corrected trading inconsistencies, improved trade window, initial slider widget

15 files changed, 486 insertions, 122 deletions

diff --git a/src/client/inventorylistview.cc b/src/client/inventorylistview.cc
index 0126ff4..d87ed2b 100644
--- a/src/client/inventorylistview.cc
+++ b/src/client/inventorylistview.cc
@@ -60,6 +60,8 @@ void InventoryListView::set_inventory(core::Inventory *inventory, core::InfoType
 	listview_timestamp = inventory->timestamp();
 	
 	event_resize();
+	
+	emit(EventListViewChanged);
 }
 
 void InventoryListView::draw()
diff --git a/src/client/trademenu.cc b/src/client/trademenu.cc
index 47655f6..0b8fb64 100644
--- a/src/client/trademenu.cc
+++ b/src/client/trademenu.cc
@@ -34,6 +34,10 @@ TradeMenu::TradeMenu(ui::Widget *parent, const char * label) : ui::Window(parent
 	menu_modelview->set_label("modelview");
 	menu_modelview->set_background(false);
 	menu_modelview->set_border(false);
+	
+	menu_slider = new ui::Slider(menu_tradewindow);
+	menu_slider->set_background(false);
+	menu_slider->set_border(true);
 
 	menu_namelabel = new ui::Label(menu_tradewindow);
 	menu_namelabel->set_label("label");
@@ -71,14 +75,10 @@ TradeMenu::TradeMenu(ui::Widget *parent, const char * label) : ui::Window(parent
 	menu_tradertext->set_font(ui::root()->font_small());
 		
 	menu_closebutton = new ui::Button(menu_tradewindow, "Return", "view hide");
-	
-	menu_buyallbutton = new ui::Button(menu_modelview, "<<");
-	menu_buybutton  = new ui::Button(menu_modelview, "<");
-	menu_sellallbutton  = new ui::Button(menu_modelview, ">>");
-	menu_sellbutton  = new ui::Button(menu_modelview, ">");
+	menu_buybutton = new ui::Button(menu_tradewindow, "Buy");
 
+	menu_listitem = 0;
 	
-	std::string test("test");
 	set_itemtype(0);
 	
 	hide();
@@ -115,78 +115,130 @@ void TradeMenu::set_item(ui::ListItem *item)
 	menu_infotext.clear();
 	menu_namelabel->set_text("Trade");
 	menu_tradertext->clear();
+	menu_buybutton->hide();
+	menu_slider->hide();
 	
+	if (item != menu_listitem) {
+		menu_slider->set_range(0, 2);
+		menu_slider->set_value(1);
+		menu_listitem = item;
+	}
+		
 	if (!item || !item->info()) {
 		menu_traderlistview->deselect();
 		menu_inventorylistview->deselect();
 					
 		menu_scrollpane->hide();
 		menu_modelview->hide();
+		menu_slider->set_range(0, 2);
+		menu_slider->set_value(1);
 		return;
 	}
 
-	long amount = 1; // reserved
+	long amount = 0; // reserved
+	
+	for (core::Info::Text::const_iterator it = item->info()->text().begin(); it != item->info()->text().end(); it++) {
+		menu_infotext.push_back((*it));
+	}
+
+	menu_scrollpane->show();
+	menu_modelview->set_modelname(item->info()->modelname());	
+	menu_modelview->show();
 	
 	if (item->parent() == menu_inventorylistview) {
-		menu_traderlistview->deselect();
-		// item in ship inventory selected (SELL)
-		menu_namelabel->set_text("Sell " + item->info()->name());
 		
-		menu_buyallbutton->hide();
-		menu_buybutton->hide();
-		
-		menu_sellallbutton->show();
-		menu_sellallbutton->set_command("remote sell " + item->info()->type()->label() + " " + item->info()->label() + " -1");
-		
-		menu_sellbutton->show();
-		menu_sellbutton->set_command("remote sell " + item->info()->type()->label() + " " + item->info()->label() + " 1");
+		// item in ship inventory selected (SELL)
 		
+		menu_traderlistview->deselect();
+				
 		const core::Item *trader_item = (menu_traderlistview->inventory() ? menu_traderlistview->inventory()->find(item->info()) : 0);
 		if (trader_item) {
+			
+			const long max_amount = item->item()->amount();
+			if (max_amount > 0) {
+				menu_slider->set_range(1, max_amount);
+				menu_slider->show();
+				
+				amount = menu_slider->value();
+				
+				std::ostringstream commandstr;
+				commandstr << "remote sell " << item->info()->type()->label() << " " << item->info()->label() << " " <<  amount;
+				menu_buybutton->set_command(commandstr.str());
+				menu_buybutton->set_text("Sell");
+				menu_buybutton->show();
+			}
+			
+			if (amount < 1) {
+				menu_buybutton->set_command("");
+				menu_buybutton->set_text("^1Can not sell");
+				menu_buybutton->show();
+			}
+			
 			std::ostringstream str;
-			str << "Price: " << std::setw(8) << amount * trader_item->price() << '\n' << "Volume: " << std::setw(7) << std::setprecision(2) << amount * trader_item->info()->volume();
+			str << "Price:   " << std::setw(12) << (amount > 0 ? amount : 1) * trader_item->price() << '\n' 
+			    << "Volume:  " << std::setw(12) << std::setprecision(2) << (float)(amount > 0 ? amount : 1) * trader_item->info()->volume();
 			menu_tradertext->set_text(str.str());
 		} else {
-			menu_tradertext->set_text("^1Can not sell here");
+			menu_tradertext->set_text("  ^1Can not sell here");
 		}
+		
+		std::ostringstream labelstr;
+		labelstr << "Sell " << item->info()->name();
+		if (amount)
+			labelstr << " (" << amount << ")";
+		menu_namelabel->set_text(labelstr.str());
+
 
 	} else if (item->parent() == menu_traderlistview) {
-		menu_inventorylistview->deselect();
-		// item in trader inventory selected (BUY)
-		menu_namelabel->set_text("Buy " + item->info()->name());
-		
-		menu_buyallbutton->show();		
-		menu_buyallbutton->set_command("remote buy " + item->info()->type()->label() + " " + item->info()->label() + " -1");
 		
-		menu_buybutton->show();
-		menu_buybutton->set_command("remote buy " + item->info()->type()->label() + " " + item->info()->label() + " 1");
-		
-		std::ostringstream str;
-		str << "Price: " << std::setw(8) << amount * item->item()->price() << '\n' << "Volume: " << std::setw(7) << std::setprecision(2) << amount * item->info()->volume();
-		menu_tradertext->set_text(str.str());
-		
-		menu_sellallbutton->hide();
-		menu_sellbutton->hide();
+		// item in trader inventory selected (BUY)
 		
-	} else {
-		menu_traderlistview->deselect();
 		menu_inventorylistview->deselect();
-		
-		menu_buyallbutton->hide();
-		menu_buybutton->hide();
-		
-		menu_sellallbutton->hide();
-		menu_sellbutton->hide();
-	}
+				
+		if (menu_inventorylistview->inventory()) {
+			
+			const long item_unit_price = item->item()->price();
+			const float item_unit_volume = item->info()->volume();
+			long max_amount = core::localcontrol()->inventory()->max_amount(core::localplayer()->credits(),  item_unit_price, item_unit_volume);
+			
+			if (item->item()->amount() >= 0) {
+				max_amount = math::min(max_amount, item->item()->amount());
+			}
+			
+			if (max_amount > 0) {
+				menu_slider->set_range(1, max_amount);
+				menu_slider->show();
+				amount = menu_slider->value();
+				
+				std::ostringstream commandstr;
+				commandstr << "remote buy " << item->info()->type()->label() << " " << item->info()->label() << " " << amount;
+				menu_buybutton->set_command(commandstr.str());
+				menu_buybutton->set_text("Buy");
+				menu_buybutton->show();
+			}
 
-	if (item->info()) {
-		for (core::Info::Text::const_iterator it = item->info()->text().begin(); it != item->info()->text().end(); it++) {
-			menu_infotext.push_back((*it));
+			if (amount < 1) {
+				menu_buybutton->set_command("");
+				menu_buybutton->set_text("^1Can not buy");
+				menu_buybutton->show();
+			}
+			
+			std::ostringstream str;
+			str << "Price:   " << std::setw(12) << (amount > 0 ? amount : 1) * item->item()->price() << '\n' 
+			<< "Volume:  " << std::setw(12) << std::setprecision(2) << (float) (amount > 0 ? amount : 1) * item->info()->volume();
+			
+			menu_tradertext->set_text(str.str());
 		}
-		menu_scrollpane->show();
 		
-		menu_modelview->set_modelname(item->info()->modelname());	
-		menu_modelview->show();
+		std::ostringstream labelstr;
+		labelstr << "Buy " << item->info()->name();
+		if (amount > 0)
+			labelstr << " (" << amount << ")";
+		menu_namelabel->set_text(labelstr.str());
+
+	} else {
+		menu_traderlistview->deselect();
+		menu_inventorylistview->deselect();
 	}
 }
 
@@ -210,26 +262,17 @@ void TradeMenu::resize()
 	menu_inventorylistview->set_size(ui::UI::elementsize.width(), menu_tradewindow->height() - smallmargin * 2.0f - fontmargin * 6.0f);
 	menu_inventorylistview->set_location(fontmargin, fontmargin * 3.0f);
 	
-	menu_inventorytext->set_size(menu_inventorylistview->width(), fontmargin);
+	menu_inventorytext->set_size(menu_inventorylistview->width(), fontmargin * 2.0f);
 	menu_inventorytext->set_location(menu_inventorylistview->left(),  menu_inventorylistview->bottom() + fontmargin);
 	
 	// resize modelview
 	menu_modelview->set_size(menu_tradewindow->width() - 2.0f * ui::UI::elementsize.width() - fontmargin * 4.0f, ui::UI::elementsize.width());
 	menu_modelview->set_location(fontmargin * 2.0f + ui::UI::elementsize.width(), fontmargin * 3.0f);
 	
-	// resize buttons
-	menu_buyallbutton->set_size(fontmargin, fontmargin);
-	menu_buyallbutton->set_location(0, menu_modelview->height() - fontmargin);
+	// resize slider
+	menu_slider->set_size(menu_modelview->width(), fontmargin);
+	menu_slider->set_location(menu_modelview->left(), menu_modelview->bottom() - menu_slider->height());
 		
-	menu_buybutton->set_size(fontmargin, fontmargin);
-	menu_buybutton->set_location(2.0f * fontmargin, menu_modelview->height() - fontmargin);
-	
-	menu_sellallbutton->set_size(fontmargin, fontmargin);
-	menu_sellallbutton->set_location(menu_modelview->width() - fontmargin, menu_modelview->height() - fontmargin);
-	
-	menu_sellbutton->set_size(fontmargin, fontmargin);
-	menu_sellbutton->set_location(menu_modelview->width() - 3.0f * fontmargin, menu_modelview->height() - fontmargin);
-	
 	// resize scrollpane
 	menu_scrollpane->set_size(menu_tradewindow->width() - 2.0f * ui::UI::elementsize.width() - fontmargin * 4.0f, menu_inventorylistview->height() + 2.0f * fontmargin - ui::UI::elementsize.width());
 	menu_scrollpane->set_location(fontmargin * 2.0f + ui::UI::elementsize.width(), fontmargin * 4.0f + ui::UI::elementsize.width());
@@ -238,18 +281,34 @@ void TradeMenu::resize()
 	menu_traderlistview->set_size(ui::UI::elementsize.width(), menu_tradewindow->height() - smallmargin * 2.0f - fontmargin * 6.0f);
 	menu_traderlistview->set_location(menu_tradewindow->width() - menu_traderlistview->width() - fontmargin, fontmargin * 3.0f);
 	
-	menu_tradertext->set_size(menu_traderlistview->width(), fontmargin);
+	menu_tradertext->set_size(menu_traderlistview->width(), fontmargin * 2.0f);
 	menu_tradertext->set_location(menu_traderlistview->left(),  menu_traderlistview->bottom() + fontmargin);
 		
-	// resize close button
+	// resize buttons
+	menu_buybutton->set_size(ui::UI::elementsize);	
+	menu_buybutton->set_location(menu_tradewindow->width() * 0.5f - ui::UI::elementsize.width() - smallmargin * 2.0f, menu_tradewindow->height() - smallmargin * 1.5f);
+	
 	menu_closebutton->set_size(ui::UI::elementsize);
-	menu_closebutton->set_location(0.5f * (menu_tradewindow->width() - ui::UI::elementsize.width()), menu_tradewindow->height() - smallmargin * 1.5f );
+	menu_closebutton->set_location(menu_tradewindow->width() * 0.5f + smallmargin * 2.0f, menu_tradewindow->height() - smallmargin * 1.5f);
 }
 
 bool TradeMenu::on_emit(Widget *sender, const Event event, void *data)
 {
-	if (event == ui::Widget::EventListItemClicked) {
-		set_item(static_cast<ui::ListItem *>(sender));
+	if (event == ui::Widget::EventSliderChanged) {
+		// slider value changed
+		if (menu_traderlistview->selected()) {
+			set_item(menu_traderlistview->selected());
+		} else {
+			set_item(menu_inventorylistview->selected());
+		}
+		return true;
+	} else if (event == ui::Widget::EventListViewChanged) {
+		// listview changed
+		if (sender == menu_traderlistview) {
+			set_item(menu_traderlistview->selected());
+		} else if (sender == menu_inventorylistview) {
+			set_item(menu_inventorylistview->selected());
+		}
 		return true;
 	}
 	
@@ -265,12 +324,15 @@ void TradeMenu::draw()
 	}
 	
 	std::stringstream str;
-	str << "Credit: " << std::setw(8) << core::localplayer()->credits();
-	
+	str << "Credits: " << std::setw(12) << core::localplayer()->credits();
+
 	if (core::localcontrol() && core::localcontrol()->inventory()) {
 		core::Inventory *inventory = core::localcontrol()->inventory();
-		str << '\n';
-		str << "Cargo: " << std::setprecision(2) << std::setw(6) << inventory->capacity_used() << " of " << inventory->capacity();
+		
+		std::stringstream cargostr;
+		cargostr << inventory->capacity_used() << " of " << inventory->capacity();
+		
+		str << '\n' << "Cargo:   " << aux::pad_left(cargostr.str(),12);
 	}
 	menu_inventorytext->set_text(str.str());
 	
diff --git a/src/client/trademenu.h b/src/client/trademenu.h
index 4682ce7..e835043 100644
--- a/src/client/trademenu.h
+++ b/src/client/trademenu.h
@@ -13,6 +13,7 @@
 #include "ui/listitem.h"
 #include "ui/modelview.h"
 #include "ui/plaintext.h"
+#include "ui/slider.h"
 #include "ui/scrollpane.h"
 #include "ui/widget.h"
 #include "client/inventorylistview.h"
@@ -44,24 +45,23 @@ private:
 	void set_item(ui::ListItem *item);
 	
 	ui::Window		*menu_tradewindow;
-	ui::Button		*menu_closebutton;
 	ui::Label		*menu_namelabel;
 	ui::PlainText		*menu_inventorytext;
 	ui::PlainText		*menu_tradertext;
 	ui::ModelView		*menu_modelview;
 	ui::ScrollPane		*menu_scrollpane;
+	ui::Slider		*menu_slider;
 	
-	ui::Button		*menu_buyallbutton;
+	ui::Button		*menu_closebutton;
 	ui::Button		*menu_buybutton;
-	ui::Button		*menu_sellallbutton;
-	ui::Button		*menu_sellbutton;
-	
+
 	InventoryListView	*menu_inventorylistview;
 	InventoryListView	*menu_traderlistview;
 	
 	ui::Text		menu_infotext;
 	
 	core::InfoType 		*menu_itemtype;
+	ui::ListItem 		*menu_listitem;
 };
 
 }
diff --git a/src/core/inventory.cc b/src/core/inventory.cc
index 03cd21e..4b9a2e5 100644
--- a/src/core/inventory.cc
+++ b/src/core/inventory.cc
@@ -97,5 +97,14 @@ void Inventory::recalculate()
 	}
 }
 
+const long Inventory::max_amount(const long credits, const long price, const float volume) const
+{
+	if ((price * volume) == 0) {
+		return 0;
+	}
+	
+	return math::min((long)(capacity_available() / volume), credits / price);
+}
+
 } // namespace core
 
diff --git a/src/core/inventory.h b/src/core/inventory.h
index 805d943..7aaf299 100644
--- a/src/core/inventory.h
+++ b/src/core/inventory.h
@@ -66,13 +66,21 @@ public:
 	}
 
 	/**
-	 * @brief return the availableinventory capacity, in cubic meters
+	 * @brief return the available inventory capacity, in cubic meters
 	 */
 	inline const float capacity_available() const {
 		return inventory_capacity - inventory_capacity_used;
 	}
 	
 	/**
+	 * @brief returns the number of units of an item that can be stored in this inventory
+	 * @param credits number of player credits, limits the amount
+	 * @param price price of a single unit
+	 * @param volume volume of a single unit
+	 */
+	const long max_amount(const long credits, const long price, const float volume) const;
+	
+	/**
 	  * @brief search the inventory for a specific item type
 	  */
 	 Item *find(const Info *info) const;
diff --git a/src/game/base/cargo.cc b/src/game/base/cargo.cc
index 382b03c..b54af55 100644
--- a/src/game/base/cargo.cc
+++ b/src/game/base/cargo.cc
@@ -257,11 +257,17 @@ void Cargo::buy(core::EntityControlable *buyer, core::Entity *seller, const int
 	}
 	
 	// if amount is set to -1. the base has a limitless supply
+	
 	if (seller_item->amount() == 0) {
 		buyer->owner()->send("^WCargo not available!");
 		return;
-	} else if ((seller_item->amount() > 0) && (negotiated_amount  > seller_item->amount())) {
-		negotiated_amount = seller_item->amount();
+		
+	} else if (seller_item->amount() > 0) {
+		
+		if (negotiated_amount  > seller_item->amount()) {
+			negotiated_amount = seller_item->amount();
+		}
+		
 		seller_item->dec_amount(negotiated_amount);
 		seller->inventory()->set_dirty();
 	}
diff --git a/src/math/functions.cc b/src/math/functions.cc
index 7fb40be..7c95a79 100644
--- a/src/math/functions.cc
+++ b/src/math/functions.cc
@@ -12,26 +12,6 @@ namespace math
 
 const float DELTA = 10e-10;
 
-float min(float a, float b)
-{
-	return (a < b ? a : b);
-}
-
-float max(float a, float b)
-{
-	return (a > b ? a : b);
-}
-
-int min(int a, int b)
-{
-	return (a < b ? a : b);
-}
-
-int max(int a, int b)
-{
-	return (a > b ? a : b);
-}
-
 float randomf(const float max)
 {
 	return ((float) rand() / (float) RAND_MAX) * max;
diff --git a/src/math/functions.h b/src/math/functions.h
index 5a53d44..8135392 100644
--- a/src/math/functions.h
+++ b/src/math/functions.h
@@ -15,17 +15,53 @@
 namespace math
 {
 
-/// return the smallest of two float values
-float min(float a, float b);
+/**
+ * @brief return the smallest of two floats
+ */
+inline const float min(const float a, const float b)
+{
+	return (a < b ? a : b);
+}
 
-/// return the smallest of two integers
-int min(int a, int b);
+/**
+ * @brief return the smallest of two integers
+ */
+inline const int min(const int a, const int b)
+{
+	return (a < b ? a : b);
+}
 
-/// return the largest of two float values
-float max(float a, float b);
+/**
+ * @brief return the smallest of two longs
+ */
+inline const long min(const long a, const long b)
+{
+	return (a < b ? a : b);
+}
 
-/// return the largest of two integers
-int max(int a, int b);
+/**
+ * @brief return the largest of two floats
+ */
+inline const float max(const float a, const float b)
+{
+	return (a > b ? a : b);
+}
+
+/**
+ * @brief return the largest of two integers
+ */
+inline const int max(const int a, const int b)
+{
+	return (a > b ? a : b);
+}
+
+/**
+ * @brief return the largest of two longs
+ */
+inline const long max(const long a, const long b)
+{
+	return (a > b ? a : b);
+}
 
 /// returns a random float
 /** The value returned will be in the interval [0-max]
@@ -63,6 +99,14 @@ inline float absf(const float f)
 	return ( f < 0.0f ? -f : f );
 }
 
+/// swap two float values
+inline void swap(float &x, float &y)
+{
+	float tmp = x;
+	x = y;
+	y = tmp;
+}
+
 } // namespace math
 
 #endif // __INCLUDED_MATH_FUNCTIONS_H__
diff --git a/src/ui/Makefile.am b/src/ui/Makefile.am
index e62a5dd..a98e964 100644
--- a/src/ui/Makefile.am
+++ b/src/ui/Makefile.am
@@ -10,12 +10,12 @@ endif
 noinst_HEADERS = bitmap.h button.h console.h container.h definitions.h font.h \
 	iconbutton.h inputbox.h label.h listitem.h listview.h \
 	menu.h modelview.h paint.h palette.h plaintext.h scrollpane.h \
-	toolbar.h ui.h widget.h window.h
+	slider.h toolbar.h ui.h widget.h window.h
 
 libui_la_SOURCES = bitmap.cc button.cc console.cc container.cc font.cc \
 	iconbutton.cc inputbox.cc label.cc listitem.cc listview.cc \
 	menu.cc modelview.cc paint.cc palette.cc plaintext.cc scrollpane.cc \
-	toolbar.cc ui.cc widget.cc window.cc
+	slider.cc toolbar.cc ui.cc widget.cc window.cc
 
 libui_la_LDFLAGS = -avoid-version -no-undefined
 
diff --git a/src/ui/listitem.h b/src/ui/listitem.h
index 1d4cd33..6fad3e9 100644
--- a/src/ui/listitem.h
+++ b/src/ui/listitem.h
@@ -43,6 +43,8 @@ public:
 		listitem_item = item;
 	}
 
+	void select();
+	
 protected:
 	/// keypress event handler
 	virtual bool on_keypress(const int key, const unsigned int modifier);
diff --git a/src/ui/listview.cc b/src/ui/listview.cc
index e503807..ced0dd6 100644
--- a/src/ui/listview.cc
+++ b/src/ui/listview.cc
@@ -90,7 +90,8 @@ bool ListView::on_emit(Widget *sender, const Event event, void *data)
 {
 	if ((sender->parent() == this) && (event == Widget::EventListItemClicked)) {
 		listview_selecteditem = static_cast<ListItem *>(sender);
-		return false; // return false because parent widgets might want to handle this event
+		emit(EventListViewChanged);
+		return true;
 	}
 	
 	return ui::Widget::on_emit(sender, event, data);
diff --git a/src/ui/slider.cc b/src/ui/slider.cc
new file mode 100644
index 0000000..5de82b2
--- /dev/null
+++ b/src/ui/slider.cc
@@ -0,0 +1,111 @@
+/*
+   ui/slider.cc
+   This file is part of the Osirion project and is distributed under
+   the terms of the GNU General Public License version 2
+*/
+
+#include "math/functions.h"
+#include "ui/paint.h"
+#include "ui/slider.h"
+
+namespace ui {
+
+Slider::Slider(Widget *parent, const float minimum, const float maximum) : Widget(parent)
+{
+	slider_minimum = minimum;
+	slider_maximum = maximum;
+	slider_value = slider_minimum;
+
+	slider_minbutton = new ui::Button(this, "<");
+	slider_minbutton->set_border(false);
+	
+	slider_maxbutton = new ui::Button(this, ">>");
+	slider_maxbutton->set_border(false);
+	
+	validate();
+}
+
+Slider::~Slider() {
+}
+
+void Slider::set_value(const float value)
+{
+	slider_value = value;
+	validate();
+}
+
+void Slider::set_minimum(const float minimum)
+{
+	slider_minimum = minimum;
+	validate();
+}
+
+void Slider::set_maximum(const float maximum)
+{
+	slider_maximum = maximum;
+	validate();
+}
+
+void Slider::set_range(const float minimum, const float maximum)
+{
+	slider_minimum = minimum;
+	slider_maximum = maximum;
+	validate();
+}
+
+void Slider::validate()
+{
+	if (slider_minimum > slider_maximum) {
+		math::swap(slider_minimum, slider_maximum);
+	}
+
+	math::clamp(slider_value, slider_minimum, slider_maximum);
+}
+
+void Slider::print(const size_t indent) const
+{
+	std::string marker("");
+	con_print << aux::pad_left(marker, indent*2) << label() << " \"" << minimum() << "-" << maximum() << "\"" << std::endl;
+}
+
+bool Slider::on_emit(Widget *sender, const Event event, void *data)
+{
+	if (event == EventButtonClicked) {
+		if (sender == slider_minbutton) {
+			slider_value = slider_minimum;
+			emit(EventSliderChanged, this);
+			return true;
+		} else if (sender == slider_maxbutton) {
+			slider_value = slider_maximum;
+			emit(EventSliderChanged, this);
+			return true;
+		}
+	}
+	
+	return false;
+}
+
+
+void Slider::resize()
+{
+	// note: slider expects width > height
+	slider_minbutton->set_size(height(), height());
+	slider_minbutton->set_location(0, 0);
+	
+	slider_maxbutton->set_size(height(), height());
+	slider_maxbutton->set_location(width() - slider_maxbutton->width(), 0);
+}
+
+void Slider::draw()
+{
+	if (slider_maximum > slider_minimum) {
+		const float range = (slider_value - slider_minimum) / (slider_maximum - slider_minimum);
+		const float x = (width() - 3.0f * height()) * range;
+		Paint::set_color(palette()->foreground());
+		Paint::draw_rectangle(math::Vector2f(global_location().x() + height() + x, global_location().y()), math::Vector2f(height(), height()));
+	}
+	
+	Widget::draw();
+}
+
+} // namespace ui
diff --git a/src/ui/slider.h b/src/ui/slider.h
new file mode 100644
index 0000000..8bcb427
--- /dev/null
+++ b/src/ui/slider.h
@@ -0,0 +1,101 @@
+/*
+   ui/slider.h
+   This file is part of the Osirion project and is distributed under
+   the terms of the GNU General Public License version 2
+*/
+
+#ifndef __INCLUDED_UI_SLIDER_H__
+#define __INCLUDED_UI_SLIDER_H__
+
+#include <string>
+#include "ui/button.h"
+#include "ui/widget.h"
+
+namespace ui
+{
+
+/**
+ * @brief a slider widget
+ */
+class Slider : public Widget
+{
+public:
+	Slider(Widget *parent, const float minimum = 0.0f, const float maximum = 1.0f);
+	~Slider();
+
+	/**
+	 * @brief the current slider value
+	 */
+	inline const float value() const {
+		return slider_value;
+	}
+	
+	/**
+	 * @brief the minimum value
+	 */
+	inline const float minimum() const {
+		return slider_minimum;
+	}
+	
+	/**
+	 * @brief the maximum value
+	 */
+	inline const float maximum() const {
+		return slider_maximum;
+	}
+		
+	/**
+	 * @brief print widget description to console
+	 */
+	virtual void print(const size_t indent) const;
+	
+	/**
+	 * @brief set the current slider value
+	 * @see value
+	 */
+	void set_value(const float value);
+	
+	/**
+	 * @brief set the minimum slider value
+	 * @see minimum
+	 */
+	void set_minimum(const float minimum);
+	
+	/**
+	 * @brief set the maximum slider value
+	 * @see maximum
+	 */
+	void set_maximum(const float maximum);
+
+	/**
+	 * @brief set the minimum and maximum slider values
+	 * @see minimum
+	 * @see maximum
+	 */
+	void set_range(const float minimum, const float maximum);
+	
+protected:
+	/// resize event handler
+	virtual void resize();
+	
+	/// draw event handler
+	virtual void draw();
+	
+	virtual bool on_emit(Widget *sender, const Event event, void *data=0);
+
+private:
+	/// validate slider value
+	void validate();
+	
+	float			slider_minimum;
+	float			slider_maximum;
+	float			slider_value;
+	
+	Button			*slider_minbutton;
+	Button			*slider_maxbutton;
+};
+
+}
+
+#endif // __INCLUDED_UI_SLIDER_H__
+
diff --git a/src/ui/widget.cc b/src/ui/widget.cc
index b3aa27c..2f35185 100644
--- a/src/ui/widget.cc
+++ b/src/ui/widget.cc
@@ -19,6 +19,7 @@ Widget::Widget(Widget *parent)
 	widget_visible = true;
 	widget_border = true;
 	widget_background = false;
+	widget_enabled = true;
 	widget_palette = 0;
 	widget_font = 0;
 	widget_label.assign("widget");
@@ -162,7 +163,7 @@ void Widget::hide()
 }
 
 
-void Widget::set_visible(bool visible)
+void Widget::set_visible(const bool visible)
 {
 	if (visible)
 		show();
@@ -170,24 +171,41 @@ void Widget::set_visible(bool visible)
 		hide();
 }
 
-void Widget::set_border(bool border)
+void Widget::enable()
+{
+	widget_enabled = true;
+}
+
+void Widget::disable()
+{
+	widget_enabled = false;
+}
+
+void Widget::set_enabled(const bool enabled)
+{
+	if (enabled)
+		enable();
+	else
+		disable();
+}
+void Widget::set_border(const bool border)
 {
 	widget_border = border;
 }
 
 
-void Widget::set_background(bool background)
+void Widget::set_background(const bool background)
 {
 	widget_background = background;
 }
 
-void Widget::set_label(std::string const & label)
+void Widget::set_label(const std::string & label)
 {
 	widget_label.assign(label);
 	aux::to_label(widget_label);
 }
 
-void Widget::set_label(char const *label)
+void Widget::set_label(const char *label)
 {
 	if (label) {
 		widget_label.assign(label);
diff --git a/src/ui/widget.h b/src/ui/widget.h
index 3ae75d2..8b61bc1 100644
--- a/src/ui/widget.h
+++ b/src/ui/widget.h
@@ -28,7 +28,7 @@ class Widget
 
 public:
 	/// types of custom events a widget can emit
-	enum Event {EventNone = 0, EventButtonClicked, EventListItemClicked};
+	enum Event {EventNone = 0, EventButtonClicked, EventListItemClicked, EventListViewChanged, EventSliderChanged};
 	
 	/// create a new widget
 	Widget(Widget *parent = 0);
@@ -128,6 +128,16 @@ public:
 		return !widget_visible;
 	}
 
+	/// true if the widget is enabled
+	inline bool enabled() const {
+		return widget_enabled;
+	}
+	
+	/// true if the widget is disabled
+	inline bool disabled() const {
+		return !widget_enabled;
+	}
+	
 	/// the palette used to draw this widget
 	const Palette *palette() const;
 
@@ -156,9 +166,18 @@ public:
 
 	/// hide the widget
 	virtual void hide();
-
+	
 	/// set visibility
-	void set_visible(bool visible = true);
+	void set_visible(const bool visible = true);
+
+	///  disable the widget
+	virtual void disable();
+	
+	/// enable the widget
+	virtual void enable();
+	
+	///set enabled or disabled state
+	void set_enabled(const bool enabled = true);
 
 	/// set input focus
 	void set_focus();
@@ -194,16 +213,16 @@ public:
 	void set_font(const Font *font);
 
 	/// set the widgets label
-	void set_label(std::string const &label);
+	void set_label(const std::string &label);
 
 	/// set the widgets label
 	void set_label(const char *label);
 
 	/// enable or disable widget border
-	void set_border(bool border = true);
+	void set_border(const bool border = true);
 
 	/// enable or disable widget background
-	void set_background(bool background = true);
+	void set_background(const bool background = true);
 	
 	/* -- event distributors --------------------------------------- */
 
@@ -354,6 +373,7 @@ private:
 	bool			widget_background;
 	bool			widget_border;
 	bool			widget_focus;
+	bool			widget_enabled;
 
 	math::Vector2f		widget_location;
 	math::Vector2f		widget_size;