Cambia el tamaño de las imágenes de WordPress sobre la marcha utilizando las funciones integradas de WordPress.
Use la función vt_resize para redimensionar dinámicamente las imágenes de WordPress ubicadas en un campo personalizado, imagen destacada, directorio de subidas, complemento WordPress de NextGen Gallery o incluso un enlace externo a una imagen externa.
Es muy fácil de usar, simplemente copie / pegue el siguiente código en el archivo functions.php de su tema de WordPress de su tema de WordPress actualmente activado.
Luego, siempre que necesite cambiar el tamaño de una imagen sobre la marcha, simplemente realice una llamada a esa función siguiendo el uso de parámetros explicado en los comentarios de la función.
Este es un ejemplo de cómo obtener automáticamente la ID de publicación, la publicación propiamente dicha, los valores del campo personalizado de la publicación, y redimensionar dinámicamente la imagen del campo personalizado que contiene la imagen para redimensionarla dinámicamente sobre la marcha.
<?php
// Place this in your functions.php
function get_postID(){
global $wp_query;
$thePostID = $wp_query->post->ID;
}
?>
<?php
// Place the following lines where you want to perform this action.
$postID = get_postID();// Obtain the current Post ID.
$post = get_post($postID);// Takes the current Post ID and returns the database record.
$custom = get_post_custom($post->ID);// Returns a multidimensional array with all custom fields of the Post.
$image = $custom['field-slug'][0];// Specify the array key of the Custom Field containing the image.
// The first parameter is blank. Meaning, we will not be using a Post Attachment.
// The second parameter is the image from our Post's Custom Field value.
// The third and fourth parameters are the width and height of the image after the re-size is performed.
// The fifth parameter means we want to crop this image.
$resizedImage = vt_resize('', $image, 190, 338, true);// Dynamically re-size our image on the fly.
echo '<img src="'.$resizedImage[url].'" width="'.$resizedImage[width].'" height="'.$resizedImage[height].'" title="'.$post->post_title.'" alt="'.$post->post_title.'" />';// The image properties are held in an array. (Use print_r($resizedImage) for array properties.)
?>
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Descripción: redimensiona las imágenes dinámicamente usando las funciones incorporadas de WordPress.
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Autor: Victor Teixeira
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Requisitos: PHP 5.2+, WordPress 3.2+
Reformateé el código fuente para que sea más legible para mis propios ojos. Si desea el código fuente original formateado, visite el enlace anterior.
<?php
/*
* Resize images dynamically using wp built in functions
* Victor Teixeira
*
* php 5.2+
*
* Exemplo de uso:
*
* <?php
* $thumb = get_post_thumbnail_id();
* $image = vt_resize($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 $crop
* @return array
*/
if(!function_exists('vt_resize')){
function vt_resize($attach_id = null, $img_url = null, $width, $height, $crop = false){
if($attach_id){
// this is an attachment, so we have the ID
$image_src = wp_get_attachment_image_src($attach_id, 'full');
$file_path = get_attached_file($attach_id);
} elseif($img_url){
// this is not an attachment, let's use the image url
$file_path = parse_url($img_url);
$file_path = $_SERVER['DOCUMENT_ROOT'].$file_path['path'];
// Look for Multisite Path
if(file_exists($file_path) === false){
global $blog_id;
$file_path = parse_url($img_url);
if(preg_match('/files/', $file_path['path'])){
$path = explode('/', $file_path['path']);
foreach($path as $k => $v){
if($v == 'files'){
$path[$k-1] = 'wp-content/blogs.dir/'.$blog_id;
}
}
$path = implode('/', $path);
}
$file_path = $_SERVER['DOCUMENT_ROOT'].$path;
}
//$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);
// check if file exists
$base_file = $file_info['dirname'].'/'.$file_info['filename'].'.'.$file_info['extension'];
if(!file_exists($base_file))
return;
$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){
// 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;
}
// $crop = false or no height set
if($crop == false OR !$height){
// 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' => $proportional_size[0],
'height' => $proportional_size[1]
);
return $vt_image;
}
}
// check if image width is smaller than set width
$img_size = getimagesize($file_path);
if($img_size[0] <= $width) $width = $img_size[0];
// Check if GD Library installed
if(!function_exists('imagecreatetruecolor')){
echo 'GD Library Error: imagecreatetruecolor does not exist - please contact your webhost and ask them to install the GD library';
return;
}
// no cache 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' => $width,
'height' => $height
);
return $vt_image;
}
}
?>