<?php
// +-----------------------------------------------------------------------+
// | Piwigo - a PHP based photo gallery                                    |
// +-----------------------------------------------------------------------+
// | Copyright(C) 2008-2013 Piwigo Team                  http://piwigo.org |
// +-----------------------------------------------------------------------+
// | This program is free software; you can redistribute it and/or modify  |
// | it under the terms of the GNU General Public License as published by  |
// | the Free Software Foundation                                          |
// |                                                                       |
// | 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 more details.                              |
// |                                                                       |
// | You should have received a copy of the GNU General Public License     |
// | along with this program; if not, write to the Free Software           |
// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
// | USA.                                                                  |
// +-----------------------------------------------------------------------+

function derivative_to_url($t)
{
  return substr($t, 0, 2);
}

function size_to_url($s)
{
  if ($s[0]==$s[1])
  {
    return $s[0];
  }
  return $s[0].'x'.$s[1];
}

function size_equals($s1, $s2)
{
  return ($s1[0]==$s2[0] && $s1[1]==$s2[1]);
}

function char_to_fraction($c)
{
	return (ord($c) - ord('a'))/25;
}

function fraction_to_char($f)
{
	return chr(ord('a') + round($f*25));
}

/** small utility to manipulate a 'rectangle'*/
final class ImageRect
{
  public $l,$t,$r,$b;

  function __construct($l)
  {
    $this->l = $this->t = 0;
    $this->r = $l[0];
    $this->b = $l[1];
  }

  function width()
  {
    return $this->r - $this->l;
  }

  function height()
  {
    return $this->b - $this->t;
  }

  /** crops horizontally this rectangle by increasing left side and/or reducing the right side.
  @param pixels the amount to substract from the width
  @param coi a 4 character string (or null) containing the center of interest*/
  function crop_h($pixels, $coi)
  {
    if ($this->width() <= $pixels)
      return;
    $tlcrop = floor($pixels/2);

    if (!empty($coi))
    {
      $coil = floor($this->r * char_to_fraction($coi[0]));
      $coir = ceil($this->r * char_to_fraction($coi[2]));
      $availableL = $coil > $this->l ? $coil - $this->l : 0;
      $availableR = $coir < $this->r ? $this->r - $coir : 0;
      if ($availableL + $availableR >= $pixels)
      {
        if ($availableL < $tlcrop)
        {
          $tlcrop = $availableL;
        }
        elseif ($availableR < $tlcrop)
        {
          $tlcrop = $pixels - $availableR;
        }
      }
    }
    $this->l += $tlcrop;
    $this->r -= $pixels - $tlcrop;
  }

  /** crops vertically this rectangle by increasing top side and/or reducing the bottom side.
  @param pixels the amount to substract from the height
  @param coi a 4 character string (or null) containing the center of interest*/
  function crop_v($pixels, $coi)
  {
    if ($this->height() <= $pixels)
      return;
    $tlcrop = floor($pixels/2);

    if (!empty($coi))
    {
      $coit = floor($this->b * char_to_fraction($coi[1]));
      $coib = ceil($this->b * char_to_fraction($coi[3]));
      $availableT = $coit > $this->t ? $coit - $this->t : 0;
      $availableB = $coib < $this->b ? $this->b - $coib : 0;
      if ($availableT + $availableB >= $pixels)
      {
        if ($availableT < $tlcrop)
        {
          $tlcrop = $availableT;
        }
        elseif ($availableB < $tlcrop)
        {
          $tlcrop = $pixels - $availableB;
        }
      }
    }
    $this->t += $tlcrop;
    $this->b -= $pixels - $tlcrop;
  }

}


/** Paramaters for derivative scaling and cropping. Instance of this class contained by DerivativeParams class.*/
final class SizingParams
{
  /**
  @param ideal_size two element array of maximum output dimensions (width, height)
  @param max_crop range 0=no cropping ... 1= max cropping (100% of width/height); expressed as a factor of the input width/height
  @param min_size used only if max_crop != 0 - two element array of output dimensions (width, height)
  */
  function __construct($ideal_size, $max_crop = 0, $min_size = null)
  {
    $this->ideal_size = $ideal_size;
    $this->max_crop = $max_crop; // range 0=no cropping ... 1= max cropping (100% of width/height)
    $this->min_size = $min_size;
  }

  static function classic($w, $h)
  {
    return new SizingParams( array($w,$h) );
  }

  static function square($w)
  {
    return new SizingParams( array($w,$w), 1, array($w,$w) );
  }

  function add_url_tokens(&$tokens)
  {
      if ($this->max_crop == 0)
      {
        $tokens[] = 's'.size_to_url($this->ideal_size);
      }
      elseif ($this->max_crop == 1 && size_equals($this->ideal_size, $this->min_size) )
      {
        $tokens[] = 'e'.size_to_url($this->ideal_size);
      }
      else
      {
        $tokens[] = size_to_url($this->ideal_size);
        $tokens[] = fraction_to_char($this->max_crop);
        $tokens[] = size_to_url($this->min_size);
      }
  }

  /* calculate the cropping rectangle and the scaled size for an input image size
  @param in_size two element array of input dimensions (width, height)
  @param coi empty or a four character encoded string containing the center of interest (unused if max_crop=0)
  @param crop_rect output ImageRect containing the cropping rectangle or null if cropping is not required
  @param scale_size output two element array containing width and height of the scaled image
  */
  function compute($in_size, $coi, &$crop_rect, &$scale_size)
  {
    $destCrop = new ImageRect($in_size);

    if ($this->max_crop > 0)
    {
      $ratio_w = $destCrop->width() / $this->ideal_size[0];
      $ratio_h = $destCrop->height() / $this->ideal_size[1];
      if ($ratio_w>1 || $ratio_h>1)
      {
        if ($ratio_w > $ratio_h)
        {
          $h = $destCrop->height() / $ratio_w;
          if ($h < $this->min_size[1])
          {
            $idealCropPx = $destCrop->width() - floor($destCrop->height() * $this->ideal_size[0] / $this->min_size[1]);
            $maxCropPx = round($this->max_crop * $destCrop->width());
            $destCrop->crop_h( min($idealCropPx, $maxCropPx), $coi);
          }
        }
        else
        {
          $w = $destCrop->width() / $ratio_h;
          if ($w < $this->min_size[0])
          {
            $idealCropPx = $destCrop->height() - floor($destCrop->width() * $this->ideal_size[1] / $this->min_size[0]);
            $maxCropPx = round($this->max_crop * $destCrop->height());
            $destCrop->crop_v( min($idealCropPx, $maxCropPx), $coi);
          }
        }
      }
    }

    $scale_size = array($destCrop->width(), $destCrop->height());

    $ratio_w = $destCrop->width() / $this->ideal_size[0];
    $ratio_h = $destCrop->height() / $this->ideal_size[1];
    if ($ratio_w>1 || $ratio_h>1)
    {
      if ($ratio_w > $ratio_h)
      {
        $scale_size[0] = $this->ideal_size[0];
        $scale_size[1] = floor(1e-6 + $scale_size[1] / $ratio_w);
      }
      else
      {
        $scale_size[0] = floor(1e-6 + $scale_size[0] / $ratio_h);
        $scale_size[1] = $this->ideal_size[1];
      }
    }
    else
    {
      $scale_size = null;
    }

    $crop_rect = null;
    if ($destCrop->width()!=$in_size[0] || $destCrop->height()!=$in_size[1] )
    {
      $crop_rect = $destCrop;
    }
  }

}


/** All needed parameters to generate a derivative image.*/
final class DerivativeParams
{
  public $type = IMG_CUSTOM; // string IMG_xxx
  public $last_mod_time = 0; // used for non-custom images to regenerate the cached files
  public $use_watermark = false;
  public $sizing; // of type SizingParams
  public $sharpen = 0; // range 0= no sharpening ... 1= max sharpening

  function __construct($sizing)
  {
    $this->sizing = $sizing;
  }

  public function __sleep()
  {
      return array('last_mod_time', 'sizing', 'sharpen');
  }

  function add_url_tokens(&$tokens)
  {
    $this->sizing->add_url_tokens($tokens);
  }

  function compute_final_size($in_size)
  {
    $this->sizing->compute( $in_size, null, $crop_rect, $scale_size );
    return $scale_size != null ? $scale_size : $in_size;
  }

  function max_width()
  {
    return $this->sizing->ideal_size[0];
  }

  function max_height()
  {
    return $this->sizing->ideal_size[1];
  }

  function is_identity($in_size)
  {
    if ($in_size[0] > $this->sizing->ideal_size[0] or
        $in_size[1] > $this->sizing->ideal_size[1] )
    {
      return false;
    }
    return true;
  }

  function will_watermark($out_size)
  {
    if ($this->use_watermark)
    {
      $min_size = ImageStdParams::get_watermark()->min_size;
      return $min_size[0]<=$out_size[0]
        || $min_size[1]<=$out_size[1];
    }
    return false;
  }
}
?>