From a75a0418be2945653b92302847c55b6376f1866a Mon Sep 17 00:00:00 2001
From: Greg Benz <greg@gregbenzphotography.com>
Date: Fri, 10 Jul 2026 13:09:10 -0500
Subject: [PATCH] Fix macOS x86_64 cross-builds with bundled dependencies

---
 .github/workflows/cmake_mac.yml | 57 ++++++++++++++++++++++++++++++++-
 CMakeLists.txt                  | 11 +++++++
 docs/building.md                | 20 ++++++++++++
 3 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/cmake_mac.yml b/.github/workflows/cmake_mac.yml
index ced89f5e..9dccd1e9 100644
--- a/.github/workflows/cmake_mac.yml
+++ b/.github/workflows/cmake_mac.yml
@@ -18,6 +18,8 @@ jobs:
             cc: clang
             cxx: clang++
             cmake-opts: '-DUHDR_BUILD_TESTS=1 -DUHDR_ENABLE_LOGS=1 -DUHDR_ENABLE_INSTALL=1 -DUHDR_ENABLE_WERROR=1'
+            run_tests: true
+            expected_arch: arm64
 
           # <macOS-latest ARM64 Platform, Release Build, Clang toolchain, Ninja generator, Build Deps>
           - name: "macOS latest ARM64 clang rel ninja with deps"
@@ -26,6 +28,8 @@ jobs:
             cc: clang
             cxx: clang++
             cmake-opts: '-DUHDR_BUILD_TESTS=1 -DUHDR_ENABLE_LOGS=1 -DUHDR_BUILD_DEPS=1 -DUHDR_ENABLE_WERROR=1'
+            run_tests: true
+            expected_arch: arm64
 
           # <macOS-latest ARM64 Platform, Release Build, Clang toolchain, Ninja generator, Static linking>
           - name: "macOS latest ARM64 clang rel ninja static"
@@ -34,6 +38,29 @@ jobs:
             cc: clang
             cxx: clang++
             cmake-opts: '-DUHDR_BUILD_TESTS=1 -DUHDR_ENABLE_LOGS=1 -DUHDR_ENABLE_INSTALL=1 -DBUILD_SHARED_LIBS=0 -DUHDR_ENABLE_WERROR=1'
+            run_tests: true
+            expected_arch: arm64
+
+          # <macOS-15 Intel Platform, Release Build, Clang toolchain, Ninja generator>
+          - name: "macOS-15 Intel clang rel ninja"
+            os: macos-15-intel
+            build_type: Release
+            cc: clang
+            cxx: clang++
+            cmake-opts: '-DUHDR_BUILD_TESTS=1 -DUHDR_ENABLE_LOGS=1 -DUHDR_ENABLE_INSTALL=1 -DUHDR_ENABLE_WERROR=1'
+            run_tests: true
+            run_cli_smoke: true
+            expected_arch: x86_64
+
+          # <macOS-latest ARM64 Platform, cross-compiled x86_64, Release Build, Clang toolchain, Ninja generator, Build Deps>
+          - name: "macOS latest ARM64 cross x86_64 clang rel ninja with deps"
+            os: macos-latest
+            build_type: Release
+            cc: clang
+            cxx: clang++
+            cmake-opts: '-DUHDR_BUILD_TESTS=1 -DUHDR_ENABLE_LOGS=1 -DUHDR_BUILD_DEPS=1 -DUHDR_ENABLE_WERROR=1 -DCMAKE_OSX_ARCHITECTURES=x86_64 -DCMAKE_OSX_DEPLOYMENT_TARGET=11.0'
+            run_tests: false
+            expected_arch: x86_64
 
     steps:
     - name: Checkout the repository
@@ -65,6 +92,34 @@ jobs:
     - name: Build
       run: cmake --build build --config ${{ matrix.config.build_type }}
 
+    - name: Verify artifact architecture
+      env:
+        EXPECTED_ARCH: ${{ matrix.config.expected_arch }}
+      shell: bash
+      run: |
+        artifacts=(
+          build/libuhdr.a
+          build/ultrahdr_app
+          build/ultrahdr_unit_test
+        )
+        if [[ -e build/libuhdr.dylib ]]; then
+          artifacts+=(build/libuhdr.dylib)
+        fi
+        if [[ -e build/turbojpeg/src/turbojpeg-build/libjpeg.a ]]; then
+          artifacts+=(build/turbojpeg/src/turbojpeg-build/libjpeg.a)
+        fi
+        for artifact in "${artifacts[@]}"; do
+          test "$(lipo -archs "$artifact")" = "$EXPECTED_ARCH"
+        done
+
     - name: Test
+      if: matrix.config.run_tests
       working-directory: build
-      run: ctest --build-config ${{ matrix.config.build_type }}
\ No newline at end of file
+      run: ctest --build-config ${{ matrix.config.build_type }}
+
+    - name: Test CLI
+      if: matrix.config.run_cli_smoke
+      run: |
+        build/ultrahdr_app -m 0 -p tests/data/raw_p010_image.p010 -w 1280 -h 720 -a 0 -z build/cli-smoke.jpeg
+        build/ultrahdr_app -m 1 -j build/cli-smoke.jpeg -P
+        build/ultrahdr_app -m 1 -j build/cli-smoke.jpeg -o 1 -O 5 -z build/cli-smoke.raw
diff --git a/CMakeLists.txt b/CMakeLists.txt
index cb4ca18f..f0481c88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -431,6 +431,17 @@ endif()
 if(DEFINED UHDR_ANDROID_NDK_PATH)
   list(APPEND UHDR_CMAKE_ARGS -DUHDR_ANDROID_NDK_PATH=${UHDR_ANDROID_NDK_PATH})
 endif()
+if(APPLE)
+  if(DEFINED CMAKE_OSX_ARCHITECTURES AND NOT "${CMAKE_OSX_ARCHITECTURES}" STREQUAL "")
+    list(APPEND UHDR_CMAKE_ARGS "-DCMAKE_OSX_ARCHITECTURES=${CMAKE_OSX_ARCHITECTURES}")
+  endif()
+  if(DEFINED CMAKE_OSX_DEPLOYMENT_TARGET AND NOT "${CMAKE_OSX_DEPLOYMENT_TARGET}" STREQUAL "")
+    list(APPEND UHDR_CMAKE_ARGS "-DCMAKE_OSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}")
+  endif()
+  if(DEFINED CMAKE_OSX_SYSROOT AND NOT "${CMAKE_OSX_SYSROOT}" STREQUAL "")
+    list(APPEND UHDR_CMAKE_ARGS "-DCMAKE_OSX_SYSROOT=${CMAKE_OSX_SYSROOT}")
+  endif()
+endif()
 
 # opengl es libraries
 if(UHDR_ENABLE_GLES)
diff --git a/docs/building.md b/docs/building.md
index 755502fb..1aa81f90 100644
--- a/docs/building.md
+++ b/docs/building.md
@@ -140,6 +140,26 @@ ninja
 ctest
 ```
 
+#### Cross-compiling for Intel on Apple Silicon
+
+From the libultrahdr source directory, build a thin x86_64 binary on an Apple
+Silicon Mac:
+
+```sh
+cmake -G Ninja -S . -B build-x86_64 \
+  -DCMAKE_OSX_ARCHITECTURES=x86_64 \
+  -DCMAKE_OSX_DEPLOYMENT_TARGET=11.0 \
+  -DUHDR_BUILD_DEPS=1 \
+  -DUHDR_BUILD_TESTS=1
+cmake --build build-x86_64
+```
+
+`UHDR_BUILD_DEPS=1` builds libjpeg-turbo and test dependencies for the
+requested architecture. When using installed dependencies instead, they must
+contain an x86_64 slice. Only one value in `CMAKE_OSX_ARCHITECTURES` is
+supported per build; universal arm64+x86_64 builds are not supported. Running
+the x86_64 tests on Apple Silicon requires Rosetta 2.
+
 This will generate the following files under `build_directory`:
 
 **libuhdr.{version}.dylib** - Shared library for the libuhdr API <br>