feat: add blurry_image Jinja extension

Adds blurry_image extension to insert an <img> tag with width &
height into a Jinja template. Optionally inserts an image of a
specific size.

Usage:

```
{% blurry_image page.image, width=250 %}
```

blurry/__init__.py

@@ -25,6 +25,7 @@
 from blurry.markdown import convert_markdown_file_to_html
 from blurry.open_graph import open_graph_meta_tags
 from blurry.plugins import discovered_html_plugins
+from blurry.plugins import discovered_jinja_extensions
 from blurry.plugins import discovered_jinja_filter_plugins
 from blurry.schema_validation import validate_front_matter_as_schema
 from blurry.settings import get_build_directory
@@ -69,6 +70,9 @@ def get_jinja_env():
                 }
             )
         ),
+        extensions=[
+            jinja_extension.load() for jinja_extension in discovered_jinja_extensions
+        ],
     )
     for filter_plugin in discovered_jinja_filter_plugins:
         try:

blurry/cli.py

@@ -2,6 +2,7 @@
 from rich.table import Table
 
 from blurry.plugins import discovered_html_plugins
+from blurry.plugins import discovered_jinja_extensions
 from blurry.plugins import discovered_jinja_filter_plugins
 from blurry.plugins import discovered_markdown_plugins
 
@@ -27,7 +28,10 @@ def print_plugin_table():
     plugin_table.add_row(
         "\n".join([p.name for p in discovered_markdown_plugins]),
         "\n".join([p.name for p in discovered_html_plugins]),
-        "\n".join([p.name for p in discovered_jinja_filter_plugins]),
+        "\n".join(
+            [p.name for p in discovered_jinja_filter_plugins]
+            + [p.name for p in discovered_jinja_extensions]
+        ),
     )
 
     console.print(plugin_table)

blurry/plugins/__init__.py

@@ -3,3 +3,4 @@
 discovered_markdown_plugins = entry_points(group="blurry.markdown_plugins")
 discovered_html_plugins = entry_points(group="blurry.html_plugins")
 discovered_jinja_filter_plugins = entry_points(group="blurry.jinja_filter_plugins")
+discovered_jinja_extensions = entry_points(group="blurry.jinja_extensions")

blurry/plugins/jinja_plugins/blurry_image_extension.py

@@ -0,0 +1,53 @@
+import mimetypes
+from pathlib import Path
+from urllib.parse import urlparse
+
+from jinja2_simple_tags import StandaloneTag
+from rich.console import Console
+from wand.exceptions import BlobError
+from wand.image import Image
+
+from blurry.images import add_image_width_to_path
+from blurry.settings import get_build_directory
+from blurry.utils import build_path_to_url
+
+warning_console = Console(stderr=True, style="bold yellow")
+
+
+class BlurryImage(StandaloneTag):
+    safe_output = True
+    tags = {"blurry_image"}
+
+    def render(self, *args, **kwargs):
+        (image_url,) = args
+        width = kwargs.get("width")
+        image_content_path: str = "." + urlparse(image_url).path
+        image_path = get_build_directory() / image_content_path
+
+        try:
+            with Image(filename=str(image_path)) as image:
+                image_width = image.width
+                image_height = image.height
+                image_mimetype = image.mimetype
+        except BlobError:
+            warning_console.print(f"Could not find image: {image_path}")
+            return ""
+
+        if width:
+            image_path = add_image_width_to_path(image_path, width)
+
+        if image_mimetype in [
+            mimetypes.types_map[".jpg"],
+            mimetypes.types_map[".png"],
+        ]:
+            image_path = Path(str(image_path).replace(image_path.suffix, ".avif"))
+
+        if not image_path.exists():
+            warning_console.print(
+                f"blurry_image: Could not find {image_path}. Skipping."
+            )
+            return ""
+
+        src = build_path_to_url(image_path)
+
+        return f'<img src="{src}" width="{image_width}" height="{image_height}" />'