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 $CFG;
  50
  51     if (function_exists('imagecopyresampled')) {
  52        return imagecopyresampled($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 $CFG;
 102
 103     if (!is_file($originalfile)) {
 104         return false;
 105     }
 106
 107     $imageinfo = getimagesize($originalfile);
 108
 109     if (empty($imageinfo)) {
 110         return false;
 111     }
 112
 113     $image = new stdClass();
 114     $image->width  = $imageinfo[0];
 115     $image->height = $imageinfo[1];
 116     $image->type   = $imageinfo[2];
 117
 118     $t = null;
 119     switch ($image->type) {
 120         case IMAGETYPE_GIF:
 121             if (function_exists('imagecreatefromgif')) {
 122                 $im = imagecreatefromgif($originalfile);
 123             } else {
 124                 debugging('GIF not supported on this server');
 125                 return false;
 126             }
 127             // Guess transparent colour from GIF.
 128             $transparent = imagecolortransparent($im);
 129             if ($transparent != -1) {
 130                 $t = imagecolorsforindex($im, $transparent);
 131             }
 132             break;
 133         case IMAGETYPE_JPEG:
 134             if (function_exists('imagecreatefromjpeg')) {
 135                 $im = imagecreatefromjpeg($originalfile);
 136             } else {
 137                 debugging('JPEG not supported on this server');
 138                 return false;
 139             }
 140             break;
 141         case IMAGETYPE_PNG:
 142             if (function_exists('imagecreatefrompng')) {
 143                 $im = imagecreatefrompng($originalfile);
 144             } else {
 145                 debugging('PNG not supported on this server');
 146                 return false;
 147             }
 148             break;
 149         default:
 150             return false;
 151     }
 152
 153     if (function_exists('imagepng')) {
 154         $imagefnc = 'imagepng';
 155         $imageext = '.png';
 156         $filters = PNG_NO_FILTER;
 157         $quality = 1;
 158     } else if (function_exists('imagejpeg')) {
 159         $imagefnc = 'imagejpeg';
 160         $imageext = '.jpg';
 161         $filters = null; // not used
 162         $quality = 90;
 163     } else {
 164         debugging('Jpeg and png not supported on this server, please fix server configuration');
 165         return false;
 166     }
 167
 168     if (function_exists('imagecreatetruecolor')) {
 169         $im1 = imagecreatetruecolor(100, 100);
 170         $im2 = imagecreatetruecolor(35, 35);
 171         $im3 = imagecreatetruecolor(512, 512);
 172         if ($image->type != IMAGETYPE_JPEG and $imagefnc === 'imagepng') {
 173             if ($t) {
 174                 // Transparent GIF hacking...
 175                 $transparentcolour = imagecolorallocate($im1 , $t['red'] , $t['green'] , $t['blue']);
 176                 imagecolortransparent($im1 , $transparentcolour);
 177                 $transparentcolour = imagecolorallocate($im2 , $t['red'] , $t['green'] , $t['blue']);
 178                 imagecolortransparent($im2 , $transparentcolour);
 179                 $transparentcolour = imagecolorallocate($im3 , $t['red'] , $t['green'] , $t['blue']);
 180                 imagecolortransparent($im3 , $transparentcolour);
 181             }
 182
 183             imagealphablending($im1, false);
 184             $color = imagecolorallocatealpha($im1, 0, 0,  0, 127);
 185             imagefill($im1, 0, 0,  $color);
 186             imagesavealpha($im1, true);
 187
 188             imagealphablending($im2, false);
 189             $color = imagecolorallocatealpha($im2, 0, 0,  0, 127);
 190             imagefill($im2, 0, 0,  $color);
 191             imagesavealpha($im2, true);
 192
 193             imagealphablending($im3, false);
 194             $color = imagecolorallocatealpha($im3, 0, 0,  0, 127);
 195             imagefill($im3, 0, 0,  $color);
 196             imagesavealpha($im3, true);
 197         }
 198     } else {
 199         $im1 = imagecreate(100, 100);
 200         $im2 = imagecreate(35, 35);
 201         $im3 = imagecreate(512, 512);
 202     }
 203
 204     $cx = $image->width / 2;
 205     $cy = $image->height / 2;
 206
 207     if ($image->width < $image->height) {
 208         $half = floor($image->width / 2.0);
 209     } else {
 210         $half = floor($image->height / 2.0);
 211     }
 212
 213     imagecopybicubic($im1, $im, 0, 0, $cx - $half, $cy - $half, 100, 100, $half * 2, $half * 2);
 214     imagecopybicubic($im2, $im, 0, 0, $cx - $half, $cy - $half, 35, 35, $half * 2, $half * 2);
 215     imagecopybicubic($im3, $im, 0, 0, $cx - $half, $cy - $half, 512, 512, $half * 2, $half * 2);
 216
 217     $fs = get_file_storage();
 218
 219     $icon = array('contextid'=>$context->id, 'component'=>$component, 'filearea'=>$filearea, 'itemid'=>$itemid, 'filepath'=>'/');
 220
 221     ob_start();
 222     if (!$imagefnc($im1, NULL, $quality, $filters)) {
 223         // keep old icons
 224         ob_end_clean();
 225         return false;
 226     }
 227     $data = ob_get_clean();
 228     imagedestroy($im1);
 229     $icon['filename'] = 'f1'.$imageext;
 230     $fs->delete_area_files($context->id, $component, $filearea, $itemid);
 231     $file1 = $fs->create_file_from_string($icon, $data);
 232
 233     ob_start();
 234     if (!$imagefnc($im2, NULL, $quality, $filters)) {
 235         ob_end_clean();
 236         $fs->delete_area_files($context->id, $component, $filearea, $itemid);
 237         return false;
 238     }
 239     $data = ob_get_clean();
 240     imagedestroy($im2);
 241     $icon['filename'] = 'f2'.$imageext;
 242     $fs->create_file_from_string($icon, $data);
 243
 244     ob_start();
 245     if (!$imagefnc($im3, NULL, $quality, $filters)) {
 246         ob_end_clean();
 247         $fs->delete_area_files($context->id, $component, $filearea, $itemid);
 248         return false;
 249     }
 250     $data = ob_get_clean();
 251     imagedestroy($im3);
 252     $icon['filename'] = 'f3'.$imageext;
 253     $fs->create_file_from_string($icon, $data);
 254
 255     return $file1->get_id();
 256 }
 257
 258 /**
 259  * Generates a thumbnail for the given image
 260  *
 261  * If the GD library has at least version 2 and PNG support is available, the returned data
 262  * is the content of a transparent PNG file containing the thumbnail. Otherwise, the function
 263  * returns contents of a JPEG file with black background containing the thumbnail.
 264  *
 265  * @param string $filepath the full path to the original image file
 266  * @param int $width the width of the requested thumbnail
 267  * @param int $height the height of the requested thumbnail
 268  * @return string|bool false if a problem occurs, the thumbnail image data otherwise
 269  */
 270 function generate_image_thumbnail($filepath, $width, $height) {
 271     global $CFG;
 272
 273     if (empty($filepath) or empty($width) or empty($height)) {
 274         return false;
 275     }
 276
 277     $imageinfo = getimagesize($filepath);
 278
 279     if (empty($imageinfo)) {
 280         return false;
 281     }
 282
 283     $originalwidth = $imageinfo[0];
 284     $originalheight = $imageinfo[1];
 285
 286     if (empty($originalwidth) or empty($originalheight)) {
 287         return false;
 288     }
 289
 290     $original = imagecreatefromstring(file_get_contents($filepath));
 291
 292     if (function_exists('imagepng')) {
 293         $imagefnc = 'imagepng';
 294         $filters = PNG_NO_FILTER;
 295         $quality = 1;
 296     } else if (function_exists('imagejpeg')) {
 297         $imagefnc = 'imagejpeg';
 298         $filters = null;
 299         $quality = 90;
 300     } else {
 301         debugging('Neither JPEG nor PNG are supported at this server, please fix the system configuration.');
 302         return false;
 303     }
 304
 305     if (function_exists('imagecreatetruecolor')) {
 306         $thumbnail = imagecreatetruecolor($width, $height);
 307         if ($imagefnc === 'imagepng') {
 308             imagealphablending($thumbnail, false);
 309             imagefill($thumbnail, 0, 0, imagecolorallocatealpha($thumbnail, 0, 0, 0, 127));
 310             imagesavealpha($thumbnail, true);
 311         }
 312     } else {
 313         $thumbnail = imagecreate($width, $height);
 314     }
 315
 316     $ratio = min($width / $originalwidth, $height / $originalheight);
 317
 318     if ($ratio < 1) {
 319         $targetwidth = floor($originalwidth * $ratio);
 320         $targetheight = floor($originalheight * $ratio);
 321     } else {
 322         // do not enlarge the original file if it is smaller than the requested thumbnail size
 323         $targetwidth = $originalwidth;
 324         $targetheight = $originalheight;
 325     }
 326
 327     $dstx = floor(($width - $targetwidth) / 2);
 328     $dsty = floor(($height - $targetheight) / 2);
 329
 330     imagecopybicubic($thumbnail, $original, $dstx, $dsty, 0, 0, $targetwidth, $targetheight, $originalwidth, $originalheight);
 331
 332     ob_start();
 333     if (!$imagefnc($thumbnail, null, $quality, $filters)) {
 334         ob_end_clean();
 335         return false;
 336     }
 337     $data = ob_get_clean();
 338     imagedestroy($original);
 339     imagedestroy($thumbnail);
 340
 341     return $data;
 342 }