adds nanobind scaffolding for future python bindinds (#205)

antond-weta · web-flow · commit bbb620080d9f · 2025-09-25T15:39:08.000+12:00
* adds nanobind scaffolding for future python bindinds

Signed-off-by: Anton Dukhovnikov &lt;antond@wetafx.co.nz&gt;

* fix formatting

Signed-off-by: Anton Dukhovnikov &lt;antond@wetafx.co.nz&gt;

---------

Signed-off-by: Anton Dukhovnikov &lt;antond@wetafx.co.nz&gt;
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -65,6 +65,7 @@ jobs:
         shell: bash
         run: |
             sudo yum install --setopt=tsflags=nodocs -y eigen3-devel ceres-solver-devel json-devel
+            sudo python -m pip install nanobind
 
       - name: Configure CMake
         # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
@@ -152,6 +153,7 @@ jobs:
         shell: bash
         run: |
             sudo yum install --setopt=tsflags=nodocs -y eigen3-devel ceres-solver-devel json-devel
+            sudo python -m pip install nanobind
 
       - name: Configure CMake
         # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -22,7 +22,11 @@ if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /WX /EHsc")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /W4 /WX")
     add_compile_definitions( NOMINMAX )
-elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+elseif (
+    "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR
+    "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR
+    "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang"
+)
     # GCC/Clang strict flags
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -Wall -Wextra -pedantic")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror -Wall -Wextra -pedantic")
@@ -69,6 +73,7 @@ endforeach()
 
 option( ENABLE_SHARED "Enable Shared Libraries" ON )
 option( RTA_CENTOS7_CERES_HACK "Work around broken config in ceres-solver 1.12" OFF )
+option( RTA_BUILD_PYTHON_BINDINGS "Build python bindings" ON )
 option( ENABLE_COVERAGE "Enable code coverage reporting" OFF )
 
 if ( ENABLE_SHARED )
@@ -93,6 +98,10 @@ add_subdirectory("src/${RAWTOACES_CORE_LIB}")
 add_subdirectory("src/${RAWTOACES_UTIL_LIB}")
 add_subdirectory("src/rawtoaces")
 
+if ( RTA_BUILD_PYTHON_BINDINGS )
+    add_subdirectory(src/bindings)
+endif ( RTA_BUILD_PYTHON_BINDINGS )
+
 enable_testing()
 add_subdirectory(tests)
 
diff --git a/README.md b/README.md
@@ -47,6 +47,7 @@ To build `rawtoaces` you would need to satisfy these dependencies:
 | `ceres`          | `1.12.0`   | Ceres Solver is an open source library for solving Non-linear Least Squares problems with bounds constraints and unconstrained optimization problems. It processes non-linear regression for rawtoaces.  | [Ceres Solver installation](http://ceres-solver.org/installation.html)|
 | `boost`          | `1.76.0`   | Boost has multiple C++ libraries that support tasks related to linear algebra, multithreading, image processing, unit testing, etc. It unit testing for rawtoaces. | [Boost download](http://www.boost.org/) |
 | `OpenImageIO`    | `3.0`      | OpenImageIO is an open source library providing vast functionality for image processing. rawtoaces relies on OpenImageIO for reading raw files, saving AcesContainer files, and also all pixel operations.  | [OpenImageIO installation](https://github.com/AcademySoftwareFoundation/OpenImageIO/blob/main/INSTALL.md) |
+| `nanobind`       | `1.9`      | nanobind is a small binding library that exposes C++ types in Python and vice versa. | [nanobind installation](https://nanobind.readthedocs.io/en/latest/installing.html) |
 
 
 ### MacOS
diff --git a/build_scripts/install_deps_linux.bash b/build_scripts/install_deps_linux.bash
@@ -8,4 +8,5 @@ time sudo apt-get -q -f install -y \
     libceres-dev \
     nlohmann-json3-dev \
     libopencv-dev \
-    openimageio-tools libopenimageio-dev
+    openimageio-tools libopenimageio-dev \
+    nanobind-dev
diff --git a/build_scripts/install_deps_mac.bash b/build_scripts/install_deps_mac.bash
@@ -2,4 +2,4 @@
 
 set -ex
 
-brew install ceres-solver nlohmann-json openimageio
+brew install ceres-solver nlohmann-json openimageio nanobind robin-map
diff --git a/build_scripts/install_deps_windows.bash b/build_scripts/install_deps_windows.bash
@@ -5,4 +5,5 @@ set -ex
 vcpkg install \
     ceres:x64-windows \
     nlohmann-json:x64-windows \
-    openimageio:x64-windows
+    openimageio:x64-windows \
+    nanobind:x64-windows
diff --git a/configure.cmake b/configure.cmake
@@ -11,3 +11,19 @@ if (RTA_CENTOS7_CERES_HACK)
 else ()
     find_package ( Ceres CONFIG REQUIRED )
 endif ()
+
+if (RTA_BUILD_PYTHON_BINDINGS)
+
+    if ( CMAKE_VERSION VERSION_LESS 3.18 )
+        set( DEV_MODULE Development )
+    else ()
+        set( DEV_MODULE Development.Module )
+    endif ()
+
+    find_package ( Python 3.8 COMPONENTS Interpreter ${DEV_MODULE} REQUIRED )
+
+    execute_process (
+        COMMAND "${Python_EXECUTABLE}" -m nanobind --cmake_dir
+        OUTPUT_STRIP_TRAILING_WHITESPACE OUTPUT_VARIABLE nanobind_ROOT)
+    find_package ( nanobind CONFIG REQUIRED )
+endif ()
diff --git a/src/bindings/CMakeLists.txt b/src/bindings/CMakeLists.txt
@@ -0,0 +1,40 @@
+cmake_minimum_required ( VERSION 3.12 )
+include_directories ( "${CMAKE_CURRENT_SOURCE_DIR}" )
+
+nanobind_add_module( rawtoaces_bindings
+    py_util.cpp py_util.h
+    py_core.cpp py_core.h
+    py_module.cpp
+)
+
+target_link_libraries( rawtoaces_bindings
+    PUBLIC
+        ${RAWTOACES_UTIL_LIB}
+)
+
+if ( "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" )
+    target_compile_options ( nanobind-static    PRIVATE -Wno-pedantic )
+    target_compile_options ( rawtoaces_bindings PRIVATE -Wno-pedantic )
+    if ( CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 10.0 )
+        target_compile_options ( nanobind-static    PRIVATE -Wno-error=zero-length-bounds )
+        target_compile_options ( rawtoaces_bindings PRIVATE -Wno-error=zero-length-bounds )
+    endif ()
+elseif ( "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang" )
+    target_compile_options ( nanobind-static    PRIVATE -Wno-error=zero-length-array )
+    target_compile_options ( rawtoaces_bindings PRIVATE -Wno-error=zero-length-array )
+endif()
+
+set_target_properties( rawtoaces_bindings PROPERTIES
+    OUTPUT_NAME "rawtoaces"
+    #EXPORT_NAME "rawtoaces"
+    #SOVERSION ${RAWTOACES_MAJOR_VERSION}.${RAWTOACES_MINOR_VERSION}.${RAWTOACES_PATCH_VERSION}
+    #VERSION ${RAWTOACES_VERSION}
+)
+
+install(
+    TARGETS rawtoaces_bindings
+    EXPORT RAWTOACESTargets
+    LIBRARY DESTINATION ${INSTALL_LIB_DIR}
+    INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+    PUBLIC_HEADER DESTINATION include/rawtoaces
+)
diff --git a/src/bindings/py_core.cpp b/src/bindings/py_core.cpp
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Contributors to the rawtoaces Project.
+
+#include "py_core.h"
+
+void core_bindings( nanobind::module_ & /*m - unused*/ )
+{
+    // TODO: add the core lib bindings here
+}
diff --git a/src/bindings/py_core.h b/src/bindings/py_core.h
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Contributors to the rawtoaces Project.
+
+#include <nanobind/nanobind.h>
+
+void core_bindings( nanobind::module_ &m );
diff --git a/src/bindings/py_module.cpp b/src/bindings/py_module.cpp
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Contributors to the rawtoaces Project.
+
+#include "py_core.h"
+#include "py_util.h"
+
+NB_MODULE( rawtoaces, m )
+{
+    core_bindings( m );
+    util_bindings( m );
+}
diff --git a/src/bindings/py_util.cpp b/src/bindings/py_util.cpp
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Contributors to the rawtoaces Project.
+
+#include "py_util.h"
+#include <nanobind/stl/string.h>
+#include <rawtoaces/image_converter.h>
+
+using namespace rta::util;
+
+void util_bindings( nanobind::module_ &m )
+{
+    nanobind::class_<ImageConverter> image_converter( m, "ImageConverter" );
+
+    image_converter.def( nanobind::init<>() );
+
+    // TODO: add the rest of the ImageConverter methods and properties
+    image_converter
+        .def_rw(
+            "settings",
+            &ImageConverter::settings ) // The Settings class is described below
+        .def( "process_image", &ImageConverter::process_image );
+
+    nanobind::class_<ImageConverter::Settings> settings(
+        image_converter, "Settings" );
+
+    // TODO: add the rest of the Settings' properties
+    settings.def( nanobind::init<>() )
+        .def_rw(
+            "WB_Method",
+            &ImageConverter::Settings::
+                WB_method ) // The WBMethod enum is described below
+        .def_rw( "illuminant", &ImageConverter::Settings::illuminant );
+
+    // TODO: add the rest of WBMethod values, add other enums following this example
+    nanobind::enum_<ImageConverter::Settings::WBMethod>( settings, "WBMethod" )
+        .value( "Metadata", ImageConverter::Settings::WBMethod::Metadata )
+        .value( "Illuminant", ImageConverter::Settings::WBMethod::Illuminant )
+        .export_values();
+}
diff --git a/src/bindings/py_util.h b/src/bindings/py_util.h
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Contributors to the rawtoaces Project.
+
+#include <nanobind/nanobind.h>
+
+void util_bindings( nanobind::module_ &m );
diff --git a/src/rawtoaces_util/CMakeLists.txt b/src/rawtoaces_util/CMakeLists.txt
@@ -50,4 +50,4 @@ install( TARGETS ${RAWTOACES_UTIL_LIB}
     LIBRARY DESTINATION ${INSTALL_LIB_DIR}
     INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
     PUBLIC_HEADER DESTINATION include/rawtoaces
-)
+)

Original file line number	Diff line number	Diff line change
`@@ -2,4 +2,4 @@`
`2`	`2`
`3`	`3`	`set -ex`
`4`	`4`
`5`		`-brew install ceres-solver nlohmann-json openimageio`
	`5`	`+brew install ceres-solver nlohmann-json openimageio nanobind robin-map`