Изменение размеров PNG с сохранением прозрачности

Брал с двух разных источников, потом собрал все в кучу

resize_class_transparent.php

Код (Text):

1. <?php
2. class Resize_Image {
3.  
4.     var $image_to_resize;
5.     var $new_width;
6.     var $new_height;
7.     var $ratio;
8.     var $new_image_name;
9.     var $save_folder;
10.  
11.     function setTransparency($new_image, $image_source)
12.     {
13.         $transparencyIndex = imagecolortransparent($image_source);
14.         $transparencyColor = array('red' => 255, 'green' => 255, 'blue' => 255);
15.        
16.         if ($transparencyIndex >= 0)
17.             $transparencyColor = imagecolorsforindex($image_source, $transparencyIndex);  
18.        
19.         $transparencyIndex = imagecolorallocate($new_image, $transparencyColor['red'], $transparencyColor['green'], $transparencyColor['blue']);
20.         imagefill($new_image, 0, 0, $transparencyIndex);
21.         imagecolortransparent($new_image, $transparencyIndex);
22.     }
23.    
24.     function resize() {
25.         if(!file_exists($this->image_to_resize)) {
26.             exit("File ".$this->image_to_resize." does not exist.");
27.         }
28.  
29.         $info = GetImageSize($this->image_to_resize);
30.  
31.         if(empty($info)) {
32.             exit("The file ".$this->image_to_resize." doesn't seem to be an image.");
33.         }
34.  
35.         $width = $info[0];
36.         $height = $info[1];
37.         $mime = $info['mime'];
38.  
39.         /* Keep Aspect Ratio? */
40.  
41.         if($this->ratio) {
42.             // if preserving the ratio, only new width or new height
43.             // is used in the computation. if both
44.             // are set, use width
45.  
46.             if (isset($this->new_width)) {
47.                 $factor = (float)$this->new_width / (float)$width;
48.                 $this->new_height = $factor * $height;
49.             } else if (isset($this->new_height)) {
50.                 $factor = (float)$this->new_height / (float)$height;
51.                 $this->new_width = $factor * $width;
52.             } else exit("?neither new height or new width has been set");
53.         }
54.  
55.         // What sort of image?
56.  
57.         $type = substr(strrchr($mime, '/'), 1);
58.  
59.         switch ($type) {
60.             case 'jpeg':
61.                 $image_create_func = 'ImageCreateFromJPEG';
62.                 $image_save_func = 'ImageJPEG';
63.           $new_image_ext = 'jpg';
64.             break;
65.  
66.            case 'png':
67.                 $image_create_func = 'ImageCreateFromPNG';
68.                 $image_save_func = 'ImagePNG';
69.                 $new_image_ext = 'png';
70.             break;
71.  
72.             case 'bmp':
73.                 $image_create_func = 'ImageCreateFromBMP';
74.                 $image_save_func = 'ImageBMP';
75.                 $new_image_ext = 'bmp';
76.             break;
77.  
78.             case 'gif':
79.                 $image_create_func = 'ImageCreateFromGIF';
80.                 $image_save_func = 'ImageGIF';
81.                 $new_image_ext = 'gif';
82.             break;
83.  
84.             case 'vnd.wap.wbmp':
85.                 $image_create_func = 'ImageCreateFromWBMP';
86.                 $image_save_func = 'ImageWBMP';
87.                  $new_image_ext = 'bmp';
88.             break;
89.  
90.             case 'xbm':
91.                 $image_create_func = 'ImageCreateFromXBM';
92.                 $image_save_func = 'ImageXBM';
93.                 $new_image_ext = 'xbm';
94.             break;
95.  
96.             default:
97.                 $image_create_func = 'ImageCreateFromJPEG';
98.                 $image_save_func = 'ImageJPEG';
99.                 $new_image_ext = 'jpg';
100.         }
101.  
102.   // New Image
103.  
104.     if ($new_image_ext == 'png' ||  $new_image_ext == 'gif' )
105.     {  
106.         echo ("прозрачный!!!");
107.         $image_c  = ImageCreateTrueColor($this->new_width, $this->new_height);
108.         $new_image = $image_create_func($this->image_to_resize);
109.         $this->setTransparency($image_c, $new_image);
110.         ImageCopyResampled($image_c, $new_image , 0, 0, 0, 0, $this->new_width, $this->new_height, $width, $height);
111.     }
112.     else
113.     {
114.        
115.         $image_c = ImageCreateTrueColor($this->new_width, $this->new_height);
116.  
117.         $new_image = $image_create_func($this->image_to_resize);
118.  
119.         ImageCopyResampled($image_c, $new_image, 0, 0, 0, 0, $this->new_width, $this->new_height, $width, $height);
120.     }
121.  
122.  
123.         if($this->save_folder) {
124.          if($this->new_image_name) {
125.                         $new_name = $this->new_image_name.'.'.$new_image_ext;
126.          } else {
127.                      $new_name = $this->new_thumb_name( basename($this->image_to_resize) ).'_resized.'.$new_image_ext;
128.          }
129.  
130.     $save_path = $this->save_folder.$new_name;
131.   } else {
132.     /* Show the image without saving it to a folder */
133.        header("Content-Type: ".$mime);
134.              $image_save_func($image_c);
135.        $save_path = '';
136.   }
137.  
138.       $process = $image_save_func($image_c, $save_path);
139.     return array('result' => $process, 'new_file_path' => $save_path);
140.   }
141.  
142.   function new_thumb_name($filename) {
143.     $string = trim($filename);
144.     $string = strtolower($string);
145.     $string = trim(ereg_replace("[^ A-Za-z0-9_]", " ", $string));
146.     $string = ereg_replace("[ tnr]+", "_", $string);
147.     $string = str_replace(" ", '_', $string);
148.     $string = ereg_replace("[ _]+", "_", $string);
149.  
150.     return $string;
151.   }
152. }
153.  
154.  
155. ?>

index.php

Код (Text):

1. <?php
2. include 'resize_class_transparent.php';
3. $image = new Resize_Image;
4.  
5. $image->new_width = 200;
6. $image->new_height = 200;
7.  
8. $image->image_to_resize = "temp.png"; // Full Path to the file
9.  
10. $image->ratio = true; // Keep Aspect Ratio?
11.  
12. // Name of the new image (optional) - If it's not set a new will be added automatically
13.  
14. $image->new_image_name =md5(date('U'));
15.  
16. /* Path where the new image should be saved. If it's not set the script will output the image without saving it */
17.  
18. $image->save_folder = 'thumbs/';
19.  
20. $process = $image->resize();
21.  
22. if($process['result'] && $image->save_folder) {
23.   echo 'The new image ('.$process['new_file_path'].') has been saved.';
24. }
25. ?>

 

Неплохая программа Изменение размера картинки. Попробуй скачать.

 

А я использую для этой цели изменение размера изображения. Неплохая программа.