Apple: Localization Schema

pxr/usd/usdUI/CMakeLists.txt

@@ -9,6 +9,7 @@ pxr_library(usdUI
         vt
         sdf
         usd
+        usdGeom
 
     PUBLIC_HEADERS
         api.h
@@ -42,3 +43,17 @@ pxr_register_test(testUsdUISceneGraphPrim
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testUsdUISceneGraphPrim"
 )
+
+pxr_build_test(testUsdUILocalizationAPI
+        LIBRARIES
+        tf
+        usd
+        usdUI
+        CPPFILES
+        testenv/testUsdUILocalizationAPI.cpp
+)
+
+pxr_register_test(testUsdUILocalizationAPI
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testUsdUILocalizationAPI"
+        EXPECTED_RETURN_CODE 0
+)

pxr/usd/usdUI/generatedSchema.classes.txt

@@ -2,13 +2,15 @@
 
 # Public Classes
 backdrop
+localizationAPI
 nodeGraphNodeAPI
 sceneGraphPrimAPI
 tokens
 
 # Python Module Files
 module.cpp
 wrapBackdrop.cpp
+wrapLocalizationAPI.cpp
 wrapNodeGraphNodeAPI.cpp
 wrapSceneGraphPrimAPI.cpp
 wrapTokens.cpp

pxr/usd/usdUI/generatedSchema.module.h

@@ -9,4 +9,5 @@
 TF_WRAP(UsdUINodeGraphNodeAPI);
 TF_WRAP(UsdUISceneGraphPrimAPI);
 TF_WRAP(UsdUIBackdrop);
+TF_WRAP(UsdUILocalizationAPI);
 TF_WRAP(UsdUITokens);

pxr/usd/usdUI/generatedSchema.usda

@@ -130,3 +130,64 @@ class Backdrop "Backdrop" (
     )
 }
 
+class "LocalizationAPI" (
+    doc = """This API describes em Language localization information for attributes.
+
+    It may be used to provide alternate language definitions for content like strings and asset paths that are
+    displayed to a user.
+    Runtimes may present the best language for a given users preference with this information.
+
+    OpenUSD leaves it up to the runtime that is consuming it to handle localized presentations.
+    As such, support for localization may vary across runtimes.
+
+    \\important Lookup of localized attributes may be expensive, so are recommended to be used sparingly
+    It is recommended, but not enforced, to only use them for strings and asset paths.
+    Support for localization of different attributes may vary depending on the application runtime that 
+    the data is brought into.
+
+
+    \\note Language identifiers must use the BCP-47 list of languages. However, since USD cannot currently use
+    hyphens in identifiers, any hyphens are replaced with underscores. This is similar in strategy to other
+    systems that adhere closely to the Unicode Identifier specification. e.g en-ca is en_CA .
+    Take care when converting language identifiers to a systems own formatting.
+
+    A default language is specifiable on a prim. This is the language that is assumed when attributes do
+    not include their own identifier for language. The default language is explicitly inherited by 
+    all prims under the current prims hierarchy.
+
+    \\note Provide default localization information on the default prim of the layer, and any top level prims.
+    It is not recommended to keep declarations of the default localization to a minimum throughout the rest of
+    the hierarchy within a single layer.
+
+    Attributes are suffixed with :lang:<identifier> when expressing languages other than the default.
+
+    For example, \"string text\" would implicitly be in the default localization language, but you may have
+    \"string text:lang:fr\" for French.
+
+    Runtimes may provide their own logic for choosing which langauge to display, but following BCP-47,
+    a recommended logic set is:
+
+    - If a preferred language is available within the set of declared languages, pick that language exactly.
+    e.g \"en_CA\" should not pick simply \"en\" if \"en_CA\" is available
+
+    - If a preferred language isn't available, check for a more specific version of that language.
+    e.g \"de_DE\" may match to \"de_DE_u_co_phonebk\"
+
+    - If a more specific language is not available, pick a less specific language.
+    e.g \"en_US\" may match to \"en\"
+
+    - If a less specific language choice is not available, pick the attribute without language specification.
+    """
+)
+{
+    uniform token localization:__INSTANCE_NAME__:language (
+        doc = """The default language for this prim hierarchy. This may only be created with the default instance name.
+
+        \\note If no default localization language is provided, the runtime may optionally try and infer the
+        language of the text.
+        If the runtime does not infer the langauge, it should assume the language is in the users preferred language,
+        which may be derived from the system or current user context.
+        """
+    )
+}
+