Add Delaunay triangulation tool

Cargo.toml

@@ -18,6 +18,10 @@ path = "tools/point-cloud/main.rs"
 name = "transform"
 path = "tools/transform/main.rs"
 
+[[bin]]
+name = "triangulate"
+path = "tools/triangulate/main.rs"
+
 [dependencies]
 clap = {version="4.0", features=["derive"]}
 delaunator = "1.0"

tools/triangulate/cmdline.rs

@@ -0,0 +1,42 @@
+use clap::{Parser, ValueEnum};
+use generative::wkio::GeometryFormat;
+use std::path::PathBuf;
+
+#[derive(Debug, Clone, ValueEnum)]
+pub enum TriangulationStrategy {
+    /// Triangulate each geometry individually
+    ///
+    /// Meaningful for polygons, not so much for points and linestrings.
+    EachGeometry,
+    /// Collapse the whole geometry collection into a point cloud to triangulate
+    WholeCollection,
+}
+
+/// Triangulate the given geometries
+#[derive(Debug, Parser)]
+#[clap(name = "triangulate", verbatim_doc_comment)]
+pub struct CmdlineOptions {
+    /// Increase logging verbosity. Defaults to ERROR level.
+    #[clap(short, long, action = clap::ArgAction::Count)]
+    pub verbosity: u8,
+
+    /// Output file to write result to. Defaults to stdout.
+    #[clap(short, long)]
+    pub output: Option<PathBuf>,
+
+    /// Output geometry format.
+    #[clap(short = 'O', long, default_value_t = GeometryFormat::Wkt)]
+    pub output_format: GeometryFormat,
+
+    /// Input file to read input from. Defaults to stdin.
+    #[clap(short, long)]
+    pub input: Option<PathBuf>,
+
+    /// Input geometry format.
+    #[clap(short = 'I', long, default_value_t = GeometryFormat::Wkt)]
+    pub input_format: GeometryFormat,
+
+    /// How to triangulate the input geometries
+    #[clap(short, long, default_value = "whole-collection")]
+    pub strategy: TriangulationStrategy,
+}

tools/triangulate/main.rs

@@ -0,0 +1,41 @@
+mod cmdline;
+use cmdline::TriangulationStrategy;
+
+use clap::Parser;
+use generative::flatten::flatten_geometries_into_points;
+use generative::stdio::{get_input_reader, get_output_writer};
+use generative::triangulation::triangulate;
+use generative::wkio::{read_geometries, write_geometries};
+use stderrlog::ColorChoice;
+
+fn main() {
+    let args = cmdline::CmdlineOptions::parse();
+
+    stderrlog::new()
+        .verbosity(args.verbosity as usize + 1) // Default to WARN level.
+        .color(ColorChoice::Auto)
+        .init()
+        .expect("Failed to initialize stderrlog");
+
+    let reader = get_input_reader(&args.input).unwrap();
+    let mut writer = get_output_writer(&args.output).unwrap();
+    let geometries = read_geometries(reader, &args.input_format); // lazily loaded
+
+    match args.strategy {
+        TriangulationStrategy::EachGeometry => {
+            let triangulations = geometries
+                .map(|geom| flatten_geometries_into_points(std::iter::once(geom)))
+                .map(triangulate);
+            for triangulation in triangulations {
+                let lines = triangulation.lines().map(geo::Geometry::Line);
+                write_geometries(&mut writer, lines, &args.output_format);
+            }
+        }
+        TriangulationStrategy::WholeCollection => {
+            let points = flatten_geometries_into_points(geometries);
+            let triangulation = triangulate(points);
+            let lines = triangulation.lines().map(geo::Geometry::Line);
+            write_geometries(writer, lines, &args.output_format);
+        }
+    }
+}