100,100);
3. <?php
5. function thumbs($FileName,$SaveTo,$SetW,$SetH){
6.     $IMGInfo= getimagesize($FileName);
7.     if(!$IMGInfo) return false;
9.     if($IMGInfo['mime']== "image/pjpeg" || $IMGInfo['mime']=="image/jpeg"){
10.         $ThisPhoto= imagecreatefromjpeg($FileName);
11.     }elseif($IMGInfo['mime']== "image/x-png" || $IMGInfo['mime']== "image/png"){
12.         $ThisPhoto= imagecreatefrompng($FileName);
13.     }elseif($IMGInfo['mime']== "image/gif"){
14.         $ThisPhoto=imagecreatefromgif($FileName);
15.     }
17.     $width=$IMGInfo[0];
18.     $height=$IMGInfo[1];
19.     $scalc = max($width/$SetW,$height/$SetH);
20.     $nw = intval($width/$scalc);
21.     $nh = intval($height/$scalc);
22.     echo "缩略大小：w$nw,h$nh <br /-->";
24.     if($SetW-$nw == 1){$nw = $SetW;}
25.     if($SetH-$nh == 1){$nh = $SetH;}
26.     echo "+修正1像素： w$nw,h$nh<br>";
28.     //补宽
29.     if($SetW-$nw > 0){
30.         $nh = $nh +(($nh/$nw) * ($SetW-$nw));
31.         echo "*需补宽".($SetW-$nw).",陪补高".(($nh/$nw) * ($SetW-$nw))."  <br>";
32.         $nw = $SetW;
33.     }
34.     //补高
35.     if($SetH-$nh > 0){
36.         $nw = $nw + (($nw/$nh) * ($SetH-$nh));
37.         echo "*需补高".($SetH-$nh).",陪补宽". (($nw/$nh) * ($SetH-$nh)) ."<br>";
38.         $nh = $SetH;
39.     }
40.     $nw = intval($nw);
41.     $nh = intval($nh);
42.     echo "+修正大小：w$nw,h$nh<br>";
44.     $px = ($SetW - $nw)/2;
45.     $py = ($SetH - $nh)/2;
46.     echo "窗口大小：w$SetW,h$SetH <br>";
47.     echo "+偏移修正：x$px,y$py <br>";
49.     $NewPhoto=imagecreatetruecolor($SetW,$SetH);
50.     imagecopyresized($NewPhoto,$ThisPhoto,$px,$py,0,0,$nw,$nh,$width,$height);
51.     ImageJpeg ($NewPhoto,$SaveTo);
52.     return true;
53. }
55. ?>