tag. Empty values will be omitted.
function image_hwstring($width, $height) {
$out = '';
if ($width)
$out .= 'width="'.intval($width).'" ';
if ($height)
$out .= 'height="'.intval($height).'" ';
return $out;
}
// Scale an image to fit a particular size (such as 'thumb' or 'medium'), and return an image URL, height and width.
// The URL might be the original image, or it might be a resized version.
// returns an array($url, $width, $height)
function image_downsize($id, $size = 'medium') {
$img_url = wp_get_attachment_url($id);
$meta = wp_get_attachment_metadata($id);
$width = $height = 0;
// plugins can use this to provide resize services
if ( $out = apply_filters('image_downsize', false, $id, $size) )
return $out;
if ( $size == 'thumb' ) {
// thumbnail: use the thumb as the displayed image, and constrain based on its dimensions
$thumb_path = wp_get_attachment_thumb_file($id);
// the actual thumbnail size isn't stored so we'll have to calculate it
if ( $thumb_path && ($info = getimagesize($thumb_path)) ) {
list( $width, $height ) = image_constrain_size_for_editor( $info[0], $info[1], $size );
$img_url = wp_get_attachment_thumb_url($id);
}
// this could be improved to provide a default thumbnail if one doesn't exist
}
elseif ( isset($meta['width'], $meta['height']) ) {
// any other type: use the real image and constrain it
list( $width, $height ) = image_constrain_size_for_editor( $meta['width'], $meta['height'], $size );
}
return array( $img_url, $width, $height );
}
// return an ![]()
tag for the given image attachment, scaling it down if requested
function get_image_tag($id, $alt, $title, $align, $rel = false, $size='medium') {
list( $img_src, $width, $height ) = image_downsize($id, $size);
$hwstring = image_hwstring($width, $height);
$html = '.' "'.attribute_escape($title).'")
';
$html = apply_filters( 'image_send_to_editor', $html, $id, $alt, $title, $align, $url );
return $html;
}
// same as wp_shrink_dimensions, except the max parameters are optional.
// if either width or height are empty, no constraint is applied on that dimension.
function wp_constrain_dimensions( $current_width, $current_height, $max_width=0, $max_height=0 ) {
if ( !$max_width and !$max_height )
return array( $current_width, $current_height );
$width_ratio = $height_ratio = 1.0;
if ( $max_width > 0 && $current_width > $max_width )
$width_ratio = $max_width / $current_width;
if ( $max_height > 0 && $current_height > $max_height )
$height_ratio = $max_height / $current_height;
// the smaller ratio is the one we need to fit it to the constraining box
$ratio = min( $width_ratio, $height_ratio );
return array( intval($current_width * $ratio), intval($current_height * $ratio) );
}
// calculate dimensions and coordinates for a resized image that fits within a specified width and height
// if $crop is true, the largest matching central portion of the image will be cropped out and resized to the required size
function image_resize_dimensions($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;
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) {
$new_w = intval($new_h * $aspect_ratio);
}
if (!$new_h) {
$new_h = intval($new_w / $aspect_ratio);
}
$size_ratio = max($new_w / $orig_w, $new_h / $orig_h);
$crop_w = ceil($new_w / $size_ratio);
$crop_h = ceil($new_h / $size_ratio);
$s_x = floor(($orig_w - $crop_w)/2);
$s_y = floor(($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)
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, $s_x, $s_y, $new_w, $new_h, $crop_w, $crop_h);
}
// Scale down an image to fit a particular size and save a new copy of the image
function image_resize( $file, $max_w, $max_h, $crop=false, $suffix=null, $dest_path=null, $jpeg_quality=75) {
$image = wp_load_image( $file );
if ( !is_resource( $image ) )
return new WP_Error('error_loading_image', $image);
list($orig_w, $orig_h, $orig_type) = getimagesize( $file );
$dims = image_resize_dimensions($orig_w, $orig_h, $max_w, $max_h, $crop);
if (!$dims)
return $dims;
list($dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h) = $dims;
$newimage = imagecreatetruecolor( $dst_w, $dst_h);
// preserve PNG transparency
if ( IMAGETYPE_PNG == $orig_type && function_exists( 'imagealphablending' ) && function_exists( 'imagesavealpha' ) ) {
imagealphablending( $newimage, false);
imagesavealpha( $newimage, true);
}
imagecopyresampled( $newimage, $image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
// we don't need the original in memory anymore
imagedestroy( $image );
// $suffix will be appended to the destination filename, just before the extension
if ( !$suffix )
$suffix = "{$dst_w}x{$dst_h}";
$info = pathinfo($file);
$dir = $info['dirname'];
$ext = $info['extension'];
$name = basename($file, ".{$ext}");
if ( !is_null($dest_path) and $_dest_path = realpath($dest_path) )
$dir = $_dest_path;
$destfilename = "{$dir}/{$name}-{$suffix}.{$ext}";
if ( $orig_type == IMAGETYPE_GIF ) {
if (!imagegif( $newimage, $destfilename ) )
return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
}
elseif ( $orig_type == IMAGETYPE_PNG ) {
if (!imagepng( $newimage, $destfilename ) )
return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
}
else {
// all other formats are converted to jpg
$destfilename = "{$dir}/{$name}-{$suffix}.jpg";
if (!imagejpeg( $newimage, $destfilename, $jpeg_quality ) )
return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
}
imagedestroy( $newimage );
// Set correct file permissions
$stat = stat( dirname( $destfilename ));
$perms = $stat['mode'] & 0000666; //same permissions as parent folder, strip off the executable bits
@ chmod( $destfilename, $perms );
return $destfilename;
}
?>