如果您真的想使用这些类，唯一的方法就是扩展两个现有的实现Wp_Image_Editor_Imagick 和Wp_Image_Editor_GD.

以下是Wp_Image_Editor_GD:

namespace WPSE98156;

use
    Wp_Image_Editor_Gd,
    Wp_Error;

class WatermarkImageEditor extends Wp_Image_Editor_Gd {

    /*
     * @param resource $stamp (A GD image resource)
     *
     * @return bool|WP_Error
     */
    public function stamp_watermark( $stamp ) {

        /**
         * The resource of the image to edit is stored in
         * $this->image, after $this->load() was called
         */
        $loaded = $this->load();
        if ( is_wp_error( $loaded ) )
            return $loaded;

        // Set the margins for the stamp and get the height/width of the stamp image
        $marge_right = 10;
        $marge_bottom = 10;
        $sx = imagesx( $stamp );
        $sy = imagesy( $stamp );

        // Copy the stamp image onto our photo using the margin offsets and the photo
        // width to calculate positioning of the stamp.
        imagecopy(
            $this->image,
            $stamp,
            imagesx( $this->image ) - $sx - $marge_right,
            imagesy( $this->image ) - $sy - $marge_bottom,
            0,
            0,
            imagesx( $stamp ),
            imagesy( $stamp )
        );
    }

    /**
     * @param array $args
     *
     * @return bool
     */
    public static function test( $args = [] ) {

        /**
         * Maybe implement your own test here, whether the environment
         * is able to deal with your implementation of the
         * stamp_watermark() method
         */
        return parent::test( $args );
    }

    /**
     * @param string $mime_type
     *
     * @return bool
     */
    public static function supports_mime_type( $mime_type ) {

        /**
         * Todo: Check here if the implementation of the method stamp_watermark()
         * can deal with the mime-types image/png, image/jpeg and image/gif
         */
        return parent::supports_mime_type( $mime_type );
    }
}

实施如下this example on php.net.

现在已经有了实现，必须使用过滤器将新类添加到可能的图像编辑器堆栈中wp_image_editors:

namespace WPSE98156;

add_filter( \'wp_image_editors\', function( $editors ) {

    if ( ! is_array( $editors ) )
        return $editors; //someone broke the filtered value

    array_unshift( $editors, WatermarkImageEditor::class );

    return $editors;
} );

现在，在调用wp_get_image_editor():

$editor = wp_get_image_editor( \'/path/to/image.jpeg\' );
if ( ! is_wp_error( $editor ) && is_callable( [ $editor, \'stamp_watermark\' ] ) && ! is_wp_error( $loaded ) ) {

    $stamp = imagecreatefrompng( \'/path/to/watermark.png\' );
    $success = $editor->stamp_watermark( $stamp );
    if ( ! is_wp_error( $success ) )
        $editor->save();
}

您也可以简单地显式创建实例。每个其他客户端，使用wp_get_image_editor() 不会知道该方法stamp_watermark() 无论如何

Some important notes:

代码未经测试。它的目的是提供第一种方法来扩展Wp_Image_Editor_Gd 类别test() 和supportet_mime_types() 根据这一点

我在实现David代码时遇到了很多问题。我有一些错误，比如“WP\\u IMAGE\\u EDITOR\\u GD”找不到，“WatermarkImageEditor”找不到……当我让它工作时，它不能与alpha通道png一起工作，所以我花了很多时间让它与它们一起工作。所以我会解释我是怎么得到它的。

将所有这些代码放在一个php文件中，我的称为水印。php。

<?php
class WatermarkImageEditor extends WP_Image_Editor_GD {
    public function stamp_watermark( $stampPath, $marginH=0, $marginV=0 ) {
        $loaded = $this->load();
        if ( is_wp_error( $loaded ) ) return $loaded;

        $stamp=imagecreatefrompng( $stampPath );
        if(is_wp_error($stamp)){ return $stamp; }
        imagealphablending($stamp, true);

        $sx = imagesx( $stamp );
        $sy = imagesy( $stamp );
        imagealphablending($this->image, true);
        imagecopy(
            $this->image, $stamp,$marginH,$this->size[\'height\']-$sy-$marginV,0,0,$sx, $sy
        );  
    }

    public static function test( $args = [] ) { return parent::test( $args ); }

    public static function supports_mime_type( $mime_type ) { return parent::supports_mime_type( $mime_type ); }
}

现在，我们需要注册过滤器。我在自己的插件中使用它，所以我在主插件文件中有此代码，但您也可以将其放在其他地方，如函数中。php。请注意，我正在使用require\\u once加载水印。php，所以水印。php必须位于同一文件夹中。

add_filter( \'wp_image_editors\', function( $editors ) {
    require_once __DIR__. \'/watermark.php\';
    if ( ! is_array( $editors ) )
        return $editors; //someone broke the filtered value
    array_unshift( $editors, "WatermarkImageEditor");
    return $editors;
} );

最后一步，调用stamp\\u watermark（）。在这个示例中，我从磁盘加载一个图像，调整其大小，放置水印，然后保存它。请注意，stamp\\u watermark（）在第一个参数上接收水印的路径或url，其他两个参数是可选边距。

$editor= wp_get_image_editor($imagePath);
$editor->resize(1920, 1080, TRUE);
if(is_callable([$editor,\'stamp_watermark\'])){
  $success = $editor->stamp_watermark( ABSPATH.\'wp-content/uploads/watermark-full.png\', 20, 20 );       
  if(!is_wp_error($success)){ $editor->save($imagePath); }
}