<?php
/*
 * bfi_thumb - WP Image Resizer v1.3
 *
 * (c) 2013 Benjamin F. Intal / Gambit
 *
 * 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, either version 3 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 more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/** Uses WP's Image Editor Class to resize and filter images
 *
 * @param $url    string the local image URL to manipulate
 * @param $params array the options to perform on the image. Keys and values supported:
 *                'width' int pixels
 *                'height' int pixels
 *                'opacity' int 0-100
 *                'color' string hex-color #000000-#ffffff
 *                'grayscale' bool
 *                'negate' bool
 *                'crop' bool
 *                'crop_only' bool
 *                'crop_x' bool string
 *                'crop_y' bool string
 *                'crop_width' bool string
 *                'crop_height' bool string
 *                'quality' int 1-100
 * @param $single boolean, if false then an array of data will be returned
 *
 * @return string|array containing the url of the resized modified image
 */

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly.

if ( ! defined( 'BFITHUMB_UPLOAD_DIR' ) ) {
	define( 'BFITHUMB_UPLOAD_DIR', 'qazana/thumbs' );
}

if ( ! function_exists( 'bfi_thumb' ) ) {

	function bfi_thumb( $url, $params = array(), $single = true ) {
		$class = BFI_Class_Factory::getNewestVersion( 'BFI_Thumb' );

		return call_user_func( array( $class, 'thumb' ), $url, $params, $single );
	}
}


/**
 * Class factory, this is to make sure that when multiple bfi_thumb scripts
 * are used (e.g. a plugin and a theme both use it), we always use the
 * latest version.
 */
if ( ! class_exists( 'BFI_Class_Factory' ) ) {

	class BFI_Class_Factory {

		public static $versions = array();
		public static $latestClass = array();

		public static function addClassVersion( $baseClassName, $className, $version ) {
			if ( empty( self::$versions[ $baseClassName ] ) ) {
				self::$versions[ $baseClassName ] = array();
			}
			self::$versions[ $baseClassName ][] = array(
				'class' => $className,
				'version' => $version,
			);
		}

		public static function getNewestVersion( $baseClassName ) {
			if ( empty( self::$latestClass[ $baseClassName ] ) ) {
				usort( self::$versions[ $baseClassName ], array( __CLASS__, "versionCompare" ) );
				self::$latestClass[ $baseClassName ] = self::$versions[ $baseClassName ][0]['class'];
				unset( self::$versions[ $baseClassName ] );
			}

			return self::$latestClass[ $baseClassName ];
		}

		public static function versionCompare( $a, $b ) {
			return version_compare( $a['version'], $b['version'] ) == 1 ? -1 : 1;
		}
	}
}


/*
 * Change the default image editors
 */
add_filter( 'wp_image_editors', 'bfi_wp_image_editor' );

// Instead of using the default image editors, use our extended ones
if ( ! function_exists( 'bfi_wp_image_editor' ) ) {

	function bfi_wp_image_editor( $editorArray ) {
		// Make sure that we use the latest versions
		return array(
			BFI_Class_Factory::getNewestVersion( 'BFI_Image_Editor_GD' ),
			BFI_Class_Factory::getNewestVersion( 'BFI_Image_Editor_Imagick' ),
		);
	}
}


/*
 * Include the WP Image classes
 */

require_once ABSPATH . WPINC . '/class-wp-image-editor.php';
require_once ABSPATH . WPINC . '/class-wp-image-editor-imagick.php';
require_once ABSPATH . WPINC . '/class-wp-image-editor-gd.php';


/*
 * Enhanced Imagemagick Image Editor
 */


if ( ! class_exists( 'BFI_Image_Editor_Imagick_1_3' ) ) {

	BFI_Class_Factory::addClassVersion( 'BFI_Image_Editor_Imagick', 'BFI_Image_Editor_Imagick_1_3', '1.3' );

	class BFI_Image_Editor_Imagick_1_3 extends WP_Image_Editor_Imagick {

		/** Changes the opacity of the image
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @param float $opacity (0.0-1.0)
		 *
		 * @return boolean|WP_Error
		 */
		public function opacity( $opacity ) {
			$opacity /= 100;

			try {
				// From: http://stackoverflow.com/questions/3538851/php-imagick-setimageopacity-destroys-transparency-and-does-nothing
				// preserves transparency
				//$this->image->setImageOpacity($opacity);
				return $this->image->evaluateImage( Imagick::EVALUATE_MULTIPLY, $opacity, Imagick::CHANNEL_ALPHA );
			} catch ( Exception $e ) {
				return new WP_Error( 'image_opacity_error', $e->getMessage() );
			}
		}

		/** Tints the image a different color
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @param string hex color e.g. #ff00ff
		 *
		 * @return boolean|WP_Error
		 */
		public function colorize( $hexColor ) {
			try {
				return $this->image->colorizeImage( $hexColor, 1.0 );
			} catch ( Exception $e ) {
				return new WP_Error( 'image_colorize_error', $e->getMessage() );
			}
		}

		/** Makes the image grayscale
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @return boolean|WP_Error
		 */
		public function grayscale() {
			try {
				return $this->image->modulateImage( 100, 0, 100 );
			} catch ( Exception $e ) {
				return new WP_Error( 'image_grayscale_error', $e->getMessage() );
			}
		}

		/** Negates the image
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @return boolean|WP_Error
		 */
		public function negate() {
			try {
				return $this->image->negateImage( false );
			} catch ( Exception $e ) {
				return new WP_Error( 'image_negate_error', $e->getMessage() );
			}
		}
	}
}


/*
 * Enhanced GD Image Editor
 */


if ( ! class_exists( 'BFI_Image_Editor_GD_1_3' ) ) {

	BFI_Class_Factory::addClassVersion( 'BFI_Image_Editor_GD', 'BFI_Image_Editor_GD_1_3', '1.3' );

	class BFI_Image_Editor_GD_1_3 extends WP_Image_Editor_GD {

		/** Rotates current image counter-clockwise by $angle.
		 * Ported from image-edit.php
		 * Added presevation of alpha channels
		 *
		 * @since  3.5.0
		 * @access public
		 *
		 * @param float $angle
		 *
		 * @return boolean|WP_Error
		 */
		public function rotate( $angle ) {
			if ( function_exists( 'imagerotate' ) ) {
				$rotated = imagerotate( $this->image, $angle, 0 );

				// Add alpha blending
				imagealphablending( $rotated, true );
				imagesavealpha( $rotated, true );

				if ( is_resource( $rotated ) ) {
					imagedestroy( $this->image );
					$this->image = $rotated;
					$this->update_size();

					return true;
				}
			}

			return new WP_Error( 'image_rotate_error', 'Image rotate failed.', $this->file );
		}

		/** Changes the opacity of the image
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @param float $opacity (0.0-1.0)
		 *
		 * @return boolean|WP_Error
		 */
		public function opacity( $opacity ) {
			$opacity /= 100;

			$filtered = $this->_opacity( $this->image, $opacity );

			if ( is_resource( $filtered ) ) {
				// imagedestroy($this->image);
				$this->image = $filtered;

				return true;
			}

			return new WP_Error( 'image_opacity_error', 'Image opacity change failed.', $this->file );
		}


		// from: http://php.net/manual/en/function.imagefilter.php
		// params: image resource id, opacity (eg. 0.0-1.0)
		protected function _opacity( $image, $opacity ) {
			if ( ! function_exists( 'imagealphablending' ) || ! function_exists( 'imagecolorat' ) || ! function_exists( 'imagecolorallocatealpha' ) || ! function_exists( 'imagesetpixel' ) ) {
				return false;
			}

			// get image width and height
			$w = imagesx( $image );
			$h = imagesy( $image );

			// turn alpha blending off
			imagealphablending( $image, false );

			// find the most opaque pixel in the image (the one with the smallest alpha value)
			$minalpha = 127;
			for ( $x = 0; $x < $w; $x++ ) {
				for ( $y = 0; $y < $h; $y++ ) {
					$alpha = ( imagecolorat( $image, $x, $y ) >> 24 ) & 0xFF;
					if ( $alpha < $minalpha ) {
						$minalpha = $alpha;
					}
				}
			}

			// loop through image pixels and modify alpha for each
			for ( $x = 0; $x < $w; $x++ ) {
				for ( $y = 0; $y < $h; $y++ ) {

					// get current alpha value (represents the TANSPARENCY!)
					$colorxy = imagecolorat( $image, $x, $y );
					$alpha = ( $colorxy >> 24 ) & 0xFF;

					// calculate new alpha
					if ( $minalpha !== 127 ) {
						$alpha = 127 + 127 * $opacity * ( $alpha - 127 ) / ( 127 - $minalpha );
					} else {
						$alpha += 127 * $opacity;
					}

					// get the color index with new alpha
					$alphacolorxy = imagecolorallocatealpha( $image, ( $colorxy >> 16 ) & 0xFF, ( $colorxy >> 8 ) & 0xFF, $colorxy & 0xFF, $alpha );

					// set pixel with the new color + opacity
					if ( ! imagesetpixel( $image, $x, $y, $alphacolorxy ) ) {
						return false;
					}
				}
			}

			imagesavealpha( $image, true );

			return $image;
		}

		/** Tints the image a different color
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @param string hex color e.g. #ff00ff
		 *
		 * @return boolean|WP_Error
		 */
		public function colorize( $hexColor ) {
			if ( function_exists( 'imagefilter' ) && function_exists( 'imagesavealpha' ) && function_exists( 'imagealphablending' ) ) {

				$hexColor = preg_replace( '#^\##', '', $hexColor );
				$r = hexdec( substr( $hexColor, 0, 2 ) );
				$g = hexdec( substr( $hexColor, 2, 2 ) );
				$b = hexdec( substr( $hexColor, 2, 2 ) );

				imagealphablending( $this->image, false );
				if ( imagefilter( $this->image, IMG_FILTER_COLORIZE, $r, $g, $b, 0 ) ) {
					imagesavealpha( $this->image, true );

					return true;
				}
			}

			return new WP_Error( 'image_colorize_error', 'Image color change failed.', $this->file );
		}

		/** Makes the image grayscale
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @return boolean|WP_Error
		 */
		public function grayscale() {
			if ( function_exists( 'imagefilter' ) ) {
				if ( imagefilter( $this->image, IMG_FILTER_GRAYSCALE ) ) {
					return true;
				}
			}

			return new WP_Error( 'image_grayscale_error', 'Image grayscale failed.', $this->file );
		}

		/** Negates the image
		 *
		 * @supports 3.5.1
		 * @access   public
		 *
		 * @return boolean|WP_Error
		 */
		public function negate() {
			if ( function_exists( 'imagefilter' ) ) {
				if ( imagefilter( $this->image, IMG_FILTER_NEGATE ) ) {
					return true;
				}
			}

			return new WP_Error( 'image_negate_error', 'Image negate failed.', $this->file );
		}
	}
}


/*
 * Main Class
 */
if ( ! class_exists( 'BFI_Thumb_1_3' ) ) {

	BFI_Class_Factory::addClassVersion( 'BFI_Thumb', 'BFI_Thumb_1_3', '1.3' );

	class BFI_Thumb_1_3 {

		/** Uses WP's Image Editor Class to resize and filter images
		 * Inspired by: https://github.com/sy4mil/Aqua-Resizer/blob/master/aq_resizer.php
		 *
		 * @param $url    string the local image URL to manipulate
		 * @param $params array the options to perform on the image. Keys and values supported:
		 *                'width' int pixels
		 *                'height' int pixels
		 *                'opacity' int 0-100
		 *                'color' string hex-color #000000-#ffffff
		 *                'grayscale' bool
		 *                'crop' bool
		 *                'negate' bool
		 *                'crop_only' bool
		 *                'crop_x' bool string
		 *                'crop_y' bool string
		 *                'crop_width' bool string
		 *                'crop_height' bool string
		 *                'quality' int 1-100
		 * @param $single boolean, if false then an array of data will be returned
		 *
		 * @return string|array
		 */
		public static function thumb( $url, $params = array(), $single = true ) {
			extract( $params );

			//validate inputs
			if ( ! $url ) {
				return false;
			}

			$crop_only = isset( $crop_only ) ? $crop_only : false;

			//define upload path & dir
			$upload_info = wp_upload_dir();
			$upload_dir = $upload_info['basedir'];
			$upload_url = $upload_info['baseurl'];
			$theme_url = get_template_directory_uri();
			$theme_dir = get_template_directory();

			// find the path of the image. Perform 2 checks:
			// #1 check if the image is in the uploads folder
			if ( strpos( $url, $upload_url ) !== false ) {
				$rel_path = str_replace( $upload_url, '', $url );
				$img_path = $upload_dir . $rel_path;
				// #2 check if the image is in the current theme folder
			} else if ( strpos( $url, $theme_url ) !== false ) {
				$rel_path = str_replace( $theme_url, '', $url );
				$img_path = $theme_dir . $rel_path;
			}

			// Fail if we can't find the image in our WP local directory
			if ( empty( $img_path ) ) {
				return $url;
			}

			// check if img path exists, and is an image indeed
			if ( ! @file_exists( $img_path ) || ! getimagesize( $img_path ) ) {
				return $url;
			}

			// This is the filename
			$basename = basename( $img_path );

			//get image info
			$info = pathinfo( $img_path );
			$ext = $info['extension'];
			list( $orig_w, $orig_h ) = getimagesize( $img_path );

			// support percentage dimensions. compute percentage based on
			// the original dimensions
			if ( isset( $width ) ) {
				if ( stripos( $width, '%' ) !== false ) {
					$width = (int) ( (float) str_replace( '%', '', $width ) / 100 * $orig_w );
				}
			}
			if ( isset( $height ) ) {
				if ( stripos( $height, '%' ) !== false ) {
					$height = (int) ( (float) str_replace( '%', '', $height ) / 100 * $orig_h );
				}
			}

			// The only purpose of this is to determine the final width and height
			// without performing any actual image manipulation, which will be used
			// to check whether a resize was previously done.
			if ( isset( $width ) && $crop_only === false ) {
				//get image size after cropping
				$dims = image_resize_dimensions( $orig_w, $orig_h, $width, isset( $height ) ? $height : null, isset( $crop ) ? $crop : false );
				$dst_w = $dims[4];
				$dst_h = $dims[5];
			} else if ( $crop_only === true ) {
				// we don't want a resize,
				// but only a crop in the image

				// get x position to start croping
				$src_x = ( isset( $crop_x ) ) ? $crop_x : 0;

				// get y position to start croping
				$src_y = ( isset( $crop_y ) ) ? $crop_y : 0;

				// width of the crop
				if ( isset( $crop_width ) ) {
					$src_w = $crop_width;
				} else if ( isset( $width ) ) {
					$src_w = $width;
				} else {
					$src_w = $orig_w;
				}

				// height of the crop
				if ( isset( $crop_height ) ) {
					$src_h = $crop_height;
				} else if ( isset( $height ) ) {
					$src_h = $height;
				} else {
					$src_h = $orig_h;
				}

				// set the width resize with the crop
				if ( isset( $crop_width ) && isset( $width ) ) {
					$dst_w = $width;
				} else {
					$dst_w = null;
				}

				// set the height resize with the crop
				if ( isset( $crop_height ) && isset( $height ) ) {
					$dst_h = $height;
				} else {
					$dst_h = null;
				}

				// allow percentages
				if ( isset( $dst_w ) ) {
					if ( stripos( $dst_w, '%' ) !== false ) {
						$dst_w = (int) ( (float) str_replace( '%', '', $dst_w ) / 100 * $orig_w );
					}
				}
				if ( isset( $dst_h ) ) {
					if ( stripos( $dst_h, '%' ) !== false ) {
						$dst_h = (int) ( (float) str_replace( '%', '', $dst_h ) / 100 * $orig_h );
					}
				}

				$dims = image_resize_dimensions( $src_w, $src_h, $dst_w, $dst_h, false );
				$dst_w = $dims[4];
				$dst_h = $dims[5];

				// Make the pos x and pos y work with percentages
				if ( stripos( $src_x, '%' ) !== false ) {
					$src_x = (int) ( (float) str_replace( '%', '', $width ) / 100 * $orig_w );
				}
				if ( stripos( $src_y, '%' ) !== false ) {
					$src_y = (int) ( (float) str_replace( '%', '', $height ) / 100 * $orig_h );
				}

				// allow center to position crop start
				if ( $src_x === 'center' ) {
					$src_x = ( $orig_w - $src_w ) / 2;
				}
				if ( $src_y === 'center' ) {
					$src_y = ( $orig_h - $src_h ) / 2;
				}
			}

			// create the suffix for the saved file
			// we can use this to check whether we need to create a new file or just use an existing one.
			$suffix = (string) filemtime( $img_path ) . ( isset( $width ) ? str_pad( (string) $width, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $height ) ? str_pad( (string) $height, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $opacity ) ? str_pad( (string) $opacity, 3, '0', STR_PAD_LEFT ) : '100' ) . ( isset( $color ) ? str_pad( preg_replace( '#^\##', '', $color ), 8, '0', STR_PAD_LEFT ) : '00000000' ) . ( isset( $grayscale ) ? ( $grayscale ? '1' : '0' ) : '0' ) . ( isset( $crop ) ? ( $crop ? '1' : '0' ) : '0' ) . ( isset( $negate ) ? ( $negate ? '1' : '0' ) : '0' ) . ( isset( $crop_only ) ? ( $crop_only ? '1' : '0' ) : '0' ) . ( isset( $src_x ) ? str_pad( (string) $src_x, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $src_y ) ? str_pad( (string) $src_y, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $src_w ) ? str_pad( (string) $src_w, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $src_h ) ? str_pad( (string) $src_h, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $dst_w ) ? str_pad( (string) $dst_w, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( isset( $dst_h ) ? str_pad( (string) $dst_h, 5, '0', STR_PAD_LEFT ) : '00000' ) . ( ( isset ( $quality ) && $quality > 0 && $quality <= 100 ) ? ( $quality ? (string) $quality : '0' ) : '0' );
			$suffix = self::base_convert_arbitrary( $suffix, 10, 36 );

			// use this to check if cropped image already exists, so we can return that instead
			$dst_rel_path = str_replace( '.' . $ext, '', basename( $img_path ) );

			// If opacity is set, change the image type to png
			if ( isset( $opacity ) ) {
				$ext = 'png';
			}


			// Create the upload subdirectory, this is where
			// we store all our generated images
			if ( defined( 'BFITHUMB_UPLOAD_DIR' ) ) {
				$upload_dir .= "/" . BFITHUMB_UPLOAD_DIR;
				$upload_url .= "/" . BFITHUMB_UPLOAD_DIR;
			} else {
				$upload_dir .= "/bfi_thumb";
				$upload_url .= "/bfi_thumb";
			}
			if ( ! is_dir( $upload_dir ) ) {
				wp_mkdir_p( $upload_dir );
			}


			// desination paths and urls
			$destfilename = "{$upload_dir}/{$dst_rel_path}-{$suffix}.{$ext}";

			// The urls generated have lower case extensions regardless of the original case
			$ext = strtolower( $ext );
			$img_url = "{$upload_url}/{$dst_rel_path}-{$suffix}.{$ext}";

			// if file exists, just return it
			if ( @file_exists( $destfilename ) && getimagesize( $destfilename ) ) {
			} else {
				// perform resizing and other filters
				$editor = wp_get_image_editor( $img_path );

				if ( is_wp_error( $editor ) ) {
					return false;
				}

				/*
				 * Perform image manipulations
				 */
				if ( $crop_only === false ) {
					if ( ( isset( $width ) && $width ) || ( isset( $height ) && $height ) ) {
						if ( is_wp_error( $editor->resize( isset( $width ) ? $width : null, isset( $height ) ? $height : null, isset( $crop ) ? $crop : false ) ) ) {
							return false;
						}
					}
				} else {
					if ( is_wp_error( $editor->crop( $src_x, $src_y, $src_w, $src_h, $dst_w, $dst_h ) ) ) {
						return false;
					}
				}

				if ( isset( $negate ) ) {
					if ( $negate ) {
						if ( is_wp_error( $editor->negate() ) ) {
							return false;
						}
					}
				}

				if ( isset( $opacity ) ) {
					if ( is_wp_error( $editor->opacity( $opacity ) ) ) {
						return false;
					}
				}

				if ( isset( $grayscale ) ) {
					if ( $grayscale ) {
						if ( is_wp_error( $editor->grayscale() ) ) {
							return false;
						}
					}
				}

				if ( isset( $color ) ) {
					if ( is_wp_error( $editor->colorize( $color ) ) ) {
						return false;
					}
				}

				// set the image quality (1-100) to save this image at
				if ( isset( $quality ) && $quality > 0 && $quality <= 100 && $ext != 'png' ) {
					$editor->set_quality( $quality );
				}

				// save our new image
				$mime_type = isset( $opacity ) ? 'image/png' : null;
				$resized_file = $editor->save( $destfilename, $mime_type );
			}

			//return the output
			if ( $single ) {
				$image = $img_url;
			} else {
				//array return
				$image = array(
					0 => $img_url,
					1 => isset( $dst_w ) ? $dst_w : $orig_w,
					2 => isset( $dst_h ) ? $dst_h : $orig_h,
				);
			}

			return $image;
		}

		/** Shortens a number into a base 36 string
		 *
		 * @param $number   string a string of numbers to convert
		 * @param $fromBase starting base
		 * @param $toBase   base to convert the number to
		 *
		 * @return string base converted characters
		 */
		protected static function base_convert_arbitrary( $number, $fromBase, $toBase ) {
			$digits = '0123456789abcdefghijklmnopqrstuvwxyz';
			$length = strlen( $number );
			$result = '';

			$nibbles = array();
			for ( $i = 0; $i < $length; ++$i ) {
				$nibbles[ $i ] = strpos( $digits, $number[ $i ] );
			}

			do {
				$value = 0;
				$newlen = 0;

				for ( $i = 0; $i < $length; ++$i ) {

					$value = $value * $fromBase + $nibbles[ $i ];

					if ( $value >= $toBase ) {
						$nibbles[ $newlen++ ] = (int) ( $value / $toBase );
						$value %= $toBase;
					} else if ( $newlen > 0 ) {
						$nibbles[ $newlen++ ] = 0;
					}
				}

				$length = $newlen;
				$result = $digits[ $value ] . $result;
			} while ( $newlen != 0 );

			return $result;
		}
	}
}


// don't use the default resizer since we want to allow resizing to larger sizes (than the original one)
// Parts are copied from media.php
// Crop is always applied (just like timthumb)
// Don't use this inside the admin since sometimes images in the media library get resized
if ( ! is_admin() ) {
	add_filter( 'image_resize_dimensions', 'bfi_image_resize_dimensions', 10, 5 );
}

if ( ! function_exists( 'bfi_image_resize_dimensions' ) ) {
	function bfi_image_resize_dimensions( $payload, $orig_w, $orig_h, $dest_w, $dest_h, $crop = false ) {
		$aspect_ratio = $orig_w / $orig_h;

		$new_w = $dest_w;
		$new_h = $dest_h;

		if ( empty( $new_w ) || $new_w < 0 ) {
			$new_w = intval( $new_h * $aspect_ratio );
		}

		if ( empty( $new_h ) || $new_h < 0 ) {
			$new_h = intval( $new_w / $aspect_ratio );
		}

		$size_ratio = max( $new_w / $orig_w, $new_h / $orig_h );

		$crop_w = round( $new_w / $size_ratio );
		$crop_h = round( $new_h / $size_ratio );
		$s_x = floor( ( $orig_w - $crop_w ) / 2 );
		$s_y = floor( ( $orig_h - $crop_h ) / 2 );

		// Safe guard against super large or zero images which might cause 500 errors
		if ( $new_w > 5000 || $new_h > 5000 || $new_w <= 0 || $new_h <= 0 ) {
			return null;
		}

		// the return array matches the parameters to imagecopyresampled()
		// int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h
		return array( 0, 0, (int) $s_x, (int) $s_y, (int) $new_w, (int) $new_h, (int) $crop_w, (int) $crop_h );
	}
}


// This function allows us to latch on WP image functions such as
// the_post_thumbnail, get_image_tag and wp_get_attachment_image_src
// so that you won't have to use the function bfi_thumb in order to do resizing.
// To make this work, in the WP image functions, when specifying an
// array for the image dimensions, add a 'bfi_thumb' => true to
// the array, then add your normal $params arguments.
//
// e.g. the_post_thumbnail( array( 1024, 400, 'bfi_thumb' => true, 'grayscale' => true ) );
add_filter( 'image_downsize', 'bfi_image_downsize', 1, 3 );

if ( ! function_exists( 'bfi_image_downsize' ) ) {
	function bfi_image_downsize( $out, $id, $size ) {
		if ( ! is_array( $size ) ) {
			return false;
		}
		if ( ! array_key_exists( 'bfi_thumb', $size ) ) {
			return false;
		}
		if ( empty( $size['bfi_thumb'] ) ) {
			return false;
		}

		$img_url = wp_get_attachment_url( $id );

		$params = $size;
		$params['width'] = ! empty( $size[0] ) ? $size[0] : '';
		$params['height'] = ! empty( $size[1] ) ? $size[1] : '';

		$resized_img_url = bfi_thumb( $img_url, $params );

		return array( $resized_img_url, $params['width'], $params['height'], false );
	}
}
