Jungfraujoch/preview/CMakeLists.txt

include(ExternalProject)

find_package(ZLIB REQUIRED)

# libjpeg-turbo: upstream does NOT support add_subdirectory/FetchContent inclusion, so build and
# install it out-of-line and import the static lib. (Adapted from aseprite's FindJpegTurbo.cmake.)
# The static lib is `jpeg-static.lib` on MSVC and `libjpeg.a` elsewhere.
IF (MSVC)
    SET(LIBJPEG_TURBO_STATIC_SUFFIX "-static")
ELSE()
    SET(LIBJPEG_TURBO_STATIC_SUFFIX "")
ENDIF()
SET(LIBJPEG_TURBO_DIR "${CMAKE_CURRENT_BINARY_DIR}/libjpeg-turbo")
SET(LIBJPEG_TURBO_LIBRARY "${LIBJPEG_TURBO_DIR}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}jpeg${LIBJPEG_TURBO_STATIC_SUFFIX}${CMAKE_STATIC_LIBRARY_SUFFIX}")
SET(LIBJPEG_TURBO_INCLUDE_DIRS "${LIBJPEG_TURBO_DIR}/include")

# An ExternalProject is a separate cmake invocation and inherits nothing, so without these it
# configures for the BUILD host: a cross build would link an x86_64 libjpeg.a into an aarch64
# binary and only fail at the final link, and a macOS build would get a libjpeg.a for another
# architecture or deployment target than the binary it goes into. CMAKE_SYSTEM_NAME only when
# actually cross-compiling: setting it is what PUTS a build into cross mode (same as zlib-ng in the
# top-level CMakeLists). libjpeg-turbo picks its own SIMD from the target arch, so NEON comes for
# free on aarch64 and nasm is simply not consulted there.
SET(LIBJPEG_TURBO_FORWARD CMAKE_TOOLCHAIN_FILE CMAKE_C_COMPILER
                          CMAKE_OSX_ARCHITECTURES CMAKE_OSX_SYSROOT CMAKE_OSX_DEPLOYMENT_TARGET)
IF (CMAKE_CROSSCOMPILING)
    LIST(APPEND LIBJPEG_TURBO_FORWARD CMAKE_SYSTEM_NAME CMAKE_SYSTEM_PROCESSOR)
ENDIF()
SET(LIBJPEG_TURBO_FORWARD_ARGS "")
FOREACH (_var IN LISTS LIBJPEG_TURBO_FORWARD)
    IF (${_var})
        LIST(APPEND LIBJPEG_TURBO_FORWARD_ARGS "-D${_var}:STRING=${${_var}}")
    ENDIF()
ENDFOREACH()

ExternalProject_Add(libjpeg-turbo-project
        URL https://github.com/libjpeg-turbo/libjpeg-turbo/archive/refs/tags/3.2.0.tar.gz
        URL_HASH SHA256=980dd81f425082aa6d7c9e47fef27554ce7a9ffc8e2f6e863b97d263c5c50858
        PREFIX "${LIBJPEG_TURBO_DIR}"
        INSTALL_DIR "${LIBJPEG_TURBO_DIR}"
        BUILD_BYPRODUCTS "${LIBJPEG_TURBO_LIBRARY}"
        CMAKE_CACHE_ARGS
        -DENABLE_SHARED:BOOL=OFF
        -DENABLE_STATIC:BOOL=ON
        -DWITH_ARITH_DEC:BOOL=ON
        -DWITH_ARITH_ENC:BOOL=ON
        -DWITH_JPEG8:BOOL=OFF
        -DWITH_JPEG7:BOOL=OFF
        -DWITH_TURBOJPEG:BOOL=OFF
        # Lazy SIMD: use NASM-accelerated SIMD when nasm is present, otherwise warn and build a
        # scalar libjpeg (REQUIRE_SIMD=OFF is libjpeg-turbo's default; pinned here to be explicit).
        -DWITH_SIMD:BOOL=ON
        -DREQUIRE_SIMD:BOOL=OFF
        -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
        -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
        -DCMAKE_INSTALL_LIBDIR:PATH=<INSTALL_DIR>/lib
        ${LIBJPEG_TURBO_FORWARD_ARGS})

# Create the include dir up front so setting INTERFACE_INCLUDE_DIRECTORIES below does not fail.
FILE(MAKE_DIRECTORY ${LIBJPEG_TURBO_INCLUDE_DIRS})

ADD_LIBRARY(JPEG::JPEG STATIC IMPORTED GLOBAL)
SET_TARGET_PROPERTIES(JPEG::JPEG PROPERTIES
        IMPORTED_LOCATION "${LIBJPEG_TURBO_LIBRARY}"
        INTERFACE_INCLUDE_DIRECTORIES "${LIBJPEG_TURBO_INCLUDE_DIRS}")

ADD_LIBRARY(JFJochPreview STATIC
        JFJochTIFF.cpp JFJochTIFF.h
        JFJochJPEG.cpp JFJochJPEG.h
        PreviewCounter.cpp PreviewCounter.h
        PreviewImage.cpp PreviewImage.h
        ZMQPreviewSocket.cpp
        ZMQPreviewSocket.h
        ZMQMetadataSocket.cpp
        ZMQMetadataSocket.h
)

# JPEG::JPEG is an IMPORTED target, so the build-order dependency on the ExternalProject must be
# attached to the consuming target instead.
ADD_DEPENDENCIES(JFJochPreview libjpeg-turbo-project)

TARGET_LINK_LIBRARIES(JFJochPreview PUBLIC JFJochZMQ JFJochCommon CBORStream2FrameSerialize)
TARGET_LINK_LIBRARIES(JFJochPreview PUBLIC JPEG::JPEG tiff tiffxx ZLIB::ZLIB)