feat: Setter for y direction in tile schemas

Author: Maximkaaa

galileo/src/tile_schema/builder.rs

@@ -339,6 +339,16 @@ impl TileSchemaBuilder {
         self.world_bounds = bounds;
         self
     }
+
+    /// Sets direction of Y-indices of the tiles.
+    ///
+    /// The direction is specified relative to the projected coordinates direction. We consider negative Y
+    /// coordinates of the projection to be at the bottom and positive at the top. So if
+    /// `VerticalDirection::TopToBottom` is set, tiles with Y index 0 will be at the very top of the map.
+    pub fn y_direction(mut self, direction: VerticalDirection) -> Self {
+        self.y_direction = direction;
+        self
+    }
 }
 
 #[cfg(test)]
@@ -621,4 +631,13 @@ mod tests {
             );
         }
     }
+
+    #[test]
+    fn setting_y_direction() {
+        let schema = TileSchemaBuilder::web_mercator(0..18)
+            .y_direction(VerticalDirection::BottomToTop)
+            .build()
+            .unwrap();
+        assert_eq!(schema.y_direction(), VerticalDirection::BottomToTop);
+    }
 }

galileo/src/tile_schema/schema.rs

@@ -66,6 +66,15 @@ impl TileSchema {
         self.tile_height
     }
 
+    /// Direction of Y-indices of the tiles.
+    ///
+    /// The direction is specified relative to the projected coordinates direction. We consider negative Y
+    /// coordinates of the projection to be at the bottom and positive at the top. So if
+    /// `VerticalDirection::TopToBottom` is set, tiles with Y index 0 will be at the very top of the map.
+    pub fn y_direction(&self) -> VerticalDirection {
+        self.y_direction
+    }
+
     /// Iterate over tile indices that should be displayed for the given map view.
     pub fn iter_tiles(&self, view: &MapView) -> Option<impl Iterator<Item = WrappingTileIndex>> {
         let resolution = view.resolution();