<?php

/**

 * Greyhound - real web management for Amarok

 * Copyright (C) 2008 Dan Fuhry

 *

 * This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied

 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.

 */

/**

 * Determines an image's filetype based on its signature.

 * @param string Path to image file

 * @return string One of gif, png, or jpg, or false if none of these.

 */

function get_image_filetype($filename)

{

  $filecontents = @file_get_contents($filename);

  if ( empty($filecontents) )

    return false;

  if ( substr($filecontents, 0, 8) == "\x89\x50\x4e\x47\x0d\x0a\x1a\x0a" )

    return 'png';

  if ( substr($filecontents, 0, 6) == 'GIF87a' || substr($filecontents, 0, 6) == 'GIF89a' )

    return 'gif';

  if ( substr($filecontents, 0, 2) == "\xFF\xD8" )

    return 'jpg';

  return false;

}

/**

 * Scales an image to the specified width and height, and writes the output to the specified

 * file. Will use ImageMagick if present, but if not will attempt to scale with GD. This will

 * always scale images proportionally, unless $preserve_ratio is set to false.

 * 

 * Ported from Enano CMS (which is also my project)

 * 

 * @param string Path to image file

 * @param string Path to output file

 * @param int Image width, in pixels

 * @param int Image height, in pixels

 * @param bool If true, the output file will be deleted if it exists before it is written

 * @param bool If true, preserves the image's aspect ratio (default)

 * @return bool True on success, false on failure

 */

function scale_image($in_file, $out_file, $width = 225, $height = 225, $unlink = false, $preserve_ratio = true)

{

  global $db, $session, $paths, $template, $plugins; // Common objects

  if ( !is_int($width) || !is_int($height) )

    return false;

  if ( !file_exists($in_file) )

    return false;

  if ( preg_match('/["\'\/\\]/', $in_file) || preg_match('/["\'\/\\]/', $out_file) )

    return false;

  if ( file_exists($out_file) && !$unlink )

    return false;

  else if ( file_exists($out_file) && $unlink )

    @unlink($out_file);

  if ( file_exists($out_file) )

    // couldn't unlink (delete) the output file

    return false;

  $file_ext = substr($in_file, ( strrpos($in_file, '.') + 1));

  switch($file_ext)

  {

    case 'png':

      $func = 'imagecreatefrompng';

      break;

    case 'jpg':

    case 'jpeg':

      $func = 'imagecreatefromjpeg';

      break;

    case 'gif':

      $func = 'imagecreatefromgif';

      break;

    case 'xpm':

      $func = 'imagecreatefromxpm';

      break;

    default:

      return false;

  }

  // try to find convert in the PATH

  // FIXME: unix specific (won't work on windows)

  $path = ( isset($_ENV['PATH']) ) ? $_ENV['PATH'] : ( isset($_SERVER['PATH']) ? $_SERVER['PATH'] : '/usr/local/bin:/usr/bin:/bin' );

  $path = explode(':', $path);

  foreach ( $path as $dir )

  {

    if ( file_exists("$dir/convert") && is_executable("$dir/convert") )

    {

      $magick_path = "$dir/convert";

    }

  }

  $can_use_magick = isset($magick_path);

  $can_use_gd = (

      function_exists('getimagesize')         &&

      function_exists('imagecreatetruecolor') &&

      function_exists('imagecopyresampled')   &&

      function_exists($func)

    );

  if ( $can_use_magick )

  {

    if ( !preg_match('/^([\/A-z0-9_-]+)$/', $magick_path) )

    {

      // ImageMagick path seems screwy

      return false;

    }

    $op = ( $preserve_ratio ) ? '>' : '!';

    $cmdline = "\"$magick_path\" \"$in_file\" -resize '{$width}x{$height}$op' \"$out_file\"";

    exec($cmdline, $output, $return);

    if ( !file_exists($out_file) )

      return false;

    return true;

  }

  else if ( $can_use_gd )

  {

    @list($width_orig, $height_orig) = @getimagesize($in_file);

    if ( !$width_orig || !$height_orig )

      return false;

    // calculate new width and height

    if ( $preserve_ratio )

    {

      $ratio = $width_orig / $height_orig;

      if ( $ratio > 1 )

      {

        // orig. width is greater that height

        $new_width = $width;

        $new_height = round( $width / $ratio );

      }

      else if ( $ratio < 1 )

      {

        // orig. height is greater than width

        $new_width = round( $height / $ratio );

        $new_height = $height;

      }

      else if ( $ratio == 1 )

      {

        $new_width = $width;

        $new_height = $width;

      }

      if ( $new_width > $width_orig || $new_height > $height_orig )

      {

        // Too big for our britches here; set it to only convert the file

        $new_width = $width_orig;

        $new_height = $height_orig;

      }

    }

    else

    {

      $new_width = $width;

      $new_height = $height;

    }

    $newimage = @imagecreatetruecolor($new_width, $new_height);

    if ( !$newimage )

      return false;

    $oldimage = @$func($in_file);

    if ( !$oldimage )

      return false;

    // Perform scaling

    imagecopyresampled($newimage, $oldimage, 0, 0, 0, 0, $new_width, $new_height, $width_orig, $height_orig);

    // Get output format

    $out_ext = substr($out_file, ( strrpos($out_file, '.') + 1));

    switch($out_ext)

    {

      case 'png':

        $outfunc = 'imagepng';

        break;

      case 'jpg':

      case 'jpeg':

        $outfunc = 'imagejpeg';

        break;

      case 'gif':

        $outfunc = 'imagegif';

        break;

      case 'xpm':

        $outfunc = 'imagexpm';

        break;

      default:

        imagedestroy($newimage);

        imagedestroy($oldimage);

        return false;

    }

    // Write output

    $outfunc($newimage, $out_file);

    // clean up

    imagedestroy($newimage);

    imagedestroy($oldimage);

    // done!

    return true;

  }

  if ( file_exists($out_file) )

    return true;

  return false;

}