diff --git a/geometry/src/lib.rs b/geometry/src/lib.rs
index 3130ab33..0875dd24 100644
--- a/geometry/src/lib.rs
+++ b/geometry/src/lib.rs
@@ -18,6 +18,7 @@ extern crate bitflags;
 pub mod clip;
 pub mod cubic_to_quadratic;
 pub mod line_segment;
+pub mod monotonic;
 pub mod normals;
 pub mod orientation;
 pub mod outline;
diff --git a/geometry/src/monotonic.rs b/geometry/src/monotonic.rs
new file mode 100644
index 00000000..67aa35ec
--- /dev/null
+++ b/geometry/src/monotonic.rs
@@ -0,0 +1,79 @@
+// pathfinder/geometry/src/monotonic.rs
+//
+// Copyright © 2019 The Pathfinder Project Developers.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Converts paths to monotonically increasing/decreasing segments.
+
+use crate::segment::{Segment, SegmentKind};
+use arrayvec::ArrayVec;
+
+// TODO(pcwalton): I think we only need to be monotonic in Y, maybe?
+pub struct MonotonicConversionIter<I>
+where
+    I: Iterator<Item = Segment>,
+{
+    iter: I,
+    buffer: ArrayVec<[Segment; 2]>,
+}
+
+impl<I> Iterator for MonotonicConversionIter<I>
+where
+    I: Iterator<Item = Segment>,
+{
+    type Item = Segment;
+
+    #[inline]
+    fn next(&mut self) -> Option<Segment> {
+        if let Some(segment) = self.buffer.pop() {
+            return Some(segment);
+        }
+
+        let segment = self.iter.next()?;
+        match segment.kind {
+            SegmentKind::None => self.next(),
+            SegmentKind::Line => Some(segment),
+            SegmentKind::Cubic => self.handle_cubic(&segment),
+            SegmentKind::Quadratic => {
+                // TODO(pcwalton): Don't degree elevate!
+                self.handle_cubic(&segment.to_cubic())
+            }
+        }
+    }
+}
+
+impl<I> MonotonicConversionIter<I>
+where
+    I: Iterator<Item = Segment>,
+{
+    #[inline]
+    pub fn new(iter: I) -> MonotonicConversionIter<I> {
+        MonotonicConversionIter {
+            iter,
+            buffer: ArrayVec::new(),
+        }
+    }
+
+    pub fn handle_cubic(&mut self, segment: &Segment) -> Option<Segment> {
+        match segment.as_cubic_segment().y_extrema() {
+            (Some(t0), Some(t1)) => {
+                let (segments_01, segment_2) = segment.as_cubic_segment().split(t1);
+                self.buffer.push(segment_2);
+                let (segment_0, segment_1) = segments_01.as_cubic_segment().split(t0 / t1);
+                self.buffer.push(segment_1);
+                Some(segment_0)
+            }
+            (Some(t0), None) | (None, Some(t0)) => {
+                let (segment_0, segment_1) = segment.as_cubic_segment().split(t0);
+                self.buffer.push(segment_1);
+                Some(segment_0)
+            }
+            (None, None) => Some(*segment),
+        }
+    }
+}
diff --git a/utils/tile-svg/src/main.rs b/utils/tile-svg/src/main.rs
index 8d70a4da..1a5e08bf 100644
--- a/utils/tile-svg/src/main.rs
+++ b/utils/tile-svg/src/main.rs
@@ -15,7 +15,6 @@ extern crate quickcheck;
 #[cfg(test)]
 extern crate rand;
 
-use arrayvec::ArrayVec;
 use byteorder::{LittleEndian, WriteBytesExt};
 use clap::{App, Arg};
 use euclid::{Point2D, Rect, Size2D};
@@ -24,10 +23,11 @@ use hashbrown::HashMap;
 use jemallocator;
 use lyon_path::iterator::PathIter;
 use pathfinder_geometry::line_segment::{LineSegmentF32, LineSegmentU4, LineSegmentU8};
+use pathfinder_geometry::monotonic::MonotonicConversionIter;
 use pathfinder_geometry::outline::{Contour, Outline, PointIndex};
 use pathfinder_geometry::point::Point2DF32;
-use pathfinder_geometry::segment::{PathEventsToSegments, Segment, SegmentFlags};
-use pathfinder_geometry::segment::{SegmentKind, SegmentsToPathEvents};
+use pathfinder_geometry::segment::{PathEventsToSegments, Segment};
+use pathfinder_geometry::segment::{SegmentFlags, SegmentsToPathEvents};
 use pathfinder_geometry::simd::{F32x4, I32x4};
 use pathfinder_geometry::stroke::{StrokeStyle, StrokeToFillIter};
 use pathfinder_geometry::transform::{Transform2DF32, Transform2DF32PathIter};
@@ -1364,69 +1364,6 @@ where
 
 // Monotonic conversion utilities
 
-// TODO(pcwalton): I think we only need to be monotonic in Y, maybe?
-struct MonotonicConversionIter<I>
-where
-    I: Iterator<Item = Segment>,
-{
-    iter: I,
-    buffer: ArrayVec<[Segment; 2]>,
-}
-
-impl<I> Iterator for MonotonicConversionIter<I>
-where
-    I: Iterator<Item = Segment>,
-{
-    type Item = Segment;
-
-    fn next(&mut self) -> Option<Segment> {
-        if let Some(segment) = self.buffer.pop() {
-            return Some(segment);
-        }
-
-        let segment = self.iter.next()?;
-        match segment.kind {
-            SegmentKind::None => self.next(),
-            SegmentKind::Line => Some(segment),
-            SegmentKind::Cubic => self.handle_cubic(&segment),
-            SegmentKind::Quadratic => {
-                // TODO(pcwalton): Don't degree elevate!
-                self.handle_cubic(&segment.to_cubic())
-            }
-        }
-    }
-}
-
-impl<I> MonotonicConversionIter<I>
-where
-    I: Iterator<Item = Segment>,
-{
-    fn new(iter: I) -> MonotonicConversionIter<I> {
-        MonotonicConversionIter {
-            iter,
-            buffer: ArrayVec::new(),
-        }
-    }
-
-    fn handle_cubic(&mut self, segment: &Segment) -> Option<Segment> {
-        match segment.as_cubic_segment().y_extrema() {
-            (Some(t0), Some(t1)) => {
-                let (segments_01, segment_2) = segment.as_cubic_segment().split(t1);
-                self.buffer.push(segment_2);
-                let (segment_0, segment_1) = segments_01.as_cubic_segment().split(t0 / t1);
-                self.buffer.push(segment_1);
-                Some(segment_0)
-            }
-            (Some(t0), None) | (None, Some(t0)) => {
-                let (segment_0, segment_1) = segment.as_cubic_segment().split(t0);
-                self.buffer.push(segment_1);
-                Some(segment_0)
-            }
-            (None, None) => Some(*segment),
-        }
-    }
-}
-
 // SortedVector
 
 #[derive(Clone, Debug)]