✨feat(image shortcodes): add lazy loading (#116)

Additionally sets the `alt` parameters as optional and cleans HTML output.

content/blog/shortcodes.ca.md

@@ -1,7 +1,7 @@
 +++
 title = "Shortcodes personalitzats"
 date = 2023-02-19
-updated = 2023-08-24
+updated = 2023-08-26
 description = "Aquest tema inclou alguns shortcodes personalitzats útils que pots utilitzar per millorar les teves publicacions. Ja sigui per mostrar imatges que s'adapten als temes clar i fosc, o per donar format a una secció de referències amb un aspecte professional, aquests shortcodes personalitzats t'ajudaran."
 
 [taxonomies]
@@ -15,6 +15,8 @@ quick_navigation_buttons = true
 
 ## Shortcodes d'imatge
 
+**Nota**: tots els shortcodes d'imatge tenen dos paràmetres opcionals: `full_width`, que té com a valor predeterminat `false` (vegeu [a sota](#imatge-d-amplada-completa)), i `lazy_loading`, que té com a valor predeterminat `true`.
+
 ### Imatges per a temes duals
 
 Útil si vols utilitzar una imatge diferent pels temes clar i fosc:

content/blog/shortcodes.es.md

@@ -1,7 +1,7 @@
 +++
 title = "Shortcodes personalizados"
 date = 2023-02-19
-updated = 2023-08-24
+updated = 2023-08-26
 description = "Este tema incluye algunos shortcodes personalizados útiles que puedes utilizar para mejorar tus publicaciones. Puedes mostrar imágenes que se adapten a los temas claro y oscuro, dar formato a una sección de referencias con un aspecto profesional, y más."
 
 [taxonomies]
@@ -13,7 +13,9 @@ toc_levels = 2
 quick_navigation_buttons = true
 +++
 
-## Shortcodes de imágenes
+## Shortcodes de imagen
+
+**Nota**: todos los shortcodes de imagen tienen dos parámetros opcionales: `full_width`, que tiene como valor predeterminado `false` (ver [más abajo](#imagen-a-ancho-completo)), y `lazy_loading`, que tiene como valor predeterminado `true`.
 
 ### Imágenes de doble tema
 

content/blog/shortcodes.md

@@ -1,7 +1,7 @@
 +++
 title = "Custom shortcodes"
 date = 2023-02-19
-updated = 2023-08-24
+updated = 2023-08-26
 description = "This theme includes some useful custom shortcodes that you can use to enhance your posts. Whether you want to display images that adapt to light and dark themes, or format a professional-looking reference section, these custom shortcodes have got you covered."
 
 [taxonomies]
@@ -15,6 +15,8 @@ quick_navigation_buttons = true
 
 ## Image shortcodes
 
+**Note**: all image shortcodes have two optional parameters: `full_width`, which defaults to `false` (see [below](#full-width-image)), and `lazy_loading`, which defaults to `true`.
+
 ### Dual theme images
 
 Useful if you want to use a different image for the light and dark themes:

templates/shortcodes/dimmable_image.html

@@ -1,8 +1,10 @@
-{% set meta = get_image_metadata(path=src, allow_missing=true) %}
+{%- set meta = get_image_metadata(path=src, allow_missing=true) -%}
+{%- set lazy_loading = lazy_loading | default(value=true) -%}
+
 {% if full_width | default(value=false) %}
     <div class="full-width">
 {% endif %}
-<img class="dimmable-image" src="{{ get_url(path=src) }}" {% if alt %}alt="{{ alt }}" {% endif %} {% if meta.width %}width="{{ meta.width }}" {% endif %} {% if meta.height %}height="{{ meta.height }}" {% endif %}/>
+<img class="dimmable-image" src="{{ get_url(path=src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if alt %} alt="{{ alt }}"{% endif %}{% if meta.width %} width="{{ meta.width }}"{% endif %}{% if meta.height %} height="{{ meta.height }}" {% endif %}/>
 {% if full_width | default(value=false) %}
     </div>
 {% endif %}

templates/shortcodes/dual_theme_image.html

@@ -1,10 +1,12 @@
-{% set light_meta = get_image_metadata(path=light_src, allow_missing=true) %}
-{% set dark_meta = get_image_metadata(path=dark_src, allow_missing=true) %}
-{% if full_width | default(value=false) %}
+{%- set light_meta = get_image_metadata(path=light_src, allow_missing=true) -%}
+{%- set dark_meta = get_image_metadata(path=dark_src, allow_missing=true) -%}
+{%- set lazy_loading = lazy_loading | default(value=true) -%}
+
+{%- if full_width | default(value=false) -%}
     <div class="full-width">
-{% endif %}
-<img src="{{ get_url(path=light_src) }}" {% if alt %}alt="{{ alt }}" {% endif %} {% if light_meta.width %}width="{{ light_meta.width }}" {% endif %} {% if light_meta.height %}height="{{ light_meta.height }}" {% endif %} class="img-light">
-<img src="{{ get_url(path=dark_src) }}" {% if alt %}alt="{{ alt }}" {% endif %} {% if dark_meta.width %}width="{{ dark_meta.width }}" {% endif %} {% if dark_meta.height %}height="{{ dark_meta.height }}" {% endif %} class="img-dark">
+{%- endif -%}
+<img src="{{ get_url(path=light_src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if alt %} alt="{{ alt }}"{% endif %}{% if light_meta.width %} width="{{ light_meta.width }}"{% endif %}{% if light_meta.height %} height="{{ light_meta.height }}"{% endif %} class="img-light">
+<img src="{{ get_url(path=dark_src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if alt %} alt="{{ alt }}"{% endif %}{% if dark_meta.width %} width="{{ dark_meta.width }}"{% endif %}{% if dark_meta.height %} height="{{ dark_meta.height }}"{% endif %} class="img-dark">
 {% if full_width | default(value=false) %}
     </div>
 {% endif %}

templates/shortcodes/full_width_image.html

@@ -1,4 +1,6 @@
-{% set meta = get_image_metadata(path=src, allow_missing=true) %}
+{%- set meta = get_image_metadata(path=src, allow_missing=true) -%}
+{%- set lazy_loading = lazy_loading | default(value=true) -%}
+
 <div class="full-width">
-<img {% if src %}src="{{ get_url(path=src) }}" {% endif %} {% if alt %}alt="{{ alt }}" {% endif %} {% if meta.width %}width="{{ meta.width }}" {% endif %} {% if meta.height %}height="{{ meta.height }}" {% endif %}/>
+    <img src="{{ get_url(path=src) }}"{% if alt %} alt="{{ alt }}"{% endif %}{% if meta.width %} width="{{ meta.width }}"{% endif %}{% if meta.height %} height="{{ meta.height }}"{% endif %}{% if lazy_loading %} loading="lazy"{% endif %}/>
 </div>

templates/shortcodes/image_hover.html

@@ -1,13 +1,12 @@
 {%- set default_meta = get_image_metadata(path=default_src, allow_missing=true) -%}
 {%- set hovered_meta = get_image_metadata(path=hovered_src, allow_missing=true) -%}
+{%- set lazy_loading = lazy_loading | default(value=true) -%}
 
-<div class="image-hover-container {% if full_width | default(value=false) %}full-width{% endif %}">
+<div class="image-hover-container{% if full_width | default(value=false) %} full-width{% endif %}">
     <div class="image-default">
-        <img src="{{ get_url(path=default_src) }}" alt="{{ default_alt }}"
-            width="{{ default_meta.width }}" height="{{ default_meta.height }}">
+        <img src="{{ get_url(path=default_src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if hovered_alt %} alt="{{ default_alt }}"{% endif %}{% if default_meta.width %} width="{{ default_meta.width }}"{% endif %}{% if default_meta.height %} height="{{ default_meta.height }}"{% endif %}>
     </div>
     <div class="image-hovered">
-        <img src="{{ get_url(path=hovered_src) }}" alt="{{ hovered_alt }}"
-            width="{{ hovered_meta.width }}" height="{{ hovered_meta.height }}">
+        <img src="{{ get_url(path=hovered_src) }}"{% if hovered_alt %} alt="{{ hovered_alt }}"{% endif %}{% if hovered_meta.width %} width="{{ hovered_meta.width }}"{% endif %}{% if hovered_meta.height %} height="{{ hovered_meta.height }}"{% endif %}>
     </div>
 </div>

templates/shortcodes/image_toggler.html

@@ -2,20 +2,18 @@
 {# allowing individual interactive elements (like toggles) to function correctly. #}
 {# This avoids conflicts when multiple instances of the shortcode are used. #}
 {%- set random_id = get_random(end=100000) -%}
-
-{% set default_meta = get_image_metadata(path=default_src, allow_missing=true) %}
-{% set toggled_meta = get_image_metadata(path=toggled_src, allow_missing=true) %}
+{%- set default_meta = get_image_metadata(path=default_src, allow_missing=true) -%}
+{%- set toggled_meta = get_image_metadata(path=toggled_src, allow_missing=true) -%}
+{%- set lazy_loading = lazy_loading | default(value=true) -%}
 
 <div class="image-toggler-container {% if full_width | default(value=false) %}full-width{% endif %}">
     <input type="checkbox" id="toggle-img-{{ random_id }}" class="image-toggler-toggle">
     <label for="toggle-img-{{ random_id }}" class="image-label">
         <div class="image-default">
-            <img src="{{ get_url(path=default_src) }}" alt="{{ default_alt }}"
-                width="{{ default_meta.width }}" height="{{ default_meta.height }}">
+            <img src="{{ get_url(path=default_src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if default_alt %} alt="{{ default_alt }}"{% endif %}{% if default_meta.width %} width="{{ default_meta.width }}"{% endif %}{% if default_meta.height %} height="{{ default_meta.height }}"{% endif %}>
         </div>
         <div class="image-toggled">
-            <img src="{{ get_url(path=toggled_src) }}" alt="{{ toggled_alt }}"
-                width="{{ toggled_meta.width }}" height="{{ toggled_meta.height }}">
+            <img src="{{ get_url(path=toggled_src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if toggled_alt %} alt="{{ toggled_alt }}"{% endif %}{% if toggled_meta.width %} width="{{ toggled_meta.width }}"{% endif %}{% if toggled_meta.height %} height="{{ toggled_meta.height }}"{% endif %}>
         </div>
     </label>
 </div>

templates/shortcodes/invertible_image.html

@@ -1,8 +1,10 @@
-{% set meta = get_image_metadata(path=src, allow_missing=true) %}
+{%- set meta = get_image_metadata(path=src, allow_missing=true) -%}
+{%- set lazy_loading = lazy_loading | default(value=true) -%}
+
 {% if full_width | default(value=false) %}
     <div class="full-width">
 {% endif %}
-<img class="invertible-image" {% if src %}src="{{ get_url(path=src) }}" {% endif %} {% if alt %}alt="{{ alt }}" {% endif %} {% if meta.width %}width="{{ meta.width }}" {% endif %} {% if meta.height %}height="{{ meta.height }}" {% endif %}/>
-{% if full_width | default(value=false) %}
+<img class="invertible-image" src="{{ get_url(path=src) }}"{% if lazy_loading %} loading="lazy"{% endif %}{% if alt %} alt="{{ alt }}"{% endif %}{% if meta.width %} width="{{ meta.width }}"{% endif %}{% if meta.height %} height="{{ meta.height }}" {% endif %}/>
+{%- if full_width | default(value=false) -%}
     </div>
-{% endif %}
+{%- endif -%}