PlugAlgo : Support array[1] -> scalar conversion for BoxPlugs

python/GafferTest/PlugAlgoTest.py

@@ -1120,6 +1120,63 @@ def testSetTypedValueFromVectorData( self ) :
 				self.assertFalse( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
 				self.assertTrue( plug.isSetToDefault() )
 
+	def testSetBoxValueFromVectorData( self ) :
+
+		for plugType in [
+			Gaffer.Box2fPlug, Gaffer.Box3fPlug,
+			Gaffer.Box2iPlug, Gaffer.Box3iPlug,
+		] :
+
+			with self.subTest( plugType = plugType ) :
+
+				plug = plugType()
+
+				minValue = plugType.PointType()
+				maxValue = plugType.PointType()
+				for i in range( 0, minValue.dimensions() ) :
+					minValue[i] = i
+					maxValue[i] = i + 1
+				value = plugType.ValueType( minValue, maxValue )
+				data = IECore.DataTraits.dataFromElement( [ value ] )
+
+				# Array length 1, can set
+
+				self.assertTrue( Gaffer.PlugAlgo.canSetValueFromData( plug, data ) )
+				self.assertTrue( plug.isSetToDefault() )
+				self.assertTrue( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
+				self.assertEqual( plug.getValue(), value )
+				self.assertFalse( plug.isSetToDefault() )
+
+				# And can set individual children
+
+				plug.setToDefault()
+				for childPlug in plug :
+					for componentPlug in childPlug :
+						self.assertTrue( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
+				self.assertEqual( plug.getValue(), value )
+				self.assertFalse( plug.isSetToDefault() )
+
+				# Array length 2, can't set
+
+				data.append( data[0] )
+				plug.setToDefault()
+				self.assertFalse( Gaffer.PlugAlgo.canSetValueFromData( plug, data ) )
+				self.assertFalse( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
+				for childPlug in plug :
+					for componentPlug in childPlug :
+						self.assertFalse( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
+				self.assertTrue( plug.isSetToDefault() )
+
+				# Array length 0, can't set
+
+				data.resize( 0 )
+				self.assertFalse( Gaffer.PlugAlgo.canSetValueFromData( plug, data ) )
+				self.assertFalse( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
+				for childPlug in plug :
+					for componentPlug in childPlug :
+						self.assertFalse( Gaffer.PlugAlgo.setValueFromData( plug, data ) )
+				self.assertTrue( plug.isSetToDefault() )
+
 	def testDependsOnCompute( self ) :
 
 		add = GafferTest.AddNode()

src/Gaffer/PlugAlgo.cpp

@@ -838,6 +838,16 @@ bool setBoxChildPlugValue( const PlugType *plug, typename PlugType::ChildType::C
 	}
 }
 
+template<typename PlugType, typename DataType>
+bool setBoxChildPlugValueFromVectorData( const PlugType *plug, typename PlugType::ChildType::ChildType *child, const DataType *data )
+{
+	if( data->readable().size() != 1 )
+	{
+		return false;
+	}
+	return setBoxChildPlugValue( plug, child, data->readable()[0] );
+}
+
 template<typename PlugType>
 bool setBoxPlugValue( const PlugType *plug, Gaffer::ValuePlug *leafPlug, const Data *value )
 {
@@ -852,6 +862,14 @@ bool setBoxPlugValue( const PlugType *plug, Gaffer::ValuePlug *leafPlug, const D
 			return setBoxChildPlugValue( plug, typedPlug, static_cast<const Box3iData *>( value )->readable() );
 		case Box2iDataTypeId :
 			return setBoxChildPlugValue( plug, typedPlug, static_cast<const Box2iData *>( value )->readable() );
+		case Box3fVectorDataTypeId :
+			return setBoxChildPlugValueFromVectorData( plug, typedPlug, static_cast<const Box3fVectorData *>( value ) );
+		case Box2fVectorDataTypeId :
+			return setBoxChildPlugValueFromVectorData( plug, typedPlug, static_cast<const Box2fVectorData *>( value ) );
+		case Box3iVectorDataTypeId :
+			return setBoxChildPlugValueFromVectorData( plug, typedPlug, static_cast<const Box3iVectorData *>( value ) );
+		case Box2iVectorDataTypeId :
+			return setBoxChildPlugValueFromVectorData( plug, typedPlug, static_cast<const Box2iVectorData *>( value ) );
 		default :
 			return false;
 	}
@@ -1018,6 +1036,14 @@ bool canSetBoxPlugValue( const Data *value )
 		case Box3iDataTypeId :
 		case Box2iDataTypeId :
 			return true;
+		case Box3fVectorDataTypeId :
+			return static_cast<const Box3fVectorData *>( value )->readable().size() == 1;
+		case Box2fVectorDataTypeId :
+			return static_cast<const Box2fVectorData *>( value )->readable().size() == 1;
+		case Box3iVectorDataTypeId :
+			return static_cast<const Box3iVectorData *>( value )->readable().size() == 1;
+		case Box2iVectorDataTypeId :
+			return static_cast<const Box2iVectorData *>( value )->readable().size() == 1;
 		default :
 			return false;
 	}