feat: render .pdn thumbnails.

docs/library/index.md

@@ -97,6 +97,7 @@ Preview support for office documents or well-known project file formats varies b
 | OpenDocument Spreadsheet      | `.ods`, `.fods`       | Embedded thumbnail                                                         |
 | OpenDocument Text             | `.odt`, `.fodt`       | Embedded thumbnail                                                         |
 | Pages (Apple iWork)           | `.pages`              | Embedded thumbnail                                                         |
+| Paint.NET                     | `.pdn`                | Embedded thumbnail                                                         |
 | PDF                           | `.pdf`                | First page render                                                          |
 | Photoshop                     | `.psd`                | Flattened image render                                                     |
 | PowerPoint (Microsoft Office) | `.pptx`, `.ppt`       | Embedded thumbnail :material-alert-circle:{ title="If available in file" } |

src/tagstudio/core/media_types.py

@@ -49,6 +49,7 @@ class MediaType(str, Enum):
     MODEL = "model"
     OPEN_DOCUMENT = "open_document"
     PACKAGE = "package"
+    PAINT_DOT_NET = "paint_dot_net"
     PDF = "pdf"
     PLAINTEXT = "plaintext"
     PRESENTATION = "presentation"
@@ -358,6 +359,7 @@ class MediaCategories:
         ".pkg",
         ".xapk",
     }
+    _PAINT_DOT_NET_SET: set[str] = {".pdn"}
     _PDF_SET: set[str] = {".pdf"}
     _PLAINTEXT_SET: set[str] = {
         ".csv",
@@ -554,6 +556,12 @@ class MediaCategories:
         is_iana=False,
         name="package",
     )
+    PAINT_DOT_NET_TYPES = MediaCategory(
+        media_type=MediaType.PAINT_DOT_NET,
+        extensions=_PAINT_DOT_NET_SET,
+        is_iana=False,
+        name="paint.net",
+    )
     PDF_TYPES = MediaCategory(
         media_type=MediaType.PDF,
         extensions=_PDF_SET,
@@ -643,6 +651,7 @@ class MediaCategories:
         MODEL_TYPES,
         OPEN_DOCUMENT_TYPES,
         PACKAGE_TYPES,
+        PAINT_DOT_NET_TYPES,
         PDF_TYPES,
         PLAINTEXT_TYPES,
         PRESENTATION_TYPES,
@@ -679,7 +688,7 @@ def is_ext_in_category(ext: str, media_cat: MediaCategory, mime_fallback: bool =
 
         Args:
             ext (str): File extension with a leading "." and in all lowercase.
-            media_cat (MediaCategory): The MediaCategory to to check for extension membership.
+            media_cat (MediaCategory): The MediaCategory to check for extension membership.
             mime_fallback (bool): Flag to guess MIME type if no set matches are made.
         """
         return media_cat.contains(ext, mime_fallback)

src/tagstudio/qt/previews/renderer.py

@@ -3,10 +3,12 @@
 # Created for TagStudio: https://github.com/CyanVoxel/TagStudio
 
 
+import base64
 import contextlib
 import hashlib
 import math
 import os
+import struct
 import tarfile
 import xml.etree.ElementTree as ET
 import zipfile
@@ -1378,6 +1380,42 @@ def _video_thumb(filepath: Path) -> Image.Image | None:
             logger.error("Couldn't render thumbnail", filepath=filepath, error=type(e).__name__)
         return im
 
+    @staticmethod
+    def _pdn_thumb(filepath: Path) -> Image.Image | None:
+        """Extract the base64-encoded thumbnail from a .pdn file header.
+
+        Args:
+            filepath (Path): The path of the .pdn file.
+
+        Returns:
+            Image: the decoded PNG thumbnail or None by default.
+        """
+        im: Image.Image | None = None
+        with open(filepath, "rb") as f:
+            try:
+                # First 4 bytes are the magic number
+                if f.read(4) != b"PDN3":
+                    return im
+
+                # Header length is a little-endian 24-bit int
+                header_size = struct.unpack("<i", f.read(3) + b"\x00")[0]
+                thumb_element = ET.fromstring(f.read(header_size)).find("./*thumb")
+                if thumb_element is None:
+                    return im
+
+                encoded_png = thumb_element.get("png")
+                if encoded_png:
+                    decoded_png = base64.b64decode(encoded_png)
+                    im = Image.open(BytesIO(decoded_png))
+                    if im.mode == "RGBA":
+                        new_bg = Image.new("RGB", im.size, color="#1e1e1e")
+                        new_bg.paste(im, mask=im.getchannel(3))
+                        im = new_bg
+            except Exception as e:
+                logger.error("Couldn't render thumbnail", filepath=filepath, error=type(e).__name__)
+
+        return im
+
     def render(
         self,
         timestamp: float,
@@ -1391,7 +1429,7 @@ def render(
         """Render a thumbnail or preview image.
 
         Args:
-            timestamp (float): The timestamp for which this this job was dispatched.
+            timestamp (float): The timestamp for which this job was dispatched.
             filepath (str | Path): The path of the file to render a thumbnail for.
             base_size (tuple[int,int]): The unmodified base size of the thumbnail.
             pixel_ratio (float): The screen pixel ratio.
@@ -1504,7 +1542,7 @@ def fetch_cached_image(file_name: Path):
                     save_to_file=file_name,
                 )
 
-            # If the normal renderer failed, fallback the the defaults
+            # If the normal renderer failed, fallback the defaults
             # (with native non-cached sizing!)
             if not image:
                 image = (
@@ -1601,7 +1639,7 @@ def _render(
         """Render a thumbnail or preview image.
 
         Args:
-            timestamp (float): The timestamp for which this this job was dispatched.
+            timestamp (float): The timestamp for which this job was dispatched.
             filepath (str | Path): The path of the file to render a thumbnail for.
             base_size (tuple[int,int]): The unmodified base size of the thumbnail.
             pixel_ratio (float): The screen pixel ratio.
@@ -1704,6 +1742,9 @@ def _render(
                     ext, MediaCategories.PDF_TYPES, mime_fallback=True
                 ):
                     image = self._pdf_thumb(_filepath, adj_size)
+                # Paint.NET ====================================================
+                elif MediaCategories.is_ext_in_category(ext, MediaCategories.PAINT_DOT_NET_TYPES):
+                    image = self._pdn_thumb(_filepath)
                 # No Rendered Thumbnail ========================================
                 if not image:
                     raise NoRendererError