From 774dd75542d37410849524f40835a6eb7342a349 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Mon, 16 Nov 2020 08:40:11 +0100
Subject: [PATCH] render: allow-overflow: require a space in the next cell

When checking if we should allow a single-width character double-width
glyph to overflow into the next cell, require the next cell to either
be empty, or contain a space.

Closes #203
---
 render.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/render.c b/render.c
index 96905c0c..12601ac2 100644
--- a/render.c
+++ b/render.c
@@ -462,12 +462,16 @@ render_cell(struct terminal *term, pixman_image_t *pix,
      *  - the *character* width is 1
      *  - the *glyph* width is at least 1.5 cells
      *  - the *glyph* width is less than 3 cells
+     *  - *this* column isn’t the last column
+     *  - *this* cells is followed by an empty cell, or a space
      */
     if (term->conf->tweak.allow_overflowing_double_width_glyphs &&
         glyph != NULL &&
         glyph->cols == 1 &&
         glyph->width >= term->cell_width * 15 / 10 &&
-        glyph->width < 3 * term->cell_width)
+        glyph->width < 3 * term->cell_width &&
+        col < term->cols - 1 &&
+        (row->cells[col + 1].wc == 0 || row->cells[col + 1].wc == L' '))
     {
         cell_cols = min(2, cols_left);
     }