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webp格式的图片有点我就不说了，不明白的可以看看下面的描述： [list title="" type="" unique_number="list_1c0476bde9d04899a71b03e4e2eeeb8e"] WebP，是一种同时提供了有损压缩与无损压缩的图片文件格式，派生自视频编码格式 VP8。WebP 最初在2010年发布，目标是减少文件大小，但达到 和 JEPG 格式相同的图片质量，希望能够减少图片档在网络上的发送时间。2011年11月8日，Google 开始让 WebP 支持无损压缩和透明色的功能。 [/list]
现在很多站点已经开始使用这个格式的图片作为主力，但是我个人还是比较推荐保留两种格式，毕竟不是所有人都喜欢webp格式的文件，同时存在源文件格式和webp格式文件才是最优解，毕竟现在的硬盘空间已经不值钱了。
看了上面的所有说明，你没有顾虑，可以看看下面的代码：
WP GD Image Engine If the file is deleted form the Media Library the created WebP conversions will also be deleted.
* Version: 1.0.0
* Requires at least: 5.5
* Requires PHP: 7.2
* Author: lowtechsun
* Author URI: https://stackoverflow.com/users/1010918/lowtechsun
* License: GPL v2 or later
* License URI: https://www.gnu.org/licenses/gpl-2.0.html
*/
//=================================================
// Security: Abort if this file is called directly
//=================================================
if ( ! defined( 'ABSPATH' ) ) {
die;
}
function debug( $info ) {
$message = null;
if ( is_string( $info ) || is_int( $info ) || is_float( $info ) ) {
$message = $info;
} else {
$message = var_export( $info, true );
}
if ( $fh = fopen( ABSPATH . '/gdwebpconvert.log', 'a' ) ) {
fputs( $fh, date( 'Y-m-d H:i:s' ) . " $message\n" );
fclose( $fh );
}
}
add_filter( 'wp_generate_attachment_metadata', 'gd_webp_converter', 10, 2 );
function gd_webp_converter( $metadata, $attachment_id ) {
$gd_webp_converter = new GDWebPConverter( $attachment_id );
$gd_webp_converter->check_file_exists( $attachment_id );
$gd_webp_converter->check_mime_type();
$gd_webp_converter->create_array_of_sizes_to_be_converted( $metadata );
$gd_webp_converter->convert_array_of_sizes();
return $metadata;
}
class GDWebPConverter {
private $file_path;
private $file_dirname;
private $file_ext;
private $file_name_no_ext;
private $array_of_sizes_to_be_converted = array();
private $array_of_sizes_to_be_deleted = array();
public function __construct( $attachment_id ) {
$this->file_path = get_attached_file( $attachment_id );
debug( $this->file_path );
// https://stackoverflow.com/questions/2183486/php-get-file-name-without-file-extension/19040276
$this->file_dirname = pathinfo( $this->file_path, PATHINFO_DIRNAME );
debug( $this->file_dirname );
$this->file_ext = strtolower( pathinfo( $this->file_path, PATHINFO_EXTENSION ) );
debug( $this->file_ext );
$this->file_name_no_ext = pathinfo( $this->file_path, PATHINFO_FILENAME );
debug( $this->file_name_no_ext );
}
public function check_file_exists( $attachment_id ) {
$file = get_attached_file( $attachment_id );
if ( ! file_exists( $file ) ) {
$message = 'The uploaded file does not exist on the server. Encoding not possible.';
debug( $message );
throw new Exception( 'The uploaded file does exist on the server. Encoding not possible.', 1 );
}
}
public function check_mime_type() {
// https://www.php.net/manual/en/function.finfo-file.php
$finfo = finfo_open( FILEINFO_MIME_TYPE );
$this->file_mime_type = finfo_file( $finfo, $this->file_path );
finfo_close( $finfo );
// debug( $this->file_mime_type );
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
$this->allowed_mime_type = array( 'image/jpeg', 'image/png' );
if ( ! in_array( $this->file_mime_type, $this->allowed_mime_type, true ) ) {
$message = 'MIME type of file not supported';
// debug( $message );
throw new Exception( 'MIME type of file not supported', 1 );
}
}
public function create_array_of_sizes_to_be_converted( $metadata ) {
// push original file to the array
array_push( $this->array_of_sizes_to_be_converted, $this->file_path );
// debug( $this->array_of_sizes_to_be_converted );
// push all created sizes of the file to the array
foreach ( $metadata['sizes'] as $value ) {
// debug( $value['file'] );
array_push( $this->array_of_sizes_to_be_converted, $this->file_dirname . '/' . $value['file'] );
}
// // debug( $this->array_of_sizes_to_be_converted );
}
public function convert_array_of_sizes() {
debug( $this->array_of_sizes_to_be_converted );
switch ( $this->file_ext ) {
case 'jpeg':
case 'jpg':
foreach ( $this->array_of_sizes_to_be_converted as $key => $value ) {
$image = imagecreatefromjpeg( $value );
if ( 0 === $key ) {
imagewebp( $image, $this->file_dirname . '/' . $this->file_name_no_ext . '.webp', 80 );
} else {
$current_size = getimagesize( $value );
// debug( $current_size );
imagewebp( $image, $this->file_dirname . '/' . $this->file_name_no_ext . '-' . $current_size[0] . 'x' . $current_size[1] . '.webp', 80 );
}
imagedestroy( $image );
}
break;
case 'png':
foreach ( $this->array_of_sizes_to_be_converted as $key => $value ) {
$image = imagecreatefrompng( $value );
imagepalettetotruecolor( $image );
imagealphablending( $image, true );
imagesavealpha( $image, true );
if ( 0 === $key ) {
imagewebp( $image, $this->file_dirname . '/' . $this->file_name_no_ext . '.webp', 80 );
} else {
$current_size = getimagesize( $value );
// debug( $current_size );
imagewebp( $image, $this->file_dirname . '/' . $this->file_name_no_ext . '-' . $current_size[0] . 'x' . $current_size[1] . '.webp', 80 );
}
imagedestroy( $image );
}
break;
// animated GIF to WebP not supported by GD - imagecreatefromgif
// case 'gif':
// foreach ( $this->array_of_sizes_to_be_converted as $key => $value ) {
// $image = imagecreatefromgif( $value );
// if ( 0 === $key ) {
// imagewebp( $image, $this->file_dirname . '/' . $this->file_name_no_ext . '.webp', 80 );
// } else {
// $current_size = getimagesize( $value );
// // debug( $current_size );
// imagewebp( $image, $this->file_dirname . '/' . $this->file_name_no_ext . '-' . $current_size[0] . 'x' . $current_size[1] . '.webp', 80 );
// }
// imagedestroy( $image );
// }
// break;
default:
return false;
}
}
public function create_array_of_sizes_to_be_deleted( $attachment_id ) {
// debug( $attachment_id );
$this->attachment_metadata_of_file_to_be_deleted = wp_get_attachment_metadata( $attachment_id );
// debug( $this->attachment_metadata_of_file_to_be_deleted );
// push original file to the array
array_push( $this->array_of_sizes_to_be_deleted, $this->file_dirname . '/' . $this->file_name_no_ext . '.webp' );
// debug( $this->array_of_sizes_to_be_converted );
// push all created sizes of the file to the array
foreach ( $this->attachment_metadata_of_file_to_be_deleted['sizes'] as $value ) {
// debug( $value );
$this->value_file_name_no_ext = pathinfo( $value['file'], PATHINFO_FILENAME );
// debug( $this->value_file_name_no_ext );
array_push( $this->array_of_sizes_to_be_deleted, $this->file_dirname . '/' . $this->value_file_name_no_ext . '.webp' );
}
// debug( $this->array_of_sizes_to_be_deleted );
}
public function delete_array_of_sizes() {
debug( $this->array_of_sizes_to_be_deleted );
foreach ( $this->array_of_sizes_to_be_deleted as $key => $value ) {
// debug( $value );
unlink( $value );
}
}
}
add_action( 'delete_attachment', 'delete_webp_conversions', 10 );
function delete_webp_conversions( $attachment_id ) {
$delete_webp_conversions = new GDWebPConverter( $attachment_id );
$delete_webp_conversions->create_array_of_sizes_to_be_deleted( $attachment_id );
$delete_webp_conversions->delete_array_of_sizes();
}
代码方面来自： https://stackoverflow.com/questions/67183333/wordpress-convert-image-to-webp-format-programmatically-with-gd-image-engine
经过测试之后，上传图片确实是可以在后台生成对应的webp图片，效果截图如下：
同样的，你可以尝试一下，上方的图片修改后缀为webp同样可以看到图片。
上面的代码直接保存为一个php文件之后，在function文件中通过include导入即可完成该功能。 [hong unique_number="hong_c7763c9c91264932b1f2339b58d88053"] 经过尝试，这里需要注意的就是PHP方面需要开启fileinfo扩展，否则会报错，报错内容大概为：Call to undefined function finfo_open() [/hong]
