feat: add multi-arch Dockerfile for ARM64 support

.dockerignore

@@ -2,6 +2,8 @@
 .dockerignore
 .git
 .gitignore
+.env
+.secrets
 .idea
 .vscode
 **/.DS_Store

.gitignore

@@ -139,3 +139,4 @@ appimage-build/
 *.patch
 *.freezed.dart
 *.g.dart
+/output/

.metadata

@@ -4,7 +4,7 @@
 # This file should be version controlled and should not be manually edited.
 
 version:
-  revision: "35c388afb57ef061d06a39b537336c87e0e3d1b1"
+  revision: "ac4e799d237041cf905519190471f657b657155a"
   channel: "stable"
 
 project_type: app
@@ -13,26 +13,23 @@ project_type: app
 migration:
   platforms:
     - platform: root
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      create_revision: ac4e799d237041cf905519190471f657b657155a
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      base_revision: ac4e799d237041cf905519190471f657b657155a
     - platform: android
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      create_revision: ac4e799d237041cf905519190471f657b657155a
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      base_revision: ac4e799d237041cf905519190471f657b657155a
     - platform: ios
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      create_revision: ac4e799d237041cf905519190471f657b657155a
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      base_revision: ac4e799d237041cf905519190471f657b657155a
     - platform: linux
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      create_revision: ac4e799d237041cf905519190471f657b657155a
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      base_revision: ac4e799d237041cf905519190471f657b657155a
     - platform: macos
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      create_revision: ac4e799d237041cf905519190471f657b657155a
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      base_revision: ac4e799d237041cf905519190471f657b657155a
-    - platform: web
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
     - platform: windows
-      create_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      create_revision: ac4e799d237041cf905519190471f657b657155a
-      base_revision: 35c388afb57ef061d06a39b537336c87e0e3d1b1
+      base_revision: ac4e799d237041cf905519190471f657b657155a
 
   # User provided section
 

Dockerfile.arm64

@@ -0,0 +1,62 @@
+# TODO: support multi-arch building
+# TODO: https://docs.docker.com/reference/build-checks/from-platform-flag-const-disallowed/
+
+# Multi-arch Dockerfile for building Flutter Linux app on ARM64 using emulation
+# Build with: docker buildx build --platform linux/arm64 -t pdf_signature_arm64 .
+
+FROM --platform=linux/arm64 ghcr.io/cirruslabs/flutter:latest AS build
+
+# Install dependencies for Linux build (if not already in the image)
+RUN apt-get update && apt-get install -y \
+    clang \
+    cmake \
+    ninja-build \
+    pkg-config \
+    libgtk-3-dev \
+    libblkid-dev \
+    liblzma-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+# Enable Linux desktop support
+RUN flutter config --enable-linux-desktop
+
+# Set working directory
+WORKDIR /app
+
+# Copy pubspec files first for better caching
+COPY pubspec.* ./
+
+# Get dependencies
+RUN flutter pub get
+
+# Copy the rest of the project
+COPY . .
+
+# Enable Linux desktop platform for the project
+RUN flutter create . --platforms linux
+
+# Generate localization and build runner
+RUN flutter gen-l10n
+RUN flutter pub run build_runner build --delete-conflicting-outputs
+
+# Build the Linux app for ARM64 (explicitly specify, though container is ARM64)
+RUN flutter build linux --target-platform linux-arm64 --release
+
+# Final stage: Create a minimal runtime image
+FROM --platform=linux/arm64 ubuntu:22.04 AS runtime
+
+# Install runtime dependencies
+RUN apt-get update && apt-get install -y \
+    libgtk-3-0 \
+    libblkid1 \
+    liblzma5 \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy the built app
+COPY --from=build /app/build/linux/arm64/release/bundle /app
+
+# Set working directory
+WORKDIR /app
+
+# Run the app with bundled libraries
+CMD ["sh", "-c", "LD_LIBRARY_PATH=/app/lib:$LD_LIBRARY_PATH ./pdf_signature"]

docs/docker_compile.md

@@ -0,0 +1,26 @@
+
+one time
+[Manage Docker as a non-root user](https://docs.docker.com/engine/install/linux-postinstall/#manage-docker-as-a-non-root-user)
+
+```bash
+docker run --privileged --rm tonistiigi/binfmt --install all
+docker buildx create --use --name multiarch
+```
+
+build
+
+```bash
+docker buildx build --platform linux/arm64 -f Dockerfile.arm64 -t pdf_signature_arm64 .
+```
+
+Extract the Built App
+
+```bash
+mkdir output
+docker run --rm -v $(pwd)/output:/output pdf_signature_arm64 cp -r /app /output
+mkdir output/lib
+# docker run --rm -v $(pwd)/output:/output pdf_signature_arm64 ldd /app/pdf_signature
+docker run --rm -v $(pwd)/output:/output pdf_signature_arm64 sh -c "ldd /app/pdf_signature | grep '=>' | awk '{print \$3}' | grep -v libc | xargs -I {} cp -L {} /output/lib"
+# docker run --rm -v $(pwd)/output:/output pdf_signature_arm64 ls /app/lib
+# tree output/
+```

pubspec.yaml

@@ -21,6 +21,14 @@ version: 1.1.0+1
 environment:
   sdk: ^3.7.0
 
+platforms:
+  android:
+  ios:
+  linux:
+  macos:
+  web:
+  windows:
+
 # Dependencies specify other packages that your package needs in order to work.
 # To automatically upgrade your package dependencies to the latest versions
 # consider running `flutter pub upgrade --major-versions`. Alternatively,