fix(CMake) split CMakeLists.txt, add options, includes and dependencies (#2753)

* fix(CMake) split CMakeLists.txt, add options, includes and dependencies

* fix(CMake) do not use 'project' keyword with ESP_PLATFORM

* fix(CMake) prefix includes with CMAKE_CURRENT_LIST_DIR

* Don't depend on CMAKE_CURRENT_SOURCE_DIR

* fix(CMake) rename baremetal.cmake to custom.cmake

* fix(CMake) add CMake documentation

cmake/custom.cmake

@@ -0,0 +1,61 @@
+# Option to define LV_LVGL_H_INCLUDE_SIMPLE, default: ON
+option(LV_LVGL_H_INCLUDE_SIMPLE
+       "Use #include \"lvgl.h\" instead of #include \"../../lvgl.h\"" ON)
+
+# Option to define LV_CONF_INCLUDE_SIMPLE, default: ON
+option(LV_CONF_INCLUDE_SIMPLE
+       "Simple include of \"lv_conf.h\" and \"lv_drv_conf.h\"" ON)
+
+# Option to set LV_CONF_PATH, if set parent path LV_CONF_DIR is added to
+# includes
+option(LV_CONF_PATH "Path defined for lv_conf.h")
+get_filename_component(LV_CONF_DIR ${LV_CONF_PATH} DIRECTORY)
+
+file(GLOB_RECURSE SOURCES ${LVGL_ROOT_DIR}/src/*.c)
+file(GLOB_RECURSE EXAMPLE_SOURCES ${LVGL_ROOT_DIR}/examples/*.c)
+
+add_library(lvgl STATIC ${SOURCES})
+add_library(lvgl::lvgl ALIAS lvgl)
+add_library(lvgl_examples STATIC ${EXAMPLE_SOURCES})
+add_library(lvgl::examples ALIAS lvgl_examples)
+
+target_compile_definitions(
+  lvgl PUBLIC $<$<BOOL:${LV_LVGL_H_INCLUDE_SIMPLE}>:LV_LVGL_H_INCLUDE_SIMPLE>
+              $<$<BOOL:${LV_CONF_INCLUDE_SIMPLE}>:LV_CONF_INCLUDE_SIMPLE>)
+
+# Include root and optional parent path of LV_CONF_PATH
+target_include_directories(lvgl SYSTEM PUBLIC ${LVGL_ROOT_DIR} ${LV_CONF_DIR})
+
+# Include /examples folder
+target_include_directories(lvgl_examples SYSTEM
+                           PUBLIC ${LVGL_ROOT_DIR}/examples)
+
+target_link_libraries(lvgl_examples PUBLIC lvgl)
+
+# Lbrary and headers can be installed to system using make install
+file(GLOB LVGL_PUBLIC_HEADERS "${CMAKE_SOURCE_DIR}/lv_conf.h"
+     "${CMAKE_SOURCE_DIR}/lvgl.h")
+
+if("${LIB_INSTALL_DIR}" STREQUAL "")
+  set(LIB_INSTALL_DIR "lib")
+endif()
+if("${INC_INSTALL_DIR}" STREQUAL "")
+  set(INC_INSTALL_DIR "include/lvgl")
+endif()
+
+install(
+  DIRECTORY "${CMAKE_SOURCE_DIR}/src"
+  DESTINATION "${CMAKE_INSTALL_PREFIX}/${INC_INSTALL_DIR}/"
+  FILES_MATCHING
+  PATTERN "*.h")
+
+set_target_properties(
+  lvgl
+  PROPERTIES OUTPUT_NAME lvgl
+             ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
+             PUBLIC_HEADER "${LVGL_PUBLIC_HEADERS}")
+
+install(
+  TARGETS lvgl
+  ARCHIVE DESTINATION "${LIB_INSTALL_DIR}"
+  PUBLIC_HEADER DESTINATION "${INC_INSTALL_DIR}")