Linux Build Support Added

.github/copilot-instructions.md

@@ -1,3 +1,8 @@
+<!--
+SPDX-FileCopyrightText: 2026 Kushview, LLC
+SPDX-License-Identifier: ISC
+-->
+
 # Copilot Instructions for LUI Project
 
 ## General Guidelines

.github/workflows/build.yml

@@ -20,8 +20,8 @@ jobs:
           - os: macos-latest
             arch: arm64
             cmake_arch: arm64
-          # - os: ubuntu-latest
-          #   arch: x64
+          - os: ubuntu-latest
+            arch: x64
           # - os: windows-latest
           #   arch: x64
 
@@ -41,9 +41,10 @@ jobs:
         if: runner.os == 'Linux'
         run: |
           sudo apt-get update
-          sudo apt-get install -y libx11-dev libgl1-mesa-dev ninja-build cmake \
+          sudo apt-get install -y libx11-dev libxcursor-dev libxext-dev libxrandr-dev \
+            libgl1-mesa-dev libepoxy-dev libcairo2-dev ninja-build cmake \
             doxygen graphviz python3-sphinx python3-sphinx-rtd-theme
-      
+
       - name: Configure CMake (macOS)
         if: runner.os == 'macOS'
         run: |

CMakeLists.txt

@@ -49,6 +49,16 @@ include(GNUInstallDirs)
 
 include(cmake/SetupCairo.cmake)
 
+# Find libepoxy for GL backend (Linux/cross-platform)
+if(UNIX AND NOT APPLE)
+    find_package(PkgConfig)
+    if(PKG_CONFIG_FOUND)
+        pkg_check_modules(LIBEPOXY epoxy)
+    endif()
+    # Find X11 and related libraries for Pugl
+    find_package(X11 REQUIRED)
+endif()
+
 # Python 3 for scripts
 find_package(Python3 REQUIRED COMPONENTS Interpreter)
 

include/lui/path.hpp

@@ -56,7 +56,7 @@ class Path {
 
     /** Copy a path */
     Path (const Path& o) { operator= (o); }
-    constexpr Path& operator= (const Path& o) {
+    Path& operator= (const Path& o) {
         std::copy (o._data.begin(), o._data.end(), _data.begin());
         return *this;
     }
@@ -69,7 +69,7 @@ class Path {
     }
 
     /** Clear the path */
-    constexpr void clear() noexcept { _data.clear(); }
+    void clear() noexcept { _data.clear(); }
 
     void begin_path() {
         clear();
@@ -177,9 +177,9 @@ class Path {
     /** End iter */
     auto end() const noexcept { return iterator (_data.cend()); }
     /** Raw data vector */
-    constexpr const auto& data() const noexcept { return _data; }
+    const auto& data() const noexcept { return _data; }
     /** Reserve amount of bytes */
-    constexpr void reserve (std::size_t n) { _data.reserve (_data.size() + n); }
+    void reserve (std::size_t n) { _data.reserve (_data.size() + n); }
 
     void add_ellipse (float x, float y, float width, float height) noexcept {
         auto hw   = width * 0.5f;

include/lui/string.hpp

@@ -7,7 +7,11 @@
 #include <cctype>
 #include <cstdint>
 #include <cstring>
+
+#if __has_include(<format>)
 #include <format>
+#endif
+
 #include <string>
 
 namespace lui {
@@ -132,22 +136,42 @@ class String final {
 
     /** Append an int */
     String& append (int i) {
+#if __has_include(<format>)
         return append_formatted ("{}", i);
+#else
+        _str.append (std::to_string (i));
+        return *this;
+#endif
     }
 
     /** Append an int64 */
     String& append (int64_t i) {
+#if __has_include(<format>)
         return append_formatted ("{}", i);
+#else
+        _str.append (std::to_string (i));
+        return *this;
+#endif
     }
 
     /** Append a float */
     String& append (float i) {
+#if __has_include(<format>)
         return append_formatted ("{}", i);
+#else
+        _str.append (std::to_string (i));
+        return *this;
+#endif
     }
 
     /** Append a double */
     String& append (double i) {
+#if __has_include(<format>)
         return append_formatted ("{}", i);
+#else
+        _str.append (std::to_string (i));
+        return *this;
+#endif
     }
 
     /** Append formatted output using C++20 std::format.
@@ -157,11 +181,13 @@ class String final {
 
         Example: str.append_formatted("Value: {}", 42);
     */
+#if __has_include(<format>)
     template <typename... Args>
     String& append_formatted (std::format_string<Args...> fmt, Args&&... args) {
         _str.append (std::format (fmt, std::forward<Args> (args)...));
         return *this;
     }
+#endif
 
     /** Create a new formatted String using C++20 std::format.
         @param fmt Format string (e.g., "{} items: {:.2f}")
@@ -170,10 +196,12 @@ class String final {
 
         Example: auto msg = String::formatted("{} + {} = {}", 1, 2, 3);
     */
+#if __has_include(<format>)
     template <typename... Args>
     static String formatted (std::format_string<Args...> fmt, Args&&... args) {
         return String (std::format (fmt, std::forward<Args> (args)...));
     }
+#endif
 
     /** Return substring by byte position and length. 
         Warning: Does not validate UTF-8 boundaries. Use with caution.

src/CMakeLists.txt

@@ -49,7 +49,8 @@ if(APPLE)
             COMPILE_FLAGS "-Wno-deprecated")
 elseif(UNIX AND NOT APPLE)
     list(APPEND LIBLUI_SOURCES 
-        embed_x11.cpp)
+        embed_x11.cpp
+        pugl/src/x11.c)
 elseif(WIN32)
     list(APPEND LIBLUI_SOURCES 
         embed_win32.cpp)
@@ -92,6 +93,21 @@ target_link_directories(lui-${LUI_ABI_VERSION} PRIVATE)
 target_link_libraries(lui-${LUI_ABI_VERSION} 
     PRIVATE Threads::Threads)
 
+# X11 support for Linux
+if(UNIX AND NOT APPLE)
+    target_compile_options(lui-${LUI_ABI_VERSION} PRIVATE -fPIC)
+    target_link_libraries(lui-${LUI_ABI_VERSION} 
+        PRIVATE 
+            X11::X11 
+            X11::Xcursor
+            X11::Xext
+            X11::Xrandr)
+    # Xsync is optional, may not be available on all systems
+    if(TARGET X11::Xsync)
+        target_link_libraries(lui-${LUI_ABI_VERSION} PRIVATE X11::Xsync)
+    endif()
+endif()
+
 # Apple frameworks
 if(APPLE)
     target_link_libraries(lui-${LUI_ABI_VERSION} 
@@ -145,6 +161,10 @@ function(lui_add_backend tgt)
 
     target_link_libraries(${tgt} PUBLIC lui-${LUI_ABI_VERSION})
 
+    if(UNIX AND NOT APPLE)
+        target_compile_options(${tgt} PRIVATE -fPIC)
+    endif()
+
     install(TARGETS ${tgt}
         LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
         ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
@@ -165,14 +185,27 @@ if(APPLE)
         pugl/src/mac_gl.m)
     target_link_libraries(lui-gl-${LUI_ABI_VERSION} 
         PRIVATE "-framework OpenGL")
+    target_compile_definitions(lui-gl-${LUI_ABI_VERSION} PRIVATE NANOVG_GL2)
+elseif(UNIX AND NOT APPLE)
+    # Linux: use libepoxy for OpenGL function loading
+    target_sources(lui-gl-${LUI_ABI_VERSION} PRIVATE
+        pugl/src/x11_gl.c)
+    if(LIBEPOXY_FOUND)
+        target_link_libraries(lui-gl-${LUI_ABI_VERSION} 
+            PRIVATE ${LIBEPOXY_LIBRARIES} GL X11)
+        target_include_directories(lui-gl-${LUI_ABI_VERSION} 
+            PRIVATE ${LIBEPOXY_INCLUDE_DIRS})
+        target_compile_definitions(lui-gl-${LUI_ABI_VERSION} PRIVATE NANOVG_GL3)
+    else()
+        message(FATAL_ERROR "libepoxy not found - required for OpenGL backend on Linux")
+    endif()
 endif()
 
 lui_add_backend(lui-gl-${LUI_ABI_VERSION})
 target_include_directories(lui-gl-${LUI_ABI_VERSION} 
     PRIVATE
         ${CMAKE_CURRENT_BINARY_DIR}
         ${CMAKE_CURRENT_SOURCE_DIR}/nanovg)
-target_compile_definitions(lui-gl-${LUI_ABI_VERSION} PRIVATE NANOVG_GL2)
 
 # Generate and install pkg-config file for OpenGL backend
 configure_file(
@@ -187,8 +220,7 @@ install(FILES ${CMAKE_BINARY_DIR}/lui-gl-${LUI_ABI_VERSION}.pc
 # Cairo Backend
 if(CAIRO_FOUND)
     add_library(lui-cairo-${LUI_ABI_VERSION}
-        cairo.cpp
-        pugl/src/mac_cairo.m)
+        cairo.cpp)
 
     lui_add_backend(lui-cairo-${LUI_ABI_VERSION})
 
@@ -203,13 +235,15 @@ if(CAIRO_FOUND)
 
     # Platform-specific Cairo libraries
     if(APPLE)
+        target_sources(lui-cairo-${LUI_ABI_VERSION}  PRIVATE pugl/src/mac_cairo.m)
         target_link_libraries(lui-cairo-${LUI_ABI_VERSION} PRIVATE
             "-framework CoreGraphics"
         )
+    elseif(UNIX AND NOT APPLE)
+        target_sources(lui-cairo-${LUI_ABI_VERSION}  PRIVATE pugl/src/x11_cairo.c)
     elseif(WIN32)
-        target_link_libraries(lui-cairo-${LUI_ABI_VERSION} PRIVATE
-            gdi32
-        )
+        target_sources(lui-cairo-${LUI_ABI_VERSION}  PRIVATE pugl/src/win_cairo.c)
+        target_link_libraries(lui-cairo-${LUI_ABI_VERSION} PRIVATE gdi32)
     endif()
 
     message(STATUS "Cairo backend enabled - building lui-cairo-${LUI_ABI_VERSION}")

src/cairo.cpp

@@ -1,6 +1,7 @@
 // Copyright 2024 Michael Fisher <mfisher@lvtk.org>
 // SPDX-License-Identifier: ISC
 
+#include <cassert>
 #include <iostream>
 
 #if _MSC_VER

src/gl.hpp

@@ -15,6 +15,8 @@
 #        undef NOMINMAX
 #    endif
 #    define NOMINMAX
+#elif __linux__
+#    include <epoxy/gl.h>
 #endif
 
 #define PUGL_DISABLE_DEPRECATED

src/nanovg.cpp

@@ -444,7 +444,7 @@ void Context::draw_image (Image i, Transform matrix) {
         handle = nvgCreateImageRGBA (ctx->ctx,
                                      i.width(),
                                      i.height(),
-                                     NVG_IMAGE_PREMULTIPLIED | NVG_IMAGE_NODELETE,
+                                     (int) NVG_IMAGE_PREMULTIPLIED | (int) NVG_IMAGE_NODELETE,
                                      i.data());
 
         if (handle <= 0) {