Add a debug background colour feature for widgets.

This feature allows a widget's background area to be coloured so it's
directly visible which area a widget occupies. This feature is meant for
debugging only and not available for LOW_MEM builds.

changelog

@@ -41,6 +41,7 @@ Version 1.7.2+svn:
    * wmllint updated to accomodate new drake names. Gladiator changes must
      still be done by hand.
    * No longer "crash" upon invalid pango markup
+   * It's now possible to display the area a widget uses, for debug purposes
 
 Version 1.7.2:
  * Campaigns:

src/gui/auxiliary/window_builder/control.cpp

@@ -34,6 +34,10 @@ tbuilder_control::tbuilder_control(const config& cfg) :
 	help(cfg["help"]),
 	use_tooltip_on_label_overflow(
 		utils::string_bool("use_tooltip_on_label_overflow", true))
+#ifndef LOW_MEM
+	, debug_border_mode(lexical_cast_default<int>(cfg["debug_border_mode"]))
+	, debug_border_colour(decode_colour(cfg["debug_border_colour"]))
+#endif
 {
 	if(definition.empty()) {
 		definition = "default";
@@ -55,6 +59,10 @@ void tbuilder_control::init_control(tcontrol* control) const
 	control->set_tooltip(tooltip);
 	control->set_help_message(help);
 	control->set_use_tooltip_on_label_overflow(use_tooltip_on_label_overflow);
+#ifndef LOW_MEM
+	control->set_debug_border_mode(debug_border_mode);
+	control->set_debug_border_colour(debug_border_colour);
+#endif
 }
 
 } // namespace implementation
@@ -114,7 +122,18 @@ void tbuilder_control::init_control(tcontrol* control) const
  *                                     set to true this will happen.
  *
  *   linked_group (string = "")        The linked group the widget belongs to.
- * @end_table
  *
+ *   debug_border_mode (unsigned = 0)  The mode for showing the debug border.
+ *                                     This border shows the area reserved for
+ *                                     a widget. This function is only meant
+ *                                     for debugging and might not be
+ *                                     available in all wesnoth binaries.
+ *                                     Available modes:
+ *                                     @* 0 no border.
+ *                                     @* 1 1 pixel border.
+ *                                     @* 2 floodfill the widget area.
+ *
+ *   debug_border_colour (colour = "") The colour of the debug border.
+ * @end_table
  */
 

src/gui/auxiliary/window_builder/control.hpp

@@ -41,6 +41,10 @@ public:
 	t_string tooltip;
 	t_string help;
 	bool use_tooltip_on_label_overflow;
+#ifndef LOW_MEM
+	int debug_border_mode;
+	unsigned debug_border_colour;
+#endif
 };
 
 } // namespace implementation

src/gui/widgets/control.cpp

@@ -43,6 +43,7 @@ tcontrol::tcontrol(const unsigned canvas_count)
 void tcontrol::set_members(const string_map& data)
 {
 	/** @todo document this feature on the wiki. */
+	/** @todo do we need to add the debug colours here as well? */
 	string_map::const_iterator itor = data.find("id");
 	if(itor != data.end()) {
 		set_id(itor->second);

src/gui/widgets/widget.cpp

@@ -33,6 +33,10 @@ twidget::twidget()
 	, clip_rect_()
 	, layout_size_(tpoint(0,0))
 	, linked_group_()
+#ifndef LOW_MEM
+	, debug_border_mode_(0)
+	, debug_border_colour_(0)
+#endif
 #ifdef DEBUG_WINDOW_LAYOUT_GRAPHS
 	, last_best_size_(tpoint(0,0))
 #endif
@@ -241,8 +245,10 @@ void twidget::draw_background(surface& frame_buffer)
 
 	if(drawing_action_ == PARTLY_DRAWN) {
 		clip_rect_setter clip(frame_buffer, clip_rect_);
+		draw_debug_border(frame_buffer);
 		impl_draw_background(frame_buffer);
 	} else {
+		draw_debug_border(frame_buffer);
 		impl_draw_background(frame_buffer);
 	}
 }
@@ -271,4 +277,27 @@ void twidget::draw_foreground(surface& frame_buffer)
 	}
 }
 
+#ifndef LOW_MEM
+void twidget::draw_debug_border(surface& frame_buffer)
+{
+	SDL_Rect r = drawing_action_ == PARTLY_DRAWN
+		? clip_rect_
+		: get_rect();
+	switch(debug_border_mode_) {
+		case 0:
+			/* DO NOTHING */
+			break;
+		case 1:
+			draw_rectangle(r.x, r.y, r.w, r.h
+					, debug_border_colour_, frame_buffer);
+			break;
+		case 2:
+			SDL_FillRect(frame_buffer, &r, debug_border_colour_);
+			break;
+		default:
+			assert(false);
+	}
+}
+#endif
+
 } // namespace gui2

src/gui/widgets/widget.hpp

@@ -447,6 +447,18 @@ public:
 	/** Returns the dirty state for a widget, final function. */
 	bool get_dirty() const { return dirty_; }
 
+#ifndef LOW_MEM
+	void set_debug_border_mode(const unsigned debug_border_mode)
+	{
+		debug_border_mode_ = debug_border_mode;
+	}
+
+	void set_debug_border_colour(const unsigned debug_border_colour)
+	{
+		debug_border_colour_ = debug_border_colour;
+	}
+#endif
+
 	/**
 	 * Draws the background of a widget.
 	 *
@@ -601,6 +613,28 @@ private:
 	 */
 	std::string linked_group_;
 
+#ifndef LOW_MEM
+	/**
+	 * Mode for drawing the debug border.
+	 *
+	 * The debug border is a helper border to determine where a widget is
+	 * placed. It's only intended for debugging purposes.
+	 *
+	 * Possible values:
+	 * - 0 no border
+	 * - 1 single pixel border
+	 * - 2 floodfilled rectangle
+	 */
+	unsigned debug_border_mode_;
+
+	/** The color for the debug border. */
+	unsigned debug_border_colour_;
+
+	void draw_debug_border(surface& frame_buffer);
+#else
+	void draw_debug_border(surface&) {}
+#endif
+
 #ifdef DEBUG_WINDOW_LAYOUT_GRAPHS
 	/**
 	 * Debug helper to store last value of get_best_size().