feat: add GUI application (mp3rgui)

- egui-based cross-platform GUI
- Track and album ReplayGain analysis
- Apply track/album gain
- File management (add, remove, drag & drop)
- Clipping detection with visual warnings
- Target volume adjustment
- Progress indicators
- CI/CD for macOS, Linux, Windows builds

Author: m_igashi

.github/workflows/release.yml

@@ -9,8 +9,8 @@ permissions:
   contents: write
 
 jobs:
-  build:
-    name: Build for ${{ matrix.target }}
+  build-cli:
+    name: Build CLI for ${{ matrix.target }}
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -53,9 +53,57 @@ jobs:
           name: mp3rgain-${{ matrix.target }}
           path: target/${{ matrix.target }}/release/mp3rgain.exe
 
+  build-gui:
+    name: Build GUI for ${{ matrix.target }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        include:
+          - target: x86_64-apple-darwin
+            os: macos-latest
+          - target: aarch64-apple-darwin
+            os: macos-latest
+          - target: x86_64-unknown-linux-gnu
+            os: ubuntu-latest
+          - target: x86_64-pc-windows-msvc
+            os: windows-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@4be9e76fd7c4901c61fb841f559994984270fce7 # stable
+        with:
+          targets: ${{ matrix.target }}
+
+      - name: Install Linux dependencies
+        if: runner.os == 'Linux'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libxkbcommon-dev libwayland-dev
+
+      - name: Build GUI
+        run: cargo build --release --manifest-path mp3rgui/Cargo.toml --target ${{ matrix.target }}
+        env:
+          RUSTFLAGS: ${{ contains(matrix.target, 'windows') && '-C target-feature=+crt-static' || '' }}
+
+      - name: Upload artifact (Unix)
+        if: runner.os != 'Windows'
+        uses: actions/upload-artifact@v4
+        with:
+          name: mp3rgui-${{ matrix.target }}
+          path: target/${{ matrix.target }}/release/mp3rgui
+
+      - name: Upload artifact (Windows)
+        if: runner.os == 'Windows'
+        uses: actions/upload-artifact@v4
+        with:
+          name: mp3rgui-${{ matrix.target }}
+          path: target/${{ matrix.target }}/release/mp3rgui.exe
+
   release:
     name: Create Release
-    needs: build
+    needs: [build-cli, build-gui]
     runs-on: macos-latest
     outputs:
       version: ${{ steps.version.outputs.version }}
@@ -111,6 +159,27 @@ jobs:
           cd ../../dist
           shasum -a 256 mp3rgain-${{ github.ref_name }}-windows-arm64.zip > mp3rgain-${{ github.ref_name }}-windows-arm64.zip.sha256
 
+      - name: Create GUI universal macOS binary
+        run: |
+          lipo -create \
+            artifacts/mp3rgui-x86_64-apple-darwin/mp3rgui \
+            artifacts/mp3rgui-aarch64-apple-darwin/mp3rgui \
+            -output dist/mp3rgui
+          chmod +x dist/mp3rgui
+          tar -czvf dist/mp3rgui-${{ github.ref_name }}-macos-universal.tar.gz -C dist mp3rgui
+          rm dist/mp3rgui
+
+      - name: Create GUI Linux tarball
+        run: |
+          cd artifacts/mp3rgui-x86_64-unknown-linux-gnu
+          chmod +x mp3rgui
+          tar -czvf ../../dist/mp3rgui-${{ github.ref_name }}-linux-x86_64.tar.gz mp3rgui
+
+      - name: Create GUI Windows zip
+        run: |
+          cd artifacts/mp3rgui-x86_64-pc-windows-msvc
+          zip ../../dist/mp3rgui-${{ github.ref_name }}-windows-x86_64.zip mp3rgui.exe
+
       - name: Extract checksums
         id: checksums
         run: |
@@ -130,6 +199,9 @@ jobs:
             dist/mp3rgain-${{ github.ref_name }}-windows-x86_64.zip.sha256
             dist/mp3rgain-${{ github.ref_name }}-windows-arm64.zip
             dist/mp3rgain-${{ github.ref_name }}-windows-arm64.zip.sha256
+            dist/mp3rgui-${{ github.ref_name }}-macos-universal.tar.gz
+            dist/mp3rgui-${{ github.ref_name }}-linux-x86_64.tar.gz
+            dist/mp3rgui-${{ github.ref_name }}-windows-x86_64.zip
           draft: true
           generate_release_notes: false
 

.gitignore

@@ -4,3 +4,4 @@ Cargo.lock
 .DS_Store
 docs/OUTREACH.md
 .claude/
+mp3rgui/target/

mp3rgui/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "mp3rgui"
+version = "0.1.0"
+edition = "2021"
+authors = ["Masanari Higashi <M-Igashi@users.noreply.github.com>"]
+description = "GUI application for mp3rgain - lossless MP3 volume adjustment"
+license = "MIT"
+repository = "https://github.com/M-Igashi/mp3rgain"
+
+[dependencies]
+eframe = "0.31"
+egui = "0.31"
+egui_extras = { version = "0.31", features = ["all_loaders"] }
+rfd = "0.15"
+image = { version = "0.25", default-features = false, features = ["png"] }
+mp3rgain = { path = ".." }
+
+[target.'cfg(windows)'.build-dependencies]
+winresource = "0.1"
+
+[profile.release]
+lto = true
+codegen-units = 1
+strip = true

mp3rgui/build.rs

@@ -0,0 +1,8 @@
+fn main() {
+    #[cfg(windows)]
+    {
+        let mut res = winresource::WindowsResource::new();
+        res.set_icon("icons/icon.ico");
+        res.compile().unwrap();
+    }
+}