Add AppImage build on linux

This consists of a meson option that
- sets a flag to make Aegisub read paths relative to the executable
- makes meson set up the symlinks like AppRun and .DirIcon as following
  the AppDir format

and a CI workflow that builds with this option, installs to an AppDir
directory, and bundles it as an AppImage.

Modified from arch1t3cht/Aegisub#12 .

Co-authored-by: Fred Brennan <copypaste@kittens.ph>

.github/workflows/ci.yml

@@ -49,6 +49,19 @@ jobs:
             buildtype: release,
             args: ''
           }
+          - name: Ubuntu AppImage
+            os: ubuntu-22.04
+            buildtype: release
+            appimage: true
+            # distro ffms is currently broken
+            args: >-
+              --prefix=/usr
+              -Dbuild_appimage=true
+              -Ddefault_library=static
+              --force-fallback-for=ffms2
+              -Davisynth=enabled
+              -Dbestsource=enabled
+              -Dvapoursynth=enabled
           - {
             name: macOS Debug,
             os: macos-latest,
@@ -102,13 +115,13 @@ jobs:
           brew install pulseaudio  # NO OpenAL in github CI
 
       - name: Install dependencies (Linux)
-        if: matrix.config.os == 'ubuntu-latest'
+        if: startsWith(matrix.config.os, 'ubuntu-')
         run: |
           sudo apt-get update
           sudo apt-get install ninja-build build-essential libx11-dev libwxgtk3.0-gtk3-dev libfreetype6-dev pkg-config libfontconfig1-dev libass-dev libasound2-dev libffms2-dev intltool libboost-all-dev
 
       - name: Configure
-        run: meson build ${{ matrix.config.args }} -Dbuildtype=${{ matrix.config.buildtype }}
+        run: meson setup build ${{ matrix.config.args }} -Dbuildtype=${{ matrix.config.buildtype }}
 
       - name: Build
         run: meson compile -C build
@@ -157,3 +170,28 @@ jobs:
           name: ${{ matrix.config.name }} - installer
           path: build/Aegisub-*.dmg
           if-no-files-found: error
+
+      # Linux artifacts (AppImage)
+      - name: Generate AppImage
+        if: matrix.config.appimage
+        run: |
+          mkdir -p appimage/appdir
+          meson install -C build --destdir=../appimage/appdir
+
+          cd appimage
+          sudo apt-get install libfuse2
+          curl -L "https://github.com/linuxdeploy/linuxdeploy/releases/download/1-alpha-20220822-1/linuxdeploy-x86_64.AppImage" -o linuxdeploy
+          curl -L "https://github.com/AppImage/AppImageKit/releases/download/13/appimagetool-x86_64.AppImage" -o appimagetool
+          chmod +x linuxdeploy appimagetool
+
+          ./linuxdeploy --appdir appdir --desktop-file=appdir/aegisub.desktop
+          ./appimagetool appdir
+          # ./appimagetool -g -s appdir --comp xz
+
+      - name: Upload artifacts - Linux AppImage
+        uses: actions/upload-artifact@v3
+        if: matrix.config.appimage
+        with:
+          name: ${{ matrix.config.name }}
+          path: appimage/*.AppImage
+          if-no-files-found: error

libaegisub/unix/path.cpp

@@ -75,14 +75,13 @@ void Path::FillPlatformSpecificPaths() {
 	SetToken("?local", home/".aegisub");
 
 #ifdef APPIMAGE_BUILD
-	agi::fs::path data = exe_dir();
+	agi::fs::path exe = exe_dir();
-	if (data == "") data = home/".aegisub";
+	agi::fs::path data_from_bin = agi::fs::path(P_DATA).lexically_relative(P_BIN);
-	SetToken("?data", data);
+	SetToken("?data", (exe != "" ? exe/data_from_bin : home/".aegisub").make_preferred());
-	SetToken("?dictionary", Decode("?data/dictionaries"));
 #else
 	SetToken("?data", P_DATA);
-	SetToken("?dictionary", "/usr/share/hunspell");
 #endif
+	SetToken("?dictionary", "/usr/share/hunspell");
 
 #else
 	agi::fs::path app_support = agi::util::GetApplicationSupportDirectory();

meson.build

@@ -1,6 +1,6 @@
 project('Aegisub', ['c', 'cpp'],
         license: 'BSD-3-Clause',
-        meson_version: '>=0.57.0',
+        meson_version: '>=0.61.0',
         default_options: ['cpp_std=c++14', 'buildtype=debugoptimized'],
         version: '3.2.2')
 
@@ -57,11 +57,15 @@ if get_option('buildtype') == 'release'
 endif
 
 conf = configuration_data()
+conf.set_quoted('P_BIN', bindir)
 conf.set_quoted('P_DATA', dataroot)
 conf.set_quoted('P_LOCALE', localedir)
 if get_option('credit') != ''
     conf.set_quoted('BUILD_CREDIT', get_option('credit'))
 endif
+if get_option('build_appimage')
+    conf.set('APPIMAGE_BUILD', 1)
+endif
 conf.set('WITH_UPDATE_CHECKER', get_option('enable_update_checker'))
 
 deps = []
@@ -94,7 +98,7 @@ deps += dependency('libass', version: '>=0.9.7',
 
 boost_modules = ['chrono', 'filesystem', 'thread', 'locale', 'regex']
 if not get_option('local_boost')
-    boost_dep = dependency('boost', version: '>=1.50.0',
+    boost_dep = dependency('boost', version: '>=1.60.0',
                             modules: boost_modules + ['system'],
                             required: false,
                             static: get_option('default_library') == 'static')

meson_options.txt

@@ -25,3 +25,4 @@ option('update_server', type: 'string', value: 'updates.aegisub.org', descriptio
 option('update_url', type: 'string', value: '/trunk', description: 'Base path to use for the update checker')
 
 option('build_osx_bundle', type: 'boolean', value: 'false', description: 'Package Aegisub.app on OSX')
+option('build_appimage', type: 'boolean', value: 'false', description: 'Prepare for AppImage packaging')

packages/meson.build

@@ -38,4 +38,10 @@ else
         install_data('desktop' / dir / 'aegisub.' + ext,
                      install_dir: datadir / 'icons' / 'hicolor' / dir / 'apps')
     endforeach
+
+    if get_option('build_appimage')
+      install_symlink('AppRun', install_dir: '/', pointing_to: bindir.strip('/') / 'aegisub')
+      install_symlink('.DirIcon', install_dir: '/', pointing_to: datadir.strip('/') / 'icons' / 'hicolor' / 'scalable' / 'apps' / 'aegisub.svg')
+      install_symlink('aegisub.desktop', install_dir: '/', pointing_to: datadir.strip('/') / 'applications' / 'aegisub.desktop')
+    endif
 endif