From b7100d57160d2ae7a38d5517f1c2cd7155737d88 Mon Sep 17 00:00:00 2001
From: Ronan Pigott <ronan@rjp.ie>
Date: Fri, 14 Jul 2023 16:53:50 -0700
Subject: [PATCH] render: use rounding for fractional scale

If we truncate the buffer dimensions we may accidentally submit a
buffer with inappropriate size.
---
 CHANGELOG.md | 3 +++
 render.c     | 4 ++--
 terminal.c   | 5 ++++-
 wayland.c    | 4 +++-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5d21bd6..5a1eaaa5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,9 @@
 ### Deprecated
 ### Removed
 ### Fixed
+
+* Use appropriate rounding when applying fractional scales.
+
 ### Security
 ### Contributors
 
diff --git a/render.c b/render.c
index 677856d8..d084a859 100644
--- a/render.c
+++ b/render.c
@@ -3856,8 +3856,8 @@ maybe_resize(struct terminal *term, int width, int height, bool force)
         scale = term->scale;
     }
 
-    width *= scale;
-    height *= scale;
+    width = round(width * scale);
+    height = round(height * scale);
 
     if (width == 0 && height == 0) {
         /*
diff --git a/terminal.c b/terminal.c
index fff55019..485e8ca3 100644
--- a/terminal.c
+++ b/terminal.c
@@ -778,7 +778,10 @@ term_set_fonts(struct terminal *term, struct fcft_font *fonts[static 4])
     sixel_cell_size_changed(term);
 
     /* Use force, since cell-width/height may have changed */
-    render_resize_force(term, term->width / term->scale, term->height / term->scale);
+    render_resize_force(
+        term,
+        round(term->width / term->scale),
+        round(term->height / term->scale));
     return true;
 }
 
diff --git a/wayland.c b/wayland.c
index a25ec0f6..9195797e 100644
--- a/wayland.c
+++ b/wayland.c
@@ -401,7 +401,9 @@ update_term_for_output_change(struct terminal *term)
 
     float old_scale = term->scale;
 
-    render_resize(term, term->width / term->scale, term->height / term->scale);
+    render_resize(term,
+                  round(term->width / term->scale),
+                  round(term->height / term->scale));
     term_font_dpi_changed(term, old_scale);
     term_font_subpixel_changed(term);
     csd_reload_font(term->window, old_scale);