From 128c5c3efabc212f74a73ce256f8b35ee3ca49a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sat, 20 Apr 2024 08:18:41 +0200
Subject: [PATCH] term: default to DPI 96, if the monitor's DPI is 0

This can happen in virtualized environments, or when running a nested
Wayland session.
---
 CHANGELOG.md |  6 ++++++
 terminal.c   | 11 +++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index feb48a3e..2851f7ba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -58,6 +58,12 @@
 ### Deprecated
 ### Removed
 ### Fixed
+
+* Crash when zooming in or out, with `dpi-aware=yes`, and the
+  monitor's DPI is 0 (this is true for, for example, nested Wayland
+  sessions, or in virtualized environments).
+
+
 ### Security
 ### Contributors
 
diff --git a/terminal.c b/terminal.c
index c027cfac..b684030e 100644
--- a/terminal.c
+++ b/terminal.c
@@ -878,10 +878,13 @@ get_font_dpi(const struct terminal *term)
             mon = &tll_front(term->wl->monitors);
     }
 
-    if (term_fractional_scaling(term))
-        return mon != NULL ? mon->dpi.physical : 96.;
-    else
-        return mon != NULL ? mon->dpi.scaled : 96.;
+    const float monitor_dpi = mon != NULL
+        ? term_fractional_scaling(term)
+            ? mon->dpi.physical
+            : mon->dpi.scaled
+        : 96.;
+
+    return monitor_dpi > 0. ? monitor_dpi : 96.;
 }
 
 static enum fcft_subpixel