From c309c9f572a331881c515d7715d474ef854ea958 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Mon, 26 Jun 2023 20:25:16 +0200
Subject: [PATCH] wayland: surface_scale(): assert surface width/height is a
 multiple of scale
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When doing legacy scaling (non-fractional scaling), assert the
surface’s width and height are multiples of the (integer) scale.
---
 wayland.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/wayland.c b/wayland.c
index 28bb2b6f..ce0e879f 100644
--- a/wayland.c
+++ b/wayland.c
@@ -1908,6 +1908,13 @@ wayl_surface_scale_explicit_width_height(
 #endif
     } else {
         LOG_DBG("scaling by a factor of %.2f (legacy)", scale);
+
+        xassert(scale == floor(scale));
+
+        const int iscale = (int)scale;
+        xassert(width % iscale == 0);
+        xassert(height % iscale == 0);
+
         wl_surface_set_buffer_scale(surf->surf, (int)scale);
     }
 }