lib/gdlib.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * gdlib.php - Collection of routines in Moodle related to
  20  * processing images using GD
  21  *
  22  * @package   core
  23  * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
  24  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25  */
  26
  27 defined('MOODLE_INTERNAL') || die();
  28
  29 /**
  30  * Copies a rectangular portion of the source image to another rectangle in the destination image
  31  *
  32  * This function calls imagecopyresampled() if it is available and GD version is 2 at least.
  33  * Otherwise it reimplements the same behaviour. See the PHP manual page for more info.
  34  *
  35  * @link http://php.net/manual/en/function.imagecopyresampled.php
  36  * @param resource $dst_img the destination GD image resource
  37  * @param resource $src_img the source GD image resource
  38  * @param int $dst_x vthe X coordinate of the upper left corner in the destination image
  39  * @param int $dst_y the Y coordinate of the upper left corner in the destination image
  40  * @param int $src_x the X coordinate of the upper left corner in the source image
  41  * @param int $src_y the Y coordinate of the upper left corner in the source image
  42  * @param int $dst_w the width of the destination rectangle
  43  * @param int $dst_h the height of the destination rectangle
  44  * @param int $src_w the width of the source rectangle
  45  * @param int $src_h the height of the source rectangle
  46  * @return bool tru on success, false otherwise
  47  */
  48 function imagecopybicubic($dst_img, $src_img, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h) {
  49     global $CFG;
  50
  51     if (function_exists('imagecopyresampled') and $CFG->gdversion >= 2) {
  52        return imagecopyresampled($dst_img, $src_img, $dst_x, $dst_y, $src_x, $src_y,
  53                                  $dst_w, $dst_h, $src_w, $src_h);
  54     }
  55
  56     $totalcolors = imagecolorstotal($src_img);
  57     for ($i=0; $i<$totalcolors; $i++) {
  58         if ($colors = imagecolorsforindex($src_img, $i)) {
  59             imagecolorallocate($dst_img, $colors['red'], $colors['green'], $colors['blue']);
  60         }
  61     }
  62
  63     $scalex = ($src_w - 1) / $dst_w;
  64     $scaley = ($src_h - 1) / $dst_h;
  65
  66     $scalex2 = $scalex / 2.0;
  67     $scaley2 = $scaley / 2.0;
  68
  69     for ($j = 0; $j < $dst_h; $j++) {
  70         $sy = $j * $scaley;
  71
  72         for ($i = 0; $i < $dst_w; $i++) {
  73             $sx = $i * $scalex;
  74
  75             $c1 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx, (int)$sy + $scaley2));
  76             $c2 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx, (int)$sy));
  77             $c3 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx + $scalex2, (int)$sy + $scaley2));
  78             $c4 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx + $scalex2, (int)$sy));
  79
  80             $red = (int) (($c1['red'] + $c2['red'] + $c3['red'] + $c4['red']) / 4);
  81             $green = (int) (($c1['green'] + $c2['green'] + $c3['green'] + $c4['green']) / 4);
  82             $blue = (int) (($c1['blue'] + $c2['blue'] + $c3['blue'] + $c4['blue']) / 4);
  83
  84             $color = imagecolorclosest($dst_img, $red, $green, $blue);
  85             imagesetpixel($dst_img, $i + $dst_x, $j + $dst_y, $color);
  86         }
  87     }
  88 }
  89
  90 /**
  91  * Stores optimised icon images in icon file area
  92  *
  93  * @param context $context
  94  * @param string $component
  95  * @param string filearea
  96  * @param int $itemid
  97  * @param string $originalfile
  98  * @return mixed new unique revision number or false if not saved
  99  */
 100 function process_new_icon($context, $component, $filearea, $itemid, $originalfile) {
 101     global $CFG;
 102
 103     if (empty($CFG->gdversion)) {
 104         return false;
 105     }
 106
 107     if (!is_file($originalfile)) {
 108         return false;
 109     }
 110
 111     $imageinfo = getimagesize($originalfile);
 112
 113     if (empty($imageinfo)) {
 114         return false;
 115     }
 116
 117     $image = new stdClass();
 118     $image->width  = $imageinfo[0];
 119     $image->height = $imageinfo[1];
 120     $image->type   = $imageinfo[2];
 121
 122     $t = null;
 123     switch ($image->type) {
 124         case IMAGETYPE_GIF:
 125             if (function_exists('imagecreatefromgif')) {
 126                 $im = imagecreatefromgif($originalfile);
 127             } else {
 128                 debugging('GIF not supported on this server');
 129                 return false;
 130             }
 131             // Guess transparent colour from GIF.
 132             $transparent = imagecolortransparent($im);
 133             if ($transparent != -1) {
 134                 $t = imagecolorsforindex($im, $transparent);
 135             }
 136             break;
 137         case IMAGETYPE_JPEG:
 138             if (function_exists('imagecreatefromjpeg')) {
 139                 $im = imagecreatefromjpeg($originalfile);
 140             } else {
 141                 debugging('JPEG not supported on this server');
 142                 return false;
 143             }
 144             break;
 145         case IMAGETYPE_PNG:
 146             if (function_exists('imagecreatefrompng')) {
 147                 $im = imagecreatefrompng($originalfile);
 148             } else {
 149                 debugging('PNG not supported on this server');
 150                 return false;
 151             }
 152             break;
 153         default:
 154             return false;
 155     }
 156
 157     if (function_exists('imagepng')) {
 158         $imagefnc = 'imagepng';
 159         $imageext = '.png';
 160         $filters = PNG_NO_FILTER;
 161         $quality = 1;
 162     } else if (function_exists('imagejpeg')) {
 163         $imagefnc = 'imagejpeg';
 164         $imageext = '.jpg';
 165         $filters = null; // not used
 166         $quality = 90;
 167     } else {
 168         debugging('Jpeg and png not supported on this server, please fix server configuration');
 169         return false;
 170     }
 171
 172     if (function_exists('imagecreatetruecolor') and $CFG->gdversion >= 2) {
 173         $im1 = imagecreatetruecolor(100, 100);
 174         $im2 = imagecreatetruecolor(35, 35);
 175         $im3 = imagecreatetruecolor(512, 512);
 176         if ($image->type != IMAGETYPE_JPEG and $imagefnc === 'imagepng') {
 177             if ($t) {
 178                 // Transparent GIF hacking...
 179                 $transparentcolour = imagecolorallocate($im1 , $t['red'] , $t['green'] , $t['blue']);
 180                 imagecolortransparent($im1 , $transparentcolour);
 181                 $transparentcolour = imagecolorallocate($im2 , $t['red'] , $t['green'] , $t['blue']);
 182                 imagecolortransparent($im2 , $transparentcolour);
 183                 $transparentcolour = imagecolorallocate($im3 , $t['red'] , $t['green'] , $t['blue']);
 184                 imagecolortransparent($im3 , $transparentcolour);
 185             }
 186
 187             imagealphablending($im1, false);
 188             $color = imagecolorallocatealpha($im1, 0, 0,  0, 127);
 189             imagefill($im1, 0, 0,  $color);
 190             imagesavealpha($im1, true);
 191
 192             imagealphablending($im2, false);
 193             $color = imagecolorallocatealpha($im2, 0, 0,  0, 127);
 194             imagefill($im2, 0, 0,  $color);
 195             imagesavealpha($im2, true);
 196
 197             imagealphablending($im3, false);
 198             $color = imagecolorallocatealpha($im3, 0, 0,  0, 127);
 199             imagefill($im3, 0, 0,  $color);
 200             imagesavealpha($im3, true);
 201         }
 202     } else {
 203         $im1 = imagecreate(100, 100);
 204         $im2 = imagecreate(35, 35);
 205         $im3 = imagecreate(512, 512);
 206     }
 207
 208     $cx = $image->width / 2;
 209     $cy = $image->height / 2;
 210
 211     if ($image->width < $image->height) {
 212         $half = floor($image->width / 2.0);
 213     } else {
 214         $half = floor($image->height / 2.0);
 215     }
 216
 217     imagecopybicubic($im1, $im, 0, 0, $cx - $half, $cy - $half, 100, 100, $half * 2, $half * 2);
 218     imagecopybicubic($im2, $im, 0, 0, $cx - $half, $cy - $half, 35, 35, $half * 2, $half * 2);
 219     imagecopybicubic($im3, $im, 0, 0, $cx - $half, $cy - $half, 512, 512, $half * 2, $half * 2);
 220
 221     $fs = get_file_storage();
 222
 223     $icon = array('contextid'=>$context->id, 'component'=>$component, 'filearea'=>$filearea, 'itemid'=>$itemid, 'filepath'=>'/');
 224
 225     ob_start();
 226     if (!$imagefnc($im1, NULL, $quality, $filters)) {
 227         // keep old icons
 228         ob_end_clean();
 229         return false;
 230     }
 231     $data = ob_get_clean();
 232     imagedestroy($im1);
 233     $icon['filename'] = 'f1'.$imageext;
 234     $fs->delete_area_files($context->id, $component, $filearea, $itemid);
 235     $file1 = $fs->create_file_from_string($icon, $data);
 236
 237     ob_start();
 238     if (!$imagefnc($im2, NULL, $quality, $filters)) {
 239         ob_end_clean();
 240         $fs->delete_area_files($context->id, $component, $filearea, $itemid);
 241         return false;
 242     }
 243     $data = ob_get_clean();
 244     imagedestroy($im2);
 245     $icon['filename'] = 'f2'.$imageext;
 246     $fs->create_file_from_string($icon, $data);
 247
 248     ob_start();
 249     if (!$imagefnc($im3, NULL, $quality, $filters)) {
 250         ob_end_clean();
 251         $fs->delete_area_files($context->id, $component, $filearea, $itemid);
 252         return false;
 253     }
 254     $data = ob_get_clean();
 255     imagedestroy($im3);
 256     $icon['filename'] = 'f3'.$imageext;
 257     $fs->create_file_from_string($icon, $data);
 258
 259     return $file1->get_id();
 260 }
 261
 262 /**
 263  * Generates a thumbnail for the given image
 264  *
 265  * If the GD library has at least version 2 and PNG support is available, the returned data
 266  * is the content of a transparent PNG file containing the thumbnail. Otherwise, the function
 267  * returns contents of a JPEG file with black background containing the thumbnail.
 268  *
 269  * @param string $filepath the full path to the original image file
 270  * @param int $width the width of the requested thumbnail
 271  * @param int $height the height of the requested thumbnail
 272  * @return string|bool false if a problem occurs, the thumbnail image data otherwise
 273  */
 274 function generate_image_thumbnail($filepath, $width, $height) {
 275     global $CFG;
 276
 277     if (empty($CFG->gdversion) or empty($filepath) or empty($width) or empty($height)) {
 278         return false;
 279     }
 280
 281     $imageinfo = getimagesize($filepath);
 282
 283     if (empty($imageinfo)) {
 284         return false;
 285     }
 286
 287     $originalwidth = $imageinfo[0];
 288     $originalheight = $imageinfo[1];
 289
 290     if (empty($originalwidth) or empty($originalheight)) {
 291         return false;
 292     }
 293
 294     $original = imagecreatefromstring(file_get_contents($filepath));
 295
 296     if (function_exists('imagepng')) {
 297         $imagefnc = 'imagepng';
 298         $filters = PNG_NO_FILTER;
 299         $quality = 1;
 300     } else if (function_exists('imagejpeg')) {
 301         $imagefnc = 'imagejpeg';
 302         $filters = null;
 303         $quality = 90;
 304     } else {
 305         debugging('Neither JPEG nor PNG are supported at this server, please fix the system configuration.');
 306         return false;
 307     }
 308
 309     if (function_exists('imagecreatetruecolor') and $CFG->gdversion >= 2) {
 310         $thumbnail = imagecreatetruecolor($width, $height);
 311         if ($imagefnc === 'imagepng') {
 312             imagealphablending($thumbnail, false);
 313             imagefill($thumbnail, 0, 0, imagecolorallocatealpha($thumbnail, 0, 0, 0, 127));
 314             imagesavealpha($thumbnail, true);
 315         }
 316     } else {
 317         $thumbnail = imagecreate($width, $height);
 318     }
 319
 320     $ratio = min($width / $originalwidth, $height / $originalheight);
 321
 322     if ($ratio < 1) {
 323         $targetwidth = floor($originalwidth * $ratio);
 324         $targetheight = floor($originalheight * $ratio);
 325     } else {
 326         // do not enlarge the original file if it is smaller than the requested thumbnail size
 327         $targetwidth = $originalwidth;
 328         $targetheight = $originalheight;
 329     }
 330
 331     $dstx = floor(($width - $targetwidth) / 2);
 332     $dsty = floor(($height - $targetheight) / 2);
 333
 334     imagecopybicubic($thumbnail, $original, $dstx, $dsty, 0, 0, $targetwidth, $targetheight, $originalwidth, $originalheight);
 335
 336     ob_start();
 337     if (!$imagefnc($thumbnail, null, $quality, $filters)) {
 338         ob_end_clean();
 339         return false;
 340     }
 341     $data = ob_get_clean();
 342     imagedestroy($original);
 343     imagedestroy($thumbnail);
 344
 345     return $data;
 346 }