pkgs: sway-background-image: fetch image directly from source

Signed-off-by: Christoph Heiss <christoph@c8h4.io>

README.md

@@ -37,7 +37,3 @@
 ## License
 
 The code is released into the public domain.
-
-Other conditions apply to the following files:
-
-- `pkgs/sway-background-image/background.jpg`: [Photo](https://unsplash.com/photos/wQLAGv4_OYs) by [Lucas Kapla](https://unsplash.com/@aznbokchoy), [Unsplash License](https://unsplash.com/license)

pkgs/default.nix

@@ -7,5 +7,5 @@ _: super:
   git-multi-shortlog = super.callPackage ./git-multi-shortlog.nix { };
   homer = super.callPackage ./homer { };
   neomutt-export-patches = super.callPackage ./neomutt-export-patches.nix { };
-  sway-background-image = super.callPackage ./sway-background-image { };
+  sway-background-image = super.callPackage ./sway-background-image.nix { };
 }

pkgs/sway-background-image.nix

@@ -0,0 +1,23 @@
+{ stdenv, fetchurl, imagemagick }:
+
+stdenv.mkDerivation rec {
+  pname = "sway-background-image";
+  version = "0.1";
+
+  src = fetchurl {
+    url = "https://images.unsplash.com/photo-1541701494587-cb58502866ab";
+    hash = "sha256-qFD7FFqY2l2Fsev/YPu1/f7f29BntxsO1ezJj2BlMs8=";
+  };
+
+  dontUnpack = true;
+
+  nativeBuildInputs = [ imagemagick ];
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out/share
+    # significantly reduces image size, 4.8MiB -> 1.7MiB
+    convert -quality 90 -resize 4096x $src $out/share/background.jpg
+    runHook postInstall
+  '';
+}

pkgs/sway-background-image/default.nix

@@ -1,14 +0,0 @@
-{ stdenv }:
-
-stdenv.mkDerivation rec {
-  pname = "sway-background-image";
-  version = "0.1";
-  dontUnpack = true;
-
-  installPhase = ''
-    runHook preInstall
-    mkdir -p $out/share
-    cp -v ${./background.jpg} $out/share/background.jpg
-    runHook postInstall
-  '';
-}