Como parte das melhorias recentes que tenho feito em vários sites, eu queria fazer imagens em galerias mostrarem versões ampliadas quando pairava sobre. Fazendo isso com o básico CSS é bastante trivial, mas eu não queria apenas expandir a imagem original, Eu queria que o navegador pegasse um novo (maior) imagem também ...
All of the images are already providing a full src-set so all I needed to do was to use a little jQuery (which is already loaded by wordpress anyway) to change the target display size to make the browser pull a larger image. O bom é que o CSS works instantly so you get a larger image using the original file, and then the quality improves a split second later as the higher res file gets loaded.
O CSS
O CSS I used is as follows. Eu simplesmente adicionei isso ao style.css do meu tema (or rather child-theme — always a good idea to use one)
dt.gallery-icon a img.size-thumbnail:flutuar { transformar: escala(3.0); }
Nota (1) — the above CSS applies to gallery images only. It is unlikely anyone would want this functionality for all images displayed anywhere on the page, but you might want it for the main content section. You would need to check how your theme structures this, but in my case the main content area is a “section” so the following code would do the job
section.entry-content p a img.size-thumbnail:flutuar { transformar: escala(3.0); }
Nota (2) — This code applies only to thumbnail images. For medium images you would replace “size-thumbnail” with “size-medium”, and for large with “size-large”.
Nota (3) — Because my thumbnails are 120x80px I want to increase them to 3x their original size. I already have a custom image size of 360×240 that wordpress creates for me that is included in the src-set. For hi-dpi screens there are also even larger image sizes that I have (e.g. 720×480). Creating additional image sizes in wordpress is easy — there are lots of good guides online if you need to do this.
Se você quiser dimensionar para 1,5x ou 2,0x, altere simplesmente o 3.0 como desejado
O jQuery
Add the following to your (filho) arquivo de script do tema (assuming it has one). If it doesn’t have one, create your own, and ‘enqueue’ it with a custom function in the (filho) theme’s functions.php
jQuery(documento).pronto(função(){ jQuery("dt.gallery-icon a img.size-thumbnail").flutuar(função(){ jQuery(este).atr("tamanhos","(largura máxima: 360px) 100vw, 360px"); }, função(){ jQuery(este).atr("tamanhos","(largura máxima: 120px) 100vw, 120px"); }); //repita o acima 5 linhas aqui para cada tamanho de imagem diferente que você deseja modificar });
The above code is applying to images with class thumbnail that are found inside any dt with a gallery-icon class — so in otherwords — only to images inside the wordpress built-in gallery structure. On hover the max-width is increased from 120 para 360 (um aumento de 3x para corresponder ao meu CSS!), and then the second part of the function restores the original 120 width when the hover stops.
Tal como acontece com o CSS acima, you can adjust the numbers to change how much the image enlarges, e você pode mudar o dt.gallery-icon a img.size-thumbnail
section to target a different element or class depending on which images you want to target.
Coloque seu próprio script na fila
If your theme didn’t have a script file and you need to enqueue your own add the following to your (filho) theme’s functions.php (assuming you called your script file image-zoom.js and saved it in the root folder of the theme)
wp_register_script( 'img-zoom', get_stylesheet_directory_uri() . '/image-zoom.js', ordem( 'jquery' ), '', true);
wp_enqueue_script( 'img-zoom' );
O acima irá registrar o seu script, in the footer, making sure it is placed after jquery (so jquery should already be available when it executes)
Adicionando tamanhos de imagem
For completeness here’s how to add custom image sizes to wordpress. Novamente, adicione isso ao seu (filho) theme’s functions.php
add_image_size( 'um quarto de largura', 192, 144, falso );
Above I’ve added a new image-size called “quarter-width” with a maximum width of 192px and a maximum height of 144px. A imagem não será cortada (daí o falso no final).
WordPress will now create images of this size automatically when you upload images (you will need to use a thumbnail rebuild plugin to recreate the thumbnails for already-uploaded images).
This new image size will NOT show up for insertion in the editor though. To make it available also add the following code to your functions.php
function my_custom_image_sizes( $tamanhos ) {
return array_merge( $tamanhos, ordem(
'quarter-width' => __('Quarter Width'),
) );
}
Respeitando as configurações existentes
Mais uma coisa que você pode querer fazer (to ensure responsive images work well) is to create larger (isto é. oi-dpi) thumbnail sizes that respect the GUI of whether to crop thumbnails or not. To do that use the code below which as you will see is slightly modified from the more basic one above
add_image_size( 'resp-thumb-2x', (get_Option( 'thumbnail_size_w' ) == 0 ? 0 : '240'), 160, get_Option( 'thumbnail_crop' ) );
O código acima verifica 2 things — firstly it checks to see if the crop option is set, e se for, it mirrors it for our new responsive size. Ele também verifica se a largura está definida para 0 (isto é. no maximum) in which case our new image will also have no maximum either. I called the new image size “resp-thumb-2x” as it is a ‘responsive’ copy of the thumbnail that is twice as large (for hi-dpi screens with double the normal pixel density). I have also created a number of other sizes to make a fairly complete set.
Note — Since my original thumbnails were 120×80 I want my new ones to be 240×160 so those are the sizes I have specified (codificado). It would be possible to get both the height and width specified for the original thumbnail and multiply both by 2 to make this function fully generic, but I didn’t do so when I was developing it so I will leave that to you to figure out!
Uma dica final
Se, como eu, you create your own full set of new image sizes, you may not want wordpress to create it’s own extra hidden sizes. In addition to the original image, and the thumbnail, the medium, e a imagem grande, wordpress also create a “post-thumbnail”, a “medium-large”, a 1536×1536 and a 2048×2048. These are disabled in 2 different ways…
Para remover o 1536 e 2048 imagens são diretas
remove_image_size( '1536x1536' ); //remova o 1536 we dont need it
remove_image_size( '2048x2048' ); //remova o 2048 nós não precisamos disso
The post-thumb and medium-large are slightly more complicated
//remove the built-in medium-large add_filter('intermediário_imagem_sizes', função($tamanhos) { return array_diff($tamanhos, ['médio Grande']); }); //remove the built-in post-thumbnail add_filter('intermediário_imagem_sizes', função($tamanhos) { return array_diff($tamanhos, ['pós-miniatura']); });
Note that removing the post-thumbnail seems to sometimes have strange effects on the image library in the editor.
Uma nota final final
When deciding on image sizes (for larger images, less so thumbnails) you ideally want a size that common aspect ratio images will always resize nicely to. For that reason I recommend the following sizes
Tamanho | Largura | Altura (4:3) | Altura (16:9) | Altura (3:2) |
---|---|---|---|---|
Trimestre | 192 | 144 | 108 | 128 |
Terceiro | 288 | 216 | 162 | 192 |
Metade | 384 | 288 | 216 | 256 |
Medium | 576 | 432 | 324 | 384 |
Cheio | 768 | 576 | 432 | 512 |
Grande | 1152 | 864 | 648 | 768 |
XL | 1536 | 1152 | 864 | 1024 |
Note how the widths specified produce whole number heights for all 3 of the most common aspect ratios. Você não vai conseguir isso com larguras como 150 or 200.
Also note the pattern in increases. Pular 2 linhas na tabela e o tamanho dobra! As linhas pares (288,576,1152 e 1535) are also 1.5x the previous size so these work well on semi-hi-dpi screens using a 50% aumento de dpi. Usando este conjunto de 7 sizes you have a good range of usable options for most viewports AND a good set of responsive images that wordpress will automatically add to the src-set since they will have consistent aspect ratios with no fractions that would lead to quality loss or cropping.
Currently for thumbnails I tend to either have unlimited width allowed OR I hard crop to a fixed 3:2 ratio so I use whole number sizes for thumbnails but I may eventually tweak my theme and extend the above system backwards by having options 48px and 96px wide (note que não há valor entre estes 2 that would work unfortunately — and since I use 60px wide mini thumbnails I haven’t opted to extend backwards). 72px funcionaria para ambos 4:3 e 3:2 (e 64px funcionaria com 4:3 e 16:9). Since a majority of my images are taken on my dSLR these are typically 3:2 (the same as the aspect ratio of traditional 35mm film) então eu poderia usar este tamanho também, que funcionaria com os tamanhos grandes em todo o caminho, but the larger sizes are not cropped whereas my thumbnails are — I’m happy for larger images to be both landscape and portrait, but I want thumbnails to typically be landscape only to fit with my design, so that’s why I haven’t extended backwards. Hopefully as more and more logos are available as SVG'S, e uma vez JPEG-XL chega no navegador em um futuro próximo, muito disso será resolvido.
“Hi James I realise it has been a long while, but I just checked this on windows 11 (build 23H2)…”