0Gerar e exibir imagens avif automaticamente com o wordpress

I have spent quite a lot of time optim­ising the per­form­ance of this site, and as part of ongo­ing work I mon­it­or new tech­no­lo­gies that could help improve the speed for vis­it­ors. I’ve been track­ing the adop­tion of next-gen­er­a­tion image formats for a while and with sup­port by web browsers now fairly wide­spread it was time to fig­ure out how to make use of these new formats in wordpress.

There are mul­tiple steps required which I have broken down into head­ings below

Ativar suporte em nginx

The first step is to enable your web serv­er (no meu caso nginx) to recog­nise the mime types of the new formats. Para fazer isso, você precisa editar mime.types, que provavelmente pode ser encontrado em /etc/nginx/mime.types. I added the fol­low­ing section

/ o conteúdo viola as regras viola as regras;
imagem / novilha;
imagem / heic-sequence heics;
imagem / novilhas de sequência de novilhas;
imagem / avif avif;
revisão de imagem / sequência avif;
imagem / jxl jxl;

Servir arquivos automaticamente onde eles estão disponíveis

The next step is to tell nginx to serve files auto­mat­ic­ally whenev­er they exist (and to fall back to older formats where a new format file does­n’t exist)
To do this first edit the main nginx con­fig file (usu­ally /etc/nginx/nginx.conf) and add the fol­low­ing sec­tion inside the http{} sec­tion of the config

map $ http_accept $ img_ext
{
   ~ image / jxl '.jxl';
   ~ image / avif '.avif';
   ~ image / webp '.webp';
   padrão      '';
}

Note that I am only try­ing to serve jxl (JPEG-XL) ou arquivos avif, você poderia adicionar mais opções (in order of pref­er­ence!) se você desejar.
Próximo, you need to add the fol­low­ing under the serv­er{} sec­tion of the nginx con­fig (which may be in the main con­fig file or may be in a sep­ar­ate con­fig file depend­ing how you’ve set up your nginx con­fig structure)

localização ~ * ^. + .(png|jpg|jpeg)$
{
   add_header Vary Aceitar;
   try_files $ uri $ img_ext $ uri = 404;
}

Now nginx will look for image.jpg.jxl and then image.jpg.avif and then image.jpg.webp and finally image.jpg when it is asked for image.jpg by any browsers that sup­port the new­er formats. Em seguida, precisamos habilitá-los no wordpress

habilitar formatos de próxima geração no wordpress

Add the fol­low­ing code to your functions.php (o ideal é fazer isso em um tema filho para que, ao atualizar seu tema, suas alterações não sejam substituídas)

/***************************************************\
* Permitir SVG suporte e outros formatos de imagem modernos *
\***************************************************/
função cc_mime_types( $mímicos )
{
   $mímicos['svg'] = 'imagem / svg + xml';
   $mímicos['webp'] = 'imagem / webp';
   $mímicos["Violar"] = "Imagem / não qualificado ';
   $mímicos['heif'] = 'imagem / heif';
   $mímicos['hex'] = "Imagem / violar a sequência de regras ';
   $mímicos['heifs'] = 'imagem / sequência heif';
   $mímicos['avif'] = 'imagem / avif';
   $mímicos['perceber'] = 'imagem / sequência-avif';
   $mímicos['jxl'] = 'imagem / jxl';
   return $ mimes;
}
add_filter( 'upload_mimes', 'cc_mime_types' );

Note that I also enabled sup­port for SVG imagens ao mesmo tempo

Now you can actu­ally upload next gen format images and use them dir­ectly in word­press if you want to, but I don’t recom­mend this as many older browsers don’t sup­port them yet — and we’ve already set up nginx to serve them intel­li­gently so we should make use of that. What we want to do is to auto­mat­ic­ally gen­er­ate the new formats when we upload images (there are plu­gins that do this for webp already, but noth­ing that does it for jxl or avif yet).

Instale libheif

This step does require access to the com­mand line of your web host, which is straight-for­ward if you run a VPS, but may not be so simple if you’re on shared host­ing in which case you might need to ask your host for support
Run the fol­low­ing bash com­mands (these are selec­ted for Centos 8, oth­er dis­tri­bu­tions may be a little different)

dnf -y install --nogpgcheck https://download1.rpmfusion.org/free/el/rpmfusion-free-release-8.noarch.rpm https://download1.rpmfusion.org/nonfree/el/rpmfusion-nonfree-release-8.noarch.rpm
dnf -y install libheif

Adicione uma função personalizada ao wordpress functions.php para compactar todas as imagens enviadas (e suas miniaturas) para o formato avif

As with the earli­er functions.php step I recom­mend adding this in a child theme

/*****************************\
* Converter png e jpg em avif *
\*****************************/
add_filter( 'wp_generate_attachment_metadata', 'jps_compress_img', 10, 2 );
função jps_compress_img( $metadados, $attach_id )
{
   // get filepath from id
   $filepath= get_attached_file($attach_id);

   // is the file a png or jpeg
   if(informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="jpg" || informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="jpeg" || informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="png")
   {
      // Se for assim, run compression of the main file to avif
      shell_exec("heif-enc $ filepath -o $ filepath.avif -q 50 -UMA");
      $partes = preg_split('~ /(?=[^ /]*$)~ ', $caminho de arquivo);

      // Then run compression of the thumbnails to avif
      $thumbpaths = $metadata['tamanhos'];
      para cada ($thumbpaths as $key => $polegar)
      {
          $thumbpath = $ thumb['Arquivo'];
          $thumbfullpath = $ partes[0] . "/" . $caminho do polegar;
          shell_exec("heif-enc $ thumbfullpath -o $ thumbfullpath.avif -q 50 -UMA");
      }
   }
   // give back what we got
   return $metadata;
}

//dont forget to delete the avifs if the attachments are deleted
function jps_delete_avif($attach_id)
{
   $all_images = get_intermediate_image_sizes($attach_id);
   para cada($all_images como $ each_img)
   {
      $each_img_det = wp_get_attachment_image_src($attach_id,$each_img);
      $each_img_path = ABSPATH.'wp-content'.substr($each_img_det[0],Strpos($each_img_det[0],"/uploads /")).'.avif';
      shell_exec("rm -f $ each_img_path");
   }
}
add_action( 'delete_attachment', 'jps_delete_avif' );

At present that is it — all images you upload will be con­ver­ted to avif cop­ies (with the ori­gin­als retained). You can regen­er­ate all of your images to cre­ate the avif files by using a plu­gin. Note — I haven’t yet set up JPEG-XL com­pres­sion as sup­port for it isn’t avail­able in main­stream browsers yet (although it is in prerelease browsers so it is com­ing very soon).

Whilst I’m cov­er­ing next gen formats and optim­isa­tion though I have one final tip — To com­press SVG imagens com gzip (or even bet­ter zop­fli and brotli). To do that requires anoth­er cus­tom function…

Bônus: SVG compressão

/*************************************************\
* Comprimir SVG mais imagens com brotli e zopfli *
\*************************************************/
add_filter( 'wp_generate_attachment_metadata', 'jps_compress_vectors', 10, 2 );
função jps_compress_vectors( $metadados, $attach_id )
{
    // get filepath from id
    $filepath= get_attached_file($attach_id);

    // is the file an svg
    if(informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="svg")
    {
       // Se for assim, run compression of it using zopfli and brotli
       shell_exec("zopfli --gzip $ filepath");
       shell_exec("brotli --best --output = $ filepath.br $ filepath");
    }

    // give back what we got
    return $metadata;
}

Observe que você precisará de gzip_static e brotli_static habilitados em sua configuração nginx.

Auto-compilar para uma versão mais recente

I found that on Cen­tos the latest ver­sion of heif-enc is 1.7 which has quite a few bugs when cre­at­ing avifs. So I opted to com­pile my own new­er (1.12) construir e usar isso. Doing so was a little com­plic­ated as it required the aom codec as a shared lib­rary. To do so run the fol­low­ing bash com­mands. Make sure to run them as a nor­mal user, não como o usuário root. Also note some of these com­mands may not be strictly needed, it took me a while to get it work­ing and I just made a note of what worked — I am by no means a linux expert!

dnf install x265 x265-devel svt-av1
export CXXFLAGS="$CXXFLAGS -fPIC"
cd ~

git clone https://aomedia.googlesource.com/aom
mkdir -p aom_build
cd aom_build
cmake ~/aom -DBUILD_SHARED_LIBS=true
make
sudo make install
cp ./libaom.so.3 /usr/bin/local/libaom.so.3

cd ~
export PKG_CONFIG_PATH=~/aom_build/
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:~/aom_build/
export LD_LIBRARY_PATH

git clone --recurse-submodules --recursive https://github.com/strukturag/libheif.git
cd libheif
./autogen.sh
./configure
make
sudo make install

LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/bin/
export LD_LIBRARY_PATH

Depois de fazer isso, make sure it works by run­ning php -a and run­ning the fol­low­ing command

shell_exec("/usr / local / bin / heif-enc -A");

You should get a full out­put, não apenas um 1 erro de linha. Assum­ing that works ok you can modi­fy your functions.php so that each of the shell-exec ref­er­ences points to /us­r/­loc­al/bin/heif-enc instead of just heif-enc

/*****************************\
* Converter png e jpg em avif *
\*****************************/
add_filter( 'wp_generate_attachment_metadata', 'jps_compress_img', 10, 2 );
função jps_compress_img( $metadados, $attach_id )
{
   // get filepath from id
   $filepath= get_attached_file($attach_id);

   // is the file a png or jpeg
   if(informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="jpg" || informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="jpeg" || informações do caminho($caminho de arquivo, PATHINFO_EXTENSION)=="png")
   {
      // Se for assim, run compression of the main file to avif
      shell_exec("/usr / local / bin / heif-enc $ filepath -o $ filepath.avif -q 50 -UMA");
      $partes = preg_split('~ /(?=[^ /]*$)~ ', $caminho de arquivo);

      // Then run compression of the thumbnails to avif
      $thumbpaths = $metadata['tamanhos'];
      para cada ($thumbpaths as $key => $polegar)
      {
          $thumbpath = $ thumb['Arquivo'];
          $thumbfullpath = $ partes[0] . "/" . $caminho do polegar;
          shell_exec("/usr / local / bin / heif-enc $ thumbfullpath -o $ thumbfullpath.avif -q 50 -UMA");
      }
   }
   // give back what we got
   return $metadata;
}

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