From f6b3caad527ebee5437559e0c1214127ba4cb876 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Fri, 16 May 2025 14:47:28 -0600
Subject: [PATCH] do not attempt to compute samples per pixel (zoom level) on
 EditingContext if _track_canvas_width is still zero

This leads to undefined/incorrect arithmetic results
---
 gtk2_ardour/editing_context.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gtk2_ardour/editing_context.cc b/gtk2_ardour/editing_context.cc
index b764df25b2..135a375231 100644
--- a/gtk2_ardour/editing_context.cc
+++ b/gtk2_ardour/editing_context.cc
@@ -2434,6 +2434,10 @@ EditingContext::reset_y_origin (double y)
 void
 EditingContext::reset_zoom (samplecnt_t spp)
 {
+	if (_track_canvas_width <= 0) {
+		return;
+	}
+
 	std::pair<timepos_t, timepos_t> ext = max_zoom_extent();
 	samplecnt_t max_extents_pp = (ext.second.samples() - ext.first.samples())  / _track_canvas_width;