アップロード時に元の画質を下げる方法
私はjpeg_qualityフィルターをこのように使えることを知っています：
add_filter('jpeg_quality', function($arg){return 75;});
thumbnail 、 medium 、および large などのアップロードプロセス中に生成される画像の画質は低下しますが、original）画像はまだ元の状態です。
originalimageがアップロードされたときの画質を落とすフィルタや関数を追加することはできますか？）
一般的に、中間サイズを再生成する必要があるかもしれない場合に備えて、私はオリジナルのアップロードされた画像ファイルを修正することをお勧めしません。
しかし、それが可能かどうか見てみましょう:-)
一般的にWordPressに画像エディタを選択させることができます。それはGdやImagickのようなモジュールに依存します。
$editor = wp_get_image_editor( $file );
しかし、これはWP_Errorオブジェクトを返す可能性があるので、使用する前にis_wp_error( $editor )で確認してください。
set_quality()やsave()のようなメソッドを通して画像エディタに物事を処理させるのは便利です。 @MerchantWebで言及されているアップロード後に画像のサイズを変更 _プラグインにそのような使用例があります。これはコアによってもさまざまな方法で使用されます。
私が理解している限り、プラグインはwp_handle_uploadフィルタにフックして、アップロードされたオリジナルのjpeg画像ファイルを修正します。
A） そのため、アップロード中にオリジナルのJPEG画像ファイルの品質を（たとえば90に）変更するために、次のようなものを使用できます。
/**
* A) Modify the quality of original jpeg images to 90, during uploads
*/
add_filter( 'wp_handle_upload', function( $data )
{
if( ! isset( $data['file'] ) || ! isset( $data['type'] ) )
return $data;
// Target jpeg images
if( in_array( $data['type'], [ 'image/jpg', 'image/jpeg' ] ) )
{
// Check for a valid image editor
$editor = wp_get_image_editor( $data['file'] );
if( ! is_wp_error( $editor ) )
{
// Set the new image quality
$result = $editor->set_quality( 90 );
// Re-save the original image file
if( ! is_wp_error( $result ) )
$editor->save( $data['file'] );
}
}
return $data;
} );
しかし、これはすべての中間サイズにも影響を与えることになります。これは、 が の前に実行されるためです。
B） media_handle_upload() 関数を見ると、代わりに wp_generate_attachment_metadata filterにフックしてオリジナルのjpeg画像ファイルを修正することを検討するかもしれません。 after 中間サイズが生成されました。
これが例です（PHP 5.4+）：
/**
* B) Modify the quality of original jpeg images to 90, during uploads
*/
add_filter( 'wp_generate_attachment_metadata', function( $metadata, $attachment_id )
{
$file = get_attached_file( $attachment_id );
$type = get_post_mime_type( $attachment_id );
// Target jpeg images
if( in_array( $type, [ 'image/jpg', 'image/jpeg' ] ) )
{
// Check for a valid image editor
$editor = wp_get_image_editor( $file );
if( ! is_wp_error( $editor ) )
{
// Set the new image quality
$result = $editor->set_quality( 90 );
// Re-save the original image file
if( ! is_wp_error( $result ) )
$editor->save( $file );
}
}
return $metadata;
}, 10, 2 );
これをさらに制限する必要がある場合は、これをwp_handle_uploadフックにラップして、wp_handle_uploadまたはsideloadのように、関連するactionコンテキストを確認します。
テスト中は品質を非常に低く設定する必要があるかもしれません。
注 ：これらはデモにすぎず、さらにテストが必要です。
更新： キッチンの壁掛け時計をイメージした簡単なテストをしました。ここでは、フルサイズの画像を品質5で再保存すると、中間サイズがすべて表示されます。
- A）も低品質です。
- B）は影響を受けません。
これが組み合わせた結果です。
この答えはあなたを助けることができます： https://wordpress.stackexchange.com/a/69287/92649
ただし、その効果を得るには、「大きい」よりも高い解像度で画像をアップロードする必要があります。
アップロード後に画像のサイズを変更するというプラグインがあります。
<?php
/*
Plugin Name: Resize Image After Upload
Plugin URI: https://wordpress.org/plugins/resize-image-after-upload/
Description: Simple plugin to automatically resize uploaded images to within specified maximum width and height. Also has option to force recompression of JPEGs. Configuration options found under <a href="options-general.php?page=resize-after-upload">Settings > Resize Image Upload</a>
Author: iamphilrae
Version: 1.7.2
Author URI: http://www.philr.ae/
Copyright (C) 2015 iamphilrae
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
$PLUGIN_VERSION = '1.7.2';
$DEBUG_LOGGER = false;
// Default plugin values
if(get_option('jr_resizeupload_version') != $PLUGIN_VERSION) {
add_option('jr_resizeupload_version', $PLUGIN_VERSION, '','yes');
add_option('jr_resizeupload_width', '1200', '', 'yes');
add_option('jr_resizeupload_height', '1200', '', 'yes');
add_option('jr_resizeupload_quality', '90', '', 'yes');
add_option('jr_resizeupload_resize_yesno', 'yes', '','yes');
add_option('jr_resizeupload_recompress_yesno', 'no', '','yes');
add_option('jr_resizeupload_convertbmp_yesno', 'no', '', 'yes');
add_option('jr_resizeupload_convertpng_yesno', 'no', '', 'yes');
add_option('jr_resizeupload_convertgif_yesno', 'no', '', 'yes');
}
// Hook in the options page
add_action('admin_menu', 'jr_uploadresize_options_page');
// Hook the function to the upload handler
add_action('wp_handle_upload', 'jr_uploadresize_resize');
/**
* Add the options page
*/
function jr_uploadresize_options_page(){
if(function_exists('add_options_page')){
add_options_page(
'Resize Image After Upload',
'Resize Image Upload',
'manage_options',
'resize-after-upload',
'jr_uploadresize_options'
);
}
} // function jr_uploadresize_options_page(){
/**
* Define the Options page for the plugin
*/
function jr_uploadresize_options(){
if(isset($_POST['jr_options_update'])) {
$resizing_enabled = trim(esc_sql($_POST['yesno']));
$force_jpeg_recompression = trim(esc_sql($_POST['recompress_yesno']));
$max_width = trim(esc_sql($_POST['maxwidth']));
$max_height = trim(esc_sql($_POST['maxheight']));
$compression_level = trim(esc_sql($_POST['quality']));
$convert_png_to_jpg = trim(esc_sql(isset($_POST['convertpng']) ? $_POST['convertpng'] : 'no'));
$convert_gif_to_jpg = trim(esc_sql(isset($_POST['convertgif']) ? $_POST['convertgif'] : 'no'));
$convert_bmp_to_jpg = trim(esc_sql(isset($_POST['convertbmp']) ? $_POST['convertbmp'] : 'no'));
// If input is not an integer, use previous setting
$max_width = ($max_width == '') ? 0 : $max_width;
$max_width = (ctype_digit(strval($max_width)) == false) ? get_option('jr_resizeupload_width') : $max_width;
update_option('jr_resizeupload_width',$max_width);
$max_height = ($max_height == '') ? 0 : $max_height;
$max_height = (ctype_digit(strval($max_height)) == false) ? get_option('jr_resizeupload_height') : $max_height;
update_option('jr_resizeupload_height',$max_height);
$compression_level = ($compression_level == '') ? 1 : $compression_level;
$compression_level = (ctype_digit(strval($compression_level)) == false) ? get_option('jr_resizeupload_quality') : $compression_level;
if($compression_level < 1) {
$compression_level = 1;
}
else if($compression_level > 100) {
$compression_level = 100;
}
update_option('jr_resizeupload_quality',$compression_level);
if ($resizing_enabled == 'yes') {
update_option('jr_resizeupload_resize_yesno','yes'); }
else {
update_option('jr_resizeupload_resize_yesno','no'); }
if ($force_jpeg_recompression == 'yes') {
update_option('jr_resizeupload_recompress_yesno','yes'); }
else {
update_option('jr_resizeupload_recompress_yesno','no'); }
if ($convert_png_to_jpg == 'yes') {
update_option('jr_resizeupload_convertpng_yesno','yes'); }
else {
update_option('jr_resizeupload_convertpng_yesno','no'); }
if ($convert_gif_to_jpg == 'yes') {
update_option('jr_resizeupload_convertgif_yesno','yes'); }
else {
update_option('jr_resizeupload_convertgif_yesno','no'); }
if ($convert_bmp_to_jpg == 'yes') {
update_option('jr_resizeupload_convertbmp_yesno','yes'); }
else {
update_option('jr_resizeupload_convertbmp_yesno','no'); }
echo('<div id="message" class="updated fade"><p><strong>Options have been updated.</strong></p></div>');
} // if
// get options and show settings form
$resizing_enabled = get_option('jr_resizeupload_resize_yesno');
$force_jpeg_recompression = get_option('jr_resizeupload_recompress_yesno');
$compression_level = intval(get_option('jr_resizeupload_quality'));
$max_width = get_option('jr_resizeupload_width');
$max_height = get_option('jr_resizeupload_height');
$convert_png_to_jpg = get_option('jr_resizeupload_convertpng_yesno');
$convert_gif_to_jpg = get_option('jr_resizeupload_convertgif_yesno');
$convert_bmp_to_jpg = get_option('jr_resizeupload_convertbmp_yesno');
?>
<style type="text/css">
.resizeimage-button {
color: #FFF;
background: none repeat scroll 0% 0% #FC9A24;
border-radius: 3px;
display: inline-block;
border-bottom: 4px solid #EC8A14;
margin-right:5px;
line-height:1.05em;
text-align: center;
text-decoration: none;
padding: 9px 20px 8px;
font-size: 15px;
font-weight: bold;
text-shadow: 0 -1px 1px rgba(0,0,0,0.2);
}
.resizeimage-button:active,
.resizeimage-button:hover,
.resizeimage-button:focus {
background-color: #EC8A14;
color: #FFF;
}
.media-upload-form div.error, .wrap div.error, .wrap div.updated {
margin: 25px 0px 25px;
}
</style>
<div class="wrap">
<form method="post" accept-charset="utf-8">
<h2><img src="<?php echo plugins_url('icon-128x128.png', __FILE__ ); ?>" style="float:right; border:1px solid #ddd;margin:0 0 15px 15px;width:100px; height:100px;" />Resize Image After Upload</h2>
<div style="max-width:700px">
<p>This plugin automatically resizes uploaded images (JPEG, GIF, and PNG) to within a given maximum width and/or height to reduce server space usage. This may be necessary due to the fact that images from digital cameras and smartphones can now be over 10MB each due to higher megapixel counts.</p>
<p>In addition, the plugin can force re-compression of uploaded JPEG images, regardless of whether they are resized or not; and convert uploaded GIF and PNG images into JPEG format.</p>
<p><strong>Note:</strong> the resizing/recompression process will discard the original uploaded file including EXIF data.</p>
<p>This plugin is not intended to replace the WordPress <em>add_image_size()</em> function, but rather complement it. Use this plugin to ensure that no excessively large images are stored on your server, then use <em>add_image_size()</em> to create versions of the images suitable for positioning in your website theme.</p>
<p>This plugin uses standard PHP image resizing functions and will require a high amount of memory (RAM) to be allocated to PHP in your php.ini file (e.g 512MB).</p>
<h4 style="font-size: 15px;font-weight: bold;margin: 2em 0 0;">Like the plugin?</h4>
<p>This plugin was written and is maintained for free (as in free beer) by me, <a href="http://philr.ae" target="_blank">Phil Rae</a>. If you find it useful please consider donating some small change or bitcoins to my beer fund because beer is very seldom free. Thanks!</p>
<p style="padding-bottom:2em;" class="resizeimage-button-wrapper">
<a class="resizeimage-button" href="https://www.Paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=3W4M254AA3KZG" target="_blank">Donate cash</a>
<a class="resizeimage-button coinbase-button" data-code="9584265cb76df0b1e99979163de143f5" data-button-style="custom_small" target="_blank" href="https://coinbase.com/checkouts/9584265cb76df0b1e99979163de143f5">Donate bitcoins</a>
</p>
</div>
<hr style="margin-top:20px; margin-bottom:0;">
<hr style="margin-top:1px; margin-bottom:40px;">
<h3>Re-sizing options</h3>
<table class="form-table">
<tr>
<th scope="row">Enable re-sizing</th>
<td valign="top">
<select name="yesno" id="yesno">
<option value="no" label="no" <?php echo ($resizing_enabled == 'no') ? 'selected="selected"' : ''; ?>>NO - do not resize images</option>
<option value="yes" label="yes" <?php echo ($resizing_enabled == 'yes') ? 'selected="selected"' : ''; ?>>YES - resize large images</option>
</select>
</td>
</tr>
<tr>
<th scope="row">Max image dimensions</th>
<td>
<fieldset><legend class="screen-reader-text"><span>Maximum width and height</span></legend>
<label for="maxwidth">Max width</label>
<input name="maxwidth" step="1" min="0" id="maxwidth" class="small-text" type="number" value="<?php echo $max_width; ?>">
<label for="maxheight">Max height</label>
<input name="maxheight" step="1" min="0" id="maxheight" class="small-text" type="number" value="<?php echo $max_height; ?>">
<p class="description">Set to zero or very high value to prevent resizing in that dimension.
<br />Recommended values: <code>1200</code></p>
</fieldset>
</td>
</tr>
</table>
<hr style="margin-top:20px; margin-bottom:30px;">
<h3>Compression options</h3>
<p style="max-width:700px">The following settings will only apply to uploaded JPEG images and images converted to JPEG format.</p>
<table class="form-table">
<tr>
<th scope="row">JPEG compression level</th>
<td valign="top">
<select id="quality" name="quality">
<?php for($i=1; $i<=100; $i++) : ?>
<option value="<?php echo $i; ?>" <?php if($compression_level == $i) : ?>selected<?php endif; ?>><?php echo $i; ?></option>
<?php endfor; ?>
</select>
<p class="description"><code>1</code> = low quality (smallest files)
<br><code>100</code> = best quality (largest files)
<br>Recommended value: <code>90</code></p>
</td>
</tr>
<tr>
<th scope="row">Force JPEG re-compression</th>
<td>
<select name="recompress_yesno" id="yesno">
<option value="no" label="no" <?php echo ($force_jpeg_recompression == 'no') ? 'selected="selected"' : ''; ?>>NO - only re-compress resized jpeg images</option>
<option value="yes" label="yes" <?php echo ($force_jpeg_recompression == 'yes') ? 'selected="selected"' : ''; ?>>YES - re-compress all uploaded jpeg images</option>
</select>
</td>
</tr>
</table>
<?php /* DEFINED HERE FOR FUTURE RELEASE - does not do anything if uncommented
<hr style="margin-top:20px; margin-bottom:20px;">
<h3>Image conversion options</h3>
<p style="max-width:700px">Photos saved as PNG and GIF images can be extremely large in file size due to their compression methods not being suited for photos. Enable these options below to automatically convert GIF and/or PNG images to JPEG.</p>
<p>When enabled, conversion will happen to all uploaded GIF/PNG images, not just ones that require resizing.</p>
<table class="form-table">
<tr>
<th scope="row">Convert GIF to JPEG</th>
<td>
<select id="convert-gif" name="convertgif">
<option value="no" <?php if($convert_gif_to_jpg == 'no') : ?>selected<?php endif; ?>>NO - just resize uploaded gif images as normal</option>
<option value="yes" <?php if($convert_gif_to_jpg == 'yes') : ?>selected<?php endif; ?>>YES - convert all uploaded gif images to jpeg</option>
</select>
</td>
</tr>
<tr>
<th scope="row">Convert PNG to JPEG</th>
<td>
<select id="convert-png" name="convertpng">
<option value="no" <?php if($convert_png_to_jpg == 'no') : ?>selected<?php endif; ?>>NO - just resize uploaded png images as normal</option>
<option value="yes" <?php if($convert_png_to_jpg == 'yes') : ?>selected<?php endif; ?>>YES - convert all uploaded png images to jpeg</option>
</select>
</td>
</tr>
</table>
*/ ?>
<hr style="margin-top:30px;">
<p class="submit" style="margin-top:10px;border-top:1px solid #eee;padding-top:20px;">
<input type="hidden" id="convert-bmp" name="convertbmp" value="no" />
<input type="hidden" name="action" value="update" />
<input id="submit" name="jr_options_update" class="button button-primary" type="submit" value="Update Options">
</p>
</form>
</div>
<?php
} // function jr_uploadresize_options(){
/**
* This function will apply changes to the uploaded file
* @param $image_data - contains file, url, type
*/
function jr_uploadresize_resize($image_data){
jr_error_log("**-start--resize-image-upload");
$resizing_enabled = get_option('jr_resizeupload_resize_yesno');
$resizing_enabled = ($resizing_enabled=='yes') ? true : false;
$force_jpeg_recompression = get_option('jr_resizeupload_recompress_yesno');
$force_jpeg_recompression = ($force_jpeg_recompression=='yes') ? true : false;
$compression_level = get_option('jr_resizeupload_quality');
$max_width = get_option('jr_resizeupload_width')==0 ? false : get_option('jr_resizeupload_width');
$max_height = get_option('jr_resizeupload_height')==0 ? false : get_option('jr_resizeupload_height');
$convert_png_to_jpg = get_option('jr_resizeupload_convertpng_yesno');
$convert_png_to_jpg = ($convert_png_to_jpg=='yes') ? true : false;
$convert_gif_to_jpg = get_option('jr_resizeupload_convertgif_yesno');
$convert_gif_to_jpg = ($convert_gif_to_jpg=='yes') ? true : false;
$convert_bmp_to_jpg = get_option('jr_resizeupload_convertbmp_yesno');
$convert_bmp_to_jpg = ($convert_bmp_to_jpg=='yes') ? true : false;
//---------- In with the old v1.6.2, new v1.7 (WP_Image_Editor) ------------
if($resizing_enabled || $force_jpeg_recompression) {
$fatal_error_reported = false;
$valid_types = array('image/gif','image/png','image/jpeg','image/jpg');
if(empty($image_data['file']) || empty($image_data['type'])) {
jr_error_log("--non-data-in-file-( ".print_r($image_data, true)." )");
$fatal_error_reported = true;
}
else if(!in_array($image_data['type'], $valid_types)) {
jr_error_log("--non-image-type-uploaded-( ".$image_data['type']." )");
$fatal_error_reported = true;
}
jr_error_log("--filename-( ".$image_data['file']." )");
$image_editor = wp_get_image_editor($image_data['file']);
$image_type = $image_data['type'];
if($fatal_error_reported || is_wp_error($image_editor)) {
jr_error_log("--wp-error-reported");
}
else {
$to_save = false;
$resized = false;
// Perform resizing if required
if($resizing_enabled) {
jr_error_log("--resizing-enabled");
$sizes = $image_editor->get_size();
if((isset($sizes['width']) && $sizes['width'] > $max_width)
|| (isset($sizes['height']) && $sizes['height'] > $max_height)) {
$image_editor->resize($max_width, $max_height, false);
$resized = true;
$to_save = true;
$sizes = $image_editor->get_size();
jr_error_log("--new-size--".$sizes['width']."x".$sizes['height']);
}
else {
jr_error_log("--no-resizing-needed");
}
}
else {
jr_error_log("--no-resizing-requested");
}
// Regardless of resizing, image must be saved if recompressing
if($force_jpeg_recompression && ($image_type=='image/jpg' || $image_type=='image/jpeg')) {
$to_save = true;
jr_error_log("--compression-level--q-".$compression_level);
}
elseif(!$resized) {
jr_error_log("--no-forced-recompression");
}
// Only save image if it has been resized or need recompressing
if($to_save) {
$image_editor->set_quality($compression_level);
$saved_image = $image_editor->save($image_data['file']);
jr_error_log("--image-saved");
}
else {
jr_error_log("--no-changes-to-save");
}
}
} // if($resizing_enabled || $force_jpeg_recompression)
else {
jr_error_log("--no-action-required");
}
jr_error_log("**-end--resize-image-upload\n");
return $image_data;
} // function jr_uploadresize_resize($image_data){
/**
* Simple debug logging function. Will only output to the log file
* if 'debugging' is turned on.
*/
function jr_error_log($message) {
global $DEBUG_LOGGER;
if($DEBUG_LOGGER) {
error_log(print_r($message, true));
}
}