add "link awareness" to font::ttext objects

If link awareness is enabled, then tokens that look like links
will be rendered thusly, and a "get_link" function is provided
to check if a layout location is pointing to a token which was
rendered as a link.

src/text.cpp

@@ -68,6 +68,8 @@ const unsigned ttext::STYLE_BOLD = TTF_STYLE_BOLD;
 const unsigned ttext::STYLE_ITALIC = TTF_STYLE_ITALIC;
 const unsigned ttext::STYLE_UNDERLINE = TTF_STYLE_UNDERLINE;
 
+static bool looks_like_url(const std::string & token);
+
 std::string escape_text(const std::string& text)
 {
 	std::string result;
@@ -99,6 +101,7 @@ ttext::ttext() :
 #endif
 	text_(),
 	markedup_text_(false),
+	link_aware_(false),
 	font_size_(14),
 	font_style_(STYLE_NORMAL),
 	foreground_color_(0xFFFFFFFF), // solid white
@@ -301,6 +304,21 @@ std::string ttext::get_token(const gui2::tpoint & position, const char * delim)
 	return txt.substr(l,r-l);
 }
 
+std::string ttext::get_link(const gui2::tpoint & position) const
+{
+	if (!link_aware_) {
+		return "";
+	}
+
+	std::string tok = get_token(position, " \n\r\t");
+
+	if (looks_like_url(tok)) {
+		return tok;
+	} else {
+		return "";
+	}
+}
+
 gui2::tpoint ttext::get_column_line(const gui2::tpoint& position) const
 {
 	recalculate();
@@ -509,6 +527,16 @@ ttext& ttext::set_maximum_length(const size_t maximum_length)
 	return *this;
 }
 
+ttext& ttext::set_link_aware(bool b)
+{
+	if (link_aware_ != b) {
+		calculation_dirty_ = true;
+		surface_dirty_ = true;
+		link_aware_ = b;
+	}
+	return *this;
+}
+
 namespace {
 
 /** Small helper class to make sure the font object is destroyed properly. */
@@ -758,7 +786,49 @@ void ttext::create_surface_buffer(const size_t size) const
 	memset(surface_buffer_, 0, size);
 }
 
-bool ttext::set_markup(const std::string& text)
+static std::string handle_token(const std::string & token);
+
+bool ttext::set_markup(const std::string & text) {
+	if (!link_aware_) {
+		return set_markup_helper(text);
+	} else {
+		std::string delim = " \n\r\t";
+
+		// Tokenize according to these delimiters, and stream the results of `handle_token` on each token to get the new text.
+
+		std::stringstream ss;
+
+		int last_delim = -1;
+		for (size_t index = 0; index < text.size(); ++index) {
+			if (delim.find(text.at(index)) != std::string::npos) {
+				ss << handle_token(text.substr(last_delim + 1, index - last_delim - 1)); // want to include chars from range since last token, dont want to include any delimiters
+				ss << text.at(index);
+				last_delim = index;
+			}
+		}
+		if (last_delim < static_cast<int>(text.size()) - 1) {
+			ss << handle_token(text.substr(last_delim + 1, text.size() - last_delim - 1));
+		}
+
+		return set_markup_helper(ss.str());
+	}
+}
+
+static bool looks_like_url(const std::string & str)
+{
+	return (str.size() >= 8) && ((str.substr(0,7) == "http://") || (str.substr(0,8) == "https://"));
+}
+
+static std::string handle_token(const std::string & token)
+{
+	if (looks_like_url(token)) {
+		return "<span underline=\'single\' color=\'#8888ff\'>" + token + "</span>";
+	} else {
+		return token;
+	}
+}
+
+bool ttext::set_markup_helper(const std::string& text)
 {
 	if(pango_parse_markup(text.c_str(), text.size()
 			, 0, NULL, NULL, NULL, NULL)) {

src/text.hpp

@@ -174,6 +174,15 @@ class ttext
 	 */
 	std::string get_token(const gui2::tpoint & position, const char * delimiters = " \n\r\t") const;
 
+	/**
+	 * Checks if position points to a character in a link in the text, returns it
+	 * if so, empty string otherwise. Link-awareness must be enabled to get results.
+	 * @param position            The pixel position in the text area.
+	 *
+	 * @returns                   The link if one is found, the empty string otherwise.
+	 */
+	std::string get_link(const gui2::tpoint & position) const;
+
 	/**
 	 * Gets the column of line of the character at the position.
 	 *
@@ -231,6 +240,9 @@ class ttext
 
 	ttext& set_maximum_length(const size_t maximum_length);
 
+	bool link_aware() const { return link_aware_; }
+
+	ttext& set_link_aware(bool b);
 private:
 
 	/***** ***** ***** *****  Pango variables ***** ***** ***** *****/
@@ -256,6 +268,9 @@ class ttext
 	/** Is the text markedup if so the markedup render routines need to be used. */
 	bool markedup_text_;
 
+	/** Are hyperlinks in the text marked-up, and will get_link return them. */
+	bool link_aware_;
+
 	/** The font size to draw. */
 	unsigned font_size_;
 
@@ -381,6 +396,7 @@ class ttext
 	 */
 	bool set_markup(const std::string& text);
 
+	bool set_markup_helper(const std::string & text);
 };
 
 } // namespace font