<?php // $Id: imageapi_gd.module,v 1.12 2008-07-09 02:49:47 dopry Exp $

/**
 * @file
 * GD2 toolkit functions
 */

/**
 * Implementation of hook_imageapi_toolkit().
 *
 * this hook only gets called to see is a module implements the imageapi hooks...
 */
function imageapi_gd_imageapi_toolkit() {
}


/**
 * Settings form for the toolkit.
 */
function imageapi_gd_settings_form() {
  $form['imageapi_jpeg_quality'] = array(
    '#type' => 'textfield',
    '#title' => t('JPEG quality'),
    '#description' => t('Define the image quality for JPEG manipulations. Ranges from 0 to 100. Higher values mean better image quality, but bigger files.'),
    '#size' => 10,
    '#maxlength' => 3,
    '#default_value' => variable_get('imageapi_jpeg_quality', 75),
    '#field_suffix' => '%',
  );
  return system_settings_form($form);
}

function imageapi_gd_image_open($image) {
  if ($image->res =  _gd_open($image->source, $image->info['extension'])) {
    return $image;
  }
  return false;
}

function imageapi_gd_image_close($image, $destination) {
  return _gd_close($image->res, $destination, $image->info['extension']);
}

function imageapi_gd_image_crop(&$image, $x, $y, $width, $height) {
  $res = _gd_create_tmp($image, $width, $height);

  if (!imagecopyresampled($res, $image->res, 0, 0, $x, $y, $width, $height, $width, $height)) {
    return false;
  }
  // destroy the original image and return the modified image.
  imagedestroy($image->res);
  $image->res = $res;
  $image->info['width'] = $width;
  $image->info['height'] = $height;
  return true;
}

function imageapi_gd_image_resize(&$image, $width, $height) {

  $res = _gd_create_tmp($image, $width, $height);

  if (!imagecopyresampled($res, $image->res, 0, 0, 0, 0, $width, $height, $image->info['width'], $image->info['height'])) {
    return false;
  }
  imagedestroy($image->res);
  // update image object
  $image->res = $res;
  $image->info['width'] = $width;
  $image->info['height'] = $height;
  return true;
}

function imageapi_gd_image_rotate(&$image, $degrees, $bgcolor) {
  $res = imagerotate($image->res, 360 - $degrees, $bgcolor);
  imagedestroy($image->res);
  $image->res = $res;
  return true;
} 

function imageapi_gd_image_sharpen(&$image, $radius, $sigma, $amount, $threshold) {
  $threshold = round($threshold * 255);
  $image->res = _gd_unsharp_mask($image->res, $radius, $sigma, $amount, $threshold);
  return true;
}

function imageapi_gd_image_desaturate(&$image) {
  return imagefilter($image->res, IMG_FILTER_GRAYSCALE);
}

/**
 * GD helper function to create an image resource from a file.
 */
function _gd_open($file, $extension) {
  $extension = str_replace('jpg', 'jpeg', $extension);
  $open_func = 'imageCreateFrom'. $extension;
  if (!function_exists($open_func)) {
    return false;
  }
  
  return $open_func($file);
}

/**
 * GD helper to write an image resource to a destination file.
 */
function _gd_close($res, $destination, $extension) {
  $extension = str_replace('jpg', 'jpeg', $extension);
  $close_func = 'image'. $extension;
  if (!function_exists($close_func)) {
    return false;
  }
  if ($extension == 'jpeg') {
    return $close_func($res, $destination, variable_get('imageapi_jpeg_quality', 75));
  }
  else {
    return $close_func($res, $destination);
  }
}

if (!function_exists('imagerotate')) {
  require_once drupal_get_path('module', 'imageapi') .'/imagerotate.inc';
}

if (!function_exists('imagefilter')) {
  require_once drupal_get_path('module', 'imageapi') .'/imagefilter.inc';
}


/** 
 * create a true color image preserving transparency from a provided
 * image.
 * @todo: add bgcolor setting to add a default background color.
 */
function _gd_create_tmp($image, $width, $height) { 
  $res = imagecreatetruecolor($width, $height);
  
  if ($image->info['extension'] == 'gif' || $image->info['extension'] == 'jpg') {
    // grab transparent color index from src.
    $transparent = imagecolortransparent($image->res);

    // if indexed transparency, lets preserve it.
    if ($transparent >= 0) {
      // get color(r,g,b) for index;
      $transparent = imagecolorsforindex($image->res, $transparent);
      // allocate to new image and get new index.
      $transparent =  (isset($color['alpha'])) 
        ? imagecolorallocatealpha($res, $color['red'], $color['green'], $color['blue'], $color['alpha'])
        : imagecolorallocate($res, $color['red'], $color['green'], $color['blue']);
 
      $transparent = imagecolorallocate($res,  $transparent['red'], $transparent['green'],  $transparent['blue']);
      // flood with our new transparent color.
      imagefill($res, 0, 0, $transparent);
      // tell the new image which color is transparent.
      imagecolortransparent($res, $transparent);
    }
  }
  elseif ($image->info['extension'] == 'png') {
    imagealphablending($res, false);
    $transparency = imagecolorallocatealpha($res, 0, 0, 0, 127);
    imagefill($res, 0, 0, $transparency);
    imagealphablending($res, true);
    imagesavealpha($res, true);
  }
  return $res;
}

/**
 * $sigma is currently unused for _gd_sharp_mask due to 3x3 convolution matrix limit.
 * we should explore properly implementing sigma.
 */
function _gd_unsharp_mask($img, $radius, $sigma, $amount, $threshold)    {  

  ////////////////////////////////////////////////////////////// 
  ////   
  ////                  Unsharp Mask for PHP - version 2.1.1   
  ////   
  ////    Unsharp mask algorithm by Torstein Hønsi 2003-07.   
  ////             thoensi_at_netcom_dot_no.   
  ////               Please leave this notice.   
  ////   
  //////////////////////////////////////////////////////////////
  
  // http://vikjavev.no/computing/ump.php

  // $img is an image that is already created within php using
  // imgcreatetruecolor. No url! $img must be a truecolor image.

  // Attempt to calibrate the parameters to Photoshop:
  if ($amount > 500) $amount = 500;
  $amount = $amount * 0.016;
  if ($radius > 50) $radius = 50;
  $radius = $radius * 2;
  if ($threshold > 255) $threshold = 255;

  $radius = abs(round($radius)); // Only integers make sense.
  if ($radius == 0) {
    return $img; imagedestroy($img);
    break;
  }

  $w = imagesx($img); $h = imagesy($img);
  $img_canvas = imagecreatetruecolor($w, $h);
  $img_blur = imagecreatetruecolor($w, $h);

  // Gaussian blur matrix:
  //                          
  //    1    2    1          
  //    2    4    2          
  //    1    2    1          
  //                          
  //////////////////////////////////////////////////  

  $matrix = array(
    array( 1, 2, 1 ),
    array( 2, 4, 2 ),
    array( 1, 2, 1 ) 
    );

  imagecopy($img_blur, $img, 0, 0, 0, 0, $w, $h);
  imageconvolution($img_blur, $matrix, 16, 0);

  if ($threshold > 0) {
    // Calculate the difference between the blurred pixels and the original
    // and set the pixels
    for ($x = 0; $x < $w-1; $x++)    { // each row
      for ($y = 0; $y < $h; $y++)    { // each pixel

        $rgb_orig = imagecolorat($img, $x, $y);
        $r_orig = (($rgb_orig >> 16) & 0xFF);
        $g_orig = (($rgb_orig >> 8) & 0xFF);
        $b_orig = ($rgb_orig & 0xFF);

        $rgb_blur = imagecolorat($img_blur, $x, $y);

        $r_blur = (($rgb_blur >> 16) & 0xFF);
        $g_blur = (($rgb_blur >> 8) & 0xFF);
        $b_blur = ($rgb_blur & 0xFF);

        // When the masked pixels differ less from the original
        // than the threshold specifies, they are set to their original value.
        $r_new = (abs($r_orig - $r_blur) >= $threshold)
          ? max(0, min(255, ($amount * ($r_orig - $r_blur)) + $r_orig))
          : $r_orig;
        $g_new = (abs($g_orig - $g_blur) >= $threshold)
          ? max(0, min(255, ($amount * ($g_orig - $g_blur)) + $g_orig))
          : $g_orig;
        $b_new = (abs($b_orig - $b_blur) >= $threshold)
          ? max(0, min(255, ($amount * ($b_orig - $b_blur)) + $b_orig))
          : $b_orig;

        if (($r_orig != $r_new) || ($g_orig != $g_new) || ($b_orig != $b_new)) {
          $pix_col = imagecolorallocate($img, $r_new, $g_new, $b_new);
          imagesetpixel($img, $x, $y, $pix_col);
        }
      }
    }
  }
  else{
    for ($x = 0; $x < $w; $x++)    { // each row
      for ($y = 0; $y < $h; $y++)    { // each pixel
        $rgb_orig = imagecolorat($img, $x, $y);
        $r_orig = (($rgb_orig >> 16) & 0xFF);
        $g_orig = (($rgb_orig >> 8) & 0xFF);
        $b_orig = ($rgb_orig & 0xFF);

        $rgb_blur = imagecolorat($img_blur, $x, $y);

        $r_blur = (($rgb_blur >> 16) & 0xFF);
        $g_blur = (($rgb_blur >> 8) & 0xFF);
        $b_blur = ($rgb_blur & 0xFF);

        $r_new = ($amount * ($r_orig - $r_blur)) + $r_orig;
        if ($r_new>255) $r_new=255;
        elseif ($r_new<0) $r_new=0;

        $g_new = ($amount * ($g_orig - $g_blur)) + $g_orig;
        if ($g_new>255) $g_new=255;
        elseif ($g_new<0) $g_new=0;

        $b_new = ($amount * ($b_orig - $b_blur)) + $b_orig;
        if ($b_new>255) $b_new=255;
        elseif ($b_new<0) $b_new=0;

        $rgb_new = ($r_new << 16) + ($g_new <<8) + $b_new;
        imagesetpixel($img, $x, $y, $rgb_new);
      }
    }
  }
  imagedestroy($img_canvas);
  imagedestroy($img_blur);

  return $img;
}