@@ Line 1: / Line 1: @@
 {{expansion|Explain how thumbnails can be configured in different file managers, preferably by linking to their articles}}
-== Creating custom thumbnailers ==
+== '''Enabling Thumbnailers''' ==
+On minimal / custom desktop environments thumbnails in file explorers may not work by default. For example:
+* GNOME environments with the option <code>services.gnome.core-utilities.enable = false;</code>
+* Custom environments built from ground-up using window managers like sway or hyperland
+=== Save yourself hours of troubleshooting!! ===
+Thumbnailers may already be installed in your system as dependencies of image/video applications but are not activated.
+Run <code>cd /run/current-system/sw/share/thumbnailers && ls</code> to list installed thumbnailers. If relevant .thumbnailer files are present and we still don't have thumbnails in our file explorer then we may need to activate them by updating symlinks to <code>share/thumbnailers</code>
+<syntaxhighlight lang="nix">
+# configuration.nix
+{
+  environment.pathsToLink = [
+    "share/thumbnailers"
+  ];
+}
+</syntaxhighlight>
+=== Enable Video Thumbnails ===
+To enable thumbnails for video files use <code>ffmpeg-headless</code> to decode videos and <code>fmpegthumbnailer</code> to generate thumbnails.
+Thumbnails for the following MimeTypes are enabled: ''video/jpeg; video/mp4; video/mpeg; video/quicktime; video/x-ms-asf; video/x-ms-wm; video/x-ms-wmv; video/x-ms-asx; video/x-ms-wmx; video/x-ms-wvx; video/x-msvideo; video/x-flv; video/x-matroska; application/x-matroska; application/mxf; video/3gp; video/3gpp; video/dv; video/divx; video/fli; video/flv; video/mp2t; video/mp4v-es; video/msvideo; video/ogg; video/vivo; video/vnd.avi; video/vnd.divx; video/vnd.mpegurl; video/vnd.rn-realvideo; application/vnd.rn-realmedia; video/vnd.vivo; video/webm; video/x-anim; video/x-avi; video/x-flc; video/x-fli; video/x-flic; video/x-m4v; video/x-mpeg; video/x-mpeg2; video/x-nsv; video/x-ogm+ogg; video/x-theora+ogg.''
+<syntaxhighlight lang="nix">
+# configuration.nix
+{ pkgs, ... }:
+{
+  environment.systemPackages = with pkgs; [
+    ffmpeg-headless
+    ffmpegthumbnailer
+  ];
+  # 'ffmpegthumbnailer.thumbnailer' is created in '/run/current-system/sw/share/thumbnailers'
+}
+</syntaxhighlight>
+=== Enable Image Thumbnails ===
+To enable thumbnails for image files use <code>gdk-pixbuf</code> to decode images and generate thumbnails.
+Thumbnails for the following MimeTypes are enabled: ''image/png; image/jpeg; image/bmp; image/x-bmp; image/x-MS-bmp; image/gif; image/x-icon; image/x-ico; image/x-win-bitmap; image/vnd.microsoft.icon; application/ico; image/ico; image/icon; text/ico; image/x-portable-anymap; image/x-portable-bitmap; image/x-portable-graymap; image/x-portable-pixmap; image/tiff; image/x-xpixmap; image/x-xbitmap; image/x-tga; image/x-icns; image/x-quicktime; image/qtif.''
+<syntaxhighlight lang="nix">
+# configuration.nix
+{ pkgs, ... }:
+{
+  environment.systemPackages = with pkgs; [
+    gdk-pixbuf
+  ];
+  # 'gdk-pixbuf-thumbnailer.thumbnailer' is created in '/run/current-system/sw/share/thumbnailers'
+}</syntaxhighlight>
+=== Enable HEIF Image Thumbnails ===
+To enable thumbnails for HEIF image format use <code>libheif</code> to decode HEIF images and <code>libheif.out</code> to generate thumbnails.
+Thumbnails for the following MimeTypes are enabled: ''image/heif; image/avif.''
+<syntaxhighlight lang="nix">
+# configuration.nix
+{ pkgs, ... }:
+{
+  environment.systemPackages = with pkgs; [
+    libheif
+    libheif.out
+  ];
+  # 'heif.thumbnailer' is created in '/run/current-system/sw/share/thumbnailers'
+}
+</syntaxhighlight>
+=== Enable RAW (Camera) Image Thumbnails ===
+==== nufraw-thumbnailer ====
+To enable thumbnails for camera RAW format use <code>nufraw</code> to decode RAW images and <code>nufraw-thumbnailer</code> to generate thumbnails.
+Thumbnails for the following MimeTypes are enabled: ''image/x-canon-cr2;image/x-canon-crw;image/x-minolta-mrw;image/x-nikon-nef;image/x-pentax-pef;image/x-panasonic-rw2;image/x-panasonic-raw2;image/x-samsung-srw;image/x-olympus-orf;image/x-sony-arw.''
+<syntaxhighlight lang="nix"># configuration.nix
+{ pkgs, ... }:
+{
+  environment.systemPackages = with pkgs; [
+    nufraw
+    nufraw-thumbnailer
+  ];
+  # 'nufraw.thumbnailer' is created in '/run/current-system/sw/share/thumbnailers'
+}</syntaxhighlight>
+nufraw-thumbnailer
+* creates thumbnails using the embedded 'jpeg' in the camera raw files. ( <code>--noexif</code> )
+* does not respect the EXIF metadata. ( <code>--embedded-image</code> )
+Output of <code>cat /run/current-system/sw/share/thumbnailers/nufraw.thumbnailer</code>:
+<syntaxhighlight lang="nix">
+[Thumbnailer Entry]
+TryExec=/nix/store/piss9dl8i5xnfm5yagdffgxycm8lsqpl-nufraw-0.43-3/bin/nufraw-batch
+Exec=/nix/store/piss9dl8i5xnfm5yagdffgxycm8lsqpl-nufraw-0.43-3/bin/nufraw-batch --silent --size %s --out-type=png --noexif --output=%o --embedded-image %i
+MimeType=image/x-canon-cr2;image/x-canon-crw;image/x-minolta-mrw;image/x-nikon-nef;image/x-pentax-pef;image/x-panasonic-rw2;image/x-panasonic-raw2;image/x-samsung-srw;image/x-olympus-orf;image/x-sony-arw
+</syntaxhighlight>
+Additional cameras<ref>https://github.com/killhellokitty/nufraw-thumbnailer</ref> beyond those listed in the stock <code>nufraw.thumbnailer</code> file are also supported. The following additional MimeTypes are supported: ''image/x-adobe-dng; image/x-dcraw; image/x-fuji-raf; image/x-kodak-dcr; image/x-kodak-k25; image/x-kodak-kdc; image/x-nikon-nrw; image/x-panasonic-raw; image/x-sigma-x3f; image/x-sony-srf; image/x-sony-sr2''
+Eg: Generate thumbnails from 'raw' data (not 'embedded jpeg') + respect EXIF (eg: rotation) metadata + add support for additional camera formats
+<syntaxhighlight lang="nix">
+# configuration.nix
+{ pkgs, ... }:
+{
+  environment.systemPackages = [
+    nufraw
+    nufraw-thumbnailer
+    # Thumbnails form 'raw' data and include EXIF tags for Adobe-DNG images
+    (writeTextDir "share/thumbnailers/my-custom-nufraw.thumbnailer" ''
+      [Thumbnailer Entry]
+      TryExec=nufraw-batch
+      Exec=nufraw-batch --silent --size %s --out-type=png --output=%o %i
+      MimeType=image/x-adobe-dng;image/x-dng;
+    '';)
+    # MimeTypes not listed here but listed in the default nufraw.thumbnailer will continue displaying
+      # thumbnails generated form the 'embedded jpeg' without the EXIF metadata
+  ];
+}
+</syntaxhighlight>
+==== gdk-pixbuf thumbnailer ====
+The gdk-pixbuf thumbnailer can also generate thumbnails (from 'embedded jpeg') for RAW camera image formats. It cannot decode 'raw' image data but can read the 'embedded jpeg'.
+<syntaxhighlight lang="nix">
+# configuration.nix
+{ pkgs, ... }:
+{
+  environment.systemPackages = [
+    gdk-pixbuf
+    (writeTextDir "share/thumbnailers/my-custom-nufraw.thumbnailer" ''
+      [Thumbnailer Entry]
+      TryExec=gdk-pixbuf-thumbnailer
+      Exec=gdk-pixbuf-thumbnailer -s %s %u %o
+      MimeType=image/x-adobe-dng;image/x-dng;image/x-canon-cr2;image/x-canon-crw;image/x-cr2;image/x-crw;
+    '';)
+  ];
+}
+</syntaxhighlight>
+== '''Creating Custom Thumbnailers''' ==
 Most package mangers accept the [https://specifications.freedesktop.org/thumbnail-spec/latest/index.html Thumbnail Managing Standard], by using it you can create your own thumbnailer for any file format, this can be done by:
@@ Line 28: / Line 191: @@
 After you have a working definition, you can make it reproducible like so:
-<syntaxhighlight lang="nix">
+<syntaxhighlight lang="nix"># configuration.nix
-# configuration.nix
 { pkgs, ... }: {
    environment.systemPackages = [
@@ Line 47: / Line 209: @@
      )
    ];
-}
+}</syntaxhighlight>
-</syntaxhighlight>
-=== FFmpeg thumbnailer ===
-On minimal GNOME environments (for example ones with the option <code>services.gnome.core-utilities.enable</code> set to <code>false</code>, or ones without <code>pkgs.gnome.totem</code>), video thumbnails do not work by default. To fix this, you can use <code>ffmpegthumbnailer</code>:
-<syntaxhighlight lang="nix">
-# configuration.nix
-{ pkgs, ... }:
-{
-  # Install ffmpegthumbnailer package
-  environment.systemPackages = [
-    pkgs.ffmpegthumbnailer
-  ];
-  # Installing above package automatically creates the ffmpegthumbnailer.thumbnailer
-    # in '/run/current-system/sw/share/thumbnailers' but thumbnails are not displayed
-    # until symlinks to 'share/thumbnailers' are defined
-  environment.pathsToLink = [
-    "share/thumbnailers"
-  ];
-}
-</syntaxhighlight>
-=== HEIC thumbnailer ===
-On minimal GNOME environments as explained in the FFmpeg thumbnailer section above HEIC thumbnails do not work despite the  <code>ffmpegthumbnailer</code> package being installed. To fix this, you can use <code>ffmpegthumbnailer</code>:
-<syntaxhighlight lang="nix">
-# configuration.nix
-{ pkgs, ... }:
-{
-}
-</syntaxhighlight>

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