bug#62994: [PATCH v4 1/3] Add face definitions for more underline styles

[mohkale@kisara.moe]

From: Mohsin Kaleem <mohkale@kisara.moe>

* src/dispextern.h (face_underline_type, syms_of_xfacse,
internal-set-lisp-face-attribute, gui_supports_face_attributes_p):
Add definitions for new underline styles of Double, Dotted and Dashed.
* lisp/cus-face.el (custom-face-attributes): Add entries for Double,
Dotted and Dashed so they can be set through `customize'.
---
 lisp/cus-face.el |  5 ++++-
 src/dispextern.h |  8 ++++++--
 src/xfaces.c     | 21 ++++++++++++++++++++-
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/lisp/cus-face.el b/lisp/cus-face.el
index 47afa841f5e..12551e37785 100644
--- a/lisp/cus-face.el
+++ b/lisp/cus-face.el
@@ -141,7 +141,10 @@ custom-face-attributes
 		   (const :format "" :value :style)
 		   (choice :tag "Style"
 			   (const :tag "Line" line)
-			   (const :tag "Wave" wave))
+			   (const :tag "Double" double)
+			   (const :tag "Wave" wave)
+			   (const :tag "Dotted" dotted)
+			   (const :tag "Dashed" dashed))
                    (const :format "" :value :position)
                    (choice :tag "Position"
                            (const :tag "At Default Position" nil)
diff --git a/src/dispextern.h b/src/dispextern.h
index 5387cb45603..470d2eea3ae 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1690,9 +1690,13 @@ #define FONT_TOO_HIGH(ft)						\
 
 enum face_underline_type
 {
+  // Note: Order matches the order of the Smulx terminfo extension.
   FACE_NO_UNDERLINE = 0,
   FACE_UNDER_LINE,
-  FACE_UNDER_WAVE
+  FACE_DOUBLE_UNDER_LINE,
+  FACE_UNDER_WAVE,
+  FACE_DOTTED_UNDER_LINE,
+  FACE_DASHED_UNDER_LINE,
 };
 
 /* Structure describing a realized face.
@@ -1776,7 +1780,7 @@ #define FONT_TOO_HIGH(ft)						\
   ENUM_BF (face_box_type) box : 2;
 
   /* Style of underlining. */
-  ENUM_BF (face_underline_type) underline : 2;
+  ENUM_BF (face_underline_type) underline : 3;
 
   /* If `box' above specifies a 3D type, true means use box_color for
      drawing shadows.  */
diff --git a/src/xfaces.c b/src/xfaces.c
index a558e7328c0..a76a9365b8a 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -3311,7 +3311,11 @@ DEFUN ("internal-set-lisp-face-attribute", Finternal_set_lisp_face_attribute,
                 }
 
               else if (EQ (key, QCstyle)
-                       && !(EQ (val, Qline) || EQ (val, Qwave)))
+                       && !(EQ (val, Qline) ||
+                            EQ (val, Qdouble) ||
+                            EQ (val, Qwave) ||
+                            EQ (val, Qdotted) ||
+                            EQ (val, Qdashed)))
                 {
                   valid_p = false;
                   break;
@@ -5266,6 +5270,7 @@ gui_supports_face_attributes_p (struct frame *f,
                                 Lisp_Object attrs[LFACE_VECTOR_SIZE],
                                 struct face *def_face)
 {
+  Lisp_Object val;
   Lisp_Object *def_attrs = def_face->lface;
   Lisp_Object lattrs[LFACE_VECTOR_SIZE];
 
@@ -5360,6 +5365,17 @@ gui_supports_face_attributes_p (struct frame *f,
       return false;
     }
 
+  /* Check supported underline styles. */
+  val = attrs[LFACE_UNDERLINE_INDEX];
+  if (!UNSPECIFIEDP (val)) {
+    if (EQ (CAR_SAFE (val), QCstyle)) {
+      if (!(EQ (CAR_SAFE (CDR_SAFE (val)), Qline) ||
+            EQ (CAR_SAFE (CDR_SAFE (val)), Qwave))) {
+        return false; /* Unsupported underline style */
+      }
+    }
+  }
+
   /* Everything checks out, this face is supported.  */
   return true;
 }
@@ -7229,6 +7245,9 @@ syms_of_xfaces (void)
   DEFSYM (QCposition, ":position");
   DEFSYM (Qline, "line");
   DEFSYM (Qwave, "wave");
+  DEFSYM (Qdouble, "double");
+  DEFSYM (Qdotted, "dotted");
+  DEFSYM (Qdashed, "dashed");
   DEFSYM (Qreleased_button, "released-button");
   DEFSYM (Qpressed_button, "pressed-button");
   DEFSYM (Qflat_button, "flat-button");
-- 
2.43.0