From 303d05904c75e734b7d6d8db1fe973885b220860 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9mi=20Thebault?= <remi.thebault@gmail.com>
Date: Fri, 20 Mar 2026 17:07:03 +0100
Subject: [PATCH] handline null in line series

---
 CHANGELOG.md                                 |   4 +
 examples/bitcoin.rs                          |   1 -
 src/data.rs                                  |  12 +-
 src/drawing/series.rs                        | 439 ++++++++++---------
 tests/refs/nulls/line-lin-null-end.png       | Bin 0 -> 15380 bytes
 tests/refs/nulls/line-lin-null-end.svg       |  11 +
 tests/refs/nulls/line-spline-null-middle.png | Bin 0 -> 25079 bytes
 tests/refs/nulls/line-spline-null-middle.svg |  16 +
 tests/src/tests.rs                           |   1 +
 tests/src/tests/nulls.rs                     |  30 ++
 10 files changed, 311 insertions(+), 203 deletions(-)
 create mode 100644 tests/refs/nulls/line-lin-null-end.png
 create mode 100644 tests/refs/nulls/line-lin-null-end.svg
 create mode 100644 tests/refs/nulls/line-spline-null-middle.png
 create mode 100644 tests/refs/nulls/line-spline-null-middle.svg
 create mode 100644 tests/src/tests/nulls.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8ef9c32..2a349f2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Handling nulls in line series
+
 ## [0.3.0] - 2026-02-19
 
 ### Changed
diff --git a/examples/bitcoin.rs b/examples/bitcoin.rs
index a1b08f2..368ddc5 100644
--- a/examples/bitcoin.rs
+++ b/examples/bitcoin.rs
@@ -3,7 +3,6 @@ use plotive::{data, des};
 mod common;
 
 fn main() {
-    // FIXME: support parsing datetime in CSV
     let btc_csv = common::example_res("BTC-USD.csv");
     let csv_data = std::fs::read_to_string(&btc_csv).unwrap();
     let data_source = data::csv::parse_str(&csv_data, Default::default()).unwrap();
diff --git a/src/data.rs b/src/data.rs
index 90d4c9f..c4c6d41 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -43,7 +43,11 @@ pub enum SampleRef<'a> {
 impl SampleRef<'_> {
     /// Check if the sample is null
     pub fn is_null(&self) -> bool {
-        matches!(self, SampleRef::Null)
+        match self {
+            SampleRef::Null => true,
+            SampleRef::Num(v) => !v.is_finite(),
+            _ => false,
+        }
     }
 
     /// Get the sample as a numeric value, if possible
@@ -200,7 +204,11 @@ pub enum Sample {
 impl Sample {
     /// Check if the sample is null
     pub fn is_null(&self) -> bool {
-        matches!(self, Sample::Null)
+        match self {
+            Sample::Null => true,
+            Sample::Num(v) => !v.is_finite(),
+            _ => false,
+        }
     }
 
     /// Get the sample as a numeric value, if possible
diff --git a/src/drawing/series.rs b/src/drawing/series.rs
index 75e76e5..98e6a9b 100644
--- a/src/drawing/series.rs
+++ b/src/drawing/series.rs
@@ -290,6 +290,196 @@ struct Line {
     interpolation: des::series::Interpolation,
 }
 
+trait Liner {
+    fn new(pt_len: usize) -> Self
+    where
+        Self: Sized;
+
+    fn start_line(&mut self, x: f32, y: f32);
+    fn cont_line(&mut self, x: f32, y: f32);
+    fn stop_line(&mut self, x: f32, y: f32) {
+        self.cont_line(x, y);
+    }
+
+    fn into_path(self) -> geom::Path;
+}
+
+struct LinearLiner {
+    pb: geom::PathBuilder,
+}
+
+impl Liner for LinearLiner {
+    fn new(pt_len: usize) -> Self {
+        LinearLiner {
+            pb: geom::PathBuilder::with_capacity(pt_len + 1, pt_len),
+        }
+    }
+
+    fn start_line(&mut self, x: f32, y: f32) {
+        self.pb.move_to(x, y);
+    }
+
+    fn cont_line(&mut self, x: f32, y: f32) {
+        self.pb.line_to(x, y);
+    }
+
+    fn into_path(self) -> geom::Path {
+        self.pb.finish().expect("Should be a valid path")
+    }
+}
+
+struct StepLiner {
+    pb: geom::PathBuilder,
+    prev_x: Option<f32>,
+    prev_y: Option<f32>,
+    step_type: des::series::Interpolation,
+}
+
+impl Liner for StepLiner {
+    fn new(_pt_len: usize) -> Self {
+        StepLiner {
+            pb: geom::PathBuilder::new(),
+            prev_x: None,
+            prev_y: None,
+            step_type: des::series::Interpolation::StepEarly, // default, will be set properly in prepare
+        }
+    }
+
+    fn into_path(self) -> geom::Path {
+        self.pb.finish().expect("Should be a valid path")
+    }
+
+    fn start_line(&mut self, x: f32, y: f32) {
+        self.prev_x = Some(x);
+        self.prev_y = Some(y);
+        self.pb.move_to(x, y);
+    }
+
+    fn cont_line(&mut self, x: f32, y: f32) {
+        if let (Some(px), Some(py)) = (self.prev_x, self.prev_y) {
+            match self.step_type {
+                des::series::Interpolation::StepEarly => {
+                    self.pb.line_to(px, y);
+                    self.pb.line_to(x, y);
+                }
+                des::series::Interpolation::StepLate => {
+                    self.pb.line_to(x, py);
+                    self.pb.line_to(x, y);
+                }
+                des::series::Interpolation::StepMiddle => {
+                    let mid_x = (px + x) / 2.0;
+                    self.pb.line_to(mid_x, py);
+                    self.pb.line_to(mid_x, y);
+                    self.pb.line_to(x, y);
+                }
+                _ => {}
+            }
+        } else {
+            self.pb.move_to(x, y);
+        }
+        self.prev_x = Some(x);
+        self.prev_y = Some(y);
+    }
+}
+
+struct CubicSplineLiner {
+    pb: geom::PathBuilder,
+    buf: [(f32, f32); 4],
+    buf_idx: usize,
+}
+
+impl CubicSplineLiner {
+    fn add_point(&mut self, points: &[(f32, f32)]) {
+        match points.len() {
+            2 => {
+                self.pb.line_to(points[1].0, points[1].1);
+            }
+            3 => {
+                unreachable!()
+                // // For the first segment, we can use a quadratic Bezier with control point at p1
+                // let cp_x = points[1].0;
+                // let cp_y = points[1].1;
+                // self.pb
+                //     .quad_to(cp_x, cp_y, points[2].0, points[2].1);
+            }
+            4 => {
+                // Calculate control points for cubic Bezier using Catmull-Rom formulation
+                // The tangent at p1 is (p2 - p0) / 2
+                // The tangent at p2 is (p3 - p1) / 2
+
+                // Tension parameter (0.5 for standard Catmull-Rom)
+                let tension = 0.5;
+
+                // Control point 1: p1 + tangent_at_p1 / 3
+                let tangent1_x = (points[2].0 - points[0].0) * tension;
+                let tangent1_y = (points[2].1 - points[0].1) * tension;
+                let cp1_x = points[1].0 + tangent1_x / 3.0;
+                let cp1_y = points[1].1 + tangent1_y / 3.0;
+
+                // Control point 2: p2 - tangent_at_p2 / 3
+                let tangent2_x = (points[3].0 - points[1].0) * tension;
+                let tangent2_y = (points[3].1 - points[1].1) * tension;
+                let cp2_x = points[2].0 - tangent2_x / 3.0;
+                let cp2_y = points[2].1 - tangent2_y / 3.0;
+
+                // Draw cubic Bezier curve
+                self.pb
+                    .cubic_to(cp1_x, cp1_y, cp2_x, cp2_y, points[2].0, points[2].1);
+            }
+            _ => {}
+        }
+    }
+}
+
+impl Liner for CubicSplineLiner {
+    fn new(_pt_len: usize) -> Self {
+        CubicSplineLiner {
+            pb: geom::PathBuilder::new(),
+            buf: [(0.0, 0.0); 4],
+            buf_idx: 0,
+        }
+    }
+
+    fn into_path(self) -> geom::Path {
+        self.pb.finish().expect("Should be a valid path")
+    }
+
+    fn start_line(&mut self, x: f32, y: f32) {
+        self.buf[0] = (x, y);
+        self.buf_idx = 1;
+        self.pb.move_to(x, y);
+    }
+
+    fn cont_line(&mut self, x: f32, y: f32) {
+        self.buf[self.buf_idx] = (x, y);
+        self.buf_idx += 1;
+        if self.buf_idx == 3 {
+            // For the first segment, we can use a quadratic Bezier with control point at p1
+            let [(x0, y0), (x1, y1), (x2, y2), _] = self.buf;
+            let points = [(x0, y0), (x0, y0), (x1, y1), (x2, y2)];
+            self.add_point(&points);
+        } else if self.buf_idx == 4 {
+            let points = self.buf;
+            self.add_point(&points);
+            // Shift buffer
+            self.buf[0] = self.buf[1];
+            self.buf[1] = self.buf[2];
+            self.buf[2] = self.buf[3];
+            self.buf_idx = 3;
+        }
+    }
+
+    fn stop_line(&mut self, x: f32, y: f32) {
+        self.cont_line(x, y);
+
+        // we draw the last segment if any
+        if self.buf_idx == 3 {
+            let points = [self.buf[0], self.buf[1], self.buf[2], self.buf[2]];
+            self.add_point(&points);
+        }
+    }
+}
+
 impl Line {
     fn prepare<D>(index: usize, des: &des::series::Line, data_source: &D) -> Result<Self, Error>
     where
@@ -319,230 +509,79 @@ impl Line {
         debug_assert!(x_col.len() == y_col.len());
 
         let path = match self.interpolation {
-            des::series::Interpolation::Linear => self.make_path_linear(rect, x_col, y_col, cm),
-            des::series::Interpolation::StepEarly => {
-                self.make_path_step_early(rect, x_col, y_col, cm)
-            }
-            des::series::Interpolation::StepLate => {
-                self.make_path_step_late(rect, x_col, y_col, cm)
+            des::series::Interpolation::Linear => {
+                let mut liner = LinearLiner::new(x_col.len());
+                self.make_line_path(rect, x_col, y_col, cm, &mut liner);
+                liner.into_path()
             }
-            des::series::Interpolation::StepMiddle => {
-                self.make_path_step_middle(rect, x_col, y_col, cm)
+            des::series::Interpolation::StepEarly
+            | des::series::Interpolation::StepLate
+            | des::series::Interpolation::StepMiddle => {
+                let mut liner = StepLiner::new(x_col.len());
+                liner.step_type = self.interpolation;
+                self.make_line_path(rect, x_col, y_col, cm, &mut liner);
+                liner.into_path()
             }
             des::series::Interpolation::Spline => {
-                self.make_path_cubic_spline(rect, x_col, y_col, cm)
+                let mut liner = CubicSplineLiner::new(x_col.len());
+                self.make_line_path(rect, x_col, y_col, cm, &mut liner);
+                liner.into_path()
             }
         };
 
         self.path = Some(path);
     }
 
-    fn make_path_linear(
-        &self,
-        rect: &geom::Rect,
-        x: &dyn data::Column,
-        y: &dyn data::Column,
-        cm: &CoordMapXy,
-    ) -> geom::Path {
-        let mut in_a_line = false;
-        let mut pb = geom::PathBuilder::with_capacity(x.len() + 1, x.len());
-        for (x, y) in x.sample_iter().zip(y.sample_iter()) {
-            if x.is_null() || y.is_null() {
-                in_a_line = false;
-                continue;
-            }
-            let (x, y) = cm.map_coord((x, y)).expect("Should be valid coordinates");
-            let x = rect.left() + x;
-            let y = rect.bottom() - y;
-            // if x_col.len() == 1024 {
-            //     println!("  adding point {} {}", x, y);
-            // }
-            if in_a_line {
-                pb.line_to(x, y);
-            } else {
-                pb.move_to(x, y);
-                in_a_line = true;
-            }
-        }
-        pb.finish().expect("Should be a valid path")
-    }
-
-    fn make_path_step_early(
+    fn make_line_path<L>(
         &self,
         rect: &geom::Rect,
         x: &dyn data::Column,
         y: &dyn data::Column,
         cm: &CoordMapXy,
-    ) -> geom::Path {
-        let mut pb = geom::PathBuilder::new();
-
-        let mut prev_x: Option<f32> = None;
-
-        for (x, y) in x.sample_iter().zip(y.sample_iter()) {
-            if x.is_null() || y.is_null() {
-                prev_x = None;
-                continue;
-            }
-            let (x, y) = cm.map_coord((x, y)).expect("Should be valid coordinates");
-            let (x, y) = plot_to_fig(rect, x, y);
-
-            if let Some(px) = prev_x {
-                pb.line_to(px, y);
-                pb.line_to(x, y);
-            } else {
-                pb.move_to(x, y);
-            }
-            prev_x = Some(x);
-        }
-
-        pb.finish().expect("Should be a valid path")
-    }
-
-    fn make_path_step_late(
-        &self,
-        rect: &geom::Rect,
-        x: &dyn data::Column,
-        y: &dyn data::Column,
-        cm: &CoordMapXy,
-    ) -> geom::Path {
-        let mut pb = geom::PathBuilder::new();
-
-        let mut prev_y: Option<f32> = None;
-
-        for (x, y) in x.sample_iter().zip(y.sample_iter()) {
-            if x.is_null() || y.is_null() {
-                prev_y = None;
-                continue;
-            }
-            let (x, y) = cm.map_coord((x, y)).expect("Should be valid coordinates");
-            let (x, y) = plot_to_fig(rect, x, y);
-
-            if let Some(py) = prev_y {
-                pb.line_to(x, py);
-                pb.line_to(x, y);
-            } else {
-                pb.move_to(x, y);
-            }
-            prev_y = Some(y);
-        }
-
-        pb.finish().expect("Should be a valid path")
-    }
-
-    fn make_path_step_middle(
-        &self,
-        rect: &geom::Rect,
-        x: &dyn data::Column,
-        y: &dyn data::Column,
-        cm: &CoordMapXy,
-    ) -> geom::Path {
-        let mut pb = geom::PathBuilder::new();
-
-        let mut prev_x: Option<f32> = None;
-        let mut prev_y: Option<f32> = None;
+        liner: &mut L,
+    ) where
+        L: Liner,
+    {
+        let mut prev = None;
+        let mut cur = None;
 
         for (x, y) in x.sample_iter().zip(y.sample_iter()) {
-            if x.is_null() || y.is_null() {
-                prev_x = None;
-                prev_y = None;
-                continue;
-            }
-            let (x, y) = cm.map_coord((x, y)).expect("Should be valid coordinates");
-            let (x, y) = plot_to_fig(rect, x, y);
-
-            if let (Some(px), Some(py)) = (prev_x, prev_y) {
-                let mx = (px + x) / 2.0;
-                pb.line_to(mx, py);
-                pb.line_to(mx, y);
-                pb.line_to(x, y);
+            let next = if x.is_null() || y.is_null() {
+                None
             } else {
-                pb.move_to(x, y);
-            }
-            prev_x = Some(x);
-            prev_y = Some(y);
-        }
-
-        pb.finish().expect("Should be a valid path")
-    }
-
-    fn make_path_cubic_spline(
-        &self,
-        rect: &geom::Rect,
-        x: &dyn data::Column,
-        y: &dyn data::Column,
-        cm: &CoordMapXy,
-    ) -> geom::Path {
-        const NAN: (f32, f32) = (f32::NAN, f32::NAN);
-        let mut buf: [(f32, f32); 4] = [NAN, NAN, NAN, NAN];
-        let mut buf_idx = 0;
-
-        let mut pb = geom::PathBuilder::new();
-
-        fn add_point(pb: &mut geom::PathBuilder, points: &[(f32, f32); 4]) {
-            // Calculate control points for cubic Bezier using Catmull-Rom formulation
-            // The tangent at p1 is (p2 - p0) / 2
-            // The tangent at p2 is (p3 - p1) / 2
-
-            // Tension parameter (0.5 for standard Catmull-Rom)
-            let tension = 0.5;
-
-            // Control point 1: p1 + tangent_at_p1 / 3
-            let tangent1_x = (points[2].0 - points[0].0) * tension;
-            let tangent1_y = (points[2].1 - points[0].1) * tension;
-            let cp1_x = points[1].0 + tangent1_x / 3.0;
-            let cp1_y = points[1].1 + tangent1_y / 3.0;
-
-            // Control point 2: p2 - tangent_at_p2 / 3
-            let tangent2_x = (points[3].0 - points[1].0) * tension;
-            let tangent2_y = (points[3].1 - points[1].1) * tension;
-            let cp2_x = points[2].0 - tangent2_x / 3.0;
-            let cp2_y = points[2].1 - tangent2_y / 3.0;
-
-            // Draw cubic Bezier curve
-            pb.cubic_to(cp1_x, cp1_y, cp2_x, cp2_y, points[2].0, points[2].1);
-        }
+                let (x, y) = cm.map_coord((x, y)).expect("Should be valid coordinates");
+                let (x, y) = plot_to_fig(rect, x, y);
+                Some((x, y))
+            };
 
-        for (x, y) in x.sample_iter().zip(y.sample_iter()) {
-            if x.is_null() || y.is_null() {
-                if buf_idx == 3 {
-                    // we draw the last segment if any
-                    add_point(&mut pb, &[buf[0], buf[1], buf[2], buf[2]]);
+            match (prev, cur, next) {
+                (_, None, _) => {}
+                (None, Some(_), None) => {
+                    // single point, no line to draw
+                }
+                (None, Some((x, y)), Some(_)) => {
+                    liner.start_line(x, y);
+                }
+                (Some(_), Some((x, y)), None) => {
+                    liner.stop_line(x, y);
+                }
+                (Some(_), Some((x, y)), Some(_)) => {
+                    liner.cont_line(x, y);
                 }
-                buf_idx = 0;
-                continue;
             }
-            let (x, y) = cm.map_coord((x, y)).expect("Should be valid coordinates");
-            let (x, y) = plot_to_fig(rect, x, y);
+            prev = cur;
+            cur = next;
+        }
 
-            // first point, or after a gap
-            if buf_idx == 0 {
-                pb.move_to(x, y);
+        match (prev, cur) {
+            (_, None) => {}
+            (None, Some(_)) => {
+                // single point, no line to draw
             }
-
-            buf[buf_idx] = (x, y);
-            buf_idx += 1;
-
-            if buf_idx == 3 {
-                // we draw the first segment
-                add_point(&mut pb, &[buf[0], buf[0], buf[1], buf[2]]);
-            } else if buf_idx == 4 {
-                // we draw a regular segment
-                add_point(&mut pb, &buf);
-
-                // Shift buffer
-                buf[0] = buf[1];
-                buf[1] = buf[2];
-                buf[2] = buf[3];
-                buf_idx = 3;
+            (Some(_), Some((x, y))) => {
+                liner.stop_line(x, y);
             }
         }
-
-        // we draw the last segment if any
-        if buf_idx == 3 {
-            add_point(&mut pb, &[buf[0], buf[1], buf[2], buf[2]]);
-        }
-
-        pb.finish().expect("Should be a valid path")
     }
 
     fn draw<S>(&self, surface: &mut S, style: &Style)
diff --git a/tests/refs/nulls/line-lin-null-end.png b/tests/refs/nulls/line-lin-null-end.png
new file mode 100644
index 0000000000000000000000000000000000000000..00cc0037e99f3975e414315fed90b280411435f1
GIT binary patch
literal 15380
zcmeHOe^Autna4|%G#8~e`9Wih+iR~gO`8kXOEggoJKiO=)|+xkOLkHM>y1fi0%Y%M
z6<A@vjm*WXrmmCgl~yX7InT3U18c&`R$2UN3Bg2hlPIi)zzXW3AS`703j1C5``+_B
z-(`0}_I>}je=;|jNivgV-+kZr`T2Q1&-4EBAAhiJ@$E}*PfJT%y#9MnJe`)dU=RHJ
z;BAZGlM(loKc%H*_pE<n?T^YAj2yq^jlX*KH}8$Jve93iJbmzI8#XnT_B6--dGWQn
z-+bRy_qPv!Z8W^q{gU;+cVriL<u-TbnF_Xa<(Z<xU+oFhI~$J<)jPE<drCLMXZQ!U
z`egGF_zeFb-T!>gbNFTWgS_OOQu;Fd$DDp)rT!}gimSS$R{xbo)wlNZ@blq}iB*o!
zD*fP!(OXp2T{LdE?ZQg7HfL~i&JMrY;2$__jvS6%Q`+qh@ALN`E*w5Qb=|9#Xw@JY
z<H^CwGlLszz1nqeOiXMQE>G{Nyip{<Z|x}!87^;zj}CPfNjHjO@?*<jYe#iyPNd0L
z%f5QDIh^qsp5}a@$rx#h@8}Kx-g{!DBYMHnDSi3*p6PV>|M0Ss&;|Ht=HMMkCotaj
zPN`N6C#qc19L7WHs!$!55+?{5Zk@Sf?2s`{d&d(e2xn|BfpaAtGG+pUQ;8Eyr-LG;
zJxPa**~aFi6MP}2&x4pWDN+{<FYg;}?c3$libP6O*xAw1hb*C$mNpB!VF{Te#pIdT
zAU|S?PDTU<pfInQDdx~>S7`P5fKyhT6~RfHrBQYCi;R$E`J=u5&WOhw8G9rB@qcq@
z*BpTZX7#|4A!&D#na%49OoC;e4ElxQ*6!l*v&QJzWk%cY;l4?3Gp{xj$q)C11H0Pj
z?9V!sXUTs}Q7=Ua-7n|&3fAn`M*M-&zCh`r&N6ATEYxj@c0Z>WeIn0fEyn`I$6mE-
zSM7lVg+m9XMuXbRh3WzGUO2N*&XO0-YzTeF&_<g+V^N-|oGg<b?XVjL>seS7g`)nS
z4L7(yTM1g8R?KV#T-njChbXo@$?@lnPFiqk#INC%`xf;~Pvo*kT+vTloq4Q9<oc@I
zUktaNx@y;c3Rf=NNlHGEVf!0XGzc+qCI-$gYsuZ)ThKRH)whF|wSqxU4Y{<Jb{mXm
z@>q6NBJ#}}cU1qdi>a;($7F>;Q(bJYORaYe>^G|W!NS}^3(Jn;O@pDFV0EcYJt*z<
z*+zVUdKMMRTE7{YRF?8|R(md+$PHagH~!YCS%l6gcYvaC*EU*K7*q;L(Wa<BDQTn-
z*bZ46mdQB(sC4It8-waYeUVmwty2pMy~5}x%lZx&+4+E5inuGT)!1HaROM?zPc9+D
z#JCZ98g4v&!@^eThS?$%miK>JT2A$NI(x=?<Y-Ujxph@{nWJ51u&zm=f*pgT;97UZ
zeGe6SPSOGTg3-R`6xJqm$7hd4TI5=L__y}{^KWk=v(AcsoCO<8LbG;Ussg*zJ$U$V
z;V!bzsqss&@hRcPww9I_&zWJ*5-IAFI@eX5TQ}YXSBAA`g=-6G%`hzASnJY;T!B`9
zr1i)Ua|zA4imp2e-q1fc`bfg)W44r))sU!K<VZ_}({24W{oJJvJ764P{3!0V4mW^`
zJ&Wo11ioUZM(j<#a3c7SCqTTl0AhXoL!q>mnnNqhZR@0ob!3;cTGz4Zad7}RvbC%X
ztRwstx~kjibPwR|SJ|c?GZiS)LL>2Ro)vP<N}jnL&jJ$5IxRf=GDv7f%8nar$-H9d
zRC-^yv>X-EhS6PjM~q_`wy|nJnwjmw)sLZhVsfPeY-{yxBlD!>+Gu@B=#=(xA846=
zfwXO^>N1UgWQcwQ7*_5UZ7<1mS#+;Modicd294oT;mIWjIzc~T>WVjOtPj{CZmCwc
zQ1*<_MoU546&Oiq*`(DqN!kXPNn+=+(oHdn{WI#kz^@c|Cb!9tf}I$IKuA6_Z{R&T
zWc)xRt<2tz%F`WV7(P7R#jW>{%Em8sz^U2ygjaq6HH}^gfmconL|eL~S4Ht8>(hC0
z9~@d305h*s5W%#(eBzCCf^ItAEKnT6WD}aqf$T`G>{5R0qU5@Hdg@=G_%Zf~<TZ%N
z2BYT~+Gu5WQPn+EZ$as65+=wJQnDU<gW6~?&;V5<O8WaENjFaIb%mGasQZn3Ypie9
zkYVZB_2`iNiQv$z1yE2<U{lVk`lfwD4U~8Y1(~8{0z?s&w$2JeNysmc?GvPDW{zSm
z$J(H}R1br;VK>yiT8khKXhwDRoexUt!HThJ!)cIp?ie5XsqA^kH<YVrnQPLTbxd{2
zdt=`GLqY7-<f&m<D<<ejh{$<t$Vng+tVG%?ux*x}BJ{Ffip1q3sgOx+Xg#-qOnc4L
zi42t3L6u)iMa_r7IH?@MV#ed!)|yH64GL^hATasrY^WPl8-oKnHmGNdg~uj$LJ$W~
z7o%p4?OF|<*)1|I^Jj<`D;1Npf}k!&?3g!7|1OgA!ddZ$GEFbs7=k_fuE3?(2qAhm
zMC|^7_FZ%U0DeKh1yPG45SE_;5T*9r_h-LHI6IbQ*iS?oH;`44D-t_&&7r**b480t
zOa7mLS^FyX`T9{?;Xl~bZ<1L%0c8*HQMMw#pCaJ0*F|!^CsAl4JWqx}QL~^5Q~ej?
zP!}Rk-%h$YLS4|(lOkcg|8lGH4AzaWk{dSV3^x&-25!jS5gq$Sl$J25ZmgXZZ-+(p
zd}mdsuW~U!4nrroAzIZ;hG8cJ@m6}B8*e26ai%&3y7Mhpuv(@d1d-?1PAdArpJYLj
zfyhX{kMOHGjHXo>Icx?lRb^KN_TeAFFOYQSRN4g!>k`~qK6P`^i9St5oKrIj3Is?(
zspIXpL@~q^!Hc3>rT0+j7=!2qTSSmg{uu8yhNXn(+=kY>$Y6B%<E$fj=sfIvEU04s
zCvZjzAXMy9j=_o$xz7qwc58|vi$a`PgS+p8vMOKMI8~m&jC=h8X&cX`0DSeC*9BU3
zT-gLrfLIWqrjrU!*f;A_(Y~L6mJ>YRQwHTJ3Y<s@?+OTZHe90&v(Hy?e@Tb{rw(vo
z>8NPwm6U)Fa6Pa%aZ-IgO56A+%8BH|b1<$`Q$(R)d5U5iyBb>s;Y)H-)Y?)wxFwnE
z!=*W*rMq0=y{>*Fo2V8c>=etYjjD)NjTT=Y9n~`{a(uw`S=!NLVwts`eMPW+W*1r|
zu_|+cE>tAL0)72w65U71B35z3(x6~z7Th`+=_a8*0QZ8%gtC3swSoBxwj-w#zxEoz
zwFh-RXg<OZf^SIR)O9_C1hBj~AE1Me_-xeQVoL=ZrxUiL{tf~BS=Tm0hiIlFG+!iI
zc<3hFM+{gjkZHw&a}yFGuuP~TLHa=;llcuJm5rcl5)>*4ApsXllTZRuHJ!2_r7&Nj
z^qd=ewQc+(Gbv@UE$mk?nFwqOW9_>#!$=7094BIXe&ax49r4J!EPLx~L^bFw2e1!8
z<A52V)ULdPR5QEffE(9w(TpPXK<G`h9A<@H_8i~3SYuKcN^qPQhMEL&uBEs`wy`$D
z`emwXHpmkjurV3+^5Lo$B<6fR@(ZBf62X~w=UZC;gR(0b<y&6$L2?hwu2PLaSb84{
z%g*xwN*%*)TQMxGXI1=o&upm~zXC<(^Q)@An8$KL$AVv2Xk|x%bSDmJZo2`jOAzx}
zgrE<a^{jRSmIizVDH^1{z<lin5E&DAgxtnMez5r!ZtwylO3n7=u}1~=d4U=$XrCum
zl5rNxH;TzP{Q_AJ&WX5);dEvejI)$)oKhY3m9Q$IULN(8uo*`dW)N7|gDI&#*w`T0
zcsJEC2;pXvn|Vy;QyT1EVt|P9pHp@My!Ub;lo~{0fxy6=77NgmjNi9ZgCWu{vV@sg
zg_jc@Ui3ykUsjTxu8Z|!`G?iZ-%T#G^GpKMuu>0<!u5}V=%fCOUXC;#z5OEJD18@t
zd#@mDqp~DtXn)R5k{nI2ydpUCuacrIZBGqeh_<4hf#L|paW0i$bo-g~(rC2_Hb$#V
z$@2k3|8su-Puu)y$}S5;`wfEKJ@fXp@!GB56fAv<gLRJ%Jt^?yO?=Sj)K>7fm;FSH
zAZ#OKklbeh1Gn(&b*(B@2!f@8laJuRcF;5swbZbTT|Rv=9RpZ_5)^E#AO=FHsviIw
z4(MGoK`f6I@`H(a4%khm{2*)C`PNeS^CXg!R3A4~)y|)SD10PUyBCwYk<Vva`%^=|
zM%61g^da(1<W}bNw<&c017Bd_2nKobuuUDiiJOh1-8^=IZ)G8sI)N&X&^~K}ZvYW~
zLREM37dMSSIfo-MWS~%X8}zz{?8Gc+dFbsl>=!rB2D|m_CGLf9=YYQg#m_|*%-<TH
zugP!i${)w_TW<kk;D3m>ahSa{i{_k#{p#7v{Iyq!jlo7-Nr-BGC0|}aLu>3#ZjNNN
z+%P2V<blp<>21i7RMF6;UHPqd!;Sr&u_6oxnv&-FZm!~(fg5~txgN!aiF8M_JO>69
zC`K-Ir)3c{H-F&?c;tDmtmU7Ao+fc3fa=vbT^0yo#$Fz<&|KlvtREm=e)E8RBPjqS
zH@G2o`T4RoksTzuEQo3nwpq&a#gN>4Gu}mxMYphgE+~<jxZ$Uhzj0T*^h_SF0dE3H
zarssDU0%Fp+qrgac_$_I1N-;}*FO9MMETu3UW2GW&^cg>Df-MaUW1b6cMigi(Rk0{
zCYBR6=B8!#CMFo9DX9pvtADUlUWG<2)>2%qlHEzPF4pPL?!;I>X$wy3qrR+~E9YE2
zSYgnlMi?nO)>Hyv@w*1>0XTEYQ4=im9o*0-ZRb?m^~}ySO#evgh->EhgM8Lk+36em
z2pTO!zf-`Rp%<XExWJ7b*&^I0bG<@3Jp0b|F7;c~VMh=Gs^)ebqytG)CRCPu0wayk
z(n8=?!gUH4uiCD6)^RxojgSCART?gw%Wygytz6U>_D*ohZ8-aOuELC`k{C|XI*s^|
zysZ6PD{=HE8V@+gNsv)*1ES3IJfzR6-#m0H{a5OO8?O8j|Ii;0zDG6)b8MxrtSU3s
z>V-%GZxgucveQ^0O}TXJzW)*>y2PbbAK%7)O^rL8D2ih}6AUQ|22T+oeeo{fi+2H^
zkLMF>uC31<z=<@<fXI;>rcW3y|AoE$R)SFaeEpHgXiJ5CvOFUYT18k0_~Ew;U15Ak
z@bVw~7tw^Z{sQRp^fXASAxLJ?0+w>buMqp$m-GipP^92f8a)R=>X-gZf1pIYZg-#c
z+p#ut)c6X%R#J@@v2TB`w|o&La0LE-?4mtfH+~19kj%^Y1>EX9&`VhHmt!OuB?dH&
zO393gY&n#@=IYvv0UUD2UA*P*JzU=4v;Os{8<1FV`b>~!&*<wkz@}Fi?CbR0ilt*#
zMBG3V!k{((!sCEgGb&F0JzbDc$>1O|1q2v~Xo9h*5N_<jTFI#V(75n81$vB`(?DO{
zgY)`}k5lge=XIu`e|tAwpN2$fTxQY5+2j@eCgvIh)|hEgLL@;&dY9%hsh&NT8@-FV
zgG4V*95n7DeJlh5?gc0=(v4Fm(umlm-Uohj95Zbiom2`vDz#xh1#7QUp3|qs=qbj;
zI_Z(LgzoP9#f~+X|I&jM8TDSGfR*%UtVp-g`!lwO!t}OdgWIO!#b%t-2>bTD8}HAj
z#l?%F!UM!6o+4HFf=f>&Y4|E*>H2BBTx@QZRqN{MAidGS<8!SZ(z7x2u#ragH_Nnj
zeAZ=jlKN^`z+(nN8-l#~X%MrDJ`Qq=ZV`AQvKD+nLyvd#7Y9x)gWk|Z4T$AYPBdg1
zf3}i!63vw4N8>#xKV(W_7x=E{j>N>DK3j|Q$zw3YEW?KF1lMHZuyjuK7JBwTk|txt
zsRqiqkmcj@rpC^-Txm6_iFBV2Kj*noEU)x>6Gj!Vp$nk##uanlFVLE5Dt=efzaN-c
zVrc8eUn?3z>r9qPXqtu-sP@6*jL(c{EuhDU?CS}71Ib<TMFN11@b4V`_z_;xI}(>O
zJ`n(CTTqUq8!h&#Z+Qps?+ePYV8AaR)@TATR~x1`Qd<#!Xwk*^kCfa(!pGMf5t0;k
zY}(E`w4cYAKbB5!D76e^sNj|r_Y(h%5?-_sT!MxGUMLK_F!iQGeW0!fbw^4Vc=t>6
z6F99&j5ke~fXC2NLV5*A0-^o`9xsiELw$k;rZUU1TTM)WUZ|wKP9lNXv?a&MVG~bD
z5}G7sphC#hUcqrK{FkPV28-ah$YJBunj7anks_p;9|zv>2s0zrA=J&94`-(T=v5Q`
z>dY@MqS%Uv^9V=<y%!@=XRKCWJN~~uJB_8>|J$S4F?(~><K3(ObsN6+O<Vuu51wfJ
IyN%ob7d|+r;s5{u

literal 0
HcmV?d00001

diff --git a/tests/refs/nulls/line-lin-null-end.svg b/tests/refs/nulls/line-lin-null-end.svg
new file mode 100644
index 0000000..f7aa21e
--- /dev/null
+++ b/tests/refs/nulls/line-lin-null-end.svg
@@ -0,0 +1,11 @@
+<svg height="300" viewBox="0 0 400 300" width="400" xmlns="http://www.w3.org/2000/svg">
+<rect fill="#ffffff" height="100%" width="100%"/>
+<clipPath id="plotive-clip1">
+<rect height="230.20801" width="360" x="20" y="20"/>
+</clipPath>
+<g clip-path="url(#plotive-clip1)">
+<path d="M40,230.20801 L120.00001,166.80533 L200,103.402664 L280,40" fill="none" stroke="#000000" stroke-width="1.5"/>
+</g>
+<path d="M-17.536001,12.719999 L-20.496002,8.528 L-18.896002,8.528 L-16.688002,11.76 L-14.496001,8.528 L-12.912001,8.528 L-15.872002,12.719999 L-12.752001,17.104 L-14.352001,17.104 L-16.688002,13.68 L-19.056002,17.104 L-20.640001,17.104 L-17.536001,12.719999 z M-3.6960006,8.384 Q-2.1280007,8.384,-1.3760004,9.072 Q-0.62400055,9.76,-0.62400055,11.264 L-0.62400055,17.104 L-1.6480007,17.104 L-1.9200006,15.8880005 L-1.9840007,15.8880005 Q-2.3520007,16.352,-2.7440004,16.664 Q-3.1360006,16.976,-3.6400008,17.12 Q-4.1440005,17.264,-4.864001,17.264 Q-5.632001,17.264,-6.248001,16.992 Q-6.864001,16.72,-7.2160006,16.152 Q-7.568001,15.584,-7.568001,14.72 Q-7.568001,13.44,-6.560001,12.7439995 Q-5.552001,12.048,-3.4560008,11.983999 L-2.0000005,11.936 L-2.0000005,11.424 Q-2.0000005,10.351999,-2.4640007,9.936 Q-2.9280005,9.5199995,-3.7760005,9.5199995 Q-4.448001,9.5199995,-5.0560007,9.719999 Q-5.6640005,9.92,-6.192001,10.176 L-6.6240005,9.12 Q-6.064001,8.816,-5.2960005,8.599999 Q-4.528001,8.384,-3.6960006,8.384 z M-3.2800007,12.96 Q-4.8800006,13.024,-5.496001,13.472 Q-6.1120005,13.92,-6.1120005,14.736 Q-6.1120005,15.456,-5.672001,15.792 Q-5.232001,16.128,-4.5440006,16.128 Q-3.4560008,16.128,-2.7360005,15.528 Q-2.0160007,14.9279995,-2.0160007,13.68 L-2.0160007,12.912 L-3.2800007,12.96 z M4.064,12.719999 L1.104,8.528 L2.704,8.528 L4.912,11.76 L7.104,8.528 L8.688001,8.528 L5.728,12.719999 L8.848001,17.104 L7.248,17.104 L4.912,13.68 L2.5440001,17.104 L0.9599999,17.104 L4.064,12.719999 z M11.904001,8.528 L11.904001,17.104 L10.496,17.104 L10.496,8.528 L11.904001,8.528 z M11.216001,5.3119993 Q11.536001,5.3119993,11.784,5.528 Q12.032001,5.7439995,12.032001,6.207999 Q12.032001,6.655999,11.784,6.879999 Q11.536001,7.104,11.216001,7.104 Q10.864,7.104,10.624001,6.879999 Q10.384001,6.655999,10.384001,6.207999 Q10.384001,5.7439995,10.624001,5.528 Q10.864,5.3119993,11.216001,5.3119993 z M20.208,14.736 Q20.208,15.568,19.792002,16.128 Q19.376001,16.688,18.608002,16.976 Q17.84,17.264,16.784,17.264 Q15.8880005,17.264,15.240001,17.12 Q14.592001,16.976,14.096001,16.72 L14.096001,15.440001 Q14.608001,15.696,15.336,15.912 Q16.064001,16.128,16.816002,16.128 Q17.888,16.128,18.368,15.784 Q18.848001,15.440001,18.848001,14.864 Q18.848001,14.544,18.672,14.288 Q18.496002,14.032,18.04,13.776 Q17.584002,13.52,16.736,13.2 Q15.904001,12.88,15.312001,12.559999 Q14.720001,12.24,14.400001,11.792 Q14.080001,11.344,14.080001,10.639999 Q14.080001,9.552,14.968001,8.96 Q15.856001,8.368,17.296001,8.368 Q18.080002,8.368,18.760002,8.5199995 Q19.44,8.672,20.032001,8.943999 L19.552002,10.063999 Q19.008001,9.84,18.416,9.68 Q17.824001,9.5199995,17.2,9.5199995 Q16.336,9.5199995,15.880001,9.799999 Q15.424001,10.08,15.424001,10.559999 Q15.424001,10.912,15.632001,11.16 Q15.840001,11.408,16.328001,11.639999 Q16.816002,11.872,17.632,12.191999 Q18.448002,12.496,19.024002,12.816 Q19.600002,13.136,19.904001,13.592 Q20.208,14.048,20.208,14.736 z" fill="#000000" stroke="none" transform="matrix(1 0 0 1 200 258.208)"/>
+<rect fill="none" height="230.20801" stroke="#000000" stroke-width="1" width="360" x="20" y="20"/>
+</svg>
\ No newline at end of file
diff --git a/tests/refs/nulls/line-spline-null-middle.png b/tests/refs/nulls/line-spline-null-middle.png
new file mode 100644
index 0000000000000000000000000000000000000000..56defe234e0f77100d1cce06f726ee8ec25d029c
GIT binary patch
literal 25079
zcmeHQ4Rlo1wGO3)R)y47jEE9jX;IUX*P<ZuGxb$VmDare#5@aR^l2L{U}_`gKi7iF
z!&IZtiV|gPsZC7^W2KTp60QglQR5gfgpei^f+UcTKPHo8CNp#1-rt=$XC@i%_}1!M
zt8cBY)pj*AbMHNOpZ)XgZ|{BB_#d||opRo#=f%avO}XW}H~la!Zo*Ua->-dk5`EHB
zdFqY0xV!e<a?_1J&Y95j`otG!-SNzu10uWkiMQS@`{lB`cdlvP9sJLIzuxxDt@dr-
zocrZo&qI|z&->$sg{vA;cGsn*tz6rXn&$7mqPe5IV&~qj@`}LPr`BZAXZ(e@;jP_!
z=rjI8yZoN!75roRLZABT8vL04$2z%bo^h9zZu|PxrN&)$dK+*2XSls5esF=!wZK@o
z+v3P5Jeo0(_}Qj;;>IPNSxYuJy*r%kuUSW53%;iIq|@_)^TccE-LH+Dbp%!i){|r`
zZ*>;D*Li2DBXHIc6q8uMmrrgk7|PJ-UQexYC4Q7eAH7nSp$%mO<tHwqN88q~Su(oI
zQYx-^Yqux<9IxhB$1cn0F8M@<=XuBec{YEOtxo&=J<Yz!^tb1-)vhM`D75fHVJonF
z_SH3k^|Ydbsk=SANMkF!wv%cFuEbA=-Z8ky;7&UR)CxTD>sHgc!WJ1+fzA=N0^elX
zNbRYxMFw>vD{KY-64O6{n8ci_s;bK@MbB64^g35(XKy)qsKk|c%3LYj&Qm+c2==&-
zF86fnfmNhSTE&J%AAPC1VR_9otG~for#%w3`O!2~+ky*@uBy4%>2Gn8SMg^)*uA6j
z+*2DCJ!1Ek+uOHWyxTn`{pPCY?fb>Ji^xdC6Gh%KZEIz2Y2^ufpv#_fW=qk1fh%KZ
zUtpncFhyLO>6({$fZt-^gJk~)WKH5biT?V;y2gUK#yd;JRbjdx%|OLen5AKSEY>de
z6%$5!oPjlg?J<{7J+w-n7pME1b;#r^8%w-@Drv9Ky%nC4Fi#N84!wO>s9!@00k2(b
z-IDv<mJ?+~U1d4ll|`#!FQLNkwu<YLUEfSTkX_iAJ<!_cZ-o@FQKQw4(f+|Q%L|h&
zBl~?z!~9M(b@r!?_VxwtZ|y8>-9WFPx4&fdzJ#SM@ou+l?F;nw{fx9ud^eU*e;&34
zV}*KUq4I0dyh@;=W~@*h-ak9q*`s<&;Oq_e8da$FuYLld##}<u|3;`@b64t5^L`?s
z-WyA(x0(obdn}<QnF)0$hS}O@eXLNc_H|d~^bHqf24XIu;_rFgJIL?EpO6=^FWSy(
z)lo=FH$rxkl<s}Wx>dv!#x)lI5ldZjbzO6Rn&wWc9$cnho3_%e*Duuum%6UAx~@Cc
zVL1>Zrs{8VET;(05u1QfWnNEX(VDoT(MqjUTo7wNuCe=%+v|FJ=V<;$4d%bL{ov<X
zyK7pD*^7OW$8Y@N?3{|qyrg}jRXX7+uk-ZL<(a3x6rcN9r+cNdHeVmkciB$F@bA_W
zp^L2URBJ5@fZ&Ok;UDiFeHk(0zCR6~FTHbZdIWM3PXOW=VM5#y0~(2GVZY{GX;`HX
zt=d&p^^R4ztu9-vh-E!7K4N`w_HF&QXS#1M7|zz_e}Wavq}bH|!({gl5hb7+v{kcj
zd%mq=UsuJ*>5{;`fnBlu`>vke-e1zDF6rL2q&Nr;1M|Hc93n;Jam4cWj-h4>6V>l^
zS5MX5%k^582)3z^0j8mAfw{5Fcvqo2O}j49^^L>>wZ#bwihS4O&6d+GU5%uNY+}BQ
zSRN@OpDh+@zC5$$xA4%cbR@0h+7vOE;<BBIp>(#MpQd;G^!kU+UJ@4kl%ICQ^3#s5
zZj`?^AOIU(W9|!$Cn}4&D|6ToV~b<1e<)MTv%7AvA4u_km@;rQ(|;7f53uG?!Mlf4
z@QW=K<)_Om{xge4_Q$hRn4bq>F+yo+SsB<BYm4R<4ldQMB?n|(&nc8v(OA^eIH|2t
z8?E#>VtHD};BoRQaXx-6-r3*IQmSWZj^WNMn`bTQ+P>s*cpqN5m+>BLQ~F~z@5{D!
zHmXmsgkOd*TAz1kUwe&nv<4dlA2pn78xF&0F@>?~<1ktn>JsP0^0Z$I`}J5jkrdO0
zfzb#!`xq#}8?oE959cNCBaE~46Fi>1#*Wsm9U~mb5wqBA7!nsWq!ms>T-F|qg`poK
z^||f&>-VP>Hlz*I(?!r!701|!u~u@Q=BcNc4%>~i7OV?C$}nB+w=owK_G?D;ZZ;oy
z5SElkjk$_e%B{ERfo{EnBM<`UTi>4f#;Tg5s|H#KfBMqQ0jDUUZ6TaqFa=<BM`i1I
zuMeC&l*`5sO=i>S5T!^yK3rCF5rma0s(6tFj^ToMgkJLN2*vp|jrjv@lP%ARl!vmj
z7d+7ZX`A~FTP<R|)ja0-N3jg(8Q;$R6FWTg#8)V2!6W`UW6}EIqQ2n{1}`JxrZ32Q
zXElham92S6ti=biwc+fE{Vz^l{NJ3L&DUJ><CKnw1USoXiUR#=w`0gzXNUoh&-Zry
zgw}=_7+=)CKKFiU8T}0W3mUTv6GS512fQL}XyyRBlof7^GgAz4w&a?3wzv1(9kl)e
z_Ed*T5+~nDsJ<j{x}+n2UuXWv&OYy)*3lYgsfd?x{6u?gF=w9Q8gpZ{X40*on0Dc{
zd&=$JYmhr6bX4i1RpdQ#6P1q=d*Q0?Uea;*-*N`NOe^Uu7fs61yp-Pc(#RQG;J%r@
zw#hDE^>DsE-|1THRL<UK9cHD4Y4aY4-<m6}-uh1UyYKXKsD!LYW_@+VM)tbZ?zwbZ
zV6e;u6?z8}um#T8IOVAbWT@1rGOwbtonMFJZ}Phw$z7}-95rY`-=t)0(dirG+sia>
zna6G(2?J}9Z2<#ISe*W2vJ1qYwFEOpUbcC!4kYJ4w<UM_lb0`iledv{ZiPzl7#G3O
zCO_^B^f)_k)t?>SuNl15JF^C`+hDR{2&lLhc^0QM1e5kX4y~|u%MU3w7Zn?3dCe^a
zM>7g9h6bjJxk#Cybn9mhUI7QiCh&VBe0F3MJ;w5Z4i!gnUx6g^z?x78^}T_fP~Dhc
zlYqC^8`dZK?gZ3hd-7QaCCIY4e`KlU4@p#uNSw6o)femr1M*~|<vsmP@-}aOd*->%
zs{kv0FV!)}d&Kr0-#gZ_v?j7nWZ!?e`w*}*?%u#j386ICHx~KNq;&3&FZwsp2(#^T
zE$KUO#1?pvb(+@(0t0r6wR0jPE{0w@eD6AbG0=W<AUP6(RG3RjYeHIdgq)?X!Rntz
zv`BKDeu&lym%(Vp2z;v|vigcZr>Dyv_&FKllE)OMQ>oCd!~-6kFhv;p(_S+THSRZ5
zDgt_zc~9R`q>V)pim@zx^fl{@hoQvf;tmiZa3-K@*%Jh6;0u^{0<$YF4b#F{>sUu{
z{v4a<WeXqrHR6`#ZDb_;neqqXE1O27^^oNgD9yc`GP=Oy9QIkM``jeh27;Fb7o=$3
zBf0(S6W<ln5RBkoeni?=O(_35(O~Y6&L3h~0K$-}8d-rW@eK1WPag!UrPW4RVXDX~
zkcoh#eSAxgwX~c%xbcexA1*Dt2oP9IQ(i*SKxw0<jD^D)G7aRia7~uuQ4~5sDKwS}
z0?utYz?zo(*0*zB-ja7UEM0sT`rPMxuMc=!Bt>W*ad4(Ax+lN1GIs_%PiO-Yd&cFw
zE^U8U?q4nzz=8L9w)LGjlcL?gx=-{G!xG}es^iH%wc2I+;4-?7J@~|aHa}msd4lZd
zW*iTNP=3Sm4&Ud>jiAiLI)(T5bZL)8bIA9SKYIT92i7UFQ2&;~6E3HD#=qDOli-(v
z#t~wo^fQV=KD24%PbJ=~VC<yEIjqJU;IbIt+rSEYN_Ec+1U<baik@j3%nkc_<;Z35
z3e0T@@jNQio<Ay65$Q$tbm>k&nkD2DmGx=QL?eXi6e?gRZBWDu&9Q&yAi0T8Hv`e8
z;fh%Utj4~~A$E?$9aT?}YLL~S>5MZGxs7D)uY~<5RZv0{b<kV8XRCexJh9T;w09LU
zQvr9cEHrIIx>%WGY8Bx)T=*5{Qkn3s8uliHCN;#4!2J9$rfQD4`7|LuG9-mA>QP<Z
z?TnzOyl!9%%}%Kbu41$aWFe-h4Up#Ky!8u-?jI!9!Z$e05%x-C1Ta12>8xisG9o|$
zWa|wPsaZuJUnbKsX1b#AT`s*on)Yrn)!wzW9R6nxzBqXRrk`f8A{>y46OzyA^&vM%
zfPY^xuz$H&!YC8o4GARkcH&mN0GlDI2J;n<AW3vjpE*C&Ceg71So(3ugaNycK<>rJ
zal|~8FtXSU;?qBzi?H6Azi)%oEByoM4_8#@Jk4=Suah4g>(Gyw@(JrAt)Y)Ip-5{m
z%ASUd)BM9+VIsFb^Npp2A1)nWf8<LWl~kExAe<dxC6<MzSVmMSUqI}|*BKs^3M1Ql
zY1tMK#(_%Yiw0|35g0|503q@I@vejyT0GA0gzKy+%_W?RnXNwdm%EW)h!>P)hO(jW
zb3%{2lizoR+j%k+mt=bAGU{)+Z_eGeA7N5I98Fit%yiYK4avZzm|^D`8H}i2RP;Ez
ziw><=aub{kBJie)#WI^gsy;Gs(wD8!o>UpFSjk(F@wb`z7mqm0)ZuQ_7j12HX8<3-
z4smf*Wo@hqX^KLF*@~-@0m9={iP>tGv&W2*6jp^XmAg&pM|N1}^i5%$MmLm+%xZG@
zB`|7E(|Glq&50I<@0>QcKwucjv%$xS7Bh$M5)H`f8D;Sfh^rBIOFYk(DE#4UQ>wqy
zYtIfbZITN0*xHzIqYecRLbXeOG>p^JO&P#|B^p$>wR0j)MaA6d%8zO5nNCmdbEgAF
zruiEU-^V0p2x3|G%iyfi2=Sl-xhqK%VQjGkQy(c9Bb#SZ!r=0cL@Tzrt=;1-$x<s_
zvdm4jz0p+mesh)WkTOvyPTLA?$S&&4M)oHjRM0uh(>AJHOiJo7XNo9XF<;Q3?M2qS
zYG22ySL(#4V=M*x&8f}(HSXJ4`^2^C!4k8l3^8K}l8PF3^rIm`j9Y&OWmHV2h$CSY
zzgUa-D2lA3gg@=oaBQm|MSW^9F*2d}VyTO!Gxvn0Q{r>xMs!%-QzgznTFg{DTaJeb
z*ud<~2W5y^;kI^$7EkKjSBnK$)Z&$*lq2Kg#1)JR$jeyEsij<o+20yUg~0v>W*e5$
znO%fP>q~JnnFMx0dS-GhFF=`?PE%AuSsv$!$T^Ulr?{n4S6O5Xbx{sXQB{W(G*j4k
zwn8D&y_btiqrjKLMr`mrXJe9&UWl1QfIdo7d?}{wL?WJ;Rs{X!H4V!R(l<rAHN_&>
zPNPADw~sC$1%6Kg5w*{o6=Ih8q%UPKl&}N6YLA=8$$pN*NX!+=)c23E&)=iTg5x^s
zEdEB$n>mURkCqwKpq7w@DH=@sav0YjE;6_4Hojkc-uvr~R+37C?NDknE4==tzbOmR
zN*pu505TQe0rOD?c!|2B0#mkj)2P^}L@KFZU#5cMO7CVVYFe@vY5vaUagx!Evh-Yw
zYc89;xKG8o5GuOb)W)?I#@(xth3bc;m?g;8HjSs@c6uGdk||M(HoB3}<RV?P*bD%I
zIK?*?vrIQiKPy30SbQvHw9MGS2vM66=O7`zWvcLuSNlv^Hw#mH!jIu)Rm)*B$W0t?
zM2fE01Bh@D0a~GL8e0hQC`77~vX01{$`bNnDjT0|T9y&1N)=R$pP?$xA@<T`*&lR|
zyC@8yo09hFHOdosgQ;HD`Z!{<wtY-wHR?EEDftbJqSt2AWL}g5-SS>ZtTrPGaPXyo
z#~E8^*LFtn$6<+@bdlP+uw-0ZYpy!7TSI|;y@@i8TyEWhQ>OSbO0A)x9I10}2>HqY
z=F40gLV*hS+JF<A$o5c0v2~alc|r{rMj}!k=UEhcCA(t*#}(?pp!l@YsL>FW^0yH5
zExnxTJCHIbql83>Nd(o-&bTg?ERa{Qwui~01;juk3*Is&W3pvXd1Xt{nJpcN5a`RO
z%t!BAM`i#u17CI&_Q(@MD2*^#REwm(M(4Q76fTgJuZlnxw|@9W9tb2yp=|Uc(Qr--
zZMlbD6b8(FmqvaxjZ0ntfJ_So7AkKYS~InXB!>YPxj=CnGCO7ncvr<u=9>DE%zG4U
zNCE=NSafna@V$6J=7^|xQG@pllo4^*Fi@TI3}dI9_t(!n2x7ugZ|=;v088|d-RLOM
z4$BZ1LW|B*5jW&+n4jQrPG6nVAd0!+m6_781nIP?Eu<+<S_M4ox$$Kom-8;#4^D$*
zZH#&Y>`{n)ZG+-)6$!D?JjQ`r;%XgoeeLP+Ebf4;WGP;U>hG(RJCn^U#7A@gxA823
zW@e3g;{0fAY%+S<=B(U%5SYq&LTUnKz^UT)F&Y@rEFpem&d#iZQ|0`bU6m-8t}|54
z)sKfae&Ko8;JModE<iy=Obz3x#mlBL)g>fTNslO3d&6Z?1JwUK?55N&Qt1uJa03y0
zFzTczjYF}-+aq1MO6c|Pg|SK2XnYKHMeI=fq8fXXR6GrKa>bCgR>jJy2-!yDcU$JH
zY-hMMVjq<FC?PrhBjRDGy+q#-u6G}x9Lmv#Qx;!}X)}@tW84)FZ66&c%8Ce;Asgy*
zqv2rhgBwAA>K`ztE4v)UVe?IHiX;o-qsgv<UBYmleHfkA)SaZ+$E)5OQCK!{kExq<
zc7;+&*-7aV5d=)Mo093~M^mS$T>q=4=}V?tX88)_CV=>rbZ3&P{DlPxaUoL&NS-+Z
z@}(K=<J?gWHtLMI)EgMFQMX0<<6tnv=5g}0Gy{x=nhZ&~wBG<MOn2l=LKQ`O6wyr%
z35W;Hg?*YG2lf0@X-~43VskWmUOlz}%kp*<WbvHppI61GGSgb8_zv6=YYNg45$>lg
zN1|vDZT3<$5umM3AvVXLOgz=j#SlOg$RrHN&)p<29?KE=qQR)iPW0(Wk}@L?a7pg<
z6!X2t0238lT?<sMnW(%`NU5kzmoX%GT`t~Hf0^ZYWI|#&5^3789y~_LDxv@{@ij@e
zFeJi5r3ln|r>nhIE_J?X?N)p>T3Ta^1icQGJ%lxoq>6eb=TH$-8PW9diEj)67~~dn
zKiq*OTE<B8z*vODdp#Zf4qRF{>TuH$;@GAkJ+0W>q5NfBHWpq}Q5^rha59w6A#Wxv
z&p<^9?HODRvz>^{1}-+YZL~+B+Y4bH_+C`;s@X@VjyUZP!KO%A31G((wF3NIwSAJH
z5X()IMy*&@%9-~{TZ!&KEC#(<C4;;dW9z`F;*N3cgNbL5op6iTYL{-F#n0!A3Y=J2
zrzhI-sddfZN`nm%A@t7T&gY>gwrhaH#4%Vq)*~fKROP?&BsEo~0{C_eV4$5Q*vx8a
zmQ-8_m?w^(D2VyeIb8W$R`cPq0hZ|s_w%y`en7=x1S@f&GFR!E*|eJ#68<p7e-WIq
z_J}0(6?Hn_oUw>jl}KA$HYPqjB6+0{J|%FL#2sn)A+p{QqhiDju;?djHdnB{5&?%;
z33{x2j9PyUhl@$gs3Q_YvW{uKNE~Bb!Fd1x&T&&~9$PQlqRb*w9kNuSU`rnxK9_4{
z2POew`#DKC%f1I!A2uw~2&hnOn%m7DWk#~KV@>O0l8W5Z<;joaxARpl778lt(Nf1*
zS0AR<K*mDoGfdMC?Nw|SGb1eYJzbv}W!8YIE&I4|4}8BP(o51lSJZH4-6o@CyqHM{
z#aL&W_GpTigA10u4p|N74~=L2U71m3J~SQ}=tfG6%D&Wl@f}l_YU`3M0?MV9C-g>=
zebK00@-Atz;woK|Z#lYu!9$SS7t76MUe1*H{&_}p5U<JtSICmA-5{J8C~&AG<JQBw
zqMYp!Dl2X`e^*JYNrld8(9g=Eog!+jvfdu{%T%#ag=RKJqg&{@X#TL$bXJCF6&~7V
zTabe!E8M?FzaN7cG;3&2j5m0^e~=vAP7TlCkOJ31D-pLj(a?68#_kkuUwULq-pgCi
zNxY})=Hc<GRNOU=LuoOdLaklMQ<KZbhFI!<GUXBOi{`EK>RUo>UGjy}FM>Xx<x%1y
za&OL_DA4}qXjO-wnd^bU33Ak(lV1H6F{^vJtOj59oXs<xKP$$73JN4-r97x|b!3C+
z%>xlq^f-G>`J*F<kFxQcNHEpHBGG>CT@nt4lSdX~)F1*`C%+r5iRU5n*ZwGq_{wQI
zil-qs-9m<Om+YYowRG@2$wfq%p>70o<Pe|!EQ6r^^8la3XJR~AR-++JXK$3^h=;u{
z8Vb~`BRSYIoK(Q6#|GK<lv||IcNzGJQ8nv76|*9<J?}93djcUgnB#TlknD=$fPujQ
zS^=|A@P|AN4f@ZA?UWrnY39+~NPgE)TvHX|ia?<<2S|rG*qNu5U}S}vg`ldgvI>;@
zqD-a{eT)g$B-13#XkC{heJk9FC#CxbP0PCYsWx~-t{I_=jYAUaz=NQMhiO2jUs`3H
z>M2mLY>T-#)&(7htX0r5IwgGwGm|AUS?Od5OA#m2m`C9m9dyT`>J9WEoA<?a=DMhQ
z;=%%+_)okD==X)XYoRJoz&n(Suan}UO#t;5&NvXOux#C&JN{y1;Si@_hz!$3_U#VB
zEY)aBuD@J3On2AWgA)RtE%96;>3AH>5%W5B_OH}|ui%4P+@i%4r!AB|TNeL#c@+WO
zlorvVK-f=qT{ud>c_gMMLWntRz1&S14pVu7ZKh5-EWC%xp5*ySg6Elw9rcDV@vUu`
zX1==^6dK#x0lkQIq2%!t8Oztzns3*b;KP#GnYY^%C8R~EjTyq|YBH6EwMVA3GPvR(
zpjekhl(Y%Z^FC*p!YJ*fC`=C&zG9nc6Dm#LgobI=yfYtBwAj2|GA%DM8^x(c?rL*+
zpw>F3QO-CSsnfjfa*aHgfv0s02grvjIl4`?I2C+S*oZn_Of%I;`^RgfYuFUjo%eBz
zbegJUQdE`PZz@S!H27yoGU2SLNSel!AlU%Y|7NQH84Ib*DEoGT>Uh4nEWU?YIr<MI
zm1LZrRPzf{@jC{?d!s1UvJXx+_oaV~IJv-hjQ<^T0iKEm0AVm%lj(NtLe(3uN7+a4
zo$ihCu!z(Q=A4?m)m-S9${d^jV~cMFv;1)<w1^8L%GSY$?KOYc^-*@X*c`^!t6Wd=
z!-!xz^Xg3#UCVLQP=XxoFAeXe(}^|mc(8GYa|O1)K;<Yo6dH8CRszDI)56A|)g_+(
z*adnUO}Q@Z50Y|XxNDe|R%0r`rTj~F+hgrSZ#920Mc|-#%q(<J>Fwqgc2z`OB_u|3
zQt3(}#c|k1*ck@AXIij*2C4YC)2Vz*(U&>y%p$fHr+MGZh1dfm@8~N6gy=F)5QFyn
zuS3@Ubrzk)^vJ$IviIpk&xNhMJ*`jvB#8ivZFG<ABopt)nwn0OcMi_b2WC_sE3Ubu
zab@=9^gSJ*W@$gZ%6{s1@r75>-_(PpADEZy*_3?P{CqZ_^{+KGbuHP>x}!%grV9@(
z>iC9_X~mMF!R>px7S!yYQ9Z#nc#G{Iv2)#74Ow|Sg-;7f4-PeThSQ(sXSj*t-IbMl
zMtiH8jvsHQmw5KjB7*_0FDbf~o;^Qj{rtAgOU`W0p)-*Rcjn!O`8OO0!I6{70^zaf
z!tg)F9<k`s>W7BrWjhP!FJHc#E}ZFl_E0~E>qXxBk`8+Iq|E+F1s}{V`~qjej#S4P
zK0_*JM`PaCfg;90%Qwb(I>;!|`@6)qNp2!xanF4zCz(CCa6jE^ck}%x_jd2x-j`1=
zk=?R3fjEYYyYF64cP$)lIaIJDBO_x2{qgAe331owo|`2uoEjhRp%QFf>(CnKGX`lt
z_?xmtkBSP^)p>jW%ecXen)(?7-**mvf6?IY;!n|=U=ZW|$%UV1&fsl&Iwbf~THaT1
zGkQ#8VN2s(r6s<%N<Ol@eIPOLi@?M$(Se=`hyQ^h(ypTOKiyw$YHjW4t?K*Ps#V4G
z;JatKE<t&Isl{7QyU^M;rS;(y?;ldysYK#t?c!ltw0UvhB<%{%1mYj1<3iJCCH7B9
ze4W{exutb~>snCAn+7=QZnW~oE!+3evK*Ri%t}97oBnHhYGq+_<-qBsmaUCBPc*iX
zgm~YNb*ym?t??wD_kVL7X&w&oaOAu>7lX?T<Ii`2V&IcUm|_x}iB6dIFdwB?eFbq3
z`T?$YJ-|(Z7EJ7LzZZy(btv@kHLOs=N`ue7sfV7t{3LgC=iUWEi93vO(nJX}7Tl=`
zlT6^|JDtf}6zMYQ0MCj!+=b1wlq@JQ|A^`kz`!1Kjv?f7r+eg=Vtr_s6T}Z60^#TZ
zam1|`OdLJHEkWEpWK8ok7V?QK;M4hT#$a716CEIWd61N86&%+HS|P~HGY<t-57I{5
z#Kyvzc`v<@!9m91qy)@oY4spRdG;5Ei2Ac1qzwog^u4oGz_Fudy9e!&fB~V`L<Gl|
z`XzK?ZQe6zUt#WZ0w5|5GeC21B?`|x5{D;o8#i8uCv12tv=-z8{3pswOc>?f51FD&
z&+dz>_Pk}tX0fwrem-OkOTy?Zy>9wb*c1MmKcDhCuT`xx*vQOFM1?&LbRZZ)d}fe^
zTpnP;Zvqa&0@I6CiB0$=rw0>IQ!oxp2ueIuWy9<m&d0$JL>8w=_<vAN^g^=LGL7s>
zevA}sn;oyjBQ^{be-)y)?<^ffml<9V=bUIwpx#h7=Ym=szRKEsFxbQv7b!8H6^9Bz
zvGC3LE~evAG~^wgfP>iB*3kQ)H2{6HjQKq$wK3l{!h|cNG#R~&(0gMLi8l!iDok_-
zl0i&!4H8R*M&l?+<U{Bp;dlRg$`^v9%-{PM_j%BB%-u7i+zg^N_fbA4+2!W@;J_iC
z=Z?n-BRCWogt{Lisn{FPDLPunK)&<nE7zeeeHeT8D>8F#iQT=&$?rO`pYQ9leq|%d
z3Op&qQz*ES51-gpI%{>7&R4QS07w;F$-(n5zrs2KAHgko+nTx9%Po+GMxc!fq$g&Q
zjV{oSlU(mGBYTwU4KoC5k5vO0J0s;O48Z_*qtJ$jQODt;_fgNsi}7U5Fs9V8V%$uW
zqaTB(1q{8W-uM|o>4d2qPQ)`5OQdcxPU_-8>(JZ7KQI-ad&MosI*OoycrfoSX&gry
z6gR;<%N7HiR>MB|SF;A#q|vu%oZSlLGp@z~Y}j8G#gy0iEAFsn^~usvf`Mz``TO2s
zzGkd4;8iiLmi!3Y7S4onap?{fZeBsqVe`?oY_q+?n1*Dk3q~St2FcAw*rFZ5m_Lof
zd>ahpTbo{~^TR8!>k2B;=bHcC$4i@lW{{buX+v0Tsa|p!WIU-2`k;4lCWu)z-qwkD
z0>;Q8$cd2#Ke3-ld*p%8cX2Z`1Onql$Kfk17Y@*J3!2FxdH+~7g2PRv$YM-<K#g`G
zRDu=24d6lft#}u?k~N9v5O7l*;i04Qf>9_#{BdwDxWPo!_^}xFbQAk=t_vU0hDD21
zEDMgnSbOmND-<<yUxXDyuehHs4rNsNnMc1h<Ti|VhEqWd`xYJ!-^#SFu^=p#Et5{~
z!Fgsp2V!_FHe5cUiKF?{*EtgLwX9?l`G6XBkkrTUso=nUsKTy)o{wZd%NL{M%LD)H
zIQ?9OJO5$01YRwQ-LP~UkMyC^z^!yl^1>Db%9MuxiQ`UMI3PG4?&@GnzCqf)hd%#0
z@QQc`L5zt8qlcVp{iwvl{5jqsx?>ui<p6C5{)fb2l^lO*U$r`(%h$WuWnwU%TaZ`)
zXhnjC@Oc+72FNw!gP}M~(eWWOm^49;CU8`-ax`pxdz@_KS8hZ!hRJddG6Vw`k3+J!
z0S<*MUNB8UINIRFSzaiq!D<t}O$Xg?Y2h>HI0QI)SVwqT90r3W(*iDe7=25;KRg7_
zBRK$##Vnpl!NG41HLzO-k%n2rtaxZBw4q`xKH|Nah$@<41$YHkOb&&Y8fPT2cUB=(
ztcB{6LY?<IJhq|ad{7V+-!OOH2ecB#L2VhG1nekVLVmokMep;D@qX~PoK4Mmm?0mc
z5U+z@-l!<D_J)2`DklAZ|JMY9<lR5+-$EE!I<aVO{w4Pww9`N65O>SXx81b!-|t-a
EKhy0{(f|Me

literal 0
HcmV?d00001

diff --git a/tests/refs/nulls/line-spline-null-middle.svg b/tests/refs/nulls/line-spline-null-middle.svg
new file mode 100644
index 0000000..6a4b7b1
--- /dev/null
+++ b/tests/refs/nulls/line-spline-null-middle.svg
@@ -0,0 +1,16 @@
+<svg height="300" viewBox="0 0 400 300" width="400" xmlns="http://www.w3.org/2000/svg">
+<rect fill="#ffffff" height="100%" width="100%"/>
+<clipPath id="plotive-clip1">
+<rect height="235.656" width="360" x="20" y="20"/>
+</clipPath>
+<g clip-path="url(#plotive-clip1)">
+<path d="M40,235.656 C45.925926,219.35133,63.703705,162.285,75.55556,137.828 C87.40741,113.371,99.259254,80.761665,111.11111,88.914 C122.96296,97.06634,134.8148,194.89433,146.66666,186.742 C158.51851,178.58968,176.2963,64.457,182.22223,40 M253.33333,137.828 C259.25925,129.67567,277.03705,80.761665,288.8889,88.914 C300.74072,97.06634,312.5926,194.89433,324.44443,186.742 C336.29626,178.58968,354.07407,64.457,360,40" fill="none" stroke="#000000" stroke-width="1.5"/>
+</g>
+<path d="M55.555553,-4 L55.555553,4 M126.666664,-4 L126.666664,4 M197.77777,-4 L197.77777,4 M268.8889,-4 L268.8889,4 M340,-4 L340,4" fill="none" stroke="#000000" stroke-width="1" transform="matrix(1 0 0 1 20 255.656)"/>
+<path d="M-2.2319999,12.828 L-7.896,12.828 L-7.896,11.952 L-5.6520004,9.684 Q-5.004,9.036,-4.5600004,8.532 Q-4.116,8.028,-3.888,7.542 Q-3.6599998,7.056,-3.6599998,6.48 Q-3.6599998,5.772,-4.08,5.406 Q-4.5,5.04,-5.172,5.04 Q-5.796,5.04,-6.2700005,5.256 Q-6.744,5.472,-7.236,5.856 L-7.8,5.148 Q-7.464,4.86,-7.0620003,4.632 Q-6.66,4.4040003,-6.186,4.2720003 Q-5.712,4.1400003,-5.172,4.1400003 Q-4.368,4.1400003,-3.7920003,4.4160004 Q-3.216,4.6920004,-2.8980002,5.202 Q-2.58,5.712,-2.58,6.42 Q-2.58,7.092,-2.856,7.68 Q-3.132,8.268,-3.624,8.838 Q-4.116,9.408,-4.776,10.056 L-6.564,11.82 L-6.564,11.868 L-2.2319999,11.868 L-2.2319999,12.828 z M-0.74400026,12.18 Q-0.74400026,11.736,-0.52800024,11.556 Q-0.31200027,11.376,-0.012000322,11.376 Q0.2999997,11.376,0.52199984,11.556 Q0.7439997,11.736,0.7439997,12.18 Q0.7439997,12.612,0.52199984,12.804 Q0.2999997,12.996,-0.012000322,12.996 Q-0.31200027,12.996,-0.52800024,12.804 Q-0.74400026,12.612,-0.74400026,12.18 z M7.884,8.532 Q7.884,9.576,7.7279997,10.392 Q7.572,11.208,7.23,11.778 Q6.888,12.348,6.342,12.648 Q5.796,12.948,5.028,12.948 Q4.068,12.948,3.4379997,12.42 Q2.8079998,11.892,2.5019999,10.902 Q2.1959999,9.912,2.1959999,8.532 Q2.1959999,7.14,2.4779997,6.156 Q2.7599998,5.172,3.3839998,4.6499996 Q4.008,4.1280003,5.028,4.1280003 Q5.988,4.1280003,6.624,4.6499996 Q7.2599998,5.172,7.572,6.156 Q7.884,7.14,7.884,8.532 z M3.2519999,8.532 Q3.2519999,9.708,3.4259996,10.488 Q3.6,11.268,3.9899998,11.658 Q4.38,12.048,5.028,12.048 Q5.6759996,12.048,6.066,11.664 Q6.456,11.28,6.6359997,10.4939995 Q6.816,9.708,6.816,8.532 Q6.816,7.356,6.6359997,6.582 Q6.456,5.808,6.066,5.418 Q5.6759996,5.028,5.028,5.028 Q4.38,5.028,3.9899998,5.418 Q3.6,5.808,3.4259996,6.582 Q3.2519999,7.356,3.2519999,8.532 z" fill="#000000" stroke="none" transform="matrix(1 0 0 1 75.55556 263.656)"/>
+<path d="M-1.848,10.884 L-3.0960002,10.884 L-3.0960002,12.828 L-4.116,12.828 L-4.116,10.884 L-8.22,10.884 L-8.22,9.984 L-4.188,4.212 L-3.0960002,4.212 L-3.0960002,9.936 L-1.848,9.936 L-1.848,10.884 z M-4.116,7.236 Q-4.116,6.924,-4.11,6.666 Q-4.104,6.408,-4.092,6.18 Q-4.08,5.952,-4.074,5.742 Q-4.0680003,5.532,-4.056,5.34 L-4.104,5.34 Q-4.2000003,5.568,-4.344,5.832 Q-4.488,6.096,-4.62,6.276 L-7.188,9.936 L-4.116,9.936 L-4.116,7.236 z M-0.74400026,12.18 Q-0.74400026,11.736,-0.52800024,11.556 Q-0.31200027,11.376,-0.012000322,11.376 Q0.2999997,11.376,0.52199984,11.556 Q0.7439997,11.736,0.7439997,12.18 Q0.7439997,12.612,0.52199984,12.804 Q0.2999997,12.996,-0.012000322,12.996 Q-0.31200027,12.996,-0.52800024,12.804 Q-0.74400026,12.612,-0.74400026,12.18 z M7.884,8.532 Q7.884,9.576,7.7279997,10.392 Q7.572,11.208,7.23,11.778 Q6.888,12.348,6.342,12.648 Q5.796,12.948,5.028,12.948 Q4.068,12.948,3.4379997,12.42 Q2.8079998,11.892,2.5019999,10.902 Q2.1959999,9.912,2.1959999,8.532 Q2.1959999,7.14,2.4779997,6.156 Q2.7599998,5.172,3.3839998,4.6499996 Q4.008,4.1280003,5.028,4.1280003 Q5.988,4.1280003,6.624,4.6499996 Q7.2599998,5.172,7.572,6.156 Q7.884,7.14,7.884,8.532 z M3.2519999,8.532 Q3.2519999,9.708,3.4259996,10.488 Q3.6,11.268,3.9899998,11.658 Q4.38,12.048,5.028,12.048 Q5.6759996,12.048,6.066,11.664 Q6.456,11.28,6.6359997,10.4939995 Q6.816,9.708,6.816,8.532 Q6.816,7.356,6.6359997,6.582 Q6.456,5.808,6.066,5.418 Q5.6759996,5.028,5.028,5.028 Q4.38,5.028,3.9899998,5.418 Q3.6,5.808,3.4259996,6.582 Q3.2519999,7.356,3.2519999,8.532 z" fill="#000000" stroke="none" transform="matrix(1 0 0 1 146.66666 263.656)"/>
+<path d="M-7.8120003,9.168 Q-7.8120003,8.424,-7.71,7.704 Q-7.6080003,6.984,-7.356,6.342 Q-7.104,5.7,-6.66,5.202 Q-6.216,4.7040005,-5.538,4.422 Q-4.86,4.1400003,-3.888,4.1400003 Q-3.6360002,4.1400003,-3.33,4.1639996 Q-3.0240002,4.1879997,-2.8320003,4.248 L-2.8320003,5.148 Q-3.0479999,5.076,-3.3179998,5.04 Q-3.5880003,5.004,-3.8640003,5.004 Q-4.6920004,5.004,-5.2440004,5.28 Q-5.796,5.556,-6.1140003,6.036 Q-6.432,6.516,-6.576,7.14 Q-6.7200003,7.764,-6.756,8.472 L-6.684,8.472 Q-6.504,8.184,-6.228,7.956 Q-5.952,7.728,-5.5620003,7.596 Q-5.172,7.464,-4.656,7.464 Q-3.9120002,7.464,-3.354,7.77 Q-2.796,8.076,-2.4840002,8.658 Q-2.172,9.24,-2.172,10.068 Q-2.172,10.956,-2.508,11.604 Q-2.8439999,12.252,-3.4500003,12.6 Q-4.056,12.948,-4.896,12.948 Q-5.5080004,12.948,-6.0360003,12.72 Q-6.564,12.492,-6.966,12.024 Q-7.368,11.556,-7.59,10.842 Q-7.8120003,10.128,-7.8120003,9.168 z M-4.908,12.06 Q-4.152,12.06,-3.684,11.574 Q-3.216,11.088,-3.216,10.068 Q-3.216,9.252,-3.63,8.771999 Q-4.044,8.292,-4.8719997,8.292 Q-5.436,8.292,-5.856,8.526 Q-6.276,8.76,-6.51,9.12 Q-6.744,9.48,-6.744,9.864 Q-6.744,10.26,-6.63,10.644 Q-6.5160003,11.028,-6.282,11.352 Q-6.0480003,11.676001,-5.7060003,11.868 Q-5.3640003,12.06,-4.908,12.06 z M-0.74400026,12.18 Q-0.74400026,11.736,-0.52800024,11.556 Q-0.31200027,11.376,-0.012000322,11.376 Q0.2999997,11.376,0.52199984,11.556 Q0.7439997,11.736,0.7439997,12.18 Q0.7439997,12.612,0.52199984,12.804 Q0.2999997,12.996,-0.012000322,12.996 Q-0.31200027,12.996,-0.52800024,12.804 Q-0.74400026,12.612,-0.74400026,12.18 z M7.884,8.532 Q7.884,9.576,7.7279997,10.392 Q7.572,11.208,7.23,11.778 Q6.888,12.348,6.342,12.648 Q5.796,12.948,5.028,12.948 Q4.068,12.948,3.4379997,12.42 Q2.8079998,11.892,2.5019999,10.902 Q2.1959999,9.912,2.1959999,8.532 Q2.1959999,7.14,2.4779997,6.156 Q2.7599998,5.172,3.3839998,4.6499996 Q4.008,4.1280003,5.028,4.1280003 Q5.988,4.1280003,6.624,4.6499996 Q7.2599998,5.172,7.572,6.156 Q7.884,7.14,7.884,8.532 z M3.2519999,8.532 Q3.2519999,9.708,3.4259996,10.488 Q3.6,11.268,3.9899998,11.658 Q4.38,12.048,5.028,12.048 Q5.6759996,12.048,6.066,11.664 Q6.456,11.28,6.6359997,10.4939995 Q6.816,9.708,6.816,8.532 Q6.816,7.356,6.6359997,6.582 Q6.456,5.808,6.066,5.418 Q5.6759996,5.028,5.028,5.028 Q4.38,5.028,3.9899998,5.418 Q3.6,5.808,3.4259996,6.582 Q3.2519999,7.356,3.2519999,8.532 z" fill="#000000" stroke="none" transform="matrix(1 0 0 1 217.77777 263.656)"/>
+<path d="M-5.052,4.1400003 Q-4.296,4.1400003,-3.7200003,4.3739996 Q-3.144,4.608,-2.8140001,5.064 Q-2.4840002,5.52,-2.4840002,6.192 Q-2.4840002,6.708,-2.7059999,7.092 Q-2.928,7.476,-3.3000002,7.77 Q-3.672,8.064,-4.116,8.292 Q-3.5880003,8.544001,-3.1560001,8.8619995 Q-2.724,9.18,-2.466,9.6 Q-2.2080002,10.02,-2.2080002,10.608 Q-2.2080002,11.328,-2.5560002,11.85 Q-2.9040003,12.372,-3.534,12.66 Q-4.164,12.948,-5.016,12.948 Q-5.94,12.948,-6.5820003,12.672 Q-7.224,12.396,-7.554,11.886 Q-7.8840003,11.376,-7.8840003,10.644 Q-7.8840003,10.056,-7.638,9.624001 Q-7.392,9.192,-6.984,8.88 Q-6.576,8.568,-6.108,8.352 Q-6.528,8.1119995,-6.87,7.806 Q-7.212,7.5,-7.41,7.104 Q-7.6080003,6.708,-7.6080003,6.18 Q-7.6080003,5.52,-7.2720003,5.07 Q-6.936,4.62,-6.36,4.38 Q-5.7840004,4.1400003,-5.052,4.1400003 z M-6.852,10.656 Q-6.852,11.28,-6.408,11.694 Q-5.9639997,12.108,-5.04,12.108 Q-4.164,12.108,-3.7020001,11.694 Q-3.2400002,11.28,-3.2400002,10.62 Q-3.2400002,10.2,-3.462,9.882 Q-3.684,9.564,-4.086,9.312 Q-4.488,9.059999,-5.04,8.856 L-5.2320004,8.784 Q-5.76,9.012,-6.12,9.276 Q-6.48,9.54,-6.6660004,9.875999 Q-6.852,10.212,-6.852,10.656 z M-5.064,4.992 Q-5.724,4.992,-6.15,5.31 Q-6.576,5.628,-6.576,6.228 Q-6.576,6.672,-6.366,6.972 Q-6.156,7.272,-5.796,7.482 Q-5.436,7.692,-5.004,7.884 Q-4.584,7.704,-4.254,7.488 Q-3.9240003,7.272,-3.7260003,6.966 Q-3.5279999,6.66,-3.5279999,6.228 Q-3.5279999,5.628,-3.948,5.31 Q-4.368,4.992,-5.064,4.992 z M-0.74400026,12.18 Q-0.74400026,11.736,-0.52800024,11.556 Q-0.31200027,11.376,-0.012000322,11.376 Q0.2999997,11.376,0.52199984,11.556 Q0.7439997,11.736,0.7439997,12.18 Q0.7439997,12.612,0.52199984,12.804 Q0.2999997,12.996,-0.012000322,12.996 Q-0.31200027,12.996,-0.52800024,12.804 Q-0.74400026,12.612,-0.74400026,12.18 z M7.884,8.532 Q7.884,9.576,7.7279997,10.392 Q7.572,11.208,7.23,11.778 Q6.888,12.348,6.342,12.648 Q5.796,12.948,5.028,12.948 Q4.068,12.948,3.4379997,12.42 Q2.8079998,11.892,2.5019999,10.902 Q2.1959999,9.912,2.1959999,8.532 Q2.1959999,7.14,2.4779997,6.156 Q2.7599998,5.172,3.3839998,4.6499996 Q4.008,4.1280003,5.028,4.1280003 Q5.988,4.1280003,6.624,4.6499996 Q7.2599998,5.172,7.572,6.156 Q7.884,7.14,7.884,8.532 z M3.2519999,8.532 Q3.2519999,9.708,3.4259996,10.488 Q3.6,11.268,3.9899998,11.658 Q4.38,12.048,5.028,12.048 Q5.6759996,12.048,6.066,11.664 Q6.456,11.28,6.6359997,10.4939995 Q6.816,9.708,6.816,8.532 Q6.816,7.356,6.6359997,6.582 Q6.456,5.808,6.066,5.418 Q5.6759996,5.028,5.028,5.028 Q4.38,5.028,3.9899998,5.418 Q3.6,5.808,3.4259996,6.582 Q3.2519999,7.356,3.2519999,8.532 z" fill="#000000" stroke="none" transform="matrix(1 0 0 1 288.8889 263.656)"/>
+<path d="M-7.644,12.828 L-8.676001,12.828 L-8.676001,6.84 Q-8.676001,6.492,-8.67,6.252 Q-8.6640005,6.012,-8.652,5.802 Q-8.64,5.592,-8.628,5.364 Q-8.82,5.556,-8.976,5.688 Q-9.132,5.82,-9.372,6.024 L-10.284,6.768 L-10.836,6.06 L-8.52,4.26 L-7.644,4.26 L-7.644,12.828 z M1.2359996,8.532 Q1.2359996,9.576,1.0799994,10.392 Q0.9239998,11.208,0.5819998,11.778 Q0.23999977,12.348,-0.30600023,12.648 Q-0.85200024,12.948,-1.6200004,12.948 Q-2.5800004,12.948,-3.2100005,12.42 Q-3.8400004,11.892,-4.1460004,10.902 Q-4.4520006,9.912,-4.4520006,8.532 Q-4.4520006,7.14,-4.1700006,6.156 Q-3.8880005,5.172,-3.2640004,4.6499996 Q-2.6400003,4.1280003,-1.6200004,4.1280003 Q-0.6600003,4.1280003,-0.024000168,4.6499996 Q0.6119995,5.172,0.9239998,6.156 Q1.2359996,7.14,1.2359996,8.532 z M-3.3960004,8.532 Q-3.3960004,9.708,-3.2220006,10.488 Q-3.0480003,11.268,-2.6580005,11.658 Q-2.2680004,12.048,-1.6200004,12.048 Q-0.9720006,12.048,-0.58200026,11.664 Q-0.19200039,11.28,-0.012000561,10.4939995 Q0.16799974,9.708,0.16799974,8.532 Q0.16799974,7.356,-0.012000561,6.582 Q-0.19200039,5.808,-0.58200026,5.418 Q-0.9720006,5.028,-1.6200004,5.028 Q-2.2680004,5.028,-2.6580005,5.418 Q-3.0480003,5.808,-3.2220006,6.582 Q-3.3960004,7.356,-3.3960004,8.532 z M2.6879995,12.18 Q2.6879995,11.736,2.9039993,11.556 Q3.1199994,11.376,3.4199994,11.376 Q3.7319994,11.376,3.9539995,11.556 Q4.1759996,11.736,4.1759996,12.18 Q4.1759996,12.612,3.9539995,12.804 Q3.7319994,12.996,3.4199994,12.996 Q3.1199994,12.996,2.9039993,12.804 Q2.6879995,12.612,2.6879995,12.18 z M11.316,8.532 Q11.316,9.576,11.16,10.392 Q11.004,11.208,10.662,11.778 Q10.32,12.348,9.774,12.648 Q9.228,12.948,8.459999,12.948 Q7.4999995,12.948,6.8699994,12.42 Q6.24,11.892,5.9339995,10.902 Q5.6279993,9.912,5.6279993,8.532 Q5.6279993,7.14,5.9099994,6.156 Q6.1919994,5.172,6.8159995,4.6499996 Q7.4399996,4.1280003,8.459999,4.1280003 Q9.42,4.1280003,10.056,4.6499996 Q10.691999,5.172,11.004,6.156 Q11.316,7.14,11.316,8.532 z M6.6839995,8.532 Q6.6839995,9.708,6.8579993,10.488 Q7.0319996,11.268,7.4219995,11.658 Q7.8119993,12.048,8.459999,12.048 Q9.108,12.048,9.497999,11.664 Q9.888,11.28,10.067999,10.4939995 Q10.247999,9.708,10.247999,8.532 Q10.247999,7.356,10.067999,6.582 Q9.888,5.808,9.497999,5.418 Q9.108,5.028,8.459999,5.028 Q7.8119993,5.028,7.4219995,5.418 Q7.0319996,5.808,6.8579993,6.582 Q6.6839995,7.356,6.6839995,8.532 z" fill="#000000" stroke="none" transform="matrix(1 0 0 1 360 263.656)"/>
+<rect fill="none" height="235.656" stroke="#000000" stroke-width="1" width="360" x="20" y="20"/>
+</svg>
\ No newline at end of file
diff --git a/tests/src/tests.rs b/tests/src/tests.rs
index f6f44b1..af84a3b 100644
--- a/tests/src/tests.rs
+++ b/tests/src/tests.rs
@@ -45,6 +45,7 @@ fn line2(x: &[f64], y: &[f64]) -> des::series::Line {
 mod axes;
 mod interp;
 mod legend;
+mod nulls;
 mod subplots;
 
 #[test]
diff --git a/tests/src/tests/nulls.rs b/tests/src/tests/nulls.rs
new file mode 100644
index 0000000..2a617cf
--- /dev/null
+++ b/tests/src/tests/nulls.rs
@@ -0,0 +1,30 @@
+use plotive::des;
+
+use super::fig_small;
+use crate::{TestHarness, assert_fig_eq_ref};
+
+#[test]
+fn line_lin_null_end() {
+    let x = vec![1.0, 2.0, 3.0, 4.0, 5.0];
+    let y = vec![1.0, 2.0, 3.0, 4.0, f64::NAN];
+    let series = des::series::Line::new(x.into(), y.into()).into();
+    let plot =
+        des::Plot::new(vec![series]).with_x_axis(des::Axis::default().with_title("x axis".into()));
+    let fig = fig_small(plot);
+
+    assert_fig_eq_ref!(&fig, "nulls/line-lin-null-end");
+}
+
+#[test]
+fn line_spline_null_middle() {
+    let x = vec![1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0];
+    let y = vec![0.0, 2.0, 3.0, 1.0, 4.0, f64::NAN, 2.0, 3.0, 1.0, 4.0];
+
+    let plot = des::series::Line::new(x.into(), y.into())
+        .with_interpolation(des::series::Interpolation::Spline)
+        .into_plot()
+        .with_x_axis(des::Axis::default().with_ticks(Default::default()));
+    let fig = fig_small(plot);
+
+    assert_fig_eq_ref!(&fig, "nulls/line-spline-null-middle");
+}