bufferstyleparameters is a string

R/sparklyr-mosaic/sparklyrMosaic/tests/testthat/testVectorFunctions.R

@@ -14,6 +14,7 @@ test_that("scalar vector functions behave as intended", {
   sdf <- mutate(sdf, "st_length" = st_length(wkt))
   sdf <- mutate(sdf, "st_perimeter" = st_perimeter(wkt))
   sdf <- mutate(sdf, "st_buffer" = st_buffer(wkt, as.double(1.1)))
+  sdf <- mutate(sdf, "st_buffer_optparams" = st_buffer(wkt, as.double(1.1), "endcap=square quad_segs=2"))
   sdf <- mutate(sdf, "st_bufferloop" = st_bufferloop(wkt, as.double(1.1), as.double(1.2)))
   sdf <- mutate(sdf, "st_convexhull" = st_convexhull(wkt))
   sdf <- mutate(sdf, "st_dump" = st_dump(wkt))

python/mosaic/api/functions.py

@@ -197,8 +197,7 @@ def st_concavehull(geom: ColumnOrName, concavity: ColumnOrName, has_holes: Any =
 def st_buffer(
         geom: ColumnOrName,
         radius: ColumnOrName,
-        quadrant_segments: Any = 8,
-        end_cap_style: Any = "round",
+        buffer_style_parameters: Any = "",
     ) -> Column:
     """
     Compute the buffered geometry based on geom and radius.
@@ -209,10 +208,11 @@ def st_buffer(
         The input geometry
     radius : Column
         The radius of buffering
-    quadrant_segments : Column
-        Number of line segments used to approximate a quarter circle (default is 8)
-    end_cap_style : Column
-        The end cap style ("round"(default)|"flat"|"square")
+    buffer_style_parameters : Column
+        "quad_segs=# endcap=round|flat|square" where "#" is the number of line segments used to
+        approximate a quarter circle (default is 8); and endcap style for line features is one of
+        listed (default="round")
+
 
     Returns
     -------
@@ -221,17 +221,14 @@ def st_buffer(
 
     """
 
-    if isinstance(quadrant_segments, int):
-        quadrant_segments = lit(quadrant_segments)
-    if isinstance(end_cap_style, str):
-        end_cap_style = lit(end_cap_style)
+    if isinstance(buffer_style_parameters, str):
+        buffer_style_parameters = lit(buffer_style_parameters)
 
     return config.mosaic_context.invoke_function(
         "st_buffer",
         pyspark_to_java_column(geom),
         pyspark_to_java_column(radius),
-        pyspark_to_java_column(quadrant_segments),
-        pyspark_to_java_column(end_cap_style),
+        pyspark_to_java_column(buffer_style_parameters),
     )
 
 

python/test/test_vector_functions.py

@@ -42,6 +42,10 @@ def test_st_bindings_happy_flow(self):
             df.withColumn("st_area", api.st_area("wkt"))
             .withColumn("st_length", api.st_length("wkt"))
             .withColumn("st_buffer", api.st_buffer("wkt", lit(1.1)))
+            .withColumn(
+                "st_buffer_optparams",
+                api.st_buffer("wkt", lit(1.1), lit("endcap=square quad_segs=2"))),
+            )
             .withColumn("st_buffer", api.st_bufferloop("wkt", lit(1.1), lit(1.2)))
             .withColumn("st_perimeter", api.st_perimeter("wkt"))
             .withColumn("st_convexhull", api.st_convexhull("wkt"))

src/main/scala/com/databricks/labs/mosaic/core/geometry/MosaicGeometry.scala

@@ -55,7 +55,7 @@ trait MosaicGeometry extends GeometryWriter with Serializable {
 
     def boundary: MosaicGeometry
 
-    def buffer(distance: Double): MosaicGeometry
+    def buffer(distance: Double, bufferStyleParameters: String = ""): MosaicGeometry
 
     def bufferCapStyle(distance: Double, capStyle: String): MosaicGeometry
 

src/main/scala/com/databricks/labs/mosaic/expressions/geometry/ST_Buffer.scala

@@ -16,15 +16,20 @@ import org.apache.spark.sql.types.DataType
   *   Expression containing the geometry.
   * @param radiusExpr
   *   The radius of the buffer.
+  * @param bufferStyleParameters
+  *   'quad_segs=# endcap=round|flat|square' where "#" is the number of line segments used to
+  *   approximate a quarter circle (default is 8); and endcap style for line features is one of
+  *   listed (default="round")
   * @param expressionConfig
   *   Mosaic execution context, e.g. geometryAPI, indexSystem, etc. Additional
   *   arguments for the expression (expressionConfigs).
   */
 case class ST_Buffer(
     inputGeom: Expression,
     radiusExpr: Expression,
+    bufferStyleParametersExpr: Expression,
     expressionConfig: MosaicExpressionConfig
-) extends UnaryVector1ArgExpression[ST_Buffer](inputGeom, radiusExpr, returnsGeometry = true, expressionConfig) {
+) extends UnaryVector2ArgExpression[ST_Buffer](inputGeom, radiusExpr, bufferStyleParametersExpr, returnsGeometry = true, expressionConfig) {
 
     override def dataType: DataType = inputGeom.dataType
 

src/main/scala/com/databricks/labs/mosaic/functions/MosaicContext.scala

@@ -548,9 +548,13 @@ class MosaicContext(indexSystem: IndexSystem, geometryAPI: GeometryAPI) extends
         def flatten_polygons(geom: Column): Column = ColumnAdapter(FlattenPolygons(geom.expr, geometryAPI.name))
         def st_area(geom: Column): Column = ColumnAdapter(ST_Area(geom.expr, expressionConfig))
         def st_buffer(geom: Column, radius: Column): Column =
-            ColumnAdapter(ST_Buffer(geom.expr, radius.cast("double").expr, expressionConfig))
+            st_buffer(geom, radius, lit(""))
         def st_buffer(geom: Column, radius: Double): Column =
-            ColumnAdapter(ST_Buffer(geom.expr, lit(radius).cast("double").expr, expressionConfig))
+            st_buffer(geom, lit(radius), lit(""))
+        def st_buffer(geom: Column, radius: Column, buffer_style_parameters: Column): Column =
+            ColumnAdapter(ST_Buffer(geom.expr, radius.cast("double").expr, buffer_style_parameters.cast("string").expr, expressionConfig))
+        def st_buffer(geom: Column, radius: Double, buffer_style_parameters: Column): Column =
+            ColumnAdapter(ST_Buffer(geom.expr, lit(radius).cast("double").expr, lit(buffer_style_parameters).cast("string").expr, expressionConfig))
         def st_bufferloop(geom: Column, r1: Column, r2: Column): Column =
             ColumnAdapter(ST_BufferLoop(geom.expr, r1.cast("double").expr, r2.cast("double").expr, expressionConfig))
         def st_bufferloop(geom: Column, r1: Double, r2: Double): Column =