fix scrolling text which contains both normal and wide characters

src/helpers.cpp

@@ -368,22 +368,16 @@ std::basic_string<my_char_t> Scroller(const std::basic_string<my_char_t> &str, s
 		std::basic_string<my_char_t>::const_iterator b = s.begin(), e = s.end();
 		for (std::basic_string<my_char_t>::const_iterator it = b+pos; it < e && len < width; ++it)
 		{
-#			ifdef _UTF8
-			len += wcwidth(*it);
-#			else
-			len++;
-#			endif
+			if ((len += wcwidth(*it)) > width)
+				break;
 			result += *it;
 		}
 		if (++pos >= s.length())
 			pos = 0;
 		for (; len < width; ++b)
 		{
-#			ifdef _UTF8
-			len += wcwidth(*b);
-#			else
-			len++;
-#			endif
+			if ((len += wcwidth(*b)) > width)
+				break;
 			result += *b;
 		}
 	}

src/strbuffer.h

@@ -169,7 +169,8 @@ template <typename C> void NCurses::basic_buffer<C>::Write(Window &w, size_t &po
 				LoadAttribute(w, lb->Value);
 				++lb;
 			}
-			len += wcwidth(s[i]);
+			if ((len += wcwidth(s[i])) > width)
+				break;
 			w << s[i];
 		}
 		if (++pos >= s.length())
@@ -184,7 +185,8 @@ template <typename C> void NCurses::basic_buffer<C>::Write(Window &w, size_t &po
 				LoadAttribute(w, lb->Value);
 				++lb;
 			}
-			len += wcwidth(s[i]);
+			if ((len += wcwidth(s[i])) > width)
+				break;
 			w << s[i];
 		}
 		// load all remained attributes to clean up