<?php

/**
 * @file
 *
 * An ImageAPI supporting additional image plugins as modules.
 * Images are treated as objects, and images are not written per
 * manipulation as Drupal's core image handling works.
 *
 *
 * imageapi image api workflow...
 * $image = imageapi_image_open($path) to get an image object for $path...
 * image_X($image, $arg1, $arg2)  to manipulate image object...
 * imageapi_image_close($image) to overwrite original image.
 *
 */

/**
 * Sharpen an image given some sharpening parameters.
 *
 * NOTE: These parameters only have an effect when Imagemagick is used.
 *       GD will used a fixed convolution matrix as described in imageapi_gd.module
 *
 * @param $image
 *   An imageapi image object returned by imageapi_image_open().
 * @param $radius
 *   The radius of the gaussian, in pixels, not counting the center pixel. (default 0.5)
 * @param $sigma
 *   The standard deviation of the gaussian, in pixels. (default 0.5)
 * @param $amount
 *   The percentage of the difference between the original and the blur image that is
 *   added back into the original. (default 100)
 * @param $threshold
 *   The threshold, as a fraction of max RGB levels, needed to apply the difference
 *   amount. (default 0.05)
 * @return
 *   True or false, based on success.
 */
function image_sharpen(&$image, $radius, $sigma, $amount, $threshold) {
  return image_toolkit_invoke('sharpen', $image, array($radius, $sigma, $amount, $threshold));
}

/**
 * Convert a hex string to its RGBA (Red, Green, Blue, Alpha) integer
 * components.
 *
 * @param $hex
 *   A string specifing an RGB color in the formats:
 *   '#ABC','ABC','#ABCD','ABCD','#AABBCC','AABBCC','#AABBCCDD','AABBCCDD'
 * @return
 *   An array with four elements for red, green, blue, and alpha.
 */
function imageapi_hex2rgba($hex) {
  $hex = ltrim($hex, '#');
  if (preg_match('/^[0-9a-f]{3}$/i', $hex)) {
    // 'FA3' is the same as 'FFAA33' so r=FF, g=AA, b=33
    $r = str_repeat($hex{0}, 2);
    $g = str_repeat($hex{1}, 2);
    $b = str_repeat($hex{2}, 2);
    $a = '0';
  }
  elseif (preg_match('/^[0-9a-f]{6}$/i', $hex)) {
    // #FFAA33 or r=FF, g=AA, b=33
    list($r, $g, $b) = str_split($hex, 2);
    $a = '0';
  }
  elseif (preg_match('/^[0-9a-f]{8}$/i', $hex)) {
    // #FFAA33 or r=FF, g=AA, b=33
    list($r, $g, $b, $a) = str_split($hex, 2);
  }
  elseif (preg_match('/^[0-9a-f]{4}$/i', $hex)) {
    // 'FA37' is the same as 'FFAA3377' so r=FF, g=AA, b=33, a=77
    $r = str_repeat($hex{0}, 2);
    $g = str_repeat($hex{1}, 2);
    $b = str_repeat($hex{2}, 2);
    $a = str_repeat($hex{3}, 2);
  }
  else {
    //error: invalide hex string, TODO: set form error..
    return false;
  }

  $r = hexdec($r);
  $g = hexdec($g);
  $b = hexdec($b);
  $a = hexdec($a);
  return array($r, $g, $b, $a);
}