[Emacs-diffs] master eae5dcd: A better fix for bug#25845

[Eli Zaretskii]

branch: master
commit eae5dcd57d1a73688ccb576decbf90fa711105e7
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    A better fix for bug#25845
    
    * src/xdisp.c (font_for_underline_metrics): New function.
    * src/dispextern.h: Add its prototype.
    * src/xterm.c (x_draw_glyph_string):
    * src/w32term.c (x_draw_glyph_string):
    * src/nsterm.m (ns_draw_text_decoration): Call it.  This avoids
    having identical code 3 times in 3 different files.
---
 src/dispextern.h |  1 +
 src/nsterm.m     | 23 +----------------------
 src/w32term.c    | 22 +---------------------
 src/xdisp.c      | 30 ++++++++++++++++++++++++++++++
 src/xterm.c      | 22 +---------------------
 5 files changed, 34 insertions(+), 64 deletions(-)

diff --git a/src/dispextern.h b/src/dispextern.h
index e030618..679820d 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -3293,6 +3293,7 @@ extern void dump_glyph_string (struct glyph_string *) 
EXTERNALLY_VISIBLE;
 
 extern void x_get_glyph_overhangs (struct glyph *, struct frame *,
                                    int *, int *);
+extern struct font *font_for_underline_metrics (struct glyph_string *);
 extern void x_produce_glyphs (struct it *);
 
 extern void x_write_glyphs (struct window *, struct glyph_row *,
diff --git a/src/nsterm.m b/src/nsterm.m
index bc89925..08ee0cd 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -3043,28 +3043,7 @@ ns_draw_text_decoration (struct glyph_string *s, struct 
face *face,
             }
           else
             {
-             /* If we are drawing in the middle of a glyph row, find
-                the first glyph in the run of underlined glyphs
-                preceding the beginning of glyph string S.  This is
-                because that glyph determines the underline position
-                and thickness for the entire run of the underlined
-                glyphs.  */
-             struct glyph *g0 = s->row->glyphs[s->area], *g;
-
-             for (g = s->first_glyph - 1; g >= g0; g--)
-               {
-                 struct face *prev_face = FACE_FROM_ID (s->f, g->face_id);
-                 if (!(prev_face && prev_face->underline_p))
-                   break;
-               }
-
-             /* Now use the font of the last glyph we saw that
-                still has the underlined_p flag set.  */
-             struct face *glyph_face = FACE_FROM_ID (s->f, g[1].face_id);
-             struct font *font = glyph_face->font;
-             if (font)
-               font_prepare_for_face (s->f, glyph_face);
-
+             struct font *font = font_for_underline_metrics (s);
               unsigned long descent = s->y + s->height - s->ybase;
 
               /* Use underline thickness of font, defaulting to 1. */
diff --git a/src/w32term.c b/src/w32term.c
index 6a98fc7..81666f5 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -2433,27 +2433,7 @@ x_draw_glyph_string (struct glyph_string *s)
                 }
               else
                 {
-                 /* If we are drawing in the middle of a glyph row,
-                    find the first glyph in the run of underlined
-                    glyphs preceding the beginning of glyph string S.
-                    This is because that glyph determines the
-                    underline position and thickness for the entire
-                    run of the underlined glyphs.  */
-                 struct glyph *g0 = s->row->glyphs[s->area], *g;
-
-                 for (g = s->first_glyph - 1; g >= g0; g--)
-                   {
-                     struct face *prev_face = FACE_FROM_ID (s->f, g->face_id);
-                     if (!(prev_face && prev_face->underline_p))
-                       break;
-                   }
-
-                 /* Now use the font of the last glyph we saw that
-                    still has the underlined_p flag set.  */
-                 struct face *glyph_face = FACE_FROM_ID (s->f, g[1].face_id);
-                 struct font *font = glyph_face->font;
-                 if (font)
-                   font_prepare_for_face (s->f, glyph_face);
+                 struct font *font = font_for_underline_metrics (s);
 
                   /* Get the underline thickness.  Default is 1 pixel.  */
                   if (font && font->underline_thickness > 0)
diff --git a/src/xdisp.c b/src/xdisp.c
index 82c4c77..1e7cb4ec 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -25948,6 +25948,36 @@ draw_glyphs (struct window *w, int x, struct glyph_row 
*row,
   return x_reached;
 }
 
+/* Find the first glyph in the run of underlined glyphs preceding the
+   beginning of glyph string S, and return its font (which could be
+   NULL).  This is needed because that font determines the underline
+   position and thickness for the entire run of the underlined glyphs.
+   This function is called from the draw_glyph_string method of GUI
+   frame's redisplay interface (RIF) when it needs to draw in an
+   underlined face.  */
+struct font *
+font_for_underline_metrics (struct glyph_string *s)
+{
+  struct glyph *g0 = s->row->glyphs[s->area], *g;
+
+  for (g = s->first_glyph - 1; g >= g0; g--)
+    {
+      struct face *prev_face = FACE_FROM_ID (s->f, g->face_id);
+      if (!(prev_face && prev_face->underline_p))
+       break;
+    }
+
+  /* If preceding glyphs are not underlined, use the font of S.  */
+  if (g == s->first_glyph - 1)
+    return s->font;
+  else
+    {
+      /* Otherwise use the font of the last glyph we saw in the above
+        loop whose face had the underline_p flag set.  */
+      return FACE_FROM_ID (s->f, g[1].face_id)->font;
+    }
+}
+
 /* Expand row matrix if too narrow.  Don't expand if area
    is not present.  */
 
diff --git a/src/xterm.c b/src/xterm.c
index 57e64c4..28faea1 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -3636,27 +3636,7 @@ x_draw_glyph_string (struct glyph_string *s)
                 }
               else
                 {
-                 /* If we are drawing in the middle of a glyph row,
-                    find the first glyph in the run of underlined
-                    glyphs preceding the beginning of glyph string S.
-                    This is because that glyph determines the
-                    underline position and thickness for the entire
-                    run of the underlined glyphs.  */
-                 struct glyph *g0 = s->row->glyphs[s->area], *g;
-
-                 for (g = s->first_glyph - 1; g >= g0; g--)
-                   {
-                     struct face *prev_face = FACE_FROM_ID (s->f, g->face_id);
-                     if (!(prev_face && prev_face->underline_p))
-                       break;
-                   }
-
-                 /* Now use the font of the last glyph we saw that
-                    still has the underlined_p flag set.  */
-                 struct face *glyph_face = FACE_FROM_ID (s->f, g[1].face_id);
-                 struct font *font = glyph_face->font;
-                 if (font)
-                   font_prepare_for_face (s->f, glyph_face);
+                 struct font *font = font_for_underline_metrics (s);
 
                   /* Get the underline thickness.  Default is 1 pixel.  */
                   if (font && font->underline_thickness > 0)