From e8db65afcb70b8669cbd49e3d7afa6210135932e Mon Sep 17 00:00:00 2001
From: Byron Gamatos <xasiklas@gmail.com>
Date: Sat, 20 Jun 2026 21:09:27 +0200
Subject: [PATCH] feat(highway-2d): render unpitched slides (slu) (#524)
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The 2D highway drew pitched slides (sl) but ignored unpitched slides (slu) —
drawNote read only opts.sl. The 3D highway already renders both (slideTrailEnd).

drawNote now draws slu as a dashed diagonal with no arrowhead (no definite
target pitch), keeping the solid arrow+arrowhead for pitched sl. The two are
mutually exclusive in the data. Chord notes flow through the same drawNote, so
chord-note unpitched slides are covered too.

Also fixes a latent pre-existing bug flagged in review: `opts?.sl || -1`
discarded a pitched slide-to-open (sl: 0); now `?? -1` preserves fret-0 targets
and keeps pitched precedence.

Codex-reviewed: no P1/P2; dash state reset on all paths, no pitched-slide
regression. node --check clean.

Closes #336. Part of got-feedback/feedback#334.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 static/highway.js | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/static/highway.js b/static/highway.js
index 6ac1f2c..4ad74d8 100644
--- a/static/highway.js
+++ b/static/highway.js
@@ -1444,7 +1444,8 @@ function createHighway() {
         const isPinchHarmonic = opts?.hp || false;
         const isChord = opts?.chord || false;
         const bend = opts?.bn || 0;
-        const slide = opts?.sl || -1;
+        const slide = opts?.sl ?? -1;  // pitched slide-to fret (-1 = none; 0 = slide to open)
+        const slu = opts?.slu ?? -1;   // unpitched slide-to fret (-1 = none)
         const hammerOn = opts?.ho || false;
         const pullOff = opts?.po || false;
         const tap = opts?.tp || false;
@@ -1637,20 +1638,29 @@ function createHighway() {
 
         if (sz < 14) return;  // Skip small technique labels
 
-        // Slide indicator (diagonal arrow)
-        if (slide >= 0) {
-            const dir = slide > fret ? -1 : 1;  // arrow direction (up or down the neck); mirror handles lefty
+        // Slide indicator (diagonal arrow). Pitched (sl) draws a solid arrow to
+        // the target fret; unpitched (slu) draws a dashed diagonal with no
+        // arrowhead (no definite target pitch). The two are mutually exclusive
+        // in the data; the 3D highway makes the same pitched/unpitched split.
+        if (slide >= 0 || slu >= 0) {
+            const pitched = slide >= 0;
+            const target = pitched ? slide : slu;
+            const dir = target > fret ? -1 : 1;  // up or down the neck; mirror handles lefty
             ctx.strokeStyle = '#fff';
             ctx.lineWidth = Math.max(2, sz / 10);
+            if (!pitched) ctx.setLineDash([Math.max(2, sz / 8), Math.max(2, sz / 8)]);
             ctx.beginPath();
             ctx.moveTo(x - sz * 0.3, y + dir * sz * 0.3);
             ctx.lineTo(x + sz * 0.3, y - dir * sz * 0.3);
             ctx.stroke();
-            // Arrowhead
-            ctx.beginPath();
-            ctx.moveTo(x + sz * 0.3, y - dir * sz * 0.3);
-            ctx.lineTo(x + sz * 0.15, y - dir * sz * 0.15);
-            ctx.stroke();
+            if (!pitched) ctx.setLineDash([]);
+            // Arrowhead only for a pitched slide (definite target pitch).
+            if (pitched) {
+                ctx.beginPath();
+                ctx.moveTo(x + sz * 0.3, y - dir * sz * 0.3);
+                ctx.lineTo(x + sz * 0.15, y - dir * sz * 0.15);
+                ctx.stroke();
+            }
         }
 
         // H/P/T label above note