Example CMake build for Skia.

cmake/CMakeLists.txt

+# Boilerplate.
+cmake_minimum_required (VERSION 3.3)   # The latest version as I write this.  May be too strict.
+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 ${ARGV})

[jcgregorio, 2015/08/30 13:25:24]

Doesn't ARGV also include the 'out' passed in as the first argument?

[mtklein, 2015/08/30 14:19:09]

Hmm, reading the docs, it may be I was looking for ARGN here.

+    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.
+
+# 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 ${ARGV})
+    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)
+
+# Skia sure ships a lot of code no one uses.
+remove_srcs (../src/animator/* ../src/*nacl* ../src/svg/* ../src/views/* ../src/xml/*)
+
+# Some files only contain code in Debug mode.  This quiets down some linker warnings.
+if (NOT CMAKE_BUILD_TYPE EQUAL Debug)
+    remove_srcs (../src/core/SkDebug.cpp ../src/utils/SkDumpCanvas.cpp)
+endif()
+
+# Remove OS-specific source files.
+if (NOT WIN32)
+    remove_srcs(../src/utils/win/* ../src/*_win*.cpp ../src/*xps* ../src/gpu/gl/angle/* ../src/*WIC* ../src/*DWRITE*)
+endif()
+if (NOT LINUX)
+    remove_srcs(../src/*linux* ../src/*FreeType* ../src/*FontConfig* ../src/*FontMgr_custom*)
+endif()
+if (NOT ANDROID)
+    remove_srcs(../src/*android* ../src/*hwui*)
+endif()
+
+# Remove processor-specific source files.
+if (NOT CMAKE_SYSTEM_PROCESSOR EQUAL ARM)
+    remove_srcs(../src/*arm* ../src/*ARM* ../src/*neon* ../src/*NEON*)
+endif()
+if (NOT CMAKE_SYSTEM_PROCESSOR EQUAL 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/glx/*
+    ../src/gpu/gl/iOS/*
+    ../src/gpu/gl/mesa/*
+    ../src/images/SkImageDecoder_FactoryDefault.cpp
+    ../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
+    ../src/utils/SkThreadUtils_pthread_other.cpp
+    )
+
+remove_srcs(../src/codec/*)  # TODO: Requires Chromium's libjpeg-turbo, and incompatible giflib.
+
+# Certain files must be compiled with support for SSSE3 or SSE4.1 intrinsics.
+file (GLOB_RECURSE ssse3_srcs ../src/*ssse3*.cpp ../src/*SSSE3*.cpp)
+file (GLOB_RECURSE sse41_srcs ../src/*sse4*.cpp ../src/*SSE4*.cpp)
+set_source_files_properties(${ssse3_srcs} PROPERTIES COMPILE_FLAGS -mssse3)
+set_source_files_properties(${sse41_srcs} PROPERTIES COMPILE_FLAGS -msse4.1)
+
+# Detect our optional dependencies.
+# If we can't find them, don't build the parts of Skia that use them.
+
+find_package (GIF)
+find_package (JPEG)
+find_package (LUA)
+find_package (PNG)
+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)
+
+if (NOT GIF_FOUND)
+    remove_srcs(../src/images/*gif*)
+endif()
+if (NOT JPEG_FOUND)
+    remove_srcs(../src/images/*jpeg*)
+endif()
+if (NOT LUA_FOUND)
+    remove_srcs(../src/utils/*lua*)
+endif()
+if (NOT PNG_FOUND)
+    remove_srcs(../src/images/*png*)
+endif()
+if (NOT ZLIB_FOUND)
+    remove_srcs(../src/pdf/*.cpp ../src/doc/SkDocument_PDF.cpp)
+else()
+    remove_srcs(../src/doc/SkDocument_PDF_None.cpp)
+endif()
+if (NOT WEBP_INCLUDE_DIRS OR NOT WEBP_LIBRARIES)
+    remove_srcs(../src/images/*webp*)
+endif()
+
+if (APPLE)
+    find_library(APPLICATION_SERVICES_FRAMEWORK ApplicationServices)
+endif()
+
+# 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
+    PRIVATE -DSKIA_DLL)
+
+target_include_directories(skia
+    PUBLIC  ${public_includes}
+    PRIVATE ${private_includes}
+            ${GIF_INCLUDE_DIRS}
+            ${JPEG_INCLUDE_DIRS}
+            ${LUA_INCLUDE_DIRS}
+            ${PNG_INCLUDE_DIRS}
+            ${WEBP_INCLUDE_DIRS}
+            ${ZLIB_INCLUDE_DIRS})
+
+target_link_libraries(skia
+    PUBLIC
+    PRIVATE ${APPLICATION_SERVICES_FRAMEWORK}
+            ${GIF_LIBRARIES}
+            ${JPEG_LIBRARIES}
+            ${LUA_LIBRARIES}
+            ${PNG_LIBRARIES}
+            ${WEBP_LIBRARIES}
+            ${ZLIB_LIBRARIES})
+
+set_target_properties(skia PROPERTIES
+    COMPILE_FLAGS "-fno-exceptions -fno-rtti -Wno-deprecated-declarations"
+    CXX_VISIBILITY_PRESET hidden
+    VISIBILITY_INLINES_HIDDEN true)
+
+# Now build a simple example app that uses Skia via libskia.so.
+find_package(OpenGL REQUIRED)
+add_executable(example example.cpp)
+target_link_libraries(example skia ${OPENGL_LIBRARIES})