### Install Flutter Development Environment

Source: https://github.com/ubuntu/yaru.dart/blob/main/README.md

Instructions to install Flutter, Git, cURL, CMake, Meson, Make, Clang, GTK development libraries, and pkg-config on Ubuntu. It also sets up the Flutter bin directory in the PATH.

```console
sudo apt -y install git curl cmake meson make clang libgtk-3-dev pkg-config && mkdir -p ~/development && cd ~/development && git clone https://github.com/flutter/flutter.git -b stable && echo 'export PATH="$PATH:$HOME/development/flutter/bin"' >> ~/.bashrc && source ~/.bashrc
```

--------------------------------

### Install VSCode via Snap

Source: https://github.com/ubuntu/yaru.dart/blob/main/README.md

Command to install Visual Studio Code using the Snap package manager on Ubuntu.

```console
sudo snap install code --classic
```

--------------------------------

### Flutter GTK Dependencies and Library Setup

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/linux/flutter/CMakeLists.txt

Finds required system packages (GTK, GLIB, GIO) using PkgConfig, defines paths for the Flutter Linux GTK library and ICU data file, and sets up an INTERFACE library target for Flutter integration.

```cmake
# === Flutter Library ===
# System-level dependencies.
find_package(PkgConfig REQUIRED)
pkg_check_modules(GTK REQUIRED IMPORTED_TARGET gtk+-3.0)
pkg_check_modules(GLIB REQUIRED IMPORTED_TARGET glib-2.0)
pkg_check_modules(GIO REQUIRED IMPORTED_TARGET gio-2.0)

set(FLUTTER_LIBRARY "${EPHEMERAL_DIR}/libflutter_linux_gtk.so")

# Published to parent scope for install step.
set(FLUTTER_LIBRARY ${FLUTTER_LIBRARY} PARENT_SCOPE)
set(FLUTTER_ICU_DATA_FILE "${EPHEMERAL_DIR}/icudtl.dat" PARENT_SCOPE)
set(PROJECT_BUILD_DIR "${PROJECT_DIR}/build/" PARENT_SCOPE)
set(AOT_LIBRARY "${PROJECT_DIR}/build/lib/libapp.so" PARENT_SCOPE)

list(APPEND FLUTTER_LIBRARY_HEADERS
  "fl_basic_message_channel.h"
  "fl_binary_codec.h"
  "fl_binary_messenger.h"
  "fl_dart_project.h"
  "fl_engine.h"
  "fl_json_message_codec.h"
  "fl_json_method_codec.h"
  "fl_message_codec.h"
  "fl_method_call.h"
  "fl_method_channel.h"
  "fl_method_codec.h"
  "fl_method_response.h"
  "fl_plugin_registrar.h"
  "fl_plugin_registry.h"
  "fl_standard_message_codec.h"
  "fl_standard_method_codec.h"
  "fl_string_codec.h"
  "fl_value.h"
  "fl_view.h"
  "flutter_linux.h"
)
list_prepend(FLUTTER_LIBRARY_HEADERS "${EPHEMERAL_DIR}/flutter_linux/")
add_library(flutter INTERFACE)
target_include_directories(flutter INTERFACE
  "${EPHEMERAL_DIR}"
)
target_link_libraries(flutter INTERFACE "${FLUTTER_LIBRARY}")
target_link_libraries(flutter INTERFACE
  PkgConfig::GTK
  PkgConfig::GLIB
  PkgConfig::GIO
)
add_dependencies(flutter flutter_assemble)

```

--------------------------------

### CMakeLists.txt Configuration for Flutter Application

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/windows/CMakeLists.txt

This CMakeLists.txt file configures the build process for a Flutter application. It sets up project properties, defines build types (Debug, Profile, Release), applies standard compilation settings, includes Flutter and runner subdirectories, and manages installation rules for the application and its assets.

```cmake
cmake_minimum_required(VERSION 3.14)
project(example LANGUAGES CXX)

# The name of the executable created for the application. Change this to change
# the on-disk name of your application.
set(BINARY_NAME "example")

# Explicitly opt in to modern CMake behaviors to avoid warnings with recent
# versions of CMake.
cmake_policy(SET CMP0063 NEW)

# Define build configuration option.
get_property(IS_MULTICONFIG GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
if(IS_MULTICONFIG)
  set(CMAKE_CONFIGURATION_TYPES "Debug;Profile;Release"
    CACHE STRING "" FORCE)
else()
  if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
    set(CMAKE_BUILD_TYPE "Debug" CACHE
      STRING "Flutter build mode" FORCE)
    set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
      "Debug" "Profile" "Release")
  endif()
endif()
# Define settings for the Profile build mode.
set(CMAKE_EXE_LINKER_FLAGS_PROFILE "${CMAKE_EXE_LINKER_FLAGS_RELEASE}")
set(CMAKE_SHARED_LINKER_FLAGS_PROFILE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE}")
set(CMAKE_C_FLAGS_PROFILE "${CMAKE_C_FLAGS_RELEASE}")
set(CMAKE_CXX_FLAGS_PROFILE "${CMAKE_CXX_FLAGS_RELEASE}")

# Use Unicode for all projects.
add_definitions(-DUNICODE -D_UNICODE)

# Compilation settings that should be applied to most targets.
#
# Be cautious about adding new options here, as plugins use this function by
# default. In most cases, you should add new options to specific targets instead
# of modifying this function.
function(APPLY_STANDARD_SETTINGS TARGET)
  target_compile_features(${TARGET} PUBLIC cxx_std_17)
  target_compile_options(${TARGET} PRIVATE /W4 /WX /wd"4100")
  target_compile_options(${TARGET} PRIVATE /EHsc)
  target_compile_definitions(${TARGET} PRIVATE "_HAS_EXCEPTIONS=0")
  target_compile_definitions(${TARGET} PRIVATE "$<CONFIG:Debug>:_DEBUG")
endfunction()

# Flutter library and tool build rules.
set(FLUTTER_MANAGED_DIR "${CMAKE_CURRENT_SOURCE_DIR}/flutter")
add_subdirectory(${FLUTTER_MANAGED_DIR})

# Application build; see runner/CMakeLists.txt.
add_subdirectory("runner")

# Generated plugin build rules, which manage building the plugins and adding
# them to the application.
include(flutter/generated_plugins.cmake)


# === Installation ===
# Support files are copied into place next to the executable, so that it can
# run in place. This is done instead of making a separate bundle (as on Linux)
# so that building and running from within Visual Studio will work.
set(BUILD_BUNDLE_DIR "$<TARGET_FILE_DIR:${BINARY_NAME}>")
# Make the "install" step default, as it's required to run.
set(CMAKE_VS_INCLUDE_INSTALL_TO_DEFAULT_BUILD 1)
if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
  set(CMAKE_INSTALL_PREFIX "${BUILD_BUNDLE_DIR}" CACHE PATH "..." FORCE)
endif()

set(INSTALL_BUNDLE_DATA_DIR "${CMAKE_INSTALL_PREFIX}/data")
set(INSTALL_BUNDLE_LIB_DIR "${CMAKE_INSTALL_PREFIX}")

install(TARGETS ${BINARY_NAME} RUNTIME DESTINATION "${CMAKE_INSTALL_PREFIX}"
  COMPONENT Runtime)

install(FILES "${FLUTTER_ICU_DATA_FILE}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}"
  COMPONENT Runtime)

install(FILES "${FLUTTER_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
  COMPONENT Runtime)

if(PLUGIN_BUNDLED_LIBRARIES)
  install(FILES "${PLUGIN_BUNDLED_LIBRARIES}"
    DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
    COMPONENT Runtime)
endif()

# Fully re-copy the assets directory on each build to avoid having stale files
# from a previous install.
set(FLUTTER_ASSET_DIR_NAME "flutter_assets")
install(CODE "
  file(REMOVE_RECURSE \"${INSTALL_BUNDLE_DATA_DIR}/${FLUTTER_ASSET_DIR_NAME}\")
  " COMPONENT Runtime)
install(DIRECTORY "${PROJECT_BUILD_DIR}/${FLUTTER_ASSET_DIR_NAME}"
  DESTINATION "${INSTALL_BUNDLE_DATA_DIR}" COMPONENT Runtime)

# Install the AOT library on non-Debug builds only.
install(FILES "${AOT_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}"
  CONFIGURATIONS Profile;Release
  COMPONENT Runtime)

```

--------------------------------

### CMakeLists.txt Configuration for Yaru Flutter App

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/linux/CMakeLists.txt

Configures the build process for a Flutter application using CMake. It sets project properties, manages build types (Debug, Profile, Release), defines compilation settings, links necessary libraries (like GTK and Flutter), and specifies installation rules for creating a relocatable bundle.

```cmake
cmake_minimum_required(VERSION 3.10)
project(runner LANGUAGES CXX)

set(BINARY_NAME "yaru_example")
set(APPLICATION_ID "com.ubuntu.yaru_example")

cmake_policy(SET CMP0063 NEW)

set(CMAKE_INSTALL_RPATH "$ORIGIN/lib")

# Root filesystem for cross-building.
if(FLUTTER_TARGET_PLATFORM_SYSROOT)
  set(CMAKE_SYSROOT ${FLUTTER_TARGET_PLATFORM_SYSROOT})
  set(CMAKE_FIND_ROOT_PATH ${CMAKE_SYSROOT})
  set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
  set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
  set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
  set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
endif()

# Configure build options.
if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
  set(CMAKE_BUILD_TYPE "Debug" CACHE
    STRING "Flutter build mode" FORCE)
  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
    "Debug" "Profile" "Release")
endif()

# Compilation settings that should be applied to most targets.
function(APPLY_STANDARD_SETTINGS TARGET)
  target_compile_features(${TARGET} PUBLIC cxx_std_14)
  target_compile_options(${TARGET} PRIVATE -Wall -Werror)
  target_compile_options(${TARGET} PRIVATE "<$<NOT:$<CONFIG:Debug>>:-O3>")
  target_compile_definitions(${TARGET} PRIVATE "<$<NOT:$<CONFIG:Debug>>:NDEBUG>")
endfunction()

set(FLUTTER_MANAGED_DIR "${CMAKE_CURRENT_SOURCE_DIR}/flutter")

# Flutter library and tool build rules.
add_subdirectory(${FLUTTER_MANAGED_DIR})

# System-level dependencies.
find_package(PkgConfig REQUIRED)
pkg_check_modules(GTK REQUIRED IMPORTED_TARGET gtk+-3.0)

add_definitions(-DAPPLICATION_ID="${APPLICATION_ID}")

# Application build
add_executable(${BINARY_NAME}
  "main.cc"
  "my_application.cc"
  "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
)
apply_standard_settings(${BINARY_NAME})
target_link_libraries(${BINARY_NAME} PRIVATE flutter)
target_link_libraries(${BINARY_NAME} PRIVATE PkgConfig::GTK)
add_dependencies(${BINARY_NAME} flutter_assemble)
# Only the install-generated bundle's copy of the executable will launch
# correctly, since the resources must in the right relative locations. To avoid
# people trying to run the unbundled copy, put it in a subdirectory instead of
# the default top-level location.
set_target_properties(${BINARY_NAME}
  PROPERTIES
  RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/intermediates_do_not_run"
)

# Generated plugin build rules, which manage building the plugins and adding
# them to the application.
include(flutter/generated_plugins.cmake)


# === Installation ===
# By default, "installing" just makes a relocatable bundle in the build
# directory.
set(BUILD_BUNDLE_DIR "${PROJECT_BINARY_DIR}/bundle")
if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
  set(CMAKE_INSTALL_PREFIX "${BUILD_BUNDLE_DIR}" CACHE PATH "..." FORCE)
endif()

# Start with a clean build bundle directory every time.
install(CODE "
  file(REMOVE_RECURSE \"${BUILD_BUNDLE_DIR}/\")
  " COMPONENT Runtime)

set(INSTALL_BUNDLE_DATA_DIR "${CMAKE_INSTALL_PREFIX}/data")
set(INSTALL_BUNDLE_LIB_DIR "${CMAKE_INSTALL_PREFIX}/lib")

install(TARGETS ${BINARY_NAME} RUNTIME DESTINATION "${CMAKE_INSTALL_PREFIX}"
  COMPONENT Runtime)

install(FILES "${FLUTTER_ICU_DATA_FILE}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}"
  COMPONENT Runtime)

install(FILES "${FLUTTER_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
  COMPONENT Runtime)

if(PLUGIN_BUNDLED_LIBRARIES)
  install(FILES "${PLUGIN_BUNDLED_LIBRARIES}"
    DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
    COMPONENT Runtime)
endif()

# Fully re-copy the assets directory on each build to avoid having stale files
# from a previous install.
set(FLUTTER_ASSET_DIR_NAME "flutter_assets")
install(CODE "
  file(REMOVE_RECURSE \"${INSTALL_BUNDLE_DATA_DIR}/${FLUTTER_ASSET_DIR_NAME}\")
  " COMPONENT Runtime)
install(DIRECTORY "${PROJECT_BUILD_DIR}/${FLUTTER_ASSET_DIR_NAME}"
  DESTINATION "${INSTALL_BUNDLE_DATA_DIR}" COMPONENT Runtime)

# Install the AOT library on non-Debug builds only.
if(NOT CMAKE_BUILD_TYPE MATCHES "Debug")
  install(FILES "${AOT_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
    COMPONENT Runtime)
endif()
```

--------------------------------

### CMake Project Initialization and Configuration

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/linux/flutter/CMakeLists.txt

Sets up the minimum CMake version, defines an ephemeral directory for generated files, and includes configuration generated by the Flutter tool. It also includes a helper function for list manipulation.

```cmake
cmake_minimum_required(VERSION 3.10)

set(EPHEMERAL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ephemeral")

# Configuration provided via flutter tool.
include(${EPHEMERAL_DIR}/generated_config.cmake)

# TODO: Move the rest of this into files in ephemeral. See
# https://github.com/flutter/flutter/issues/57146.

# Serves the same purpose as list(TRANSFORM ... PREPEND ...),
# which isn't available in 3.10.
function(list_prepend LIST_NAME PREFIX)
    set(NEW_LIST "")
    foreach(element ${${LIST_NAME}})
        list(APPEND NEW_LIST "${PREFIX}${element}")
    endforeach(element)
    set(${LIST_NAME} "${NEW_LIST}" PARENT_SCOPE)
endfunction()

```

--------------------------------

### Flutter Windows App CMake Configuration

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/windows/runner/CMakeLists.txt

Configures the CMake build system for a Flutter application on Windows. It defines the main executable target, lists source files, sets version-specific preprocessor definitions, and links necessary libraries like flutter and dwmapi.lib.

```cmake
cmake_minimum_required(VERSION 3.14)
project(runner LANGUAGES CXX)

# Define the application target. To change its name, change BINARY_NAME in the
# top-level CMakeLists.txt, not the value here, or `flutter run` will no longer
# work.
#
# Any new source files that you add to the application should be added here.
add_executable(${BINARY_NAME} WIN32
  "flutter_window.cpp"
  "main.cpp"
  "utils.cpp"
  "win32_window.cpp"
  "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
  "Runner.rc"
  "runner.exe.manifest"
)

# Apply the standard set of build settings. This can be removed for applications
# that need different build settings.
apply_standard_settings(${BINARY_NAME})

# Add preprocessor definitions for the build version.
target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION=\"${FLUTTER_VERSION}\"")
target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_MAJOR=${FLUTTER_VERSION_MAJOR}")
target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_MINOR=${FLUTTER_VERSION_MINOR}")
target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_PATCH=${FLUTTER_VERSION_PATCH}")
target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_BUILD=${FLUTTER_VERSION_BUILD}")

# Disable Windows macros that collide with C++ standard library functions.
target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")

# Add dependency libraries and include directories. Add any application-specific
# dependencies here.
target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")

# Run the Flutter tool portions of the build. This must not be removed.
add_dependencies(${BINARY_NAME} flutter_assemble)

```

--------------------------------

### Flutter Build Configuration

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/windows/flutter/CMakeLists.txt

This CMake script configures Flutter-level build steps. It sets up the Flutter library, defines C++ wrapper sources for plugins and the application runner, and integrates with the Flutter tool backend for assembly. It should not be edited directly.

```CMake
cmake_minimum_required(VERSION 3.14)

set(EPHEMERAL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ephemeral")

# Configuration provided via flutter tool.
include(${EPHEMERAL_DIR}/generated_config.cmake)

# TODO: Move the rest of this into files in ephemeral. See
# https://github.com/flutter/flutter/issues/57146.
set(WRAPPER_ROOT "${EPHEMERAL_DIR}/cpp_client_wrapper")

# Set fallback configurations for older versions of the flutter tool.
if (NOT DEFINED FLUTTER_TARGET_PLATFORM)
  set(FLUTTER_TARGET_PLATFORM "windows-x64")
endif()

# === Flutter Library ===
set(FLUTTER_LIBRARY "${EPHEMERAL_DIR}/flutter_windows.dll")

# Published to parent scope for install step.
set(FLUTTER_LIBRARY ${FLUTTER_LIBRARY} PARENT_SCOPE)
set(FLUTTER_ICU_DATA_FILE "${EPHEMERAL_DIR}/icudtl.dat" PARENT_SCOPE)
set(PROJECT_BUILD_DIR "${PROJECT_DIR}/build/" PARENT_SCOPE)
set(AOT_LIBRARY "${PROJECT_DIR}/build/windows/app.so" PARENT_SCOPE)

list(APPEND FLUTTER_LIBRARY_HEADERS
  "flutter_export.h"
  "flutter_windows.h"
  "flutter_messenger.h"
  "flutter_plugin_registrar.h"
  "flutter_texture_registrar.h"
)
list(TRANSFORM FLUTTER_LIBRARY_HEADERS PREPEND "${EPHEMERAL_DIR}/")
add_library(flutter INTERFACE)
target_include_directories(flutter INTERFACE
  "${EPHEMERAL_DIR}"
)
target_link_libraries(flutter INTERFACE "${FLUTTER_LIBRARY}.lib")
add_dependencies(flutter flutter_assemble)

# === Wrapper ===
list(APPEND CPP_WRAPPER_SOURCES_CORE
  "core_implementations.cc"
  "standard_codec.cc"
)
list(TRANSFORM CPP_WRAPPER_SOURCES_CORE PREPEND "${WRAPPER_ROOT}/")
list(APPEND CPP_WRAPPER_SOURCES_PLUGIN
  "plugin_registrar.cc"
)
list(TRANSFORM CPP_WRAPPER_SOURCES_PLUGIN PREPEND "${WRAPPER_ROOT}/")
list(APPEND CPP_WRAPPER_SOURCES_APP
  "flutter_engine.cc"
  "flutter_view_controller.cc"
)
list(TRANSFORM CPP_WRAPPER_SOURCES_APP PREPEND "${WRAPPER_ROOT}/")

# Wrapper sources needed for a plugin.
add_library(flutter_wrapper_plugin STATIC
  ${CPP_WRAPPER_SOURCES_CORE}
  ${CPP_WRAPPER_SOURCES_PLUGIN}
)
apply_standard_settings(flutter_wrapper_plugin)
set_target_properties(flutter_wrapper_plugin PROPERTIES
  POSITION_INDEPENDENT_CODE ON)
set_target_properties(flutter_wrapper_plugin PROPERTIES
  CXX_VISIBILITY_PRESET hidden)
target_link_libraries(flutter_wrapper_plugin PUBLIC flutter)
target_include_directories(flutter_wrapper_plugin PUBLIC
  "${WRAPPER_ROOT}/include"
)
add_dependencies(flutter_wrapper_plugin flutter_assemble)

# Wrapper sources needed for the runner.
add_library(flutter_wrapper_app STATIC
  ${CPP_WRAPPER_SOURCES_CORE}
  ${CPP_WRAPPER_SOURCES_APP}
)
apply_standard_settings(flutter_wrapper_app)
target_link_libraries(flutter_wrapper_app PUBLIC flutter)
target_include_directories(flutter_wrapper_app PUBLIC
  "${WRAPPER_ROOT}/include"
)
add_dependencies(flutter_wrapper_app flutter_assemble)

# === Flutter tool backend ===
# _phony_ is a non-existent file to force this command to run every time,
# since currently there's no way to get a full input/output list from the
# flutter tool.
set(PHONY_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/_phony_")
set_source_files_properties("${PHONY_OUTPUT}" PROPERTIES SYMBOLIC TRUE)
add_custom_command(
  OUTPUT ${FLUTTER_LIBRARY} ${FLUTTER_LIBRARY_HEADERS}
    ${CPP_WRAPPER_SOURCES_CORE} ${CPP_WRAPPER_SOURCES_PLUGIN}
    ${CPP_WRAPPER_SOURCES_APP}
    ${PHONY_OUTPUT}
  COMMAND ${CMAKE_COMMAND} -E env
    ${FLUTTER_TOOL_ENVIRONMENT}
    "${FLUTTER_ROOT}/packages/flutter_tools/bin/tool_backend.bat"
      ${FLUTTER_TARGET_PLATFORM} $<CONFIG>
  VERBATIM
)
add_custom_target(flutter_assemble DEPENDS
  "${FLUTTER_LIBRARY}"
  ${FLUTTER_LIBRARY_HEADERS}
  ${CPP_WRAPPER_SOURCES_CORE}
  ${CPP_WRAPPER_SOURCES_PLUGIN}
  ${CPP_WRAPPER_SOURCES_APP}
)
```

--------------------------------

### Flutter Tool Backend Integration

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/linux/flutter/CMakeLists.txt

Configures a custom command to execute the Flutter tool backend script, which is essential for building the Flutter engine and related assets. This command is triggered by a custom target named 'flutter_assemble'.

```cmake
# === Flutter tool backend ===
# _phony_ is a non-existent file to force this command to run every time,
# since currently there's no way to get a full input/output list from the
# flutter tool.
add_custom_command(
  OUTPUT ${FLUTTER_LIBRARY} ${FLUTTER_LIBRARY_HEADERS}
    ${CMAKE_CURRENT_BINARY_DIR}/_phony_
  COMMAND ${CMAKE_COMMAND} -E env
    ${FLUTTER_TOOL_ENVIRONMENT}
    "${FLUTTER_ROOT}/packages/flutter_tools/bin/tool_backend.sh"
      ${FLUTTER_TARGET_PLATFORM} ${CMAKE_BUILD_TYPE}
  VERBATIM
)
add_custom_target(flutter_assemble DEPENDS
  "${FLUTTER_LIBRARY}"
  ${FLUTTER_LIBRARY_HEADERS}
)

```

--------------------------------

### Service Worker Registration and Script Loading

Source: https://github.com/ubuntu/yaru.dart/blob/main/example/web/index.html

Handles the registration of a service worker for caching and offline capabilities. It dynamically loads the main application script ('main.dart.js') after service worker activation or falls back to a direct script load if service workers are not supported or fail to load within a timeout. This ensures efficient application loading and updates.

```javascript
var serviceWorkerVersion = null;
var scriptLoaded = false;

function loadMainDartJs() {
    if (scriptLoaded) {
        return;
    }
    scriptLoaded = true;
    var scriptTag = document.createElement('script');
    scriptTag.src = 'main.dart.js';
    scriptTag.type = 'application/javascript';
    document.body.append(scriptTag);
}

if ('serviceWorker' in navigator) {
    // Service workers are supported. Use them.
    window.addEventListener('load', function () {
        // Wait for registration to finish before dropping the <script> tag.
        // Otherwise, the browser will load the script multiple times,
        // potentially different versions.
        var serviceWorkerUrl = 'flutter_service_worker.js?v=' + serviceWorkerVersion;
        navigator.serviceWorker.register(serviceWorkerUrl)
            .then((reg) => {
                function waitForActivation(serviceWorker) {
                    serviceWorker.addEventListener('statechange', () => {
                        if (serviceWorker.state == 'activated') {
                            console.log('Installed new service worker.');
                            loadMainDartJs();
                        }
                    });
                }

                if (!reg.active && (reg.installing || reg.waiting)) {
                    // No active web worker and we have installed or are installing
                    // one for the first time. Simply wait for it to activate.
                    waitForActivation(reg.installing || reg.waiting);
                } else if (!reg.active.scriptURL.endsWith(serviceWorkerVersion)) {
                    // When the app updates the serviceWorkerVersion changes, so we
                    // need to ask the service worker to update.
                    console.log('New service worker available.');
                    reg.update();
                    waitForActivation(reg.installing);
                } else {
                    // Existing service worker is still good.
                    console.log('Loading app from service worker.');
                    loadMainDartJs();
                }
            });

        // If service worker doesn't succeed in a reasonable amount of time,
        // fallback to plaint <script> tag.
        setTimeout(() => {
            if (!scriptLoaded) {
                console.warn(
                    'Failed to load app from service worker. Falling back to plain <script> tag.',
                );
                loadMainDartJs();
            }
        }, 4000);
    });
} else {
    // Service workers not supported. Just drop the <script> tag.
    loadMainDartJs();
}
```

--------------------------------

### Generate Yaru Icon Font

Source: https://github.com/ubuntu/yaru.dart/blob/main/README.md

Executes the icon font generator tool to process SVG files from a specified directory and generate an icon font file along with a Dart class for accessing the icons.

```bash
yaru_icon_font_generator assets/icons assets/yaru_icons.otf --output-class-file=lib/src/yaru_icons.dart -r
```

--------------------------------

### Activate Icon Font Generator

Source: https://github.com/ubuntu/yaru.dart/blob/main/README.md

Activates the icon_font_generator tool from a specific Git repository and branch, required for working with icon assets. This tool helps in generating icon fonts from SVG files.

```dart
dart pub global activate -sgit https://github.com/Jupi007/icon_font_generator.git --git-ref yaru
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.