<?php
// $id: $

/**
 * @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() {
  $form['image_jpeg_quality'] = array(
    '#type' => 'textfield',
    '#title' => t('JPEG quality'),
    '#description' => t('Define the image quality for JPEG manipulations. Ranges from 0 to 100. Higher values mean better image quality, but bigger files.'),
    '#size' => 10,
    '#maxlength' => 3,
    '#default_value' => variable_get('image_jpeg_quality', 75),
    '#field_suffix' => '%',
  );
  return system_settings_form($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) {
  $res = imageCreateTrueColor($width, $height);
  if (!imageCopy($res, $image->res, 0, 0, $x, $y, $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) {
  $res = imageCreateTrueColor($width, $height);
  if ($image->info['extension'] == 'png') {
    $transparency = imagecolorallocatealpha($res, 0, 0, 0, 127);
    imagealphablending($res, FALSE);
    imagefilledrectangle($res, 0, 0, $width, $height, $transparency);
    imagealphablending($res, TRUE);
    imagesavealpha($res, TRUE);
  }
  elseif ($image->info['extension'] == 'gif') {
    $transparency = imagecolortransparent($image->res);
    // If we have a specific transparent color.
    if ($transparency >= 0) {
      // Get the original image's transparent color's RGB values.
      $color = imagecolorsforindex($image->res, $transparency);
      // Allocate the same color in the new image resource.
      if (isset($color['alpha'])) {
        $transparency = imagecolorallocatealpha($res, $color['red'], $color['green'], $color['blue'], $color['alpha']);
      }
      else {
        $transparency = imagecolorallocate($res, $color['red'], $color['green'], $color['blue']);
      }
      // Completely fill the background of the new image with allocated color.
      imagefill($res, 0, 0, $transparency);
      // Set the background color for new image to transparent.
      imagecolortransparent($res, $transparency);
    }
  }
  if (!imageCopyResampled($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, $degrees, $bgcolor);
  imageDestroy($image->res);
  $image->res = $res;
  return TRUE;
} 

function imageapi_gd_image_desaturate(&$image) {
  if (function_exists('imagefilter')) { // PHP 5
    if (!imagefilter($image->res, IMG_FILTER_GRAYSCALE)) {
       return FALSE;
    }
  } 
  else {                              // PHP < 5
    $res = imageCreateTrueColor($image->info['width'], $image->info['height']);
    for ($y = 0; $y < $image->info['height']; ++$y) {
      for ($x = 0; $x < $image->info['width']; ++$x) {
        $rgb = imagecolorat($image->res, $x, $y);
        if (imageistruecolor($image->res)) {
          $red   = ($rgb >> 16) & 0xFF;
          $green = ($rgb >> 8)  & 0xFF;
          $blue  = $rgb & 0xFF;
        } 
        else {
          $rgb = imagecolorsforindex($image->res, $rgb);
          $red   = $rgb['red'];
          $green = $rgb['green'];
          $blue  = $rgb['blue'];
        }
         
        $gray = round(.299*$red + .587*$green + .114*$blue);
         
        // shift gray level to the left
        $grayR = $gray << 16;   // R: red
        $grayG = $gray << 8;    // G: green
        $grayB = $gray;         // B: blue
        $grayColor = $grayR | $grayG | $grayB;
        
        // set the pixel color
        imagesetpixel($res, $x, $y, $grayColor);
        imagecolorallocate($res, $gray, $gray, $gray);
      }
    }
    imageDestroy($image->res);
    $image->res = $res;
  }
  return TRUE;
}

/**
 * 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('image_jpeg_quality', 75));
  }
  else {
    return $close_func($res, $destination);
  }
}