master aca1e31e36: Implement recent improvements to underline display on PGTK

[Po Lu]

branch: master
commit aca1e31e36b600174d9b4b194894ef53a351064f
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Implement recent improvements to underline display on PGTK
    
    * src/pgtkterm.c (pgtk_draw_glyph_string): Respect new underline
    face fields.
---
 src/pgtkterm.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/pgtkterm.c b/src/pgtkterm.c
index 1195d53d32..0155ae991d 100644
--- a/src/pgtkterm.c
+++ b/src/pgtkterm.c
@@ -2527,8 +2527,12 @@ pgtk_draw_glyph_string (struct glyph_string *s)
              unsigned long thickness, position;
              int y;
 
-             if (s->prev && s->prev->face->underline
-                 && s->prev->face->underline == FACE_UNDER_LINE)
+             if (s->prev
+                 && s->prev->face->underline == FACE_UNDER_LINE
+                 && (s->prev->face->underline_at_descent_line_p
+                     == s->face->underline_at_descent_line_p)
+                 && (s->prev->face->underline_pixels_above_descent_line
+                     == s->face->underline_pixels_above_descent_line))
                {
                  /* We use the same underline style as the previous one.  */
                  thickness = s->prev->underline_thickness;
@@ -2543,8 +2547,11 @@ pgtk_draw_glyph_string (struct glyph_string *s)
                    thickness = font->underline_thickness;
                  else
                    thickness = 1;
-                 if (x_underline_at_descent_line)
-                   position = (s->height - thickness) - (s->ybase - s->y);
+                 if ((x_underline_at_descent_line
+                      || s->face->underline_at_descent_line_p))
+                   position = ((s->height - thickness)
+                               - (s->ybase - s->y)
+                               - s->face->underline_pixels_above_descent_line);
                  else
                    {
                      /* Get the underline position.  This is the recommended
@@ -2563,7 +2570,11 @@ pgtk_draw_glyph_string (struct glyph_string *s)
                      else
                        position = underline_minimum_offset;
                    }
-                 position = max (position, underline_minimum_offset);
+
+                 /* Ignore minimum_offset if the amount of pixels was
+                    explictly specified.  */
+                 if (!s->face->underline_pixels_above_descent_line)
+                   position = max (position, underline_minimum_offset);
                }
              /* Check the sanity of thickness and position.  We should
                 avoid drawing underline out of the current line area.  */