From 48d5bd1aeec47303356e34c5fd21141f068f1643 Mon Sep 17 00:00:00 2001
From: EricKuck <github@kuckhq.com>
Date: Mon, 12 Oct 2026 18:27:47 -0400
Subject: [PATCH] AI import: gradient stops listed upwards aren't reversed, so
 a midpoint stays on the stop that starts its part of the ramp

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/eps/src/import/ai/paint.rs |  7 +++++--
 crates/eps/src/import/ai/tests.rs | 13 +++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/crates/eps/src/import/ai/paint.rs b/crates/eps/src/import/ai/paint.rs
index 99e66150..038299ea 100644
--- a/crates/eps/src/import/ai/paint.rs
+++ b/crates/eps/src/import/ai/paint.rs
@@ -158,8 +158,11 @@ impl GradientDef {
         if self.gradient.stops.is_empty() {
             return None;
         }
-        // Stops come last first: reversed, stops sharing a ramp point keep their order.
-        self.gradient.stops.reverse();
+        // Stops are listed along the ramp from either end: listed downwards they're reversed, so
+        // stops sharing a ramp point keep their order (and each its midpoint, to the next stop).
+        if self.gradient.stops.first().zip(self.gradient.stops.last()).is_some_and(|(first, last)| first.offset > last.offset) {
+            self.gradient.stops.reverse();
+        }
         self.gradient.stops.sort_by(|a, b| a.offset.total_cmp(&b.offset));
         Some((self.name, self.gradient))
     }
diff --git a/crates/eps/src/import/ai/tests.rs b/crates/eps/src/import/ai/tests.rs
index 18756d35..2f9552b5 100644
--- a/crates/eps/src/import/ai/tests.rs
+++ b/crates/eps/src/import/ai/tests.rs
@@ -410,6 +410,19 @@ fn stops_sharing_a_ramp_point_keep_their_order() {
     assert_eq!(colors, [Color::rgb(0.0, 0.0, 1.0), Color::rgb(0.0, 1.0, 0.0), Color::rgb(1.0, 0.0, 0.0)]);
 }
 
+#[test]
+fn stops_listed_upwards_keep_the_midpoint_of_the_one_that_starts_the_ramp() {
+    // GUARDS: reversing a list that runs upwards swaps two stops at 0, and the ramp to 100 takes the
+    // midpoint of the zero-length part between them.
+    let defs = "%AI5_BeginGradient: (U)\n(U) 0 3 Bd\n[\n<00FF>\n0\n%_0 0 0 0 1 1 1 2 1 6 50 0 Bs\n\
+                %_0 0 0 0 1 1 1 2 1 6 87 0 Bs\n%_0 0 0 0 0 0 0 2 1 6 50 100 Bs\nBD\n%AI5_EndGradient\n";
+    let art_ = format!("{}Bb\n1 (U) 0 0 0 1 1 0 0 1 0 0 1 Bg\n10 0 0 10 100 50 Xm\nf\n0 BB\n", rect_path(0.0, 0.0, 200.0, 100.0));
+    let doc = read_ok(&format!("{defs}{}", layer(&art_))).doc;
+    let Paint::Gradient(g) = fill(&art(&doc)[0]) else { panic!() };
+    let midpoints: Vec<_> = g.gradient.stops.iter().map(|s| s.midpoint).collect();
+    assert_eq!(midpoints, [0.5, 0.87, 0.5]);
+}
+
 #[test]
 fn per_anchor_data_reads() {
     let art_ = format!("{RED}{}f\n(00800080) Xt 0 XD\n%_(00004000) Xt 1 XD\n", rect_path(0.0, 0.0, 10.0, 10.0));