get python bindings working from venv/setup.py #15

CMakeLists.txt

@@ -33,3 +33,4 @@ endif()
 add_subdirectory(openpiv)
 add_subdirectory(test)
 add_subdirectory(examples)
+add_subdirectory(pybind)

README.md

@@ -43,6 +43,35 @@ The binaries are located in the build directory:
     * average_subtract
   * openpiv -> libopenpivcore.so
 
+### Python Bindings
+
+Python bindings are made through pybind11. Building python modules appears to be a non-trivial
+subject, however as openpivcore is based on vcpkg and cmake, a setup.py is provided to
+build the core library as well as the python bindings using cmake.
+
+Although vcpkg provides pybind11, this is not used as it has a dependency on vcpkg's python; the
+aim is to allow the python bindings to work with the user's installed version of python. As such,
+the supplied `pyproject.toml` specifies pybind11 as a required dependency.
+
+To build using pip/setuptools:
+
+* create a venv at the same level as the openpivcore directory
+* activate the venv
+* run pip against the name of the directory containing the openpiv code e.g. `pip install openpiv-c-qt/`
+
+To build using cmake:
+
+* install pybind11 using pip
+* specify the location of the installed pybind11 libs/cmake modules using `-DCMAKE_PREFIX_PATH=<path to pybind11>`
+  * you can use pip & sed to find this: `pip show pybind11 | sed -n '/^Location/ s/.* \(.*\)/\1/ p'`
+* specify that the python bindings should be built: `-DBUILD_PYBIND=ON`
+
+e.g.
+
+```
+cmake -B build -S . -DBUILD_PYBIND=ON -DCMAKE_PREFIX_PATH=$(pip show pybind11 | sed -n '/^Location/ s/.* \(.*\)/\1/ p')
+```
+
 ### Raspberry Pi
 
 Build times are, as expected, much slower than on a modern Intel CPU, but the code
@@ -174,6 +203,7 @@ These are captured in `vcpkg.json`:
   * benchmark: used to run performance benchmarks
   * async++ (optional): implements c++17 parallel algorithms
   * cxxopts: nice command line parsing
+  * pybind11
 
 ## Examples
 
@@ -187,6 +217,7 @@ These are captured in `vcpkg.json`:
 * build
   * [x] travis/github actions/CI
   * [x] add clang/windows/OS X build
+  * [ ] python bindings
 * core
   * [x] logging
   * [ ] iostream ops for ImageLoaders
@@ -218,7 +249,7 @@ These are captured in `vcpkg.json`:
     * [ ] openCL
     * [ ] apply kernel in Fourier space
     * [ ] use SIMD?
-    * [ ] real -> complex FFT/correlation of real data
+    * [x] real -> complex FFT/correlation of real data
   * [ ] direct correlation
   * [x] peak detection
   * [x] peak fitting

pybind/CMakeLists.txt

@@ -0,0 +1,27 @@
+
+option(BUILD_PYBIND "build python bindings" OFF)
+
+if (BUILD_PYBIND)
+  message("building python bindings")
+
+  find_package(pybind11)
+
+  include_directories(${CMAKE_SOURCE_DIR}/openpiv)
+  if (pybind11_FOUND)
+    pybind11_add_module(
+      pyopenpivcore
+      core/module.cpp
+      core/point.cpp
+      core/rect.cpp
+      core/size.cpp
+      core/vector.cpp
+    )
+    target_link_libraries(
+      pyopenpivcore
+      PRIVATE openpivcore)
+
+    if (UNIX AND APPLE)
+      set_target_properties(pyopenpivcore PROPERTIES SUFFIX ".so")
+    endif()
+  endif()
+endif()

pyproject.toml

@@ -8,19 +8,10 @@ requires = [
 ]
 build-backend = "setuptools.build_meta"
 
-[tool.isort]
-profile = "black"
-
-[tool.pytest.ini_options]
-minversion = "6.0"
-addopts = ["-ra", "--showlocals", "--strict-markers", "--strict-config"]
-xfail_strict = true
-filterwarnings = ["error"]
-testpaths = ["tests"]
-
 [tool.cibuildwheel]
-test-command = "pytest {project}/tests"
-test-extras = ["test"]
-test-skip = ["*universal2:arm64"]
+# test-command = "pytest {project}/tests"
+# test-extras = ["test"]
+# test-skip = ["*universal2:arm64"]
+
 # Setuptools bug causes collision between pypy and cpython artifacts
-before-build = "rm -rf {project}/build"
+#before-build = "rm -rf {project}/build {project}/*.egg-info"

setup.py

@@ -1,10 +1,13 @@
+from glob import glob
 import os
 import re
 import subprocess
 import sys
 
-from setuptools import Extension, setup
-from setuptools.command.build_ext import build_ext
+from distutils import sysconfig as ds
+from setuptools import setup
+from setuptools import Extension as _extension
+from setuptools.command.build_ext import build_ext as _build_ext
 
 # Convert distutils Windows platform specifiers to CMake -A arguments
 PLAT_TO_CMAKE = {
@@ -18,20 +21,21 @@
 # A CMakeExtension needs a sourcedir instead of a file list.
 # The name must be the _single_ output extension from the CMake build.
 # If you need multiple extensions, see scikit-build.
-class CMakeExtension(Extension):
+class CMakeExtension(_extension):
     def __init__(self, name, sourcedir=""):
-        Extension.__init__(self, name, sources=[])
+        super().__init__(name, sources=[])
         self.sourcedir = os.path.abspath(sourcedir)
 
 
-class CMakeBuild(build_ext):
+class CMakeBuild(_build_ext):
     def build_extension(self, ext):
         extdir = os.path.abspath(os.path.dirname(self.get_ext_fullpath(ext.name)))
 
         # required for auto-detection & inclusion of auxiliary "native" libs
         if not extdir.endswith(os.path.sep):
             extdir += os.path.sep
 
+        # check for mode
         debug = int(os.environ.get("DEBUG", 0)) if self.debug is None else self.debug
         cfg = "Debug" if debug else "Release"
 
@@ -40,22 +44,20 @@ def build_extension(self, ext):
         cmake_generator = os.environ.get("CMAKE_GENERATOR", "")
 
         # Set Python_EXECUTABLE instead if you use PYBIND11_FINDPYTHON
-        # EXAMPLE_VERSION_INFO shows you how to pass a value into the C++ code
-        # from Python.
         cmake_args = [
             f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY={extdir}",
+            f"-DCMAKE_PREFIX_PATH={ds.get_python_lib()}",
+            "-DBUILD_PYBIND=ON",
             f"-DPYTHON_EXECUTABLE={sys.executable}",
             f"-DCMAKE_BUILD_TYPE={cfg}",  # not used on MSVC, but no harm
         ]
         build_args = []
+
         # Adding CMake arguments set as environment variable
         # (needed e.g. to build for ARM OSx on conda-forge)
         if "CMAKE_ARGS" in os.environ:
             cmake_args += [item for item in os.environ["CMAKE_ARGS"].split(" ") if item]
 
-        # In this example, we pass in the version to C++. You might not need to.
-        cmake_args += [f"-DEXAMPLE_VERSION_INFO={self.distribution.get_version()}"]
-
         if self.compiler.compiler_type != "msvc":
             # Using Ninja-build since it a) is available as a wheel and b)
             # multithreads automatically. MSVC would require all variables be
@@ -111,7 +113,7 @@ def build_extension(self, ext):
             os.makedirs(build_temp)
 
         subprocess.check_call(["cmake", ext.sourcedir] + cmake_args, cwd=build_temp)
-        subprocess.check_call(["cmake", "--build", "."] + build_args, cwd=build_temp)
+        subprocess.check_call(["cmake", "--build", ".", "--clean-first"] + build_args, cwd=build_temp)
 
 
 # The information here can also be placed in setup.cfg - better separation of
@@ -123,7 +125,7 @@ def build_extension(self, ext):
     author_email="[email protected]",
     description="Python bindings for libopenpivcore",
     long_description="",
-    ext_modules=[CMakeExtension("pyopenpivcore")],
+    ext_modules=[ CMakeExtension("pyopenpivcore") ],
     cmdclass={"build_ext": CMakeBuild},
     zip_safe=False,
     extras_require={"test": ["pytest>=6.0"]},

vcpkg.json

@@ -8,7 +8,6 @@
         "tiff",
         "benchmark",
         "asyncplusplus",
-        "pybind11",
         { "name": "mimalloc", "platform": "!(arm | uwp)" }
     ]
 }