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 
4.  
5. <?php 
6. class resizeimage{ 
7.  
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 $im; 
26.      
27.     function resizeimage($img, $wid, $hei,$c,$dstpath){ 
28.      
29.           $this--->srcimg = $img; 
30.           $this->resize_width = $wid; 
31.           $this->resize_height = $hei; 
32.           $this->cut = $c; 
33.      
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.      } 
47.      
48.     function newimg(){ 
49.      
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)/($this->height); 
54.          
55.         if(($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,$this->dstimg); 
104.             } 
105.         } 
106.    } 
107.      
108.     //初始化图象 
109.     function initi_img(){ 
110.  
111.         if($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){ 
126.      
127.         $full_length  = strlen($this->srcimg); 
128.         $type_length  = strlen($this->type); 
129.         $name_length  = $full_length-$type_length; 
130.  
131.         $name = substr($this->srcimg,0,$name_length-1); 
132.         $this->dstimg = $dstpath; 
133.  
134.         //echo $this->dstimg; 
135.     } 
136. } 
137.  
138. ?> 

自定义方法，代码如下:

1. thumbs('shawn.jpg','shawnsun.jpg',100,100); 
2.  
3. <?php 
4.  
5. function thumbs($FileName,$SaveTo,$SetW,$SetH){ 
6.     $IMGInfo= getimagesize($FileName); 
7.     if(!$IMGInfo) return false; 
8.          
9.     if($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.     } 
16.      
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$nh <br /-->"; 
23.      
24.     if($SetW-$nw == 1){$nw = $SetW;} 
25.     if($SetH-$nh == 1){$nh = $SetH;} 
26.     echo "+修正1像素： w$nw,h$nh<br>"; 
27.      
28.     //补宽 
29.     if($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>"; 
43.      
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>"; 
48.      
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. } 
54.      
55. ?> 
56.  

出处：http://www.phpfensi.com/php/20210302/13800.html