Improve the showing of scrollbars.

The not needed scrollbars are no longer shown, the space reserved for
them is not always freed. (Easyclose still doesn't work as wanted.)

RELEASE_NOTES

@@ -25,11 +25,6 @@ again by the load-game dialog.
 
 ***
 
-The drawing engine for the new widgets is rewritten, the engine does show
-scrollbars too often, which will be fixed later.
-
-***
-
 The game now has two ingame dialogs, the old one and a new one. The new one
 shows a transparent portait which will be scaled to fit nicely on the screen.
 This might need some tuning. This means all portraits made by Kitty and the new

data/gui/default/window/mp_method_selection.cfg

@@ -104,6 +104,7 @@
 						definition = "default"
 
 						vertical_scrollbar_mode = "never"
+						horizontal_scrollbar_mode = "never"
 						assume_fixed_row_size = "true"
 
 						[list_definition]

src/gui/widgets/scrollbar_container.cpp

@@ -181,6 +181,38 @@ tpoint tscrollbar_container::calculate_best_size() const
 	return result;
 }
 
+static void set_scrollbar_mode(tgrid* scrollbar_grid, tscrollbar_* scrollbar,
+		tscrollbar_container::tscrollbar_mode& scrollbar_mode,
+		const unsigned items, const unsigned visible_items)
+{
+
+	assert(scrollbar_grid && scrollbar);
+	if(scrollbar_mode != tscrollbar_container::HIDE) {
+
+		scrollbar->set_item_count(items);
+		scrollbar->set_visible_items(visible_items);
+
+		const bool scrollbar_needed = 
+			items > visible_items;
+
+		if(!scrollbar_needed) {
+
+			// Hide the scrollbar
+			if(scrollbar_mode == tscrollbar_container::SHOW_WHEN_NEEDED) {
+				if(true) { // extra setting
+					scrollbar_mode = tscrollbar_container::HIDE;
+				} else {
+					scrollbar_grid->set_visible(twidget::HIDDEN);
+				}
+			}
+		}
+	}
+
+	if(scrollbar_mode == tscrollbar_container::HIDE) {
+		scrollbar_grid->set_visible(twidget::INVISIBLE);
+	}
+}
+
 void tscrollbar_container::
 		set_size(const tpoint& origin, const tpoint& size)
 {
@@ -214,21 +246,22 @@ void tscrollbar_container::
 
 
 	// Set vertical scrollbar
-	assert(vertical_scrollbar_);
-	if(vertical_scrollbar_mode_ != HIDE) {
-		vertical_scrollbar_->set_item_count(content_grid_size.y);
-		vertical_scrollbar_->set_visible_items(content_->get_height());
-	}
+	set_scrollbar_mode(vertical_scrollbar_grid_, vertical_scrollbar_,
+			vertical_scrollbar_mode_, 
+			content_grid_->get_height(),
+			content_->get_height());
 
 	// Set horizontal scrollbar
-	assert(horizontal_scrollbar_);
-	if(horizontal_scrollbar_mode_ != HIDE) {
-		horizontal_scrollbar_->set_item_count(content_grid_size.x);
-		horizontal_scrollbar_->set_visible_items(content_->get_width());
-	}
+	set_scrollbar_mode(horizontal_scrollbar_grid_, horizontal_scrollbar_,
+			horizontal_scrollbar_mode_, 
+			content_grid_->get_width(),
+			content_->get_width());
+
+	// Update the buttons.
+	set_scrollbar_button_status();
 }
 
-void tscrollbar_container:: set_origin(const tpoint& origin)
+void tscrollbar_container::set_origin(const tpoint& origin)
 {
 	// Inherited.
 	tcontainer_::set_origin(origin);
@@ -373,6 +406,8 @@ void tscrollbar_container::finalize_setup()
 	vertical_scrollbar_->
 		set_callback_positioner_move(callback_vertical_scrollbar);
 
+	show_vertical_scrollbar();
+
 	/***** Setup horizontal scrollbar *****/
 	horizontal_scrollbar_grid_ =
 		find_widget<tgrid>("_horizontal_scrollbar_grid", false, true);
@@ -383,6 +418,8 @@ void tscrollbar_container::finalize_setup()
 	horizontal_scrollbar_->
 		set_callback_positioner_move(callback_horizontal_scrollbar);
 
+	show_horizontal_scrollbar();
+
 	/***** Setup the scrollbar buttons *****/
 	typedef std::pair<std::string, tscrollbar_::tscroll> hack;
 	foreach(const hack& item, scroll_lookup()) {
@@ -430,7 +467,7 @@ void tscrollbar_container::
 {
 	if(vertical_scrollbar_mode_ != scrollbar_mode) {
 		vertical_scrollbar_mode_ = scrollbar_mode;
-		show_vertical_scrollbar(vertical_scrollbar_mode_ != HIDE);
+		show_vertical_scrollbar();
 	}
 }
 
@@ -439,20 +476,34 @@ void tscrollbar_container::
 {
 	if(horizontal_scrollbar_mode_ != scrollbar_mode) {
 		horizontal_scrollbar_mode_ = scrollbar_mode;
-		show_horizontal_scrollbar(horizontal_scrollbar_mode_ != HIDE);
+		show_horizontal_scrollbar();
 	}
 }
 
-void tscrollbar_container::show_vertical_scrollbar(const bool /*show*/)
+void tscrollbar_container::show_vertical_scrollbar()
 {
-	/** @todo implement the new visibility. */
-//	vertical_scrollbar_grid_->set_visible(show);
+	if(!vertical_scrollbar_grid_) {
+		return;
+	}
+
+	if(vertical_scrollbar_mode_ == HIDE) {
+		vertical_scrollbar_grid_->set_visible(twidget::INVISIBLE);
+	} else {
+		vertical_scrollbar_grid_->set_visible(twidget::VISIBLE);
+	}
 }
 
-void tscrollbar_container::show_horizontal_scrollbar(const bool /*show*/)
+void tscrollbar_container::show_horizontal_scrollbar()
 {
-	/** @todo implement the new visibility. */
-//	horizontal_scrollbar_grid_->set_visible(show);
+	if(!horizontal_scrollbar_grid_) {
+		return;
+	}
+
+	if(horizontal_scrollbar_mode_ == HIDE) {
+		horizontal_scrollbar_grid_->set_visible(twidget::INVISIBLE);
+	} else {
+		horizontal_scrollbar_grid_->set_visible(twidget::VISIBLE);
+	}
 }
 
 void tscrollbar_container::set_scrollbar_button_status()

src/gui/widgets/scrollbar_container.hpp

@@ -233,21 +233,11 @@ private:
 	 */
 	virtual void finalize_subclass() {}
 
-	/**
-	 * Shows the vertical scrollbar.
-	 *
-	 * @param show                If true the scrollbar is shown, hidden
-	 *                            otherwise.
-	 */
-	void show_vertical_scrollbar(const bool show);
+	/** Sets the visible state of the vertical scrollbar. */
+	void show_vertical_scrollbar();
 
-	/**
-	 * Shows the horizontal scrollbar.
-	 *
-	 * @param show                If true the scrollbar is shown, hidden
-	 *                            otherwise.
-	 */
-	void show_horizontal_scrollbar(const bool show);
+	/** Sets the visible state of the horizontal scrollbar. */
+	void show_horizontal_scrollbar();
 
 	/** Inherited from tcontrol. */
 	const std::string& get_control_type() const

src/gui/widgets/window_builder.cpp

@@ -685,7 +685,10 @@ twidget* tbuilder_label::build() const
 
 tbuilder_listbox::tbuilder_listbox(const config& cfg) :
 	tbuilder_control(cfg),
-	scrollbar_mode(get_scrollbar_mode(cfg["vertical_scrollbar_mode"])),
+	vertical_scrollbar_mode(
+			get_scrollbar_mode(cfg["vertical_scrollbar_mode"])),
+	horizontal_scrollbar_mode(
+			get_scrollbar_mode(cfg["horizontal_scrollbar_mode"])),
 	header(cfg.child("header") ? new tbuilder_grid(*(cfg.child("header"))) : 0),
 	footer(cfg.child("footer") ? new tbuilder_grid(*(cfg.child("footer"))) : 0),
 	list_builder(0),
@@ -705,6 +708,9 @@ tbuilder_listbox::tbuilder_listbox(const config& cfg) :
  *     vertical_scrollbar_mode (scrollbar_mode = auto)
  *                                     Determines whether or not to show the
  *                                     scrollbar.
+ *     horizontal_scrollbar_mode (scrollbar_mode = auto)
+ *                                     Determines whether or not to show the
+ *                                     scrollbar.
  *
  *     header (section = [])           Defines the grid for the optional header.
  *     footer (section = [])           Defines the grid for the optional footer.
@@ -776,6 +782,9 @@ twidget* tbuilder_listbox::build() const
 
 	listbox->set_list_builder(list_builder); // FIXME in finalize???
 
+	listbox->set_vertical_scrollbar_mode(vertical_scrollbar_mode);
+	listbox->set_horizontal_scrollbar_mode(horizontal_scrollbar_mode);
+
 	DBG_GUI << "Window builder: placed listbox '" << id << "' with defintion '"
 		<< definition << "'.\n";
 

src/gui/widgets/window_builder_private.hpp

@@ -158,7 +158,9 @@ public:
 
 	twidget* build () const;
 
-	tscrollbar_container::tscrollbar_mode scrollbar_mode;
+	tscrollbar_container::tscrollbar_mode 
+			vertical_scrollbar_mode,
+			horizontal_scrollbar_mode;
 
 	tbuilder_grid_ptr header;
 	tbuilder_grid_ptr footer;