From 8d94285a5d04f9acbb62a721f431061798cd5175 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 19 Dec 2017 00:54:04 +0530
Subject: [PATCH] Ensure underlines are rendered even for fonts with very poor
 metrics

Fixes #236
---
 kitty/fonts.c         | 2 ++
 kitty/fonts/render.py | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/kitty/fonts.c b/kitty/fonts.c
index bba2847b8..91c6bae64 100644
--- a/kitty/fonts.c
+++ b/kitty/fonts.c
@@ -289,6 +289,8 @@ update_cell_metrics() {
     if (cell_height < 4) { PyErr_SetString(PyExc_ValueError, "line height too small after adjustment"); return NULL; }
     if (cell_height > 1000) { PyErr_SetString(PyExc_ValueError, "line height too large after adjustment"); return NULL; }
     underline_position = MIN(cell_height - 1, underline_position);
+    // ensure there is at least a couple of pixels available to render styled underlines
+    while (underline_position > baseline + 1 && cell_height - underline_position < 2) underline_position--;
     if (line_height_adjustment > 1) {
         baseline += MIN(cell_height - 1, (unsigned)line_height_adjustment / 2);
         underline_position += MIN(cell_height - 1, (unsigned)line_height_adjustment / 2);
diff --git a/kitty/fonts/render.py b/kitty/fonts/render.py
index 821b20010..0264596a9 100644
--- a/kitty/fonts/render.py
+++ b/kitty/fonts/render.py
@@ -73,7 +73,7 @@ def resize_fonts(new_sz):
 
 def add_line(buf, cell_width, position, thickness, cell_height):
     y = position - thickness // 2
-    while thickness > 0 and y > -1 and y < cell_height - 1:
+    while thickness > 0 and y > -1 and y < cell_height:
         thickness -= 1
         ctypes.memset(ctypes.addressof(buf) + (cell_width * y), 255, cell_width)
         y += 1