<?php
/**
 * WordPress API for media display.
 *
 * @package WordPress
 * @subpackage Media
 */

/**
 * Retrieve additional image sizes.
 *
 * @since 4.7.0
 *
 * @global array $_wp_additional_image_sizes
 *
 * @return array Additional images size data.
 */
function wp_get_additional_image_sizes() {
	global $_wp_additional_image_sizes;
	if ( ! $_wp_additional_image_sizes ) {
		$_wp_additional_image_sizes = array();
	}
	return $_wp_additional_image_sizes;
}

/**
 * Scale down the default size of an image.
 *
 * This is so that the image is a better fit for the editor and theme.
 *
 * The `$size` parameter accepts either an array or a string. The supported string
 * values are 'thumb' or 'thumbnail' for the given thumbnail size or defaults at
 * 128 width and 96 height in pixels. Also supported for the string value is
 * 'medium', 'medium_large' and 'full'. The 'full' isn't actually supported, but any value other
 * than the supported will result in the content_width size or 500 if that is
 * not set.
 *
 * Finally, there is a filter named {@see 'editor_max_image_size'}, that will be
 * called on the calculated array for width and height, respectively. The second
 * parameter will be the value that was in the $size parameter. The returned
 * type for the hook is an array with the width as the first element and the
 * height as the second element.
 *
 * @since 2.5.0
 *
 * @global int   $content_width
 *
 * @param int          $width   Width of the image in pixels.
 * @param int          $height  Height of the image in pixels.
 * @param string|array $size    Optional. Image size. Accepts any valid image size, or an array
 *                              of width and height values in pixels (in that order).
 *                              Default 'medium'.
 * @param string       $context Optional. Could be 'display' (like in a theme) or 'edit'
 *                              (like inserting into an editor). Default null.
 * @return array Width and height of what the result image should resize to.
 */
function image_constrain_size_for_editor( $width, $height, $size = 'medium', $context = null ) {
	global $content_width;

	$_wp_additional_image_sizes = wp_get_additional_image_sizes();

	if ( ! $context )
		$context = is_admin() ? 'edit' : 'display';

	if ( is_array($size) ) {
		$max_width = $size[0];
		$max_height = $size[1];
	}
	elseif ( $size == 'thumb' || $size == 'thumbnail' ) {
		$max_width = intval(get_option('thumbnail_size_w'));
		$max_height = intval(get_option('thumbnail_size_h'));
		// last chance thumbnail size defaults
		if ( !$max_width && !$max_height ) {
			$max_width = 128;
			$max_height = 96;
		}
	}
	elseif ( $size == 'medium' ) {
		$max_width = intval(get_option('medium_size_w'));
		$max_height = intval(get_option('medium_size_h'));

	}
	elseif ( $size == 'medium_large' ) {
		$max_width = intval( get_option( 'medium_large_size_w' ) );
		$max_height = intval( get_option( 'medium_large_size_h' ) );

		if ( intval( $content_width ) > 0 ) {
			$max_width = min( intval( $content_width ), $max_width );
		}
	}
	elseif ( $size == 'large' ) {
		/*
		 * We're inserting a large size image into the editor. If it's a really
		 * big image we'll scale it down to fit reasonably within the editor
		 * itself, and within the theme's content width if it's known. The user
		 * can resize it in the editor if they wish.
		 */
		$max_width = intval(get_option('large_size_w'));
		$max_height = intval(get_option('large_size_h'));
		if ( intval($content_width) > 0 ) {
			$max_width = min( intval($content_width), $max_width );
		}
	} elseif ( ! empty( $_wp_additional_image_sizes ) && in_array( $size, array_keys( $_wp_additional_image_sizes ) ) ) {
		$max_width = intval( $_wp_additional_image_sizes[$size]['width'] );
		$max_height = intval( $_wp_additional_image_sizes[$size]['height'] );
		// Only in admin. Assume that theme authors know what they're doing.
		if ( intval( $content_width ) > 0 && 'edit' === $context ) {
			$max_width = min( intval( $content_width ), $max_width );
		}
	}
	// $size == 'full' has no constraint
	else {
		$max_width = $width;
		$max_height = $height;
	}

	/**
	 * Filters the maximum image size dimensions for the editor.
	 *
	 * @since 2.5.0
	 *
	 * @param array        $max_image_size An array with the width as the first element,
	 *                                     and the height as the second element.
	 * @param string|array $size           Size of what the result image should be.
	 * @param string       $context        The context the image is being resized for.
	 *                                     Possible values are 'display' (like in a theme)
	 *                                     or 'edit' (like inserting into an editor).
	 */
	list( $max_width, $max_height ) = apply_filters( 'editor_max_image_size', array( $max_width, $max_height ), $size, $context );

	return wp_constrain_dimensions( $width, $height, $max_width, $max_height );
}

/**
 * Retrieve width and height attributes using given width and height values.
 *
 * Both attributes are required in the sense that both parameters must have a
 * value, but are optional in that if you set them to false or null, then they
 * will not be added to the returned string.
 *
 * You can set the value using a string, but it will only take numeric values.
 * If you wish to put 'px' after the numbers, then it will be stripped out of
 * the return.
 *
 * @since 2.5.0
 *
 * @param int|string $width  Image width in pixels.
 * @param int|string $height Image height in pixels.
 * @return string HTML attributes for width and, or height.
 */
function image_hwstring( $width, $height ) {
	$out = '';
	if ($width)
		$out .= 'width="'.intval($width).'" ';
	if ($height)
		$out .= 'height="'.intval($height).'" ';
	return $out;
}

/**
 * Scale an image to fit a particular size (such as 'thumb' or 'medium').
 *
 * Array with image url, width, height, and whether is intermediate size, in
 * that order is returned on success is returned. $is_intermediate is true if
 * $url is a resized image, false if it is the original.
 *
 * The URL might be the original image, or it might be a resized version. This
 * function won't create a new resized copy, it will just return an already
 * resized one if it exists.
 *
 * A plugin may use the {@see 'image_downsize'} filter to hook into and offer image
 * resizing services for images. The hook must return an array with the same
 * elements that are returned in the function. The first element being the URL
 * to the new image that was resized.
 *
 * @since 2.5.0
 *
 * @param int          $id   Attachment ID for image.
 * @param array|string $size Optional. Image size to scale to. Accepts any valid image size,
 *                           or an array of width and height values in pixels (in that order).
 *                           Default 'medium'.
 * @return false|array Array containing the image URL, width, height, and boolean for whether
 *                     the image is an intermediate size. False on failure.
 */
function image_downsize( $id, $size = 'medium' ) {
	$is_image = wp_attachment_is_image( $id );

	/**
	 * Filters whether to preempt the output of image_downsize().
	 *
	 * Passing a truthy value to the filter will effectively short-circuit
	 * down-sizing the image, returning that value as output instead.
	 *
	 * @since 2.5.0
	 *
	 * @param bool         $downsize Whether to short-circuit the image downsize. Default false.
	 * @param int          $id       Attachment ID for image.
	 * @param array|string $size     Size of image. Image size or array of width and height values (in that order).
	 *                               Default 'medium'.
	 */
	if ( $out = apply_filters( 'image_downsize', false, $id, $size ) ) {
		return $out;
	}

	$img_url = wp_get_attachment_url($id);
	$meta = wp_get_attachment_metadata($id);
	$width = $height = 0;
	$is_intermediate = false;
	$img_url_basename = wp_basename($img_url);

	// If the file isn't an image, attempt to replace its URL with a rendered image from its meta.
	// Otherwise, a non-image type could be returned.
	if ( ! $is_image ) {
		if ( ! empty( $meta['sizes'] ) ) {
			$img_url = str_replace( $img_url_basename, $meta['sizes']['full']['file'], $img_url );
			$img_url_basename = $meta['sizes']['full']['file'];
			$width = $meta['sizes']['full']['width'];
			$height = $meta['sizes']['full']['height'];
		} else {
			return false;
		}
	}

	// try for a new style intermediate size
	if ( $intermediate = image_get_intermediate_size($id, $size) ) {
		$img_url = str_replace($img_url_basename, $intermediate['file'], $img_url);
		$width = $intermediate['width'];
		$height = $intermediate['height'];
		$is_intermediate = true;
	}
	elseif ( $size == 'thumbnail' ) {
		// fall back to the old thumbnail
		if ( ($thumb_file = wp_get_attachment_thumb_file($id)) && $info = getimagesize($thumb_file) ) {
			$img_url = str_replace($img_url_basename, wp_basename($thumb_file), $img_url);
			$width = $info[0];
			$height = $info[1];
			$is_intermediate = true;
		}
	}
	if ( !$width && !$height && isset( $meta['width'], $meta['height'] ) ) {
		// any other type: use the real image
		$width = $meta['width'];
		$height = $meta['height'];
	}

	if ( $img_url) {
		// we have the actual image size, but might need to further constrain it if content_width is narrower
		list( $width, $height ) = image_constrain_size_for_editor( $width, $height, $size );

		return array( $img_url, $width, $height, $is_intermediate );
	}
	return false;

}

/**
 * Register a new image size.
 *
 * Cropping behavior for the image size is dependent on the value of $crop:
 * 1. If false (default), images will be scaled, not cropped.
 * 2. If an array in the form of array( x_crop_position, y_crop_position ):
 *    - x_crop_position accepts 'left' 'center', or 'right'.
 *    - y_crop_position accepts 'top', 'center', or 'bottom'.
 *    Images will be cropped to the specified dimensions within the defined crop area.
 * 3. If true, images will be cropped to the specified dimensions using center positions.
 *
 * @since 2.9.0
 *
 * @global array $_wp_additional_image_sizes Associative array of additional image sizes.
 *
 * @param string     $name   Image size identifier.
 * @param int        $width  Image width in pixels.
 * @param int        $height Image height in pixels.
 * @param bool|array $crop   Optional. Whether to crop images to specified width and height or resize.
 *                           An array can specify positioning of the crop area. Default false.
 */
function add_image_size( $name, $width = 0, $height = 0, $crop = false ) {
	global $_wp_additional_image_sizes;

	$_wp_additional_image_sizes[ $name ] = array(
		'width'  => absint( $width ),
		'height' => absint( $height ),
		'crop'   => $crop,
	);
}

/**
 * Check if an image size exists.
 *
 * @since 3.9.0
 *
 * @param string $name The image size to check.
 * @return bool True if the image size exists, false if not.
 */
function has_image_size( $name ) {
	$sizes = wp_get_additional_image_sizes();
	return isset( $sizes[ $name ] );
}

/**
 * Remove a new image size.
 *
 * @since 3.9.0
 *
 * @global array $_wp_additional_image_sizes
 *
 * @param string $name The image size to remove.
 * @return bool True if the image size was successfully removed, false on failure.
 */
function remove_image_size( $name ) {
	global $_wp_additional_image_sizes;

	if ( isset( $_wp_additional_image_sizes[ $name ] ) ) {
		unset( $_wp_additional_image_sizes[ $name ] );
		return true;
	}

	return false;
}

/**
 * Registers an image size for the post thumbnail.
 *
 * @since 2.9.0
 *
 * @see add_image_size() for details on cropping behavior.
 *
 * @param int        $width  Image width in pixels.
 * @param int        $height Image height in pixels.
 * @param bool|array $crop   Optional. Whether to crop images to specified width and height or resize.
 *                           An array can specify positioning of the crop area. Default false.
 */
function set_post_thumbnail_size( $width = 0, $height = 0, $crop = false ) {
	add_image_size( 'post-thumbnail', $width, $height, $crop );
}

/**
 * Gets an img tag for an image attachment, scaling it down if requested.
 *
 * The {@see 'get_image_tag_class'} filter allows for changing the class name for the
 * image without having to use regular expressions on the HTML content. The
 * parameters are: what WordPress will use for the class, the Attachment ID,
 * image align value, and the size the image should be.
 *
 * The second filter, {@see 'get_image_tag'}, has the HTML content, which can then be
 * further manipulated by a plugin to change all attribute values and even HTML
 * content.
 *
 * @since 2.5.0
 *
 * @param int          $id    Attachment ID.
 * @param string       $alt   Image Description for the alt attribute.
 * @param string       $title Image Description for the title attribute.
 * @param string       $align Part of the class name for aligning the image.
 * @param string|array $size  Optional. Registered image size to retrieve a tag for. Accepts any
 *                            valid image size, or an array of width and height values in pixels
 *                            (in that order). Default 'medium'.
 * @return string HTML IMG element for given image attachment
 */
function get_image_tag( $id, $alt, $title, $align, $size = 'medium' ) {

	list( $img_src, $width, $height ) = image_downsize($id, $size);
	$hwstring = image_hwstring($width, $height);

	$title = $title ? 'title="' . esc_attr( $title ) . '" ' : '';

	$class = 'align' . esc_attr($align) .' size-' . esc_attr($size) . ' wp-image-' . $id;

	/**
	 * Filters the value of the attachment's image tag class attribute.
	 *
	 * @since 2.6.0
	 *
	 * @param string       $class CSS class name or space-separated list of classes.
	 * @param int          $id    Attachment ID.
	 * @param string       $align Part of the class name for aligning the image.
	 * @param string|array $size  Size of image. Image size or array of width and height values (in that order).
	 *                            Default 'medium'.
	 */
	$class = apply_filters( 'get_image_tag_class', $class, $id, $align, $size );

	$html = '<img src="' . esc_attr($img_src) . '" alt="' . esc_attr($alt) . '" ' . $title . $hwstring . 'class="' . $class . '" />';

	/**
	 * Filters the HTML content for the image tag.
	 *
	 * @since 2.6.0
	 *
	 * @param string       $html  HTML content for the image.
	 * @param int          $id    Attachment ID.
	 * @param string       $alt   Alternate text.
	 * @param string       $title Attachment title.
	 * @param string       $align Part of the class name for aligning the image.
	 * @param string|array $size  Size of image. Image size or array of width and height values (in that order).
	 *                            Default 'medium'.
	 */
	return apply_filters( 'get_image_tag', $html, $id, $alt, $title, $align, $size );
}

/**
 * Calculates the new dimensions for a down-sampled image.
 *
 * If either width or height are empty, no constraint is applied on
 * that dimension.
 *
 * @since 2.5.0
 *
 * @param int $current_width  Current width of the image.
 * @param int $current_height Current height of the image.
 * @param int $max_width      Optional. Max width in pixels to constrain to. Default 0.
 * @param int $max_height     Optional. Max height in pixels to constrain to. Default 0.
 * @return array First item is the width, the second item is the height.
 */
function wp_constrain_dimensions( $current_width, $current_height, $max_width = 0, $max_height = 0 ) {
	if ( !$max_width && !$max_height )
		return array( $current_width, $current_height );

	$width_ratio = $height_ratio = 1.0;
	$did_width = $did_height = false;

	if ( $max_width > 0 && $current_width > 0 && $current_width > $max_width ) {
		$width_ratio = $max_width / $current_width;
		$did_width = true;
	}

	if ( $max_height > 0 && $current_height > 0 && $current_height > $max_height ) {
		$height_ratio = $max_height / $current_height;
		$did_height = true;
	}

	// Calculate the larger/smaller ratios
	$smaller_ratio = min( $width_ratio, $height_ratio );
	$larger_ratio  = max( $width_ratio, $height_ratio );

	if ( (int) round( $current_width * $larger_ratio ) > $max_width || (int) round( $current_height * $larger_ratio ) > $max_height ) {
 		// The larger ratio is too big. It would result in an overflow.
		$ratio = $smaller_ratio;
	} else {
		// The larger ratio fits, and is likely to be a more "snug" fit.
		$ratio = $larger_ratio;
	}

	// Very small dimensions may result in 0, 1 should be the minimum.
	$w = max ( 1, (int) round( $current_width  * $ratio ) );
	$h = max ( 1, (int) round( $current_height * $ratio ) );

	// Sometimes, due to rounding, we'll end up with a result like this: 465x700 in a 177x177 box is 117x176... a pixel short
	// We also have issues with recursive calls resulting in an ever-changing result. Constraining to the result of a constraint should yield the original result.
	// Thus we look for dimensions that are one pixel shy of the max value and bump them up

	// Note: $did_width means it is possible $smaller_ratio == $width_ratio.
	if ( $did_width && $w == $max_width - 1 ) {
		$w = $max_width; // Round it up
	}

	// Note: $did_height means it is possible $smaller_ratio == $height_ratio.
	if ( $did_height && $h == $max_height - 1 ) {
		$h = $max_height; // Round it up
	}

	/**
	 * Filters dimensions to constrain down-sampled images to.
	 *
	 * @since 4.1.0
	 *
	 * @param array $dimensions     The image width and height.
	 * @param int 	$current_width  The current width of the image.
	 * @param int 	$current_height The current height of the image.
	 * @param int 	$max_width      The maximum width permitted.
	 * @param int 	$max_height     The maximum height permitted.
	 */
	return apply_filters( 'wp_constrain_dimensions', array( $w, $h ), $current_width, $current_height, $max_width, $max_height );
}

/**
 * Retrieves calculated resize dimensions for use in WP_Image_Editor.
 *
 * Calculates dimensions and coordinates for a resized image that fits
 * within a specified width and height.
 *
 * Cropping behavior is dependent on the value of $crop:
 * 1. If false (default), images will not be cropped.
 * 2. If an array in the form of array( x_crop_position, y_crop_position ):
 *    - x_crop_position accepts 'left' 'center', or 'right'.
 *    - y_crop_position accepts 'top', 'center', or 'bottom'.
 *    Images will be cropped to the specified dimensions within the defined crop area.
 * 3. If true, images will be cropped to the specified dimensions using center positions.
 *
 * @since 2.5.0
 *
 * @param int        $orig_w Original width in pixels.
 * @param int        $orig_h Original height in pixels.
 * @param int        $dest_w New width in pixels.
 * @param int        $dest_h New height in pixels.
 * @param bool|array $crop   Optional. Whether to crop image to specified width and height or resize.
 *                           An array can specify positioning of the crop area. Default false.
 * @return false|array False on failure. Returned array matches parameters for `imagecopyresampled()`.
 */
function image_resize_dimensions( $orig_w, $orig_h, $dest_w, $dest_h, $crop = false ) {

	if ($orig_w <= 0 || $orig_h <= 0)
		return false;
	// at least one of dest_w or dest_h must be specific
	if ($dest_w <= 0 && $dest_h <= 0)
		return false;

	/**
	 * Filters whether to preempt calculating the image resize dimensions.
	 *
	 * Passing a non-null value to the filter will effectively short-circuit
	 * image_resize_dimensions(), returning that value instead.
	 *
	 * @since 3.4.0
	 *
	 * @param null|mixed $null   Whether to preempt output of the resize dimensions.
	 * @param int        $orig_w Original width in pixels.
	 * @param int        $orig_h Original height in pixels.
	 * @param int        $dest_w New width in pixels.
	 * @param int        $dest_h New height in pixels.
	 * @param bool|array $crop   Whether to crop image to specified width and height or resize.
	 *                           An array can specify positioning of the crop area. Default false.
	 */
	$output = apply_filters( 'image_resize_dimensions', null, $orig_w, $orig_h, $dest_w, $dest_h, $crop );
	if ( null !== $output )
		return $output;

	if ( $crop ) {
		// crop the largest possible portion of the original image that we can size to $dest_w x $dest_h
		$aspect_ratio = $orig_w / $orig_h;
		$new_w = min($dest_w, $orig_w);
		$new_h = min($dest_h, $orig_h);

		if ( ! $new_w ) {
			$new_w = (int) round( $new_h * $aspect_ratio );
		}

		if ( ! $new_h ) {
			$new_h = (int) round( $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);

		if ( ! is_array( $crop ) || count( $crop ) !== 2 ) {
			$crop = array( 'center', 'center' );
		}

		list( $x, $y ) = $crop;

		if ( 'left' === $x ) {
			$s_x = 0;
		} elseif ( 'right' === $x ) {
			$s_x = $orig_w - $crop_w;
		} else {
			$s_x = floor( ( $orig_w - $crop_w ) / 2 );
		}

		if ( 'top' === $y ) {
			$s_y = 0;
		} elseif ( 'bottom' === $y ) {
			$s_y = $orig_h - $crop_h;
		} else {
			$s_y = floor( ( $orig_h - $crop_h ) / 2 );
		}
	} else {
		// don't crop, just resize using $dest_w x $dest_h as a maximum bounding box
		$crop_w = $orig_w;
		$crop_h = $orig_h;

		$s_x = 0;
		$s_y = 0;

		list( $new_w, $new_h ) = wp_constrain_dimensions( $orig_w, $orig_h, $dest_w, $dest_h );
	}

	// if the resulting image would be the same size or larger we don't want to resize it
	if ( $new_w >= $orig_w && $new_h >= $orig_h && $dest_w != $orig_w && $dest_h != $orig_h ) {
		return false;
	}

	// 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 );

}

/**
 * Resizes an image to make a thumbnail or intermediate size.
 *
 * The returned array has the file size, the image width, and image height. The
 * {@see 'image_make_intermediate_size'} filter can be used to hook in and change the
 * values of the returned array. The only parameter is the resized file path.
 *
 * @since 2.5.0
 *
 * @param string $file   File path.
 * @param int    $width  Image width.
 * @param int    $height Image height.
 * @param bool   $crop   Optional. Whether to crop image to specified width and height or resize.
 *                       Default false.
 * @return false|array False, if no image was created. Metadata array on success.
 */
function image_make_intermediate_size( $file, $width, $height, $crop = false ) {
	if ( $width || $height ) {
		$editor = wp_get_image_editor( $file );

		if ( is_wp_error( $editor ) || is_wp_error( $editor->resize( $width, $height, $crop ) ) )
			return false;

		$resized_file = $editor->save();

		if ( ! is_wp_error( $resized_file ) && $resized_file ) {
			unset( $resized_file['path'] );
			return $resized_file;
		}
	}
	return false;
}

/**
 * Helper function to test if aspect ratios for two images match.
 *
 * @since 4.6.0
 *
 * @param int $source_width  Width of the first image in pixels.
 * @param int $source_height Height of the first image in pixels.
 * @param int $target_width  Width of the second image in pixels.
 * @param int $target_height Height of the second image in pixels.
 * @return bool True if aspect ratios match within 1px. False if not.
 */
function wp_image_matches_ratio( $source_width, $source_height, $target_width, $target_height ) {
	/*
	 * To test for varying crops, we constrain the dimensions of the larger image
	 * to the dimensions of the smaller image and see if they match.
	 */
	if ( $source_width > $target_width ) {
		$constrained_size = wp_constrain_dimensions( $source_width, $source_height, $target_width );
		$expected_size = array( $target_width, $target_height );
	} else {
		$constrained_size = wp_constrain_dimensions( $target_width, $target_height, $source_width );
		$expected_size = array( $source_width, $source_height );
	}

	// If the image dimensions are within 1px of the expected size, we consider it a match.
	$matched = ( abs( $constrained_size[0] - $expected_size[0] ) <= 1 && abs( $constrained_size[1] - $expected_size[1] ) <= 1 );

	return $matched;
}

/**
 * Retrieves the image's intermediate size (resized) path, width, and height.
 *
 * The $size parameter can be an array with the width and height respectively.
 * If the size matches the 'sizes' metadata array for width and height, then it
 * will be used. If there is no direct match, then the nearest image size larger
 * than the specified size will be used. If nothing is found, then the function
 * will break out and return false.
 *
 * The metadata 'sizes' is used for compatible sizes that can be used for the
 * parameter $size value.
 *
 * The url path will be given, when the $size parameter is a string.
 *
 * If you are passing an array for the $size, you should consider using
 * add_image_size() so that a cropped version is generated. It's much more
 * efficient than having to find the closest-sized image and then having the
 * browser scale down the image.
 *
 * @since 2.5.0
 *
 * @param int          $post_id Attachment ID.
 * @param array|string $size    Optional. Image size. Accepts any valid image size, or an array
 *                              of width and height values in pixels (in that order).
 *                              Default 'thumbnail'.
 * @return false|array $data {
 *     Array of file relative path, width, and height on success. Additionally includes absolute
 *     path and URL if registered size is passed to $size parameter. False on failure.
 *
 *     @type string $file   Image's path relative to uploads directory
 *     @type int    $width  Width of image
 *     @type int    $height Height of image
 *     @type string $path   Image's absolute filesystem path.
 *     @type string $url    Image's URL.
 * }
 */
function image_get_intermediate_size( $post_id, $size = 'thumbnail' ) {
	if ( ! $size || ! is_array( $imagedata = wp_get_attachment_metadata( $post_id ) ) || empty( $imagedata['sizes'] )  ) {
		return false;
	}

	$data = array();

	// Find the best match when '$size' is an array.
	if ( is_array( $size ) ) {
		$candidates = array();

		if ( ! isset( $imagedata['file'] ) && isset( $imagedata['sizes']['full'] ) ) {
			$imagedata['height'] = $imagedata['sizes']['full']['height'];
			$imagedata['width']  = $imagedata['sizes']['full']['width'];
		}

		foreach ( $imagedata['sizes'] as $_size => $data ) {
			// If there's an exact match to an existing image size, short circuit.
			if ( $data['width'] == $size[0] && $data['height'] == $size[1] ) {
				$candidates[ $data['width'] * $data['height'] ] = $data;
				break;
			}

			// If it's not an exact match, consider larger sizes with the same aspect ratio.
			if ( $data['width'] >= $size[0] && $data['height'] >= $size[1] ) {
				// If '0' is passed to either size, we test ratios against the original file.
				if ( 0 === $size[0] || 0 === $size[1] ) {
					$same_ratio = wp_image_matches_ratio( $data['width'], $data['height'], $imagedata['width'], $imagedata['height'] );
				} else {
					$same_ratio = wp_image_matches_ratio( $data['width'], $data['height'], $size[0], $size[1] );
				}

				if ( $same_ratio ) {
					$candidates[ $data['width'] * $data['height'] ] = $data;
				}
			}
		}

		if ( ! empty( $candidates ) ) {
			// Sort the array by size if we have more than one candidate.
			if ( 1 < count( $candidates ) ) {
				ksort( $candidates );
			}

			$data = array_shift( $candidates );
		/*
		 * When the size requested is smaller than the thumbnail dimensions, we
		 * fall back to the thumbnail size to maintain backwards compatibility with
		 * pre 4.6 versions of WordPress.
		 */
		} elseif ( ! empty( $imagedata['sizes']['thumbnail'] ) && $imagedata['sizes']['thumbnail']['width'] >= $size[0] && $imagedata['sizes']['thumbnail']['width'] >= $size[1] ) {
			$data = $imagedata['sizes']['thumbnail'];
		} else {
			return false;
		}

		// Constrain the width and height attributes to the requested values.
		list( $data['width'], $data['height'] ) = image_constrain_size_for_editor( $data['width'], $data['height'], $size );

	} elseif ( ! empty( $imagedata['sizes'][ $size ] ) ) {
		$data = $imagedata['sizes'][ $size ];
	}

	// If we still don't have a match at this point, return false.
	if ( empty( $data ) ) {
		return false;
	}

	// include the full filesystem path of the intermediate file
	if ( empty( $data['path'] ) && ! empty( $data['file'] ) && ! empty( $imagedata['file'] ) ) {
		$file_url = wp_get_attachment_url($post_id);
		$data['path'] = path_join( dirname($imagedata['file']), $data['file'] );
		$data['url'] = path_join( dirname($file_url), $data['file'] );
	}

	/**
	 * Filters the output of image_get_intermediate_size()
	 *
	 * @since 4.4.0
	 *
	 * @see image_get_intermediate_size()
	 *
	 * @param array        $data    Array of file relative path, width, and height on success. May also include
	 *                              file absolute path and URL.
	 * @param int          $post_id The post_id of the image attachment
	 * @param string|array $size    Registered image size or flat array of initially-requested height and width
	 *                              dimensions (in that order).
	 */
	return apply_filters( 'image_get_intermediate_size', $data, $post_id, $size );
}

/**
 * Gets the available intermediate image sizes.
 *
 * @since 3.0.0
 *
 * @return array Returns a filtered array of image size strings.
 */
function get_intermediate_image_sizes() {
	$_wp_additional_image_sizes = wp_get_additional_image_sizes();
	$image_sizes = array('thumbnail', 'medium', 'medium_large', 'large'); // Standard sizes
	if ( ! empty( $_wp_additional_image_sizes ) ) {
		$image_sizes = array_merge( $image_sizes, array_keys( $_wp_additional_image_sizes ) );
	}

	/**
	 * Filters the list of intermediate image sizes.
	 *
	 * @since 2.5.0
	 *
	 * @param array $image_sizes An array of intermediate image sizes. Defaults
	 *                           are 'thumbnail', 'medium', 'medium_large', 'large'.
	 */
	return apply_filters( 'intermediate_image_sizes', $image_sizes );
}

/**
 * Retrieve an image to represent an attachment.
 *
 * A mime icon for files, thumbnail or intermediate size for images.
 *
 * The returned array contains four values: the URL of the attachment image src,
 * the width of the image file, the height of the image file, and a boolean
 * representing whether the returned array describes an intermediate (generated)
 * image size or the original, full-sized upload.
 *
 * @since 2.5.0
 *
 * @param int          $attachment_id Image attachment ID.
 * @param string|array $size          Optional. Image size. Accepts any valid image size, or an array of width
 *                                    and height values in pixels (in that order). Default 'thumbnail'.
 * @param bool         $icon          Optional. Whether the image should be treated as an icon. Default false.
 * @return false|array Returns an array (url, width, height, is_intermediate), or false, if no image is available.
 */
function wp_get_attachment_image_src( $attachment_id, $size = 'thumbnail', $icon = false ) {
	// get a thumbnail or intermediate image if there is one
	$image = image_downsize( $attachment_id, $size );
	if ( ! $image ) {
		$src = false;

		if ( $icon && $src = wp_mime_type_icon( $attachment_id ) ) {
			/** This filter is documented in wp-includes/post.php */
			$icon_dir = apply_filters( 'icon_dir', ABSPATH . WPINC . '/images/media' );

			$src_file = $icon_dir . '/' . wp_basename( $src );
			@list( $width, $height ) = getimagesize( $src_file );
		}

		if ( $src && $width && $height ) {
			$image = array( $src, $width, $height );
		}
	}
	/**
	 * Filters the image src result.
	 *
	 * @since 4.3.0
	 *
	 * @param array|false  $image         Either array with src, width & height, icon src, or false.
	 * @param int          $attachment_id Image attachment ID.
	 * @param string|array $size          Size of image. Image size or array of width and height values
	 *                                    (in that order). Default 'thumbnail'.
	 * @param bool         $icon          Whether the image should be treated as an icon. Default false.
	 */
	return apply_filters( 'wp_get_attachment_image_src', $image, $attachment_id, $size, $icon );
}

/**
 * Get an HTML img element representing an image attachment
 *
 * While `$size` will accept an array, it is better to register a size with
 * add_image_size() so that a cropped version is generated. It's much more
 * efficient than having to find the closest-sized image and then having the
 * browser scale down the image.
 *
 * @since 2.5.0
 *
 * @param int          $attachment_id Image attachment ID.
 * @param string|array $size          Optional. Image size. Accepts any valid image size, or an array of width
 *                                    and height values in pixels (in that order). Default 'thumbnail'.
 * @param bool         $icon          Optional. Whether the image should be treated as an icon. Default false.
 * @param string|array $attr          Optional. Attributes for the image markup. Default empty.
 * @return string HTML img element or empty string on failure.
 */
function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = false, $attr = '') {
	$html = '';
	$image = wp_get_attachment_image_src($attachment_id, $size, $icon);
	if ( $image ) {
		list($src, $width, $height) = $image;
		$hwstring = image_hwstring($width, $height);
		$size_class = $size;
		if ( is_array( $size_class ) ) {
			$size_class = join( 'x', $size_class );
		}
		$attachment = get_post($attachment_id);
		$default_attr = array(
			'src'	=> $src,
			'class'	=> "attachment-$size_class size-$size_class",
			'alt'	=> trim( strip_tags( get_post_meta( $attachment_id, '_wp_attachment_image_alt', true ) ) ),
		);

		$attr = wp_parse_args( $attr, $default_attr );

		// Generate 'srcset' and 'sizes' if not already present.
		if ( empty( $attr['srcset'] ) ) {
			$image_meta = wp_get_attachment_metadata( $attachment_id );

			if ( is_array( $image_meta ) ) {
				$size_array = array( absint( $width ), absint( $height ) );
				$srcset = wp_calculate_image_srcset( $size_array, $src, $image_meta, $attachment_id );
				$sizes = wp_calculate_image_sizes( $size_array, $src, $image_meta, $attachment_id );

				if ( $srcset && ( $sizes || ! empty( $attr['sizes'] ) ) ) {
					$attr['srcset'] = $srcset;

					if ( empty( $attr['sizes'] ) ) {
						$attr['sizes'] = $sizes;
					}
				}
			}
		}

		/**
		 * Filters the list of attachment image attributes.
		 *
		 * @since 2.8.0
		 *
		 * @param array        $attr       Attributes for the image markup.
		 * @param WP_Post      $attachment Image attachment post.
		 * @param string|array $size       Requested size. Image size or array of width and height values
		 *                                 (in that order). Default 'thumbnail'.
		 */
		$attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment, $size );
		$attr = array_map( 'esc_attr', $attr );
		$html = rtrim("<img $hwstring");
		foreach ( $attr as $name => $value ) {
			$html .= " $name=" . '"' . $value . '"';
		}
		$html .= ' />';
	}

	return $html;
}

/**
 * Get the URL of an image attachment.
 *
 * @since 4.4.0
 *
 * @param int          $attachment_id Image attachment ID.
 * @param string|array $size          Optional. Image size to retrieve. Accepts any valid image size, or an array
 *                                    of width and height values in pixels (in that order). Default 'thumbnail'.
 * @param bool         $icon          Optional. Whether the image should be treated as an icon. Default false.
 * @return string|false Attachment URL or false if no image is available.
 */
function wp_get_attachment_image_url( $attachment_id, $size = 'thumbnail', $icon = false ) {
	$image = wp_get_attachment_image_src( $attachment_id, $size, $icon );
	return isset( $image['0'] ) ? $image['0'] : false;
}

/**
 * Get the attachment path relative to the upload directory.
 *
 * @since 4.4.1
 * @access private
 *
 * @param string $file Attachment file name.
 * @return string Attachment path relative to the upload directory.
 */
function _wp_get_attachment_relative_path( $file ) {
	$dirname = dirname( $file );

	if ( '.' === $dirname ) {
		return '';
	}

	if ( false !== strpos( $dirname, 'wp-content/uploads' ) ) {
		// Get the directory name relative to the upload directory (back compat for pre-2.7 uploads)
		$dirname = substr( $dirname, strpos( $dirname, 'wp-content/uploads' ) + 18 );
		$dirname = ltrim( $dirname, '/' );
	}

	return $dirname;
}

/**
 * Get the image size as array from its meta data.
 *
 * Used for responsive images.
 *
 * @since 4.4.0
 * @access private
 *
 * @param string $size_name  Image size. Accepts any valid image size name ('thumbnail', 'medium', etc.).
 * @param array  $image_meta The image meta data.
 * @return array|bool Array of width and height values in pixels (in that order)
 *                    or false if the size doesn't exist.
 */
function _wp_get_image_size_from_meta( $size_name, $image_meta ) {
	if ( $size_name === 'full' ) {
		return array(
			absint( $image_meta['width'] ),
			absint( $image_meta['height'] ),
		);
	} elseif ( ! empty( $image_meta['sizes'][$size_name] ) ) {
		return array(
			absint( $image_meta['sizes'][$size_name]['width'] ),
			absint( $image_meta['sizes'][$size_name]['height'] ),
		);
	}

	return false;
}

/**
 * Retrieves the value for an image attachment's 'srcset' attribute.
 *
 * @since 4.4.0
 *
 * @see wp_calculate_image_srcset()
 *
 * @param int          $attachment_id Image attachment ID.
 * @param array|string $size          Optional. Image size. Accepts any valid image size, or an array of
 *                                    width and height values in pixels (in that order). Default 'medium'.
 * @param array        $image_meta    Optional. The image meta data as returned by 'wp_get_attachment_metadata()'.
 *                                    Default null.
 * @return string|bool A 'srcset' value string or false.
 */
function wp_get_attachment_image_srcset( $attachment_id, $size = 'medium', $image_meta = null ) {
	if ( ! $image = wp_get_attachment_image_src( $attachment_id, $size ) ) {
		return false;
	}

	if ( ! is_array( $image_meta ) ) {
		$image_meta = wp_get_attachment_metadata( $attachment_id );
	}

	$image_src = $image[0];
	$size_array = array(
		absint( $image[1] ),
		absint( $image[2] )
	);

	return wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id );
}

/**
 * A helper function to calculate the image sources to include in a 'srcset' attribute.
 *
 * @since 4.4.0
 *
 * @param array  $size_array    Array of width and height values in pixels (in that order).
 * @param string $image_src     The 'src' of the image.
 * @param array  $image_meta    The image meta data as returned by 'wp_get_attachment_metadata()'.
 * @param int    $attachment_id Optional. The image attachment ID to pass to the filter. Default 0.
 * @return string|bool          The 'srcset' attribute value. False on error or when only one source exists.
 */
function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id = 0 ) {
	/**
	 * Let plugins pre-filter the image meta to be able to fix inconsistencies in the stored data.
	 *
	 * @since 4.5.0
	 *
	 * @param array  $image_meta    The image meta data as returned by 'wp_get_attachment_metadata()'.
	 * @param array  $size_array    Array of width and height values in pixels (in that order).
	 * @param string $image_src     The 'src' of the image.
	 * @param int    $attachment_id The image attachment ID or 0 if not supplied.
	 */
	$image_meta = apply_filters( 'wp_calculate_image_srcset_meta', $image_meta, $size_array, $image_src, $attachment_id );

	if ( empty( $image_meta['sizes'] ) || ! isset( $image_meta['file'] ) || strlen( $image_meta['file'] ) < 4 ) {
		return false;
	}

	$image_sizes = $image_meta['sizes'];

	// Get the width and height of the image.
	$image_width = (int) $size_array[0];
	$image_height = (int) $size_array[1];

	// Bail early if error/no width.
	if ( $image_width < 1 ) {
		return false;
	}

	$image_basename = wp_basename( $image_meta['file'] );

	/*
	 * WordPress flattens animated GIFs into one frame when generating intermediate sizes.
	 * To avoid hiding animation in user content, if src is a full size GIF, a srcset attribute is not generated.
	 * If src is an intermediate size GIF, the full size is excluded from srcset to keep a flattened GIF from becoming animated.
	 */
	if ( ! isset( $image_sizes['thumbnail']['mime-type'] ) || 'image/gif' !== $image_sizes['thumbnail']['mime-type'] ) {
		$image_sizes[] = array(
			'width'  => $image_meta['width'],
			'height' => $image_meta['height'],
			'file'   => $image_basename,
		);
	} elseif ( strpos( $image_src, $image_meta['file'] ) ) {
		return false;
	}

	// Retrieve the uploads sub-directory from the full size image.
	$dirname = _wp_get_attachment_relative_path( $image_meta['file'] );

	if ( $dirname ) {
		$dirname = trailingslashit( $dirname );
	}

	$upload_dir = wp_get_upload_dir();
	$image_baseurl = trailingslashit( $upload_dir['baseurl'] ) . $dirname;

	/*
	 * If currently on HTTPS, prefer HTTPS URLs when we know they're supported by the domain
	 * (which is to say, when they share the domain name of the current request).
	 */
	if ( is_ssl() && 'https' !== substr( $image_baseurl, 0, 5 ) && parse_url( $image_baseurl, PHP_URL_HOST ) === $_SERVER['HTTP_HOST'] ) {
		$image_baseurl = set_url_scheme( $image_baseurl, 'https' );
	}

	/*
	 * Images that have been edited in WordPress after being uploaded will
	 * contain a unique hash. Look for that hash and use it later to filter
	 * out images that are leftovers from previous versions.
	 */
	$image_edited = preg_match( '/-e[0-9]{13}/', wp_basename( $image_src ), $image_edit_hash );

	/**
	 * Filters the maximum image width to be included in a 'srcset' attribute.
	 *
	 * @since 4.4.0
	 *
	 * @param int   $max_width  The maximum image width to be included in the 'srcset'. Default '1600'.
	 * @param array $size_array Array of width and height values in pixels (in that order).
	 */
	$max_srcset_image_width = apply_filters( 'max_srcset_image_width', 1600, $size_array );

	// Array to hold URL candidates.
	$sources = array();

	/**
	 * To make sure the ID matches our image src, we will check to see if any sizes in our attachment
	 * meta match our $image_src. If no matches are found we don't return a srcset to avoid serving
	 * an incorrect image. See #35045.
	 */
	$src_matched = false;

	/*
	 * Loop through available images. Only use images that are resized
	 * versions of the same edit.
	 */
	foreach ( $image_sizes as $image ) {
		$is_src = false;

		// Check if image meta isn't corrupted.
		if ( ! is_array( $image ) ) {
			continue;
		}

		// If the file name is part of the `src`, we've confirmed a match.
		if ( ! $src_matched && false !== strpos( $image_src, $dirname . $image['file'] ) ) {
			$src_matched = $is_src = true;
		}

		// Filter out images that are from previous edits.
		if ( $image_edited && ! strpos( $image['file'], $image_edit_hash[0] ) ) {
			continue;
		}

		/*
		 * Filters out images that are wider than '$max_srcset_image_width' unless
		 * that file is in the 'src' attribute.
		 */
		if ( $max_srcset_image_width && $image['width'] > $max_srcset_image_width && ! $is_src ) {
			continue;
		}

		// If the image dimensions are within 1px of the expected size, use it.
		if ( wp_image_matches_ratio( $image_width, $image_height, $image['width'], $image['height'] ) ) {
			// Add the URL, descriptor, and value to the sources array to be returned.
			$source = array(
				'url'        => $image_baseurl . $image['file'],
				'descriptor' => 'w',
				'value'      => $image['width'],
			);

			// The 'src' image has to be the first in the 'srcset', because of a bug in iOS8. See #35030.
			if ( $is_src ) {
				$sources = array( $image['width'] => $source ) + $sources;
			} else {
				$sources[ $image['width'] ] = $source;
			}
		}
	}

	/**
	 * Filters an image's 'srcset' sources.
	 *
	 * @since 4.4.0
	 *
	 * @param array  $sources {
	 *     One or more arrays of source data to include in the 'srcset'.
	 *
	 *     @type array $width {
	 *         @type string $url        The URL of an image source.
	 *         @type string $descriptor The descriptor type used in the image candidate string,
	 *                                  either 'w' or 'x'.
	 *         @type int    $value      The source width if paired with a 'w' descriptor, or a
	 *                                  pixel density value if paired with an 'x' descriptor.
	 *     }
	 * }
	 * @param array  $size_array    Array of width and height values in pixels (in that order).
	 * @param string $image_src     The 'src' of the image.
	 * @param array  $image_meta    The image meta data as returned by 'wp_get_attachment_metadata()'.
	 * @param int    $attachment_id Image attachment ID or 0.
	 */
	$sources = apply_filters( 'wp_calculate_image_srcset', $sources, $size_array, $image_src, $image_meta, $attachment_id );

	// Only return a 'srcset' value if there is more than one source.
	if ( ! $src_matched || count( $sources ) < 2 ) {
		return false;
	}

	$srcset = '';

	foreach ( $sources as $source ) {
		$srcset .= str_replace( ' ', '%20', $source['url'] ) . ' ' . $source['value'] . $source['descriptor'] . ', ';
	}

	return rtrim( $srcset, ', ' );
}

/**
 * Retrieves the value for an image attachment's 'sizes' attribute.
 *
 * @since 4.4.0
 *
 * @see wp_calculate_image_sizes()
 *
 * @param int          $attachment_id Image attachment ID.
 * @param array|string $size          Optional. Image size. Accepts any valid image size, or an array of width
 *                                    and height values in pixels (in that order). Default 'medium'.
 * @param array        $image_meta    Optional. The image meta data as returned by 'wp_get_attachment_metadata()'.
 *                                    Default null.
 * @return string|bool A valid source size value for use in a 'sizes' attribute or false.
 */
function wp_get_attachment_image_sizes( $attachment_id, $size = 'medium', $image_meta = null ) {
	if ( ! $image = wp_get_attachment_image_src( $attachment_id, $size ) ) {
		return false;
	}

	if ( ! is_array( $image_meta ) ) {
		$image_meta = wp_get_attachment_metadata( $attachment_id );
	}

	$image_src = $image[0];
	$size_array = array(
		absint( $image[1] ),
		absint( $image[2] )
	);

	return wp_calculate_image_sizes( $size_array, $image_src, $image_meta, $attachment_id );
}

/**
 * Creates a 'sizes' attribute value for an image.
 *
 * @since 4.4.0
 *
 * @param array|string $size          Image size to retrieve. Accepts any valid image size, or an array
 *                                    of width and height values in pixels (in that order). Default 'medium'.
 * @param string       $image_src     Optional. The URL to the image file. Default null.
 * @param array        $image_meta    Optional. The image meta data as returned by 'wp_get_attachment_metadata()'.
 *                                    Default null.
 * @param int          $attachment_id Optional. Image attachment ID. Either `$image_meta` or `$attachment_id`
 *                                    is needed when using the image size name as argument for `$size`. Default 0.
 * @return string|bool A valid source size value for use in a 'sizes' attribute or false.
 */
function wp_calculate_image_sizes( $size, $image_src = null, $image_meta = null, $attachment_id = 0 ) {
	$width = 0;

	if ( is_array( $size ) ) {
		$width = absint( $size[0] );
	} elseif ( is_string( $size ) ) {
		if ( ! $image_meta && $attachment_id ) {
			$image_meta = wp_get_attachment_metadata( $attachment_id );
		}

		if ( is_array( $image_meta ) ) {
			$size_array = _wp_get_image_size_from_meta( $size, $image_meta );
			if ( $size_array ) {
				$width = absint( $size_array[0] );
			}
		}
	}

	if ( ! $width ) {
		return false;
	}

	// Setup the default 'sizes' attribute.
	$sizes = sprintf( '(max-width: %1$dpx) 100vw, %1$dpx', $width );

	/**
	 * Filters the output of 'wp_calculate_image_sizes()'.
	 *
	 * @since 4.4.0
	 *
	 * @param string       $sizes         A source size value for use in a 'sizes' attribute.
	 * @param array|string $size          Requested size. Image size or array of width and height values
	 *                                    in pixels (in that order).
	 * @param string|null  $image_src     The URL to the image file or null.
	 * @param array|null   $image_meta    The image meta data as returned by wp_get_attachment_metadata() or null.
	 * @param int          $attachment_id Image attachment ID of the original image or 0.
	 */
	return apply_filters( 'wp_calculate_image_sizes', $sizes, $size, $image_src, $image_meta, $attachment_id );
}

/**
 * Filters 'img' elements in post content to add 'srcset' and 'sizes' attributes.
 *
 * @since 4.4.0
 *
 * @see wp_image_add_srcset_and_sizes()
 *
 * @param string $content The raw post content to be filtered.
 * @return string Converted content with 'srcset' and 'sizes' attributes added to images.
 */
function wp_make_content_images_responsive( $content ) {
	if ( ! preg_match_all( '/<img [^>]+>/', $content, $matches ) ) {
		return $content;
	}

	$selected_images = $attachment_ids = array();

	foreach( $matches[0] as $image ) {
		if ( false === strpos( $image, ' srcset=' ) && preg_match( '/wp-image-([0-9]+)/i', $image, $class_id ) &&
			( $attachment_id = absint( $class_id[1] ) ) ) {

			/*
			 * If exactly the same image tag is used more than once, overwrite it.
			 * All identical tags will be replaced later with 'str_replace()'.
			 */
			$selected_images[ $image ] = $attachment_…