Replace mutable z api with separate constructor

Author: msvbg

Cargo.lock

@@ -19,7 +19,7 @@ usingz = ["clipper2c-sys/usingz"]
 
 [dependencies]
 libc = "0.2"
-clipper2c-sys = "0.1.4"
+clipper2c-sys = { path = "../clipper2c-sys" }
 thiserror = "1.0.59"
 serde = { version = "1", features = ["derive"], optional = true }
 
@@ -34,4 +34,4 @@ serde_json = "1"
 features = ["doc-images"]
 
 [patch.crates-io]
-clipper2c-sys = { rev = "210878394637f94bcd3a476bdf24ddf4ba8a39fd", git = "https://github.com/tirithen/clipper2c-sys" }
+# clipper2c-sys = { rev = "210878394637f94bcd3a476bdf24ddf4ba8a39fd", git = "https://github.com/tirithen/clipper2c-sys" }

Cargo.toml

@@ -132,7 +132,7 @@ impl<P: PointScaler> Clipper<NoSubjects, P> {
     ///
     /// let mut clipper = Clipper::<NoSubjects, Centi>::new();
     /// clipper.set_z_callback(|_: Point<_>, _: Point<_>, _: Point<_>, _: Point<_>, p: &mut Point<_>| {
-    ///     p.set_z(1);
+    ///     *p = Point::new(p.x(), p.y(), 1);
     /// });
     /// ```
     pub fn set_z_callback(
@@ -460,7 +460,7 @@ mod test {
                       _e2bot: Point<_>,
                       _e2top: Point<_>,
                       p: &mut Point<_>| {
-                    p.set_z(1);
+                    *p = Point::new_with_z(p.x(), p.y(), 1);
                     success.set(true);
                 },
             );

src/clipper.rs

@@ -159,6 +159,19 @@ impl<P: PointScaler> Point<P> {
         )
     }
 
+    #[cfg(feature = "usingz")]
+    /// Create a new point with user data.
+    pub fn new_with_z(x: f64, y: f64, z: i64) -> Self {
+        Self(
+            ClipperPoint64 {
+                x: P::scale(x) as i64,
+                y: P::scale(y) as i64,
+                z,
+            },
+            PhantomData,
+        )
+    }
+
     /// Create a new point from scaled values, this means that point is
     /// constructed as is without applying the scaling multiplier.
     pub fn from_scaled(x: i64, y: i64) -> Self {
@@ -201,12 +214,6 @@ impl<P: PointScaler> Point<P> {
     pub fn z(&self) -> i64 {
         self.0.z
     }
-
-    #[cfg(feature = "usingz")]
-    /// Sets the user data of the point.
-    pub fn set_z(&mut self, z: i64) {
-        self.0.z = z;
-    }
 }
 
 impl<P: PointScaler> Default for Point<P> {