Docstrings for PyMaterialXCore classes.

Mostly copied from corresponding C++ header files, but using backticks to
automatically link to relevant sections in the Python API documentation,
e.g. `Document` to link to `PyMaterialXCore.Document.html`.

Using `mod.attr("<name>").doc() = ...` syntax so that this patch only adds
new lines, rather than modifying existing lines.

Using `:see:` fields to link to the corresponding C++ API docs page.

Demo of generated HTML page available here:
https://stefanhabel.github.io/generated/PyMaterialXCore.html

Split from #1567.

Update #342.

Signed-off-by: Stefan Habel <19556655+StefanHabel@users.noreply.github.com>

source/PyMaterialX/PyMaterialXCore/PyDefinition.cpp

@@ -35,6 +35,13 @@ void bindPyDefinition(py::module& mod)
         .def_readonly_static("CHANNEL_NODE_GROUP", &mx::NodeDef::CHANNEL_NODE_GROUP)
         .def_readonly_static("ORGANIZATION_NODE_GROUP", &mx::NodeDef::ORGANIZATION_NODE_GROUP)
         .def_readonly_static("TRANSLATION_NODE_GROUP", &mx::NodeDef::TRANSLATION_NODE_GROUP);
+    mod.attr("NodeDef").doc() = R"docstring(
+    A node definition element within a `Document`.
+
+    A `NodeDef` provides the declaration of a node interface, which may then
+    be instantiated as a `Node`.
+
+    :see: https://materialx.org/docs/api/class_node_def.html)docstring";
 
     py::class_<mx::Implementation, mx::ImplementationPtr, mx::InterfaceElement>(mod, "Implementation")
         .def("setFile", &mx::Implementation::setFile)
@@ -51,6 +58,14 @@ void bindPyDefinition(py::module& mod)
         .def_readonly_static("CATEGORY", &mx::Implementation::CATEGORY)
         .def_readonly_static("FILE_ATTRIBUTE", &mx::Implementation::FILE_ATTRIBUTE)
         .def_readonly_static("FUNCTION_ATTRIBUTE", &mx::Implementation::FUNCTION_ATTRIBUTE);
+    mod.attr("Implementation").doc() = R"docstring(
+    An implementation element within a `Document`.
+
+    An `Implementation` is used to associate external source code with a specific
+    `NodeDef`, providing a definition for the node that may either be universal or
+    restricted to a specific target.
+
+    :see: https://materialx.org/docs/api/class_implementation.html)docstring";
 
     py::class_<mx::TypeDef, mx::TypeDefPtr, mx::Element>(mod, "TypeDef")
         .def("setSemantic", &mx::TypeDef::setSemantic)
@@ -67,12 +82,24 @@ void bindPyDefinition(py::module& mod)
         .def_readonly_static("CATEGORY", &mx::TypeDef::CATEGORY)
         .def_readonly_static("SEMANTIC_ATTRIBUTE", &mx::TypeDef::SEMANTIC_ATTRIBUTE)
         .def_readonly_static("CONTEXT_ATTRIBUTE", &mx::TypeDef::CONTEXT_ATTRIBUTE);
+    mod.attr("TypeDef").doc() = R"docstring(
+    A type definition element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_type_def.html)docstring";
 
     py::class_<mx::Member, mx::MemberPtr, mx::TypedElement>(mod, "Member")
         .def_readonly_static("CATEGORY", &mx::TypeDef::CATEGORY);
+    mod.attr("Member").doc() = R"docstring(
+    A member element within a `TypeDef`.
+
+    :see: https://materialx.org/docs/api/class_member.html)docstring";
 
     py::class_<mx::Unit, mx::UnitPtr, mx::Element>(mod, "Unit")
         .def_readonly_static("CATEGORY", &mx::Unit::CATEGORY);
+    mod.attr("Unit").doc() = R"docstring(
+    A unit declaration element within a `UnitDef`.
+
+    :see: https://materialx.org/docs/api/class_unit.html)docstring";
 
     py::class_<mx::UnitDef, mx::UnitDefPtr, mx::Element>(mod, "UnitDef")
         .def("setUnitType", &mx::UnitDef::setUnitType)
@@ -83,10 +110,18 @@ void bindPyDefinition(py::module& mod)
         .def("getUnits", &mx::UnitDef::getUnits)
         .def_readonly_static("CATEGORY", &mx::UnitDef::CATEGORY)
         .def_readonly_static("UNITTYPE_ATTRIBUTE", &mx::UnitDef::UNITTYPE_ATTRIBUTE);
+    mod.attr("UnitDef").doc() = R"docstring(
+    A unit definition element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_unit_def.html)docstring";
 
     py::class_<mx::UnitTypeDef, mx::UnitTypeDefPtr, mx::Element>(mod, "UnitTypeDef")
         .def("getUnitDefs", &mx::UnitTypeDef::getUnitDefs)
         .def_readonly_static("CATEGORY", &mx::UnitTypeDef::CATEGORY);
+    mod.attr("UnitTypeDef").doc() = R"docstring(
+    A unit type definition element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_unit_type_def.html)docstring";
 
     py::class_<mx::AttributeDef, mx::AttributeDefPtr, mx::TypedElement>(mod, "AttributeDef")
         .def("setAttrName", &mx::AttributeDef::setAttrName)
@@ -98,8 +133,16 @@ void bindPyDefinition(py::module& mod)
         .def("setExportable", &mx::AttributeDef::setExportable)         
         .def("getExportable", &mx::AttributeDef::getExportable)         
         .def_readonly_static("CATEGORY", &mx::AttributeDef::CATEGORY);
+    mod.attr("AttributeDef").doc() = R"docstring(
+    An attribute definition element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_attribute_def.html)docstring";
 
     py::class_<mx::TargetDef, mx::TargetDefPtr, mx::TypedElement>(mod, "TargetDef")
         .def("getMatchingTargets", &mx::TargetDef::getMatchingTargets)
         .def_readonly_static("CATEGORY", &mx::TargetDef::CATEGORY);
+    mod.attr("TargetDef").doc() = R"docstring(
+    The definition of an implementation target as a `TypedElement`.
+
+    :see: https://materialx.org/docs/api/class_target_def.html)docstring";
 }

source/PyMaterialX/PyMaterialXCore/PyDocument.cpp

@@ -117,4 +117,10 @@ void bindPyDocument(py::module& mod)
         .def("setColorManagementConfig", &mx::Document::setColorManagementConfig)
         .def("hasColorManagementConfig", &mx::Document::hasColorManagementConfig)
         .def("getColorManagementConfig", &mx::Document::getColorManagementConfig);
+    mod.attr("Document").doc() = R"docstring(
+    A MaterialX document, which represents the top-level element in the MaterialX ownership hierarchy.
+
+    Use the factory function `createDocument()` to create a `Document` instance.
+
+    :see: https://materialx.org/docs/api/class_document.html)docstring";
 }

source/PyMaterialX/PyMaterialXCore/PyElement.cpp

@@ -128,6 +128,18 @@ void bindPyElement(py::module& mod)
         BIND_ELEMENT_FUNC_INSTANCE(Token)
         BIND_ELEMENT_FUNC_INSTANCE(TypeDef)
         BIND_ELEMENT_FUNC_INSTANCE(Visibility);
+    mod.attr("Element").doc() = R"docstring(
+    The base class for MaterialX elements.
+
+    An `Element` is a named object within a `Document`, which may possess any
+    number of child elements and attributes.
+
+    Inherited by: `TypedElement`, `GeomElement`, `Backdrop`, `Collection`,
+    `CommentElement`, `GenericElement`, `Look`, `LookGroup`, `NewlineElement`,
+    `PropertySet`, `TypeDef`, `Unit`, `UnitDef`, `UnitTypeDef`, `VariantSet`,
+    and `VariantAssign`.
+
+    :see: https://materialx.org/docs/api/class_element.html)docstring";
 
     py::class_<mx::TypedElement, mx::TypedElementPtr, mx::Element>(mod, "TypedElement")
         .def("setType", &mx::TypedElement::setType)
@@ -137,6 +149,13 @@ void bindPyElement(py::module& mod)
         .def("isMultiOutputType", &mx::TypedElement::isMultiOutputType)
         .def("getTypeDef", &mx::TypedElement::getTypeDef)
         .def_readonly_static("TYPE_ATTRIBUTE", &mx::TypedElement::TYPE_ATTRIBUTE);
+    mod.attr("TypedElement").doc() = R"docstring(
+    The base class for typed elements.
+
+    Inherited by: `InterfaceElement`, `ValueElement`, `AttributeDef`,
+    `GeomPropDef`, `Member`, and `TargetDef`.
+
+    :see: https://materialx.org/docs/api/class_typed_element.html)docstring";
 
     py::class_<mx::ValueElement, mx::ValueElementPtr, mx::TypedElement>(mod, "ValueElement")
         .def("setValueString", &mx::ValueElement::setValueString)
@@ -192,18 +211,49 @@ void bindPyElement(py::module& mod)
         BIND_VALUE_ELEMENT_FUNC_INSTANCE(booleanarray, mx::BoolVec)
         BIND_VALUE_ELEMENT_FUNC_INSTANCE(floatarray, mx::FloatVec)
         BIND_VALUE_ELEMENT_FUNC_INSTANCE(stringarray, mx::StringVec);
+    mod.attr("ValueElement").doc() = R"docstring(
+    The base class for elements that support typed values.
+
+    Inherited by: `PortElement`, `GeomProp`, `Property`, `PropertyAssign`, and
+    `Token`.
+
+    :see: https://materialx.org/docs/api/class_value_element.html)docstring";
 
     py::class_<mx::Token, mx::TokenPtr, mx::ValueElement>(mod, "Token")
         .def_readonly_static("CATEGORY", &mx::Token::CATEGORY);
+    mod.attr("Token").doc() = R"docstring(
+    A token element representing a string value.
+
+    Token elements are used to define input and output values for string
+    substitutions in image filenames.
+
+    :see: https://materialx.org/docs/api/class_token.html)docstring";
 
     py::class_<mx::CommentElement, mx::CommentElementPtr, mx::Element>(mod, "CommentElement")
         .def_readonly_static("CATEGORY", &mx::CommentElement::CATEGORY);
+    mod.attr("CommentElement").doc() = R"docstring(
+    An element representing a block of descriptive text within a `Document`,
+    which will be stored as a comment when the document is written out.
+
+    The comment text may be accessed with the methods `Element.getDocString()`
+    and `Element.setDocString()`.
+
+    :see: https://materialx.org/docs/api/class_comment_element.html)docstring";
 
     py::class_<mx::NewlineElement, mx::NewlineElementPtr, mx::Element>(mod, "NewlineElement")
         .def_readonly_static("CATEGORY", &mx::NewlineElement::CATEGORY);
+    mod.attr("NewlineElement").doc() = R"docstring(
+    An element representing a newline within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_newline_element.html)docstring";
 
     py::class_<mx::GenericElement, mx::GenericElementPtr, mx::Element>(mod, "GenericElement")
         .def_readonly_static("CATEGORY", &mx::GenericElement::CATEGORY);
+    mod.attr("GenericElement").doc() = R"docstring(
+    A generic element subclass, for instantiating elements with unrecognized
+    categories.
+
+    :see: https://materialx.org/docs/api/class_generic_element.html)docstring";
 
     py::class_<mx::StringResolver, mx::StringResolverPtr>(mod, "StringResolver")
         .def("setFilePrefix", &mx::StringResolver::setFilePrefix)
@@ -217,10 +267,33 @@ void bindPyElement(py::module& mod)
         .def("setGeomNameSubstitution", &mx::StringResolver::setGeomNameSubstitution)
         .def("getGeomNameSubstitutions", &mx::StringResolver::getGeomNameSubstitutions)
         .def("resolve", &mx::StringResolver::resolve);
+    mod.attr("StringResolver").doc() = R"docstring(
+    A helper object for applying string modifiers to data values in the context
+    of a specific element and geometry.
+
+    A `StringResolver` may be constructed through the `Element.createStringResolver()`
+    method, which initializes it in the context of a specific `Element`, geometry,
+    and material.
+
+    Calling the `StringResolver.resolve()` method applies all modifiers to a
+    particular string value.
+
+    Methods such as `StringResolver.setFilePrefix()` may be used to edit the
+    stored string modifiers before calling `StringResolver.resolve()`.
+
+    :see: https://materialx.org/docs/api/class_string_resolver.html)docstring";
 
     py::class_<mx::ElementPredicate>(mod, "ElementPredicate");
+    mod.attr("ElementPredicate").doc() = R"docstring(
+    A function that takes an `Element` and returns a `bool`,
+    to check whether some criteria has passed.)docstring";
 
     py::register_exception<mx::ExceptionOrphanedElement>(mod, "ExceptionOrphanedElement");
+    mod.attr("ExceptionOrphanedElement").doc() = R"docstring(
+    A type of exception that is raised when an `Element` is used after its
+    owning `Document` has gone out of scope.
+
+    :see: https://materialx.org/docs/api/class_exception_orphaned_element.html)docstring";
 
     mod.def("targetStringsMatch", &mx::targetStringsMatch);
     mod.def("prettyPrint", &mx::prettyPrint);

source/PyMaterialX/PyMaterialXCore/PyException.cpp

@@ -13,6 +13,11 @@ namespace mx = MaterialX;
 void bindPyException(py::module& mod)
 {
     static py::exception<mx::Exception> pyException(mod, "Exception");
+    mod.attr("Exception").doc() = R"docstring(
+    The base class for exceptions that are propagated from the MaterialX
+    library to the client application.
+
+    :see: https://materialx.org/docs/api/class_exception.html)docstring";
 
     py::register_exception_translator(
         [](std::exception_ptr errPtr)

source/PyMaterialX/PyMaterialXCore/PyGeom.cpp

@@ -24,6 +24,14 @@ void bindPyGeom(py::module& mod)
         .def("getCollectionString", &mx::GeomElement::getCollectionString)
         .def("setCollection", &mx::GeomElement::setCollection)
         .def("getCollection", &mx::GeomElement::getCollection);
+    mod.attr("GeomElement").doc() = R"docstring(
+    The base class for geometric elements, which support bindings to geometries
+    and geometric collections.
+
+    Inherited by: `GeomInfo`, `MaterialAssign`, `PropertySetAssign`, and
+    `Visibility`.
+
+    :see: https://materialx.org/docs/api/class_geom_element.html)docstring";
 
     py::class_<mx::GeomInfo, mx::GeomInfoPtr, mx::GeomElement>(mod, "GeomInfo")
         .def("addGeomProp", &mx::GeomInfo::addGeomProp)
@@ -52,9 +60,18 @@ void bindPyGeom(py::module& mod)
         BIND_GEOMINFO_FUNC_INSTANCE(floatarray, mx::FloatVec)
         BIND_GEOMINFO_FUNC_INSTANCE(stringarray, mx::StringVec)
         .def_readonly_static("CATEGORY", &mx::GeomInfo::CATEGORY);
+    mod.attr("GeomInfo").doc() = R"docstring(
+    A geometry info element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_geom_info.html)docstring";
 
     py::class_<mx::GeomProp, mx::GeomPropPtr, mx::ValueElement>(mod, "GeomProp")
         .def_readonly_static("CATEGORY", &mx::GeomProp::CATEGORY);
+    mod.attr("GeomProp").doc() = R"docstring(
+    A geometric property element within a `GeomInfo`.
+
+    :see: https://materialx.org/docs/api/class_geom_prop.html
+    )docstring";
 
     py::class_<mx::GeomPropDef, mx::GeomPropDefPtr, mx::TypedElement>(mod, "GeomPropDef")
         .def("setGeomProp", &mx::GeomPropDef::setGeomProp)
@@ -70,6 +87,18 @@ void bindPyGeom(py::module& mod)
         .def("hasGeomProp", &mx::GeomPropDef::hasGeomProp)
         .def("getGeomProp", &mx::GeomPropDef::getGeomProp)
         .def_readonly_static("CATEGORY", &mx::GeomPropDef::CATEGORY);
+    mod.attr("GeomPropDef").doc() = R"docstring(
+    An element representing a declaration of geometric property data.
+
+    A `GeomPropDef` element contains a reference to a geometric node and a set
+    of modifiers for that node. For example, a world-space normal can be
+    declared as a reference to the `"normal"` geometric node with a space
+    setting of `"world"`, or a specific set of texture coordinates can be
+    declared as a reference to the `"texcoord"` geometric node with an index
+    setting of `"1"`.
+
+    :see: https://materialx.org/docs/api/class_geom_prop_def.html
+    )docstring";
 
     py::class_<mx::Collection, mx::CollectionPtr, mx::Element>(mod, "Collection")
         .def("setIncludeGeom", &mx::Collection::setIncludeGeom)
@@ -87,6 +116,10 @@ void bindPyGeom(py::module& mod)
         .def("hasIncludeCycle", &mx::Collection::hasIncludeCycle)
         .def("matchesGeomString", &mx::Collection::matchesGeomString)
         .def_readonly_static("CATEGORY", &mx::Collection::CATEGORY);
+    mod.attr("Collection").doc() = R"docstring(
+    A collection element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_collection.html)docstring";
 
     mod.def("geomStringsMatch", &mx::geomStringsMatch);
 

source/PyMaterialX/PyMaterialXCore/PyInterface.cpp

@@ -30,6 +30,14 @@ void bindPyInterface(py::module& mod)
         .def("getConnectedNode", &mx::PortElement::getConnectedNode)
         .def("setConnectedOutput", &mx::PortElement::setConnectedOutput)
         .def("getConnectedOutput", &mx::PortElement::getConnectedOutput);
+    mod.attr("PortElement").doc() = R"docstring(
+    The base class for port elements.
+
+    Port elements support spatially-varying upstream connections to nodes.
+
+    Inherited by: `Input` and `Output`.
+
+    :see: https://materialx.org/docs/api/class_port_element.html)docstring";
 
     py::class_<mx::Input, mx::InputPtr, mx::PortElement>(mod, "Input")
         .def("setDefaultGeomPropString", &mx::Input::setDefaultGeomPropString)
@@ -40,11 +48,22 @@ void bindPyInterface(py::module& mod)
         .def("setConnectedInterfaceName", &mx::Input::setConnectedInterfaceName)
         .def("getInterfaceInput", &mx::Input::getInterfaceInput)
         .def_readonly_static("CATEGORY", &mx::Input::CATEGORY);
+    mod.attr("Input").doc() = R"docstring(
+    An input element within a `Node` or `NodeDef`.
+
+    An `Input` holds either a uniform value or a connection to a spatially-varying
+    `Output`, either of which may be modified within the scope of a `Material`.
+
+    :see: https://materialx.org/docs/api/class_input.html)docstring";
 
     py::class_<mx::Output, mx::OutputPtr, mx::PortElement>(mod, "Output")
         .def("hasUpstreamCycle", &mx::Output::hasUpstreamCycle)
         .def_readonly_static("CATEGORY", &mx::Output::CATEGORY)
         .def_readonly_static("DEFAULT_INPUT_ATTRIBUTE", &mx::Output::DEFAULT_INPUT_ATTRIBUTE);
+    mod.attr("Output").doc() = R"docstring(
+    A spatially-varying output element within a `NodeGraph` or `NodeDef`.
+
+    :see: https://materialx.org/docs/api/class_output.html)docstring";
 
     py::class_<mx::InterfaceElement, mx::InterfaceElementPtr, mx::TypedElement>(mod, "InterfaceElement")
         .def("setNodeDefString", &mx::InterfaceElement::setNodeDefString)
@@ -111,4 +130,14 @@ void bindPyInterface(py::module& mod)
         BIND_INTERFACE_TYPE_INSTANCE(floatarray, mx::FloatVec)
         BIND_INTERFACE_TYPE_INSTANCE(stringarray, mx::StringVec)
         .def_readonly_static("NODE_DEF_ATTRIBUTE", &mx::InterfaceElement::NODE_DEF_ATTRIBUTE);
+    mod.attr("InterfaceElement").doc() = R"docstring(
+    The base class for interface elements.
+
+    An `InterfaceElement` supports a set of `Input` and `Output` elements, with
+    an API for setting their values.
+
+    Inherited by: `GraphElement`, `Implementation`, `Node`, `NodeDef`, and
+    `Variant`.
+
+    :see: https://materialx.org/docs/api/class_interface_element.html)docstring";
 }

source/PyMaterialX/PyMaterialXCore/PyLook.cpp

@@ -47,6 +47,10 @@ void bindPyLook(py::module& mod)
         .def("getActiveVisibilities", &mx::Look::getActiveVisibilities)
         .def("removeVisibility", &mx::Look::removeVisibility)
         .def_readonly_static("CATEGORY", &mx::Look::CATEGORY);
+    mod.attr("Look").doc() = R"docstring(
+    A look element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_look.html)docstring";
 
     py::class_<mx::LookGroup, mx::LookGroupPtr, mx::Element>(mod, "LookGroup")
         .def("getLooks", &mx::LookGroup::getLooks)
@@ -56,6 +60,10 @@ void bindPyLook(py::module& mod)
         .def_readonly_static("CATEGORY", &mx::LookGroup::CATEGORY)
         .def_readonly_static("LOOKS_ATTRIBUTE", &mx::LookGroup::LOOKS_ATTRIBUTE)
         .def_readonly_static("ACTIVE_ATTRIBUTE", &mx::LookGroup::ACTIVE_ATTRIBUTE);
+    mod.attr("LookGroup").doc() = R"docstring(
+    A look group element within a `Document`.
+
+    :see: https://materialx.org/docs/api/class_look_group.html)docstring";
 
     py::class_<mx::MaterialAssign, mx::MaterialAssignPtr, mx::GeomElement>(mod, "MaterialAssign")
         .def("setMaterial", &mx::MaterialAssign::setMaterial)
@@ -66,6 +74,10 @@ void bindPyLook(py::module& mod)
         .def("getExclusive", &mx::MaterialAssign::getExclusive)
         .def("getReferencedMaterial", &mx::MaterialAssign::getReferencedMaterial)
         .def_readonly_static("CATEGORY", &mx::MaterialAssign::CATEGORY);
+    mod.attr("MaterialAssign").doc() = R"docstring(
+    A material assignment element within a `Look`.
+
+    :see: https://materialx.org/docs/api/class_material_assign.html)docstring";
 
     py::class_<mx::Visibility, mx::VisibilityPtr, mx::GeomElement>(mod, "Visibility")
         .def("setViewerGeom", &mx::Visibility::setViewerGeom)
@@ -80,6 +92,15 @@ void bindPyLook(py::module& mod)
         .def("setVisible", &mx::Visibility::setVisible)
         .def("getVisible", &mx::Visibility::getVisible)
         .def_readonly_static("CATEGORY", &mx::Visibility::CATEGORY);
+    mod.attr("Visibility").doc() = R"docstring(
+    A visibility element within a `Look`.
+
+    Describes the visibility relationship between two geometries or geometric
+    collections.
+
+    :todo: Add a `Look.geomIsVisible()` method that computes the visibility
+        between two geometries in the context of a specific `Look`.
+    :see: https://materialx.org/docs/api/class_visibility.html)docstring";
 
     mod.def("getGeometryBindings", &mx::getGeometryBindings,
         py::arg("materialNode") , py::arg("geom") = mx::UNIVERSAL_GEOM_NAME);