numworks-epsilon: add .desktop file (#382979)

pkgs/by-name/nu/numworks-epsilon/package.nix

@@ -11,6 +11,8 @@
   gcc-arm-embedded,
   pkg-config,
   python3Packages,
+  makeDesktopItem,
+  copyDesktopItems,
 }:
 
 stdenv.mkDerivation rec {
@@ -24,7 +26,11 @@ stdenv.mkDerivation rec {
     hash = "sha256-w9ddcULE1MrGnYcXA0qOg1elQv/eBhcXqhMSjWT3Bkk=";
   };
 
-  nativeBuildInputs = [ pkg-config ];
+  nativeBuildInputs = [
+    pkg-config
+    copyDesktopItems
+  ];
+
   buildInputs = [
     libpng
     libjpeg
@@ -47,9 +53,38 @@ stdenv.mkDerivation rec {
     mkdir -p $out/bin
     cp -r ./output/release/simulator/linux/* $out/bin/
 
+    # Build the logo
+    assets="$src/ion/src/simulator/assets"
+    logo_dir="$out/share/icons/hicolor/scalable/apps"
+    logo="$logo_dir/numworks.svg"
+    mkdir -p "$logo_dir"
+
+    # Take opening svg tag
+    grep '<svg' "$assets/logo.svg" > "$logo"
+
+    # Insert path from logo mask and change color
+    grep path "$assets/icon_mask.svg" | sed 's/fill="[^"]*"/fill="#edb14b"/' >> "$logo"
+
+    # Add remainder of logo
+    grep -v '<svg' "$assets/logo.svg" >> "$logo"
+
     runHook postInstall
   '';
 
+  desktopItems = [
+    (makeDesktopItem {
+      name = "epsilon";
+      exec = "epsilon";
+      icon = "numworks";
+      desktopName = "NumWorks Epsilon Calculator";
+      categories = [
+        "Utility"
+        "Math"
+      ];
+      type = "Application";
+    })
+  ];
+
   meta = with lib; {
     description = "Simulator for Epsilon, a High-performance graphing calculator operating system";
     homepage = "https://numworks.com/";