From 0f39437315f04841f4e804818dce8baa5c5f629f Mon Sep 17 00:00:00 2001
From: Ray Chason <ray.chason@protonmail.com>
Date: Sat, 8 Aug 2026 18:01:06 -0400
Subject: [PATCH] Implement underline and italic

---
 include/winX.h    |  1 +
 win/X11/winX.c    | 45 +++++++++++++++++++++++++++++++++++++++++++++
 win/X11/winstat.c | 24 ++++++++++++++++++++++--
 3 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/include/winX.h b/include/winX.h
index 9cc55e09a..935fd5f5c 100644
--- a/include/winX.h
+++ b/include/winX.h
@@ -514,6 +514,7 @@ extern void X11_preference_update(const char *);
 extern void X11_update_inventory(int);
 extern win_request_info *X11_ctrl_nhwindow(winid, int, win_request_info *);
 extern X11_map_symbol X11_glyph_char(const glyph_info *);
+extern XFontStruct *X11_italic_font(Display *, XFontStruct *);
 #ifdef ENHANCED_SYMBOLS
 extern XFontStruct *X11_unicode_font(Display *, XFontStruct *);
 #endif
diff --git a/win/X11/winX.c b/win/X11/winX.c
index 1b3089e9e..2abf03c20 100644
--- a/win/X11/winX.c
+++ b/win/X11/winX.c
@@ -3004,6 +3004,51 @@ X11_glyph_char(const glyph_info *glyphinfo)
 #endif
 }
 
+/* Given an XFontStruct, return a corresponding italic font */
+XFontStruct *
+X11_italic_font(Display *display, XFontStruct *font)
+{
+    Atom font_atom;
+    if (!XGetFontProperty(font, XA_FONT, &font_atom)) {
+        return NULL;
+    }
+
+    const char *font_name = XGetAtomName(display, font_atom);
+    if (font_name == NULL) {
+        return NULL;
+    }
+
+    /* Proceed to the slant */
+    unsigned dashes = 4;
+    const char *p = font_name;
+    while (dashes != 0) {
+        const char *q = strchr(p, '-');
+        if (q == NULL) {
+            break;
+        }
+        p = q + 1;
+        --dashes;
+    }
+
+    /* Try substituting "i" for the slant */
+    char italic_font[BUFSZ];
+    int pre = (int)(p - font_name);
+    p += strcspn(p, "-");
+    Snprintf(italic_font, sizeof(italic_font), "%.*sI%s", pre, font_name, p);
+    XFontStruct *font2 = XLoadQueryFont(display, italic_font);
+    printf("italic font=%p\n", (void *)font2);
+    if (font2 != NULL) {
+        return font2;
+    }
+
+    /* Try substituting "o" */
+    Snprintf(italic_font, sizeof(italic_font), "%.*sO%s", pre, font_name, p);
+    font2 = XLoadQueryFont(display, italic_font);
+    printf("oblique font=%p\n", (void *)font2);
+
+    return font2;
+}
+
 #ifdef ENHANCED_SYMBOLS
 /* Given an XFontStruct, return a corresponding font that supports Unicode */
 XFontStruct *
diff --git a/win/X11/winstat.c b/win/X11/winstat.c
index 8d7f3230c..8d09f3ae2 100644
--- a/win/X11/winstat.c
+++ b/win/X11/winstat.c
@@ -1264,6 +1264,7 @@ tty_render_text(Widget w, int x, int y, const char *text, int color, int attr,
     XGCValues values;
     Pixel fgpixel, bgpixel;
     XFontStruct *font;
+    XFontStruct *font_italic = NULL; /* custodial */
     int goldwidth = 0;
 
     /* Get default foreground and background colors, and font */
@@ -1294,6 +1295,15 @@ tty_render_text(Widget w, int x, int y, const char *text, int color, int attr,
         font = wp->boldfs;
     }
 
+    /* Implement italic font */
+    if (attr & HL_ITALIC) {
+        /* font may also be bold */
+        font_italic = X11_italic_font(XtDisplay(w), font);
+        if (font_italic != NULL) {
+            font = font_italic;
+        }
+    }
+
     /* Implement dim text */
     if (attr & HL_DIM) {
         fgpixel = (fgpixel & 0xFEFEFE) >> 1;
@@ -1370,18 +1380,28 @@ tty_render_text(Widget w, int x, int y, const char *text, int color, int attr,
     }
 
     /* Get the width of the rendered string */
-    int width = XTextWidth(font, text, strlen(text));
+    int width = XTextWidth(font, text, strlen(text)) + goldwidth;
 
     /* Render the string */
     XDrawImageString(XtDisplay(w), XtWindow(w), ggc,
                      x + goldwidth, y + font->max_bounds.ascent,
                      text, strlen(text));
 
+    /* Implement underline */
+    if (attr & HL_ULINE) {
+        XDrawLine(XtDisplay(w), XtWindow(w), ggc,
+                  x, y + font->max_bounds.ascent,
+                  x + width - 1, y + font->max_bounds.ascent);
+    }
+
     /* Release resources */
     XtReleaseGC(w, ggc);
+    if (font_italic != NULL) {
+        XFreeFont(XtDisplay(w), font_italic);
+    }
 
     /* Caller will advance x by the width */
-    return goldwidth + width;
+    return width;
 }
 
 /*ARGSUSED*/