Add Display for Bounds and Center (#22)

Additionally, ran new fmt to keep things a bit cleaner:

```
cargo +nightly fmt -- --config imports_granularity=Module,group_imports=StdExternalCrate
```

- [x] I agree to follow the project's [code of
conduct](https://github.com/georust/geo/blob/master/CODE_OF_CONDUCT.md).
- [x] I added an entry to `CHANGES.md` if knowledge of this change could
be valuable to users.
---

CHANGELOG.md

@@ -1,3 +1,7 @@
+<a name="v0.3.3"></a>
+### v0.3.3 (2022-11-07)
+* Add `Display` with precision support for `Bounds` and `Center` structs
+
 <a name="v0.3.2"></a>
 ### v0.3.2 (2022-10-30)
 * Add `Bounds::from` for `[f64; 4]`, `[f32; 4]`, `[i32; 4]`

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tilejson"
-version = "0.3.2"
+version = "0.3.3"
 description = "Library for serializing the TileJSON file format"
 authors = [
     "Stepan Kuzmin <[email protected]>",

src/bounds.rs

@@ -1,10 +1,12 @@
-use crate::ParseBoundsError::{BadLen, ParseCoordError};
-use serde_tuple::{Deserialize_tuple, Serialize_tuple};
-use std::fmt::{Display, Formatter};
+use std::fmt::{Display, Formatter, Write as _};
 use std::num::ParseFloatError;
 use std::ops::{Add, AddAssign};
 use std::str::FromStr;
 
+use serde_tuple::{Deserialize_tuple, Serialize_tuple};
+
+use crate::ParseBoundsError::{BadLen, ParseCoordError};
+
 #[derive(Serialize_tuple, Deserialize_tuple, PartialEq, Debug, Copy, Clone)]
 pub struct Bounds {
     pub left: f64,
@@ -75,6 +77,29 @@ impl Default for Bounds {
     }
 }
 
+impl Display for Bounds {
+    /// Format Bounds struct as a comma-separated string.
+    /// Accepts all precision formatting parameters as for floats.
+    ///
+    /// ```
+    /// # use tilejson::Bounds;
+    /// # use std::str::FromStr;
+    /// let bounds = Bounds::new(-1.5, -2.5, 3.5, 4.5);
+    /// assert_eq!(bounds.to_string(), "-1.5,-2.5,3.5,4.5");
+    /// assert_eq!(format!("{:.2}", bounds), "-1.50,-2.50,3.50,4.50");
+    /// assert_eq!(Bounds::from_str(&bounds.to_string()).unwrap(), bounds);
+    /// ```
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.left.fmt(f)?;
+        f.write_char(',')?;
+        self.bottom.fmt(f)?;
+        f.write_char(',')?;
+        self.right.fmt(f)?;
+        f.write_char(',')?;
+        self.top.fmt(f)
+    }
+}
+
 impl Add for Bounds {
     type Output = Bounds;
 

src/center.rs

@@ -1,8 +1,9 @@
-use serde_tuple::{Deserialize_tuple, Serialize_tuple};
-use std::fmt::{Display, Formatter};
+use std::fmt::{Display, Formatter, Write as _};
 use std::num::{ParseFloatError, ParseIntError};
 use std::str::FromStr;
 
+use serde_tuple::{Deserialize_tuple, Serialize_tuple};
+
 #[derive(Serialize_tuple, Deserialize_tuple, PartialEq, Debug, Default, Copy, Clone)]
 pub struct Center {
     pub longitude: f64,
@@ -20,6 +21,27 @@ impl Center {
     }
 }
 
+impl Display for Center {
+    /// Format center struct as a comma-separated string.
+    /// Longitude and latitude are formatted with specified precision parameters.
+    ///
+    /// ```
+    /// # use tilejson::Center;
+    /// # use std::str::FromStr;
+    /// let center = Center::new(1.5, -2.5, 8);
+    /// assert_eq!(center.to_string(), "1.5,-2.5,8");
+    /// assert_eq!(format!("{:.2}", center), "1.50,-2.50,8");
+    /// assert_eq!(Center::from_str(&center.to_string()).unwrap(), center);
+    /// ```
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.longitude.fmt(f)?;
+        f.write_char(',')?;
+        self.latitude.fmt(f)?;
+        f.write_char(',')?;
+        write!(f, "{}", self.zoom)
+    }
+}
+
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum ParseCenterError {
     /// Incorrect number of values

src/tilejson.rs

@@ -1,9 +1,11 @@
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
 use crate::bounds::Bounds;
 use crate::center::Center;
 use crate::vector_layer::VectorLayer;
-use serde::{Deserialize, Serialize};
-use serde_json::Value;
-use std::collections::HashMap;
 
 /// TileJSON struct represents tilejson-spec metadata as specified by
 /// <https://github.com/mapbox/tilejson-spec> (version 3.0.0)

src/vector_layer.rs

@@ -1,6 +1,7 @@
+use std::collections::HashMap;
+
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
-use std::collections::HashMap;
 
 /// Each object describes one layer of vector tile data.
 ///