1 class image_thumbnail
  2 {
  3   var $source_file;
  4   var $target_path;
  5   var $target_file;
  6   var $file_info = array();
  7 
  8   function image_thumbnail($source_file, $target_path, $max_width, $max_height, $keep_ratio = true, $type = NULL)
  9   {
 10     $this->file_info['error'] = 0;
 11     $this->source_file = $source_file;
 12     $this->target_path = $target_path;
 13     $this->set_size($max_width, $max_height, $keep_ratio);
 14     
 15     if($type == NULL)
 16       $this->file_info['type'] = $this->get_file_extensition($source_file);
 17     else
 18       $this->file_info['type'] = $type;
 19   }
 20 
 21   function set_size($max_width, $max_height, $keep_ratio)
 22   {
 23     $file_info = @getimagesize($this->source_file);
 24 
 25     if(intval($max_width) <= 0)
 26       $max_width  = $file_info && $file_info[0] > 0 ? $file_info[0] : 1;
 27 
 28     if(intval($max_height) <= 0)
 29       $max_height = $file_info && $file_info[1] > 0 ? $file_info[1] : 1;
 30 
 31     if($keep_ratio && $file_info)
 32     {
 33       if($file_info[0] / $max_width < $file_info[1] / $max_height)
 34       {
 35         $this->file_info['width']  = round($max_height * ($file_info[0] / $file_info[1]));
 36         $this->file_info['height'] = $max_height;
 37       }
 38       else
 39       {
 40         $this->file_info['width']  = $max_width;
 41         $this->file_info['height'] = round($max_width * ($file_info[1] / $file_info[0]));
 42       }
 43     }
 44     else
 45     {
 46       $this->file_info['width']  = $max_width;
 47       $this->file_info['height'] = $max_height;
 48     }
 49   }
 50 
 51   function has_error()
 52   {
 53     return $this->file_info['error'] != 0;
 54   }
 55 
 56   function get_error()
 57   {
 58     switch($this->file_info['error'])
 59     {
 60     case 1:
 61       return 'Die Quelldatei konnte nicht gefunden werden oder war nicht lesbar.';
 62 
 63     case 2:
 64       return 'Das Zielverzeichnis existiert nicht und konnte nicht angelegt werden.';
 65 
 66     case 3:
 67       return 'Das Zielverzeichnis ist schreibgeschützt.';
 68 
 69     case 4:
 70       return 'Der gewünschte Bildtyp für die Zieldatei wird von der verwendeten Bildbibliothek nicht unterstützt.';
 71 
 72     case 5:
 73       return 'Die Quelldatei konnte nicht geöffnet werden, der Bildtyp wird von der verwendeten Bildbibliothek nicht unterstützt.';
 74 
 75     case 6:
 76       return 'Das Thumbnail konnte nicht geschrieben werden, eventuell wird der gewünschte Bildtyp von der verwendeten Bildbibliothek nicht unterstützt oder es konnte nicht in das Zielverzeichnis geshcrieben werden.';
 77 
 78     case 99:
 79       return 'Die GD-Bildbiblieothek wurde nicht gefunden.';
 80     }
 81   }
 82 
 83   function get_file_extensition($filename)
 84   {
 85     if(strpos($filename, '.', 0) === false)
 86       return substr($filename, -3);
 87     else
 88       return strtolower(preg_replace("/^(.*?)\./", "", $filename));
 89   }
 90 
 91   function get_image_types()
 92   {
 93     $image_types = array();
 94 
 95     if(function_exists('imagetypes'))
 96     {
 97       if(imagetypes() & IMG_GIF)
 98         $image_types['gif'] = 'gif';
 99 
100       if(imagetypes() & IMG_JPEG)
101         $image_types['jpg'] = 'jpg';
102 
103       if(imagetypes() & IMG_PNG)
104         $image_types['png'] = 'png';
105 
106       if(imagetypes() & IMG_WBMP)
107         $image_types['wbmp'] = 'wbmp';
108     }
109 
110     return $image_types;
111   }
112 
113   function generate_thumbnail()
114   {
115     if(!file_exists($this->source_file) || !is_readable($this->source_file))
116     {
117       $this->file_info['error'] = 1;
118       return false;
119     }
120 
121     /* Try to create a sub dir in image directory, if not exist. The user
122      * will get a warning, if this operation fails.
123      */
124     if(!file_exists($this->target_path) && !@mkdir($this->target_path, 0755))
125     {
126       $this->file_info['error'] = 2;
127       return false;
128     }
129 
130     if(!is_writable($this->target_path) || !@is_dir($this->target_path))
131     {
132       $this->file_info['error'] = 3;
133       return false;
134     }
135 
136     if(!in_array($this->file_info['type'], $this->get_image_types()))
137     {
138       $this->file_info['error'] = 4;
139       return false;
140     }
141 
142     $this->target_file = md5(microtime()) . '.' . $this->file_info['type'];
143     $this->file_info['extenstion'] = $this->get_file_extensition($this->source_file);
144 
145     // check weather the gd-image module is installed or not
146     if(function_exists('imagetypes'))
147     {
148       $source_image = false;
149 
150       switch($this->file_info['extenstion'])
151       {
152       case 'gif':
153         if(function_exists('imagecreatefromgif'))
154           $source_image = @imagecreatefromgif($this->source_file);
155         break;
156 
157       case 'jpg':
158       case 'jpeg':
159       case 'pjpg':
160       case 'pjpeg':
161         if(function_exists('imagecreatefromjpeg'))
162           $source_image = @imagecreatefromjpeg($this->source_file);
163         break;
164 
165       case 'png':
166         if(function_exists('imagecreatefrompng'))
167           $source_image = @imagecreatefrompng($this->source_file);
168         break;
169 
170       case 'wbmp':
171         if(function_exists('imagecreatefromwbmp'))
172           $source_image = @imagecreatefromwbmp($this->source_file);
173         break;
174       }
175 
176       if(!$source_image)
177       {
178         $this->file_info['error'] = 5;
179         return false;
180       }
181 
182       $source_image_width  = imagesx($source_image);
183       $source_image_height = imagesy($source_image);
184 
185       /* Try to use gd 2.0 and the better resampling method.
186        */
187       if(function_exists('imagecreatetruecolor') && function_exists('imagecopyresampled'))
188       {
189         $target_image = @imagecreatetruecolor($this->file_info['width'], $this->file_info['height']);
190 
191         if($target_image)
192           imagecopyresampled($target_image, $source_image, 0,0, 0,0, $this->file_info['width']+1, $this->file_info['height']+1, $source_image_width, $source_image_height);
193       }
194 
195       /* If gd 2.0 is not installed or the php version is to old use the old
196        * resizing method.
197        */
198       if(!$target_image)
199       {
200         $target_image = @imagecreate($this->file_info['width'], $this->file_info['height']);
201 
202         if($target_image)
203           imagecopyresized($target_image, $source_image, 0,0, 0,0, $this->file_info['width']+1, $this->file_info['height']+1, $source_image_width, $source_image_height);
204       }
205 
206       $created_image = false;
207 
208       switch($this->file_info['type'])
209       {
210       case 'gif':
211         if(function_exists('imagegif'))
212           $created_image = imagegif($target_image, $this->target_path . $this->target_file);
213         break;
214 
215       case 'jpg':
216         if(function_exists('imagejpeg'))
217           $created_image = imagejpeg($target_image, $this->target_path . $this->target_file);
218         break;
219 
220       case 'png':
221         if(function_exists('imagepng'))
222           $created_image = imagepng($target_image, $this->target_path . $this->target_file);
223         break;
224 
225       case 'wbmp':
226         if(function_exists('imagewbmp'))
227           $created_image = imagewbmp($target_image, $this->target_path . $this->target_file);
228         break;
229       }
230 
231       imagedestroy($source_image);
232       imagedestroy($target_image);
233 
234       if(!$created_image)
235       {
236         $this->file_info['error'] = 6;
237         return false;
238       }
239     }
240     else
241     {
242       $this->file_info['error'] = 99;
243       return false;
244     }
245 
246     $this->file_info['size'] = @filesize($this->target_path . $this->target_file);
247 
248     return true;
249   }
250 
251   function get_file_info()
252   {
253     $this->file_info['target_file'] = $this->target_file;
254     $this->file_info['target_path'] = $this->target_path;
255 
256     return $this->file_info;
257   }
258 }
   

 
1 $thumb = new image_thumbnail('image.jpg', './', '400', '400');
2 
3 if($thumb->generate_thumbnail())
4   echo 'Das Thumbnail wurde generiert: <a href="' . $thumb->target_file . '">Anzeigen</a>';
5 else
6   die($thumb->get_error());