From 9b28a5083edecacfac3c7e16308bd8af3f4773a2 Mon Sep 17 00:00:00 2001
From: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
Date: Tue, 14 May 2019 10:17:16 +0900
Subject: [PATCH] Avoid artifacts in ftx and ftcr font backend drivers

* src/ftcrfont.c (ftcrfont_open):
* src/ftfont.c (ftfont_open2): Make font->height equal to sum of font->ascent
and font->descent.  Respect :minspace property.
(ftfont_open2): Remove redundant assignment.
(syms_of_ftfont) <QCminspace>: New DEFSYM.
---
 src/ftcrfont.c | 14 ++++++++++++--
 src/ftfont.c   | 30 +++++++++++++++++++++++++-----
 2 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/src/ftcrfont.c b/src/ftcrfont.c
index 8a1c9a48e1f..e7c73eac4d3 100644
--- a/src/ftcrfont.c
+++ b/src/ftcrfont.c
@@ -160,8 +160,18 @@ ftcrfont_open (struct frame *f, Lisp_Object entity, int pixel_size)
 	  cairo_font_extents_t extents;
 	  cairo_scaled_font_extents (ftcrfont_info->cr_scaled_font, &extents);
 	  font->ascent = lround (extents.ascent);
-	  font->descent = lround (extents.descent);
-	  font->height = lround (extents.height);
+	  Lisp_Object val = assq_no_quit (QCminspace,
+					  AREF (entity, FONT_EXTRA_INDEX));
+	  if (!(CONSP (val) && NILP (XCDR (val))))
+	    {
+	      font->descent = lround (extents.descent);
+	      font->height = font->ascent + font->descent;
+	    }
+	  else
+	    {
+	      font->height = lround (extents.height);
+	      font->descent = font->height - font->ascent;
+	    }
 
 	  cairo_glyph_t stack_glyph;
 	  int n = 0;
diff --git a/src/ftfont.c b/src/ftfont.c
index d0078a37701..4770c3c40b3 100644
--- a/src/ftfont.c
+++ b/src/ftfont.c
@@ -1108,7 +1108,6 @@ ftfont_open2 (struct frame *f,
     return Qnil;
   filename = XCAR (val);
   idx = XCDR (val);
-  val = XCDR (cache);
   cache_data = xmint_pointer (XCDR (cache));
   ft_face = cache_data->ft_face;
   if (cache_data->face_refcount > 0)
@@ -1172,20 +1171,38 @@ ftfont_open2 (struct frame *f,
   font->driver = &ftfont_driver;
   font->encoding_charset = font->repertory_charset = -1;
 
+  val = assq_no_quit (QCminspace, AREF (entity, FONT_EXTRA_INDEX));
+  bool no_leading_p = !(CONSP (val) && NILP (XCDR (val)));
   upEM = ft_face->units_per_EM;
   scalable = (FIXNUMP (AREF (entity, FONT_AVGWIDTH_INDEX))
 	      && XFIXNUM (AREF (entity, FONT_AVGWIDTH_INDEX)) == 0);
   if (scalable)
     {
       font->ascent = ft_face->ascender * size / upEM + 0.5;
-      font->descent = - ft_face->descender * size / upEM + 0.5;
-      font->height = ft_face->height * size / upEM + 0.5;
+      if (no_leading_p)
+	{
+	  font->descent = - ft_face->descender * size / upEM + 0.5;
+	  font->height = font->ascent + font->descent;
+	}
+      else
+	{
+	  font->height = ft_face->height * size / upEM + 0.5;
+	  font->descent = font->height - font->ascent;
+	}
     }
   else
     {
       font->ascent = ft_face->size->metrics.ascender >> 6;
-      font->descent = - ft_face->size->metrics.descender >> 6;
-      font->height = ft_face->size->metrics.height >> 6;
+      if (no_leading_p)
+	{
+	  font->descent = - ft_face->size->metrics.descender >> 6;
+	  font->height = font->ascent + font->descent;
+	}
+      else
+	{
+	  font->height = ft_face->size->metrics.height >> 6;
+	  font->descent = font->height - font->ascent;
+	}
     }
   if (FIXNUMP (AREF (entity, FONT_SPACING_INDEX)))
     spacing = XFIXNUM (AREF (entity, FONT_SPACING_INDEX));
@@ -2769,6 +2786,9 @@ syms_of_ftfont (void)
   DEFSYM (Qsans, "sans");
   DEFSYM (Qsans__serif, "sans serif");
 
+  /* The boolean-valued font property key specifying the use of leading.  */
+  DEFSYM (QCminspace, ":minspace");
+
   staticpro (&freetype_font_cache);
   freetype_font_cache = list1 (Qt);
 
-- 
2.39.2