使用内置的WordPress函数即时调整WordPress图像的大小。
使用该vt_resize功能可以动态调整自定义字段中的WordPress图像，特色图像，上载目录，NextGen Gallery WordPress插件甚至是指向非现场图像的外部链接的大小。
使用非常简单，只需将以下代码复制/粘贴到functions.php当前激活的WordPress主题的WordPress主题 文件中。
然后，在需要动态调整图像大小的任何地方，只需按照函数注释中说明的参数用法对该函数进行调用即可。
这是一个示例，该示例自动获取帖子ID，帖子本身，帖子的自定义字段值，并从包含要动态调整大小的图像的“自定义字段”中动态调整图像的大小。
<?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.)
?>
- 说明：使用WordPress内置函数动态调整图像大小。
- 作者： Victor Teixeira
- 要求： PHP 5.2+，WordPress 3.2+
我重新格式化了源代码，以使我自己更可读。如果您想要原始格式的源代码，请访问上面的链接。
<?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;
}
}
?>
<?php $main_image = of_get_option('of_main_image'); $thepost = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE guid = '$main_image'" ) ); $theID = $thepost->ID; echo wp_get_attachment_image( $theID, 'homepage_main' ); ?>有人在这里看到任何安全漏洞或奇怪之处吗？可能对其他人也有用。谢谢！