Dynamic Image Resizing

<?php
/*
* Resize images dynamically using wp built in functions
* @author Victor Teixeira
* @link http://core.trac.wordpress.org/ticket/15311
*
* php 5.2+
*
* Exemple use:
*
* <?php
* $thumb = get_post_thumbnail_id();
* $image = be_image_resize( $thumb,'' , 140, 110, true );
* ?>
* <img src="<?php echo $image[url]; ?>" width="<?php echo $image[width]; ?>" height="<?php echo $image[height]; ?>" />
*
* @param int $attach_id
* @param string $img_url
* @param int $width
* @param int $height
* @param bool $crop
* @return array
*/
function be_image_resize( $attach_id = null, $img_url = null, $width, $height, $crop = false ) {
// this is an attachment, so we have the ID
if ( $attach_id ) {
$image_src = wp_get_attachment_image_src( $attach_id, 'full' );
$file_path = get_attached_file( $attach_id );
// this is not an attachment, let's use the image url
} else if ( $img_url ) {
$file_path = parse_url( $img_url );
$file_path = ltrim( $file_path['path'], '/' );
//$file_path = rtrim( ABSPATH, '/' ).$file_path['path'];
$orig_size = getimagesize( $file_path );
$image_src[0] = $img_url;
$image_src[1] = $orig_size[0];
$image_src[2] = $orig_size[1];
}
$file_info = pathinfo( $file_path );
$extension = '.'. $file_info['extension'];
// the image path without the extension
$no_ext_path = $file_info['dirname'].'/'.$file_info['filename'];
$cropped_img_path = $no_ext_path.'-'.$width.'x'.$height.$extension;
// checking if the file size is larger than the target size
// if it is smaller or the same size, stop right here and return
if ( $image_src[1] > $width || $image_src[2] > $height ) {
// the file is larger, check if the resized version already exists (for crop = true but will also work for crop = false if the sizes match)
if ( file_exists( $cropped_img_path ) ) {
$cropped_img_url = str_replace( basename( $image_src[0] ), basename( $cropped_img_path ), $image_src[0] );
$vt_image = array (
'url' => $cropped_img_url,
'width' => $width,
'height' => $height
);
return $vt_image;
}
// crop = false
if ( $crop == false ) {
// calculate the size proportionaly
$proportional_size = wp_constrain_dimensions( $image_src[1], $image_src[2], $width, $height );
$resized_img_path = $no_ext_path.'-'.$proportional_size[0].'x'.$proportional_size[1].$extension;
// checking if the file already exists
if ( file_exists( $resized_img_path ) ) {
$resized_img_url = str_replace( basename( $image_src[0] ), basename( $resized_img_path ), $image_src[0] );
$vt_image = array (
'url' => $resized_img_url,
'width' => $new_img_size[0],
'height' => $new_img_size[1]
);
return $vt_image;
}
}
// no cached files - let's finally resize it
$new_img_path = image_resize( $file_path, $width, $height, $crop );
$new_img_size = getimagesize( $new_img_path );
$new_img = str_replace( basename( $image_src[0] ), basename( $new_img_path ), $image_src[0] );
// resized output
$vt_image = array (
'url' => $new_img,
'width' => $new_img_size[0],
'height' => $new_img_size[1]
);
return $vt_image;
}
// default output - without resizing
$vt_image = array (
'url' => $image_src[0],
'width' => $image_src[1],
'height' => $image_src[2]
);
return $vt_image;
}
/**
* Returns a dynamically resized image
*
* Example: be_get_post_thumbnail( $post->ID, 90, 90, true );
*
* @param int $post_id
* @param int $width
* @param int $height
* @param bool $crop
* @return string $image
*/
function be_get_post_thumbnail( $post_id = '', $width = '', $height = '', $crop = false ) {
$attach_id = get_post_thumbnail_id( $post_id );
$image = be_image_resize( $attach_id, null, $width, $height, $crop );
return '<img src="' . $image['url'] . '" />';
}
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Bill Erickson

Bill Erickson is a freelance WordPress developer and a contributing developer to the Genesis framework. For the past 14 years he has worked with attorneys, publishers, corporations, and non-profits, building custom websites tailored to their needs and goals.

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