path-util: Fix same-z-plane for 2D Vectors

CHANGES.md

@@ -2,6 +2,7 @@
 - Fixed mark `inset:` style getting applied twice (#1099)
 - Fixes `matrix.diag` function typo
 - Added a new `make-ctx` function for creating a new canvas context without a canvas
+- Fixed a bug with hobby and boolean rejecting two component vectors
 
 # 0.5.1
 - Added the `boolean` draw function for path boolean operations.

src/draw/boolean.typ

@@ -75,12 +75,12 @@
 
 // Projects a CeTZ 3D path to a 2D wire path, asserting all vertices share the
 // same z-plane (within `tol`) and all subpaths are closed.
-#let _path3d-to-wire2d(path3d, tol: 1e-6) = {
+#let _path3d-to-wire2d(path3d, eps: 1e-6) = {
   if path3d.len() == 0 {
     return ((subpaths: ()), 0.0)
   }
 
-  let (z0, same-z) = path-util.same-z-plane(path3d, tol: tol)
+  let (z0, same-z) = path-util.same-z-plane(path3d, eps: eps)
   assert(same-z, message: "boolean: all input vertices must lie in a single z-plane.")
 
   let drop-z(v) = (v.at(0), v.at(1))

src/path-util.typ

@@ -93,19 +93,19 @@
 /// `true` iff every other vertex is within `tol` of that z-coordinate.
 /// 
 /// - path (path): Input path; must be non-empty
-/// - tol (float): Absolute z tolerance
+/// - eps (float): Absolute z tolerance
 /// -> array Tuple of the form (z, same-z)
-#let same-z-plane(path, tol: 1e-6) = {
+#let same-z-plane(path, eps: 1e-6) = {
   assert(
     path.len() > 0,
     message: "Cannot determine z-plane of an empty path",
   )
-  let z0 = path.first().at(0).at(2)
+  let z0 = path.first().at(0).at(2, default: 0.0)
   for (origin, _, segments) in path {
-    if calc.abs(origin.at(2) - z0) > tol { return (z0, false) }
+    if calc.abs(origin.at(2, default: 0.0) - z0) > eps { return (z0, false) }
     for (kind, ..args) in segments {
       for v in args {
-        if calc.abs(v.at(2) - z0) > tol { return (z0, false) }
+        if calc.abs(v.at(2, default: 0.0) - z0) > eps { return (z0, false) }
       }
     }
   }