Add Nix flakes

CMakeLists.txt

@@ -468,3 +468,9 @@ install(
     DESTINATION share/licenses/${PROJECT_NAME}
     COMPONENT documentation
 )
+
+install(
+    FILES oshot.desktop
+    DESTINATION share/applications
+    COMPONENT documentation
+)

README.md

@@ -74,6 +74,31 @@ If when starting oshot, it starts to flick a screen black (or it won't launch),
 
 If still errors, please open an [Issue](https://github.com/Toni500github/oshot/issues) and take a screenshot/paste the text of the error appearing in the console when executing oshot
 
+### NixOS
+On NixOS, TESSDATA_PREFIX will need to be set for oshot to find the languages.
+You have two ways to do this, depending on how you installed tesseract.
+
+If you installed tesseract in `environment.systemPackages`, set the following variable:
+```nix
+environment.sessionVariables = {
+    # Change tesseract to tesseract5 if that's the package you used.
+    "TESSDATA_PREFIX" = "${pkgs.tesseract}/share/tessdata";
+};
+```
+
+If you installed tesseract in `users.users.<user>.packages`, you could use the above method, but it's better you use home-manager.
+If you have home-manager, add this in your home.nix:
+```nix
+systemd.user.sessionVariables = {
+    # Change tesseract to tesseract5 if that's the package you used.
+    "TESSDATA_PREFIX" = "${pkgs.tesseract}/share/tessdata";
+};
+```
+
+> **__Notice:__** If you're not using systemd, the home-manager solution won't work. We assume you'll be able to find a replacement yourself if you're not using systemd.
+
+If this doesn't work, while `echo $TESSDATA_PREFIX` returns a valid result, check your config file.
+
 ## Usage
 https://github.com/user-attachments/assets/8367490a-f7b0-4320-86e9-8ef8764a56b5
 <!--https://github.com/user-attachments/assets/ac505de6-0818-4d67-bb51-064d86f1f970-->

flake.nix

@@ -0,0 +1,30 @@
+{
+  description = "Nix flake for oshot; a simple and lightweight tool for extracting text from a screenshot/image (on the fly)";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }: {
+    packages.x86_64-linux.oshot =
+      with import nixpkgs { system = "x86_64-linux"; };
+      stdenv.mkDerivation {
+        name = "oshot";
+        src = self;
+        nativeBuildInputs = [ cmake gnumake pkg-config git ];
+        buildInputs = [ glfw3 leptonica libx11.dev tesseract zbar.dev libappindicator-gtk3.dev dbus.dev systemd.dev libsysprof-capture pcre2.dev libxdmcp.dev libuuid.dev libselinux.dev libsepol.dev libthai.dev libdatrie.dev libdeflate lerc.dev xz.dev zstd.dev libwebp libxkbcommon.dev libepoxy.dev libxtst giflib ];
+        configurePhase = ''
+          cmake -DCMAKE_BUILD_PREFIX=/usr -DDEBUG=0 -G "Unix Makefiles" -B build -S .
+        '';
+        buildPhase = ''
+          cmake --build build -j$(nproc)
+        '';
+        installPhase = ''
+          install -Dm755 build/oshot $out/bin/oshot
+          install -Dm644 oshot.desktop $out/share/applications/oshot.desktop
+          install -Dm644 LICENSE $out/share/licenses/oshot/LICENSE
+        '';
+      };
+    packages.x86_64-linux.default = self.packages.x86_64-linux.oshot;
+  };
+}

include/config.hpp

@@ -290,6 +290,7 @@ void apply_imgui_theme();
 // default config
 inline constexpr std::string_view AUTOCONFIG = R"#([default]
 # Default Path to where we'll use all the '.traineddata' models.
+# The TESSDATA_PREFIX environment variable supersedes this.
 ocr-path = "{}"
 
 # Default OCR model.

src/config.cpp

@@ -61,6 +61,12 @@ void Config::LoadConfigFile(const std::string& filename)
 
     File.allow_out_edit = GetValue<bool>("default.allow-edit-ocr", false);  // deprecated
     File.allow_out_edit = GetValue<bool>("default.allow-text-edit", File.allow_out_edit);
+
+    const char* tessdata_prefix;
+    if ((tessdata_prefix = getenv("TESSDATA_PREFIX")))
+    {
+        File.ocr_path = tessdata_prefix;
+    }
 }
 
 void Config::LoadThemeFile(const std::string& filename)