PHP画图之GD库的使用——略缩图（二）

 1 <?php 
 2     // 将图像等比放大或缩小
 3     class resize{
 4 
 5         private $src;
 6         private $image;
 7         private $width;
 8         private $height;
 9         private $imageType;
10         private $imageResize;
11         private $newWidth;
12         private $newHeight;
13 
14         // 文件路径名，期待文件的宽度
15         public function __construct($fileName, $newWidth){
16 
17             $this->src = $fileName;
18             $this->newWidth = $newWidth;
19             $this->imageType = exif_imagetype($fileName);
20             $this->image = $this->openImage($this->src);
21             if($this->image){
22                 $this->width = imagesx($this->image);
23                 $this->height = imagesy($this->image);
24             }
25             
26 
27         }
28 
29         
30         private function openImage($file){
31 
32             switch ($this->imageType) {
33                 case IMAGETYPE_GIF:
34                     $img = imagecreatefromgif($file);
35                     break;
36 
37                 case IMAGETYPE_JPEG:
38                     $img = imagecreatefromjpeg($file);
39                     break;
40 
41                 case IMAGETYPE_PNG:
42                     $img = imagecreatefrompng($file);
43                     break;    
44             }
45 
46             return $img;
47         }
48 
49 
50         private function saveImage(){
51 
52             switch ($this->imageType) {
53                 case IMAGETYPE_GIF:
54                     header("Content-type: " . image_type_to_mime_type(IMAGETYPE_GIF));
55                     imagegif($this->imageResize);
56                     break;
57 
58                 case IMAGETYPE_JPEG:
59                     header("Content-type: " . image_type_to_mime_type(IMAGETYPE_JPEG));
60                     imagejpeg($this->imageResize);
61                     break;
62 
63                 case IMAGETYPE_PNG:
64                     header("Content-type: " . image_type_to_mime_type(IMAGETYPE_PNG));
65                     imagepng($this->imageResize);
66                     break;    
67             }
68 
69             imagedestroy($this->image);
70             imagedestroy($this->imageResize);
71         }
72 
73 
74         public function resizeImage(){
75 
76             $ratio = $this->height/$this->width;
77             $this->newHeight = $this->newWidth*$ratio;
78             $this->imageResize = imagecreatetruecolor($this->newWidth, $this->newHeight);
79             imagecopyresampled($this->imageResize, $this->image, 0, 0, 0, 0, $this->newWidth, $this->newHeight, $this->width, $this->height);
80             $this->saveImage();
81         }
82 
83     }
84 
85 
86     $img1 = new resize(‘GD/img/logo.png‘,50);
87     $img1->resizeImage();
88 
89 
90  ?>