add option to align wrapped lines under the nick or message

When nick indentation is off, lines after the first wrap back to the
left edge, under the timestamp. Add a text_wrap_align preference
(start of line, prefix, message) so they can line up under the nick or
the message text instead. It is applied at wrap time, so existing
scrollback is re-wrapped when the setting changes, and the menu is
greyed out while nick indentation is on.

src/fe-gtk/xtext.c

@@ -81,6 +81,7 @@ struct textentry
 	gint16 mark_end;
 	int indent;
 	gint16 left_len;
+	gint16 stamp_len;	/* bytes of str taken by the timestamp (no-indent mode) */
 	GSList *slp;
 	GArray *sublines;	/* byte offsets at the end of each screen row */
 	int subline_count;
@@ -296,6 +297,7 @@ static void gtk_xtext_get_property (GObject *object, guint prop_id,
 static void gtk_xtext_render_ents (GtkXText * xtext, textentry *, textentry *);
 static void gtk_xtext_recalc_widths (xtext_buffer *buf, int);
 static void gtk_xtext_fix_indent (xtext_buffer *buf);
+static int gtk_xtext_text_width (GtkXText *xtext, unsigned char *text, int len);
 static int gtk_xtext_find_subline (GtkXText *xtext, textentry *ent, int line);
 /* For use by gtk_xtext_strip_color() and its callers -- */
 struct offlen_s {
@@ -1322,6 +1324,36 @@ gtk_xtext_selection_clear (xtext_buffer *buf)
 	return ret;
 }
 
+/* x position that the lines after the first of 'ent' start at */
+
+static int
+gtk_xtext_cont_indent (xtext_buffer *buf, textentry *ent)
+{
+	int w, off;
+
+	if (ent->left_len != -1 || prefs.hex_text_wrap_align < 1)
+		return buf->indent;
+
+	/* 1 = under the prefix (nick), 2 = under the message */
+	off = ent->stamp_len;
+	if (prefs.hex_text_wrap_align >= 2)
+	{
+		/* the nick (or "*") is the first word after the timestamp */
+		while (off < ent->str_len && ent->str[off] != ' ')
+			off++;
+		while (off < ent->str_len && ent->str[off] == ' ')
+			off++;
+	}
+	if (off <= 0 || off >= ent->str_len)
+		return buf->indent;
+
+	w = ent->indent + gtk_xtext_text_width (buf->xtext, ent->str, off);
+	/* leave room for the text, or just wrap normally */
+	if (w > (buf->window_width - MARGIN) / 2)
+		return buf->indent;
+	return w;
+}
+
 static int
 find_x (GtkXText *xtext, textentry *ent, int x, int subline, int indent)
 {
@@ -1414,7 +1446,7 @@ gtk_xtext_find_x (GtkXText * xtext, int x, textentry * ent, int subline,
 	if (subline < 1)
 		indent = ent->indent;
 	else
-		indent = xtext->buffer->indent;
+		indent = gtk_xtext_cont_indent (xtext->buffer, ent);
 
 	if (line > gtk_adjustment_get_page_size (xtext->adj) || line < 0)
 	{
@@ -4035,7 +4067,7 @@ gtk_xtext_render_line (GtkXText * xtext, textentry * ent, int line,
 			taken--;
 		}
 
-		indent = xtext->buffer->indent;
+		indent = gtk_xtext_cont_indent (xtext->buffer, ent);
 		line++;
 		taken++;
 		str += len;
@@ -4296,7 +4328,7 @@ gtk_xtext_lines_taken (xtext_buffer *buf, textentry *ent)
 			str += len;
 			end = str - ent->str;
 			g_array_append_val (ent->sublines, end);
-			indent = buf->indent;
+			indent = gtk_xtext_cont_indent (buf, ent);
 		}
 		while (str < ent->str + ent->str_len);
 	}
@@ -5376,6 +5408,7 @@ gtk_xtext_append_indent (xtext_buffer *buf,
 	prefix_width = gtk_xtext_text_width (buf->xtext, str, left_len + 1);
 
 	ent->left_len = left_len;
+	ent->stamp_len = 0;
 	ent->str = str;
 	ent->str_len = left_len + 1 + right_len;
 	ent->indent = buf->indent - prefix_width;
@@ -5421,6 +5454,14 @@ gtk_xtext_append_indent (xtext_buffer *buf,
 
 void
 gtk_xtext_append (xtext_buffer *buf, unsigned char *text, int len, time_t stamp)
+{
+	gtk_xtext_append_wrap (buf, text, len, stamp, 0);
+}
+
+/* stamp_len: how many bytes at the start of text are the timestamp */
+
+void
+gtk_xtext_append_wrap (xtext_buffer *buf, unsigned char *text, int len, time_t stamp, int stamp_len)
 {
 	textentry *ent;
 
@@ -5438,6 +5479,7 @@ gtk_xtext_append (xtext_buffer *buf, unsigned char *text, int len, time_t stamp)
 		memcpy (ent->str, text, len);
 	ent->indent = 0;
 	ent->left_len = -1;
+	ent->stamp_len = (stamp_len > 0 && stamp_len < ent->str_len) ? stamp_len : 0;
 
 	gtk_xtext_append_entry (buf, ent, stamp);
 }
@@ -5474,7 +5516,7 @@ gtk_xtext_lastlog (xtext_buffer *out, xtext_buffer *search_area)
 			}
 			else
 			{
-				gtk_xtext_append (out, ent->str, ent->str_len, 0);
+				gtk_xtext_append_wrap (out, ent->str, ent->str_len, 0, ent->stamp_len);
 			}
 
 			if (out->text_last)