cmake/CMakeLists.txt

# Boilerplate.
cmake_minimum_required (VERSION 3.1)   # First version with CMAKE_CXX_STANDARD.
project (skimake)
set (CMAKE_CXX_STANDARD 11)

# Default to Release mode.  We're mainly targeting Skia users, not Skia developers.
if (NOT CMAKE_BUILD_TYPE)
    set (CMAKE_BUILD_TYPE Release)
endif ()

# To first approximation, the Skia library comprises all .cpp files under src/.
file (GLOB_RECURSE srcs ../src/*.cpp)

function (find_include_dirs out)
    file (GLOB_RECURSE headers ${ARGN})
    foreach (path ${headers})
        get_filename_component (dir ${path} PATH)
        list (APPEND include_dirs ${dir})
    endforeach()
    list (REMOVE_DUPLICATES include_dirs)
    set (${out} ${include_dirs} PARENT_SCOPE)
endfunction()

# We need src/ directories and include/private on our path when building Skia.
# Users should be able to use Skia with only include/ directories that are not include/private.
find_include_dirs(private_includes ../src/*.h ../include/private/*.h)
find_include_dirs(public_includes ../include/*.h)
list (REMOVE_ITEM public_includes ${private_includes})  # Easiest way to exclude private.
file (GLOB default_include_config "../include/config")
list (REMOVE_ITEM public_includes ${default_include_config})
set (userconfig_directory ${CMAKE_BINARY_DIR}/include)
list (APPEND public_includes ${userconfig_directory})

# These guys are third_party but provided by a Skia checkout.
list (APPEND srcs             ../third_party/etc1/etc1.cpp ../third_party/ktx/ktx.cpp)
list (APPEND private_includes ../third_party/etc1          ../third_party/ktx)

function (remove_srcs)
    file (GLOB_RECURSE to_remove ${ARGN})
    list (REMOVE_ITEM srcs ${to_remove})
    set (srcs ${srcs} PARENT_SCOPE)
endfunction()

# This file is empty and is only used to trick GYP.
remove_srcs (../src/core/SkForceCPlusPlusLinking.cpp)
# This file forces linking for all our supported image decoders.  We're more fine-grained.
remove_srcs (../src/images/SkForceLinking.cpp)
# Chrome only?
remove_srcs (../src/ports/SkFontHost_fontconfig.cpp
             ../src/fonts/SkFontMgr_fontconfig.cpp
             ../src/ports/SkFontConfigInterface_direct.cpp
             ../src/ports/SkFontConfigInterface_direct_factory.cpp
             ../src/ports/SkFontConfigInterface_direct_google3.cpp
             ../src/ports/SkFontConfigInterface_direct_google3_factory.cpp)
# Alternative font managers.
remove_srcs (../src/ports/SkFontMgr_custom*.cpp)

# Skia sure ships a lot of code no one uses.
remove_srcs (../src/animator/* ../src/*nacl* ../src/svg/* ../src/views/* ../src/xml/*)
foreach (include animator svg svg/parser views views/animated xml)
  file (GLOB globed_include ../include/${include})
  list (REMOVE_ITEM public_includes ${globed_include})
endforeach()

# Remove OS-specific source files.
if (NOT UNIX)
    remove_srcs(../src/ports/*_posix.cpp
                ../src/ports/SkTLS_pthread.cpp
                ../src/ports/SkTime_Unix.cpp
                ../src/utils/SkThreadUtils_pthread.cpp)
endif()
if (APPLE OR NOT UNIX)
    remove_srcs(../src/gpu/gl/glx/*
                ../src/images/SkImageDecoder_FactoryDefault.cpp
                ../src/ports/SkFontMgr_fontconfig*.cpp
                ../src/ports/SkFontMgr_android*.cpp
                ../src/*FreeType*)
endif()

# Remove processor-specific source files.
if (NOT CMAKE_SYSTEM_PROCESSOR STREQUAL ARM)
    remove_srcs(../src/*arm* ../src/*ARM* ../src/*neon* ../src/*NEON*)
endif()
if (NOT CMAKE_SYSTEM_PROCESSOR STREQUAL MIPS)
    remove_srcs(../src/*mips* ../src/*MIPS*)
endif()

# Make our ports choices.
remove_srcs(
    ../src/*moz*   # We're probably not Mozilla.
    ../src/gpu/GrContextFactory.cpp                  # For internal testing only.
    ../src/gpu/gl/GrGLCreateNativeInterface_none.cpp
    ../src/gpu/gl/GrGLDefaultInterface_none.cpp
    ../src/gpu/gl/SkCreatePlatformGLContext*.cpp     # For internal testing only.
    ../src/gpu/gl/command_buffer/*
    ../src/gpu/gl/egl/*
    ../src/gpu/gl/iOS/*
    ../src/opts/SkBitmapProcState_opts_none.cpp
    ../src/opts/SkBlitMask_opts_none.cpp
    ../src/opts/SkBlitRow_opts_none.cpp
    ../src/ports/SkFontMgr_empty_factory.cpp
    ../src/ports/SkGlobalInitialization_chromium.cpp
    ../src/ports/SkImageDecoder_empty.cpp
    ../src/ports/SkImageGenerator_none.cpp
    ../src/ports/SkTLS_none.cpp)

if (WIN32)
    if(SKIA_GDI)
        remove_srcs(../src/ports/SkFontMgr_win_dw_factory.cpp)
    else()
        remove_srcs(../src/ports/SkFontMgr_win_gdi_factory.cpp)
    endif()
endif()

remove_srcs(../src/gpu/gl/angle/*)  # TODO
remove_srcs(../src/codec/* ../src/android/*)  # TODO: Requires Chromium's libjpeg-turbo, and incompatible giflib.

# Certain files must be compiled with support for SSSE3, SSE4.1, AVX, or AVX2 intrinsics.
file (GLOB_RECURSE ssse3_srcs ../src/*ssse3*.cpp ../src/*SSSE3*.cpp)
file (GLOB_RECURSE sse41_srcs ../src/*sse4*.cpp ../src/*SSE4*.cpp)
file (GLOB_RECURSE avx_srcs   ../src/*_avx.cpp)
file (GLOB_RECURSE avx2_srcs  ../src/*_avx2.cpp)
set_source_files_properties(${ssse3_srcs} PROPERTIES COMPILE_FLAGS -mssse3)
set_source_files_properties(${sse41_srcs} PROPERTIES COMPILE_FLAGS -msse4.1)
set_source_files_properties(${avx_srcs}   PROPERTIES COMPILE_FLAGS -mavx)
set_source_files_properties(${avx2_srcs}  PROPERTIES COMPILE_FLAGS -mavx2)

# Detect our optional dependencies.
# If we can't find them, don't build the parts of Skia that use them.
find_package (EXPAT)
find_package (Lua)
find_package (ZLIB)
# No find_package for libwebp as far as I can tell, so simulate it here.
find_path (WEBP_INCLUDE_DIRS "webp/decode.h")
find_library (WEBP_LIBRARIES webp)
find_path (OSMESA_INCLUDE_DIRS "GL/osmesa.h")
find_library(OSMESA_LIBRARIES "OSMesa")

if (UNIX AND NOT APPLE)
    find_package (Freetype)
    # Same deal for fontconfig.
    find_path (FONTCONFIG_INCLUDE_DIRS "fontconfig/fontconfig.h")
    find_library (FONTCONFIG_LIBRARIES fontconfig)
    find_package (GIF)
    find_package (JPEG)
    find_package (PNG)
endif()

# TODO: macro away this if (found) ... else() ... endif() stuff.

if (EXPAT_FOUND)
    list (APPEND private_includes ${EXPAT_INCLUDE_DIRS})
    list (APPEND libs             ${EXPAT_LIBRARIES})
else()
    remove_srcs (../src/ports/SkFontMgr_android_parser.cpp)
endif()

if (GIF_FOUND)
    list (APPEND private_includes ${GIF_INCLUDE_DIRS})
    list (APPEND libs             ${GIF_LIBRARIES})
else()
    remove_srcs(../src/images/*gif*)
endif()

if (JPEG_FOUND)
    list (APPEND private_includes ${JPEG_INCLUDE_DIRS})
    list (APPEND libs             ${JPEG_LIBRARIES})
else()
    remove_srcs(../src/images/*jpeg*)
endif()

if (LUA_FOUND)
    list (APPEND private_includes ${LUA_INCLUDE_DIR})
    list (APPEND libs             ${LUA_LIBRARIES})
else()
    remove_srcs(../src/utils/*Lua*)
endif()

if (PNG_FOUND)
    list (APPEND private_includes ${PNG_INCLUDE_DIRS})
    list (APPEND libs             ${PNG_LIBRARIES})
else()
    remove_srcs(../src/images/*png*)
endif()

if (ZLIB_FOUND)
    list (APPEND private_includes ${ZLIB_INCLUDE_DIRS})
    list (APPEND libs             ${ZLIB_LIBRARIES})
    remove_srcs(../src/doc/SkDocument_PDF_None.cpp)
else()
    remove_srcs(../src/pdf/*.cpp ../src/doc/SkDocument_PDF.cpp)
endif()

if (WEBP_INCLUDE_DIRS AND WEBP_LIBRARIES)
    list (APPEND private_includes ${WEBP_INCLUDE_DIRS})
    list (APPEND libs             ${WEBP_LIBRARIES})
else()
    remove_srcs(../src/images/*webp*)
endif()

if (FREETYPE_FOUND)
    list (APPEND private_includes ${FREETYPE_INCLUDE_DIRS})
    list (APPEND libs             ${FREETYPE_LIBRARIES})
endif()

if (FONTCONFIG_INCLUDE_DIRS AND FONTCONFIG_LIBRARIES)
    list (APPEND private_includes ${FONTCONFIG_INCLUDE_DIRS})
    list (APPEND libs             ${FONTCONFIG_LIBRARIES})
endif()

if (APPLE)
    find_library(APPLICATION_SERVICES_FRAMEWORK ApplicationServices REQUIRED)
    list (APPEND libs ${APPLICATION_SERVICES_FRAMEWORK})
endif()

if (OSMESA_LIBRARIES AND OSMESA_INCLUDE_DIRS)
    list (APPEND libs             ${OSMESA_LIBRARIES})
    list (APPEND private_includes ${OSMESA_INCLUDE_DIRS})
    list (APPEND public_defines   "-DSK_MESA=1")
    set (SK_MESA 1)
else()
    remove_srcs(../src/gpu/gl/mesa/*)
endif()

if (WIN32)
    list (APPEND libs FontSub.lib Usp10.lib)
endif()

find_package(OpenGL REQUIRED)
list (APPEND libs  ${OPENGL_LIBRARIES})

# This is our main output, libskia.so.
# We mostly build an .so here because it helps test we've linked everything,
# not so much that we think Skia is a good candidate to ship as a shared library.
add_library (skia SHARED ${srcs})

target_compile_definitions(skia
    PUBLIC  ${public_defines}
    PRIVATE -DSKIA_DLL -DSKIA_IMPLEMENTATION=1)

target_include_directories(skia
    PUBLIC  ${public_includes}
    PRIVATE ${private_includes})

target_link_libraries(skia
    PUBLIC
    PRIVATE ${libs})

if (MSVC)
    set(cc_flags "/w /GR-")
else()
    set(cc_flags "-w -fno-rtti -fno-exceptions")
endif()

set_target_properties(skia PROPERTIES
    COMPILE_FLAGS ${cc_flags}
    CXX_VISIBILITY_PRESET hidden
    VISIBILITY_INLINES_HIDDEN true)

# Experimental C API install:
file(GLOB c_headers "../include/c/*.h")
install(FILES ${c_headers} DESTINATION include)
install(TARGETS skia DESTINATION lib)

# SkUserConfig.h
if (CMAKE_BUILD_TYPE STREQUAL Release)
    set (SK_RELEASE 1)
else()
    set (SK_RELEASE 0)
endif()
configure_file ("SkUserConfig.h.in" "${userconfig_directory}/SkUserConfig.h")

# skia_link_arguments.txt
set (link_arguments ${CMAKE_BINARY_DIR}/skia_link_arguments.txt)
file (WRITE ${link_arguments} "-L${CMAKE_BINARY_DIR}\n")
file (APPEND ${link_arguments} "-lskia\n")
file (APPEND ${link_arguments} "-Wl,-rpath,${CMAKE_BINARY_DIR}\n")

# skia_compile_arguments.txt
set (compile_arguments ${CMAKE_BINARY_DIR}/skia_compile_arguments.txt)
file (WRITE ${compile_arguments} "--std=c++11\n")
foreach (include ${public_includes})
  get_filename_component (abs_include ${include} ABSOLUTE)
  file (APPEND ${compile_arguments} "-I${abs_include}\n")
endforeach()

# cmake .
# cmake --build . --target skia
# c++ -c @skia_compile_arguments.txt example.cpp
# c++ example.o @skia_link_arguments.txt

# skia.h
set (bad_files GrGLConfig_chrome.h SkJSONCPP.h SkParsePaint.h)
# make `c++ @skia_compile_arguments.txt include/skia.h` work.
set (skia_h_path ${userconfig_directory}/skia.h)
file (WRITE ${skia_h_path} "// skia.h generated by CMake.\n")
file(APPEND ${skia_h_path} "#ifndef skia_DEFINED\n")
file(APPEND ${skia_h_path} "#define skia_DEFINED\n")
foreach (include ${public_includes})
  if (NOT include STREQUAL userconfig_directory)
    file (APPEND ${skia_h_path} "\n")
    file (GLOB all_public_headers ${include}/*.h)
    foreach (public_header ${all_public_headers})
      get_filename_component (filename_component ${public_header} NAME)
      if (NOT ";${bad_files};" MATCHES ";${filename_component};")
        file (APPEND ${skia_h_path} "#include \"${filename_component}\"\n")
      endif ()
    endforeach()
  endif()
endforeach()
file(APPEND ${skia_h_path} "\n#endif  // skia_DEFINED\n")

# Now build a simple example app that uses Skia via libskia.so.
add_executable(example example.cpp)
target_link_libraries(example skia ${OPENGL_LIBRARIES})