PHP: creare immagini thumbnail

This entry was posted on January 8th, 2009 and is filed under php.

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Da sastgroup una comoda funzione per creare le thumbnail di immagini di grandi dimensioni. Comoda ad esempio per creare i back-office di siti che necessitano di gallery.

Il codice è visualizzabile dopo il link.


function create_img_gd($imgfile, $imgthumb, $newwidth) {
  if (function_exists("imagecreate")) {
    $imginfo = getimagesize($imgfile);

    switch($imginfo[2]) {
      case 1:
          $type = IMG_GIF;
          break;
      case 2:
          $type = IMG_JPG;
          break;
      case 3:
          $type = IMG_PNG;
          break;
      case 4:
          $type = IMG_WBMP;
          break;
      default:
          return $imgfile;
          break;
    }

    switch($type) {
      case IMG_GIF:
          if (!function_exists("imagecreatefromgif")) return $imgfile;
          $srcImage = imagecreatefromgif("$imgfile");
          break;
      case IMG_JPG:
          if (!function_exists("imagecreatefromjpeg")) return $imgfile;
          $srcImage = imagecreatefromjpeg($imgfile);
          break;
      case IMG_PNG:
          if(!function_exists("imagecreatefrompng")) return $imgfile;
          $srcImage = imagecreatefrompng("$imgfile");
          break;
      case IMG_WBMP:
          if (!function_exists("imagecreatefromwbmp")) return $imgfile;
          $srcImage = imagecreatefromwbmp("$imgfile");
          break;
      default:
          return $imgfile;
    }

    if ($srcImage){
      $srcWidth = $imginfo[0];
      $srcHeight = $imginfo[1];
      $ratioWidth = $srcWidth / $newwidth;
      $destWidth = $newwidth;
      $destHeight = $srcHeight / $ratioWidth;
      $destImage = imagecreatetruecolor($destWidth, $destHeight);
      imagealphablending($destImage, true);
      imagealphablending($srcImage, false);
      imagecopyresized($destImage, $srcImage, 0, 0, 0, 0, $destWidth, $destHeight, $srcWidth, $srcHeight);

      switch($type) {
        case IMG_GIF:
            imagegif($destImage, "$imgthumb");
            break;
        case IMG_JPG:
            imagejpeg($destImage, "$imgthumb");
            break;
        case IMG_PNG:
            imagepng($destImage, "$imgthumb");
            break;
        case IMG_WBMP:
            imagewbmp($destImage, "$imgthumb");
            break;
      }

      imagedestroy($srcImage);
      imagedestroy($destImage);
      return $imgthumb;
    } else {return $imgfile;}
  } else {return $imgfile;}
}

Via | sastgroup