geo-traits WKB example

src/lib.rs

@@ -16,3 +16,50 @@ pub mod table;
 pub(crate) mod test;
 pub mod trait_;
 mod util;
+
+#[cfg(test)]
+mod test2 {
+    use crate::algorithm::native::bounding_rect::BoundingRect;
+    use crate::array::WKBBuilder;
+    use crate::io::wkb::reader::WKBGeometry;
+    use crate::test::polygon::p0;
+    use crate::trait_::GeometryArrayAccessor;
+
+    #[test]
+    fn test_wkb_to_bbox() {
+        // A builder for a columnar WKB arrays
+        let mut wkb_builder = WKBBuilder::<i32>::new();
+        // Add a geo polygon to the WKB array
+        // This uses geo-traits to serialize to WKB and adds the binary to the array
+        wkb_builder.push_polygon(Some(&p0()));
+
+        // Finish the builder, creating an array of logical length 1.
+        let wkb_arr = wkb_builder.finish();
+
+        // Access the WKB scalar at position 0
+        // This is a reference onto the array. At this point the WKB is just a "blob" with no other
+        // information.
+        let wkb_scalar = wkb_arr.value(0);
+
+        // This is a "parsed" WKB object. The [WKBGeometry] type is an enum over each geometry
+        // type. WKBGeometry itself implements GeometryTrait but we need to unpack this to a
+        // WKBPolygon to access the object that has the PolygonTrait impl
+        let wkb_object = wkb_scalar.to_wkb_object();
+
+        // This is a WKBPolygon. It's already been scanned to know where each ring starts and ends,
+        // so it's O(1) from this point to access any single coordinate.
+        let wkb_polygon = match wkb_object {
+            WKBGeometry::Polygon(wkb_polygon) => wkb_polygon,
+            _ => unreachable!(),
+        };
+
+        // Add this wkb object directly into the BoundingRect
+        let mut bounding_rect = BoundingRect::new();
+        bounding_rect.add_polygon(&wkb_polygon);
+
+        assert_eq!(bounding_rect.minx, -111.);
+        assert_eq!(bounding_rect.miny, 41.);
+        assert_eq!(bounding_rect.maxx, -104.);
+        assert_eq!(bounding_rect.maxy, 45.);
+    }
+}