feat(dist): appimage

• Added AppImage packaging for Linux and wired it into GitHub release CI.

  - lwjgl3/build.gradle
      - added :lwjgl3:bundleLinuxAppImage
      - it builds from the existing bundleLinuxDir output, creates an AppDir, writes:
          - AppRun
          - octodraw.desktop
          - octodraw.png
      - stages the Linux bundle under usr/lib/octodraw
      - uses APPIMAGETOOL env var if provided, otherwise appimagetool
      - outputs dist/octodraw-dist-<version>-linux.AppImage
  - .github/workflows/release.yml
      - Linux job now downloads appimagetool
      - Linux build now runs:
          - :lwjgl3:bundleLinuxTar
          - :lwjgl3:bundleLinuxAppImage
          - :lwjgl3:jarLinux
          - :core:pluginApiJar
      - uploaded Linux artifacts now include dist/*.AppImage
      - release upload now includes *.AppImage

  What this does not change:

  - Android
  - Windows
  - portable desktop tar build
  - webcomponent build

  Use:

  - local:
      - APPIMAGETOOL=/path/to/appimagetool ./gradlew :lwjgl3:bundleLinuxAppImage -PreleaseNumber=<version>
  - CI:
      - handled automatically by the updated release workflow

Author: alferio

.github/workflows/release.yml

@@ -27,13 +27,22 @@ jobs:
         with:
           distribution: "temurin"
           java-version: "21"
+      - name: Fetch appimagetool
+        run: |
+          set -euo pipefail
+          curl -fsSL -o "$RUNNER_TEMP/appimagetool.AppImage" \
+            https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-x86_64.AppImage
+          chmod +x "$RUNNER_TEMP/appimagetool.AppImage"
       - name: Build Linux bundle + JVM jars
-        run: ./gradlew :lwjgl3:bundleLinuxTar :lwjgl3:jarLinux :core:pluginApiJar -PreleaseNumber="${{ inputs.tag }}"
+        env:
+          APPIMAGETOOL: ${{ runner.temp }}/appimagetool.AppImage
+        run: ./gradlew :lwjgl3:bundleLinuxTar :lwjgl3:bundleLinuxAppImage :lwjgl3:jarLinux :core:pluginApiJar -PreleaseNumber="${{ inputs.tag }}"
       - uses: actions/upload-artifact@v4
         with:
           name: octodraw-linux
           path: |
             dist/*.tar.gz
+            dist/*.AppImage
             lwjgl3/build/libs/*.jar
             core/build/libs/octodraw-plugin*.jar
 
@@ -369,7 +378,7 @@ jobs:
           else
             gh release edit "$TAG" --draft="$DRAFT" --prerelease="$PRERELEASE"
           fi
-          files=$(find artifacts -type f \( -name "*.zip" -o -name "*.tar.gz" -o -name "*.snap" -o -name "*.jar" -o -name "*.msi" -o -name "*.msix" -o -name "*.apk" -o -name "*.aab" \))
+          files=$(find artifacts -type f \( -name "*.zip" -o -name "*.tar.gz" -o -name "*.AppImage" -o -name "*.snap" -o -name "*.jar" -o -name "*.msi" -o -name "*.msix" -o -name "*.apk" -o -name "*.aab" \))
           if [ -z "$files" ]; then
             echo "No release artifacts found."
             exit 1

lwjgl3/build.gradle

@@ -789,6 +789,110 @@ configureBundleTask("bundleWin", "win", tasks.named("fetchJdkWin"), file("$jdkCa
 configureBundleTask("bundleMacArm64", "mac", tasks.named("fetchJdkMacArm64"), file("$jdkCacheDir/mac-arm64"), true, false)
 configureBundleTarTask("bundleLinuxTar", "linux", tasks.named("fetchJdkLinux"), file("$jdkCacheDir/linux-x64"), true)
 configureBundleTarTask("bundleMacArm64Tar", "mac", tasks.named("fetchJdkMacArm64"), file("$jdkCacheDir/mac-arm64"), true)
+tasks.register("bundleLinuxAppImage") {
+  dependsOn "bundleLinuxDir"
+  outputs.file rootProject.file("dist/octodraw-dist-${bundleVersion}-linux.AppImage")
+  doLast {
+    if (!os.contains("linux")) {
+      throw new GradleException("AppImage packaging is only supported on Linux hosts.")
+    }
+    def appImageToolPath = System.getenv("APPIMAGETOOL") ?: "appimagetool"
+    def probe = null
+    try {
+      probe = new ProcessBuilder(appImageToolPath, "--version")
+        .directory(project.projectDir)
+        .redirectErrorStream(true)
+        .start()
+      probe.inputStream.text
+    } catch (IOException ignored) {
+      probe = null
+    }
+    if (probe == null || probe.waitFor() != 0) {
+      throw new GradleException("appimagetool not found. Install appimagetool or set APPIMAGETOOL.")
+    }
+
+    def bundleDir = rootProject.file("dist/octodraw-dist-${bundleVersion}-linux")
+    if (!bundleDir.exists()) {
+      throw new GradleException("Linux bundle directory not found: ${bundleDir}")
+    }
+
+    def appDir = file("$buildDir/appimage/Octodraw.AppDir")
+    def outFile = rootProject.file("dist/octodraw-dist-${bundleVersion}-linux.AppImage")
+    project.delete(appDir)
+    project.delete(outFile)
+
+    def payloadDir = new File(appDir, "usr/lib/octodraw")
+    def binDir = new File(appDir, "usr/bin")
+    def applicationsDir = new File(appDir, "usr/share/applications")
+    def iconDir = new File(appDir, "usr/share/icons/hicolor/512x512/apps")
+    [payloadDir, binDir, applicationsDir, iconDir].each { it.mkdirs() }
+
+    project.copy {
+      from(bundleDir)
+      into(payloadDir)
+    }
+
+    def launcher = new File(binDir, "octodraw")
+    launcher.text = """#!/bin/sh
+set -eu
+HERE="\$(CDPATH= cd -- "\$(dirname -- "\$0")" && pwd)"
+APPDIR="\$(CDPATH= cd -- "\$HERE/../.." && pwd)"
+exec "\$APPDIR/usr/lib/octodraw/octodraw-jre" "\$@"
+"""
+    launcher.setExecutable(true, false)
+
+    def appRun = new File(appDir, "AppRun")
+    appRun.text = """#!/bin/sh
+set -eu
+HERE="\$(CDPATH= cd -- "\$(dirname -- "\$0")" && pwd)"
+exec "\$HERE/usr/bin/octodraw" "\$@"
+"""
+    appRun.setExecutable(true, false)
+
+    def desktopEntry = """[Desktop Entry]
+Name=Octodraw
+Comment=3D drafting and modeling tool
+Exec=octodraw %U
+Icon=octodraw
+Terminal=false
+Type=Application
+Categories=Graphics;3DGraphics;Engineering;
+MimeType=application/octet-stream;
+StartupWMClass=Octodraw
+"""
+    new File(appDir, "octodraw.desktop").text = desktopEntry
+    new File(applicationsDir, "octodraw.desktop").text = desktopEntry
+
+    def iconSource = rootProject.file("assets/appicon_512x512.png")
+    if (!iconSource.exists()) {
+      iconSource = rootProject.file("assets/appicon.png")
+    }
+    project.copy {
+      from(iconSource)
+      into(appDir)
+      rename { "octodraw.png" }
+    }
+    project.copy {
+      from(iconSource)
+      into(iconDir)
+      rename { "octodraw.png" }
+    }
+
+    ensureUnixRuntimeExecutables(payloadDir)
+
+    def pack = new ProcessBuilder(appImageToolPath, appDir.absolutePath, outFile.absolutePath)
+      .directory(rootProject.projectDir)
+      .inheritIO()
+    pack.environment().put("ARCH", "x86_64")
+    if (appImageToolPath.endsWith(".AppImage")) {
+      pack.environment().put("APPIMAGE_EXTRACT_AND_RUN", "1")
+    }
+    def process = pack.start()
+    if (process.waitFor() != 0) {
+      throw new GradleException("appimagetool failed while building ${outFile.name}.")
+    }
+  }
+}
 
 tasks.register("bundleLinuxSnap") {
   outputs.file rootProject.file("dist/octodraw-dist-${bundleVersion}-linux.snap")