From 87d17f6624b029067f2a62dadc269321a4753232 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Wed, 6 Jul 2022 20:04:14 +0200
Subject: [PATCH] Prevent rendering outside of canvas scroll groups

This fixes automation lanes bleeding into the ruler area.

The bounding box of all items in the main canvas group starts
at -0.5, and the cursor-scroll-group at -1.5. This is calculated
to include line-width, and outlines outside the item(s).

A scroll-group however must not extend its render area to
render those.
---
 libs/canvas/scroll_group.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libs/canvas/scroll_group.cc b/libs/canvas/scroll_group.cc
index fbea90a2c6..c24c07e01c 100644
--- a/libs/canvas/scroll_group.cc
+++ b/libs/canvas/scroll_group.cc
@@ -53,6 +53,9 @@ ScrollGroup::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) c
 		return;
 	}
 
+	r.x0 = max (r.x0, 0.);
+	r.y0 = max (r.y0, 0.);
+
 	Rect self (_position.x + r.x0,
 	           _position.y + r.y0,
 	           _position.x + r.x1,