trade updates

19 files changed, 257 insertions, 55 deletions

diff --git a/doc/GAMEPLAY b/doc/GAMEPLAY
index 54766ad..79fafba 100644
--- a/doc/GAMEPLAY
+++ b/doc/GAMEPLAY
@@ -149,10 +149,9 @@ Traveling
 
 Capital Ships
 
-	As the player earns money, he will hopefully eventually be able
-	to buy very large capital ships. Apart from beeing large and powerful,
-	capship can be docked by other players and used like any other dockable
-	planet or station.
+	As the player earns money, he will eventually be able to buy very large capital ships. 
+	Apart from beeing large and powerful, capship can be docked by other players and 
+	used like any other dockable planet or station.
 
 	A ship docked at the capship is able to use it as a carrier, and launch
 	when the carrier has reached its destination, or circumstances require it.
diff --git a/doc/TODO b/doc/TODO
index ef42f7f..3349760 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -5,26 +5,15 @@
 
   ------------------------------------------------------------------
 
-version 0.1.0:
+general:
 	documentation cleanup
 	finish player guide
-	udpate user manual
-	
-	SVN reorganisation
-	data reorganization
-
-	fix ui widget hierarchy
-
-version 0.2.0:
-	cargo
-	inventories
+	update user manual
 	server-client event system, hit-once lightweight entities
 	explosion events
 	sound events
 	world sounds
 	eject/beam cargo
-	
-version 0.3.0:
 	weapons
 	ship improvements (radars, shield, armor)
 	
@@ -37,13 +26,12 @@ filesystem:
 	fs_base, fs_mod, fs_game, to be used by modules
 	
 model:
-	read .ase material name
-	correct .map texture scaling issues
-	import .ase models into .map files (+submodel instancing) (ok, misc_model)
-	correct misc_model position issue when importing .map files
+	.ase submaterials
+	.3ds support
+	.md3 support
 
 core:
-	BUG dedicated server does not show chat messages
+	BUG dedicated server does not show chat messages (to be verified)
 	fix game.ini load/save sequence
 	
 network:
@@ -57,6 +45,7 @@ network:
 	fix lag/client interpolation
 	cl_prediction or cl_interpolation
 	detect and disconnect clients behaving badly
+
 	EXT messages, update extended property "ext id prop value prop value etc", type checking/seperator etc..
 	EXT zone/color/shield/armor/health
 	
@@ -66,25 +55,19 @@ client:
 	fix camera frustum clip (size issue, postponed)
 	tracking camera absolute speed/position
 	gui concept artwork
-	sanitize view menu remote command (ok)
-	fix map/hud selection interaction
-	split chat into chatwindow, chatbox and chathistory
-	add statuswindow and inventorywindow.h
 
 render:
 	star light strenght
 	sphere texture distortion at the poles
 
 ui:
-	add generic trade/inventory widget
+	
 
 sound:
 	entity/event positional sounds
 	jump drive sound events
 
 game:
-	player credits (ok)
-
 	entity health/shield/armor
 
 data:
@@ -92,4 +75,4 @@ data:
 	rename skies (lindblade1, lindblade2, ...)
 	
 win32 port:
-	pdcurses support (ok)
+
diff --git a/src/client/inventorylistview.cc b/src/client/inventorylistview.cc
index 1b46fd0..d2752d6 100644
--- a/src/client/inventorylistview.cc
+++ b/src/client/inventorylistview.cc
@@ -11,17 +11,23 @@ namespace client {
 
 InventoryListView::InventoryListView(ui::Widget *parent) : ui::ListView (parent)
 {
+	listview_timestamp = 0;
 	set_inventory(0, 0);
 }
 
 InventoryListView::~InventoryListView() {
 }
 
-void InventoryListView::set_inventory(core::Inventory *inventory, core::InfoType *info_type)
+void InventoryListView::set_inventory(core::Inventory *inventory, core::InfoType *infotype)
 {
 	remove_children();
 	
-	if (!inventory || !info_type) {
+	listview_inventory = inventory;
+	listview_infotype = infotype;
+	
+	const core::Item *selecteditem = (selected() ? selected()->item() : 0);
+	
+	if (!inventory || !infotype) {
 		return;
 	}
 	
@@ -31,15 +37,38 @@ void InventoryListView::set_inventory(core::Inventory *inventory, core::InfoType
 	for (core::Inventory::Items::const_iterator it = inventory->items().begin(); it != inventory->items().end(); it++) {
 		core::Item *item = (*it);
 	
-		if (item->info() && item->info()->type() == info_type) {
-			ui::ListItem *listitem = 0;	
-			listitem = new ui::ListItem(this, item->info()->name().c_str());
+		if (item->info() && (item->info()->type() == infotype) && (item->amount() != 0) ) {
+			ui::ListItem *listitem = 0;
+			
+			std::ostringstream str;
+			str << item->info()->name().c_str();
+			
+			if (item->amount() > 0) {
+				str << " (" << item->amount() << ")";
+			}
+			listitem = new ui::ListItem(this, str.str().c_str());
 			listitem->set_height(listitem->font()->height() * 2.0f);
+			listitem->set_item(item);
 			listitem->set_info(item->info());
+			// preserve previous selection during update
+			if (item == selecteditem) {
+				ui::ListView::select(listitem);
+			}
 		}
 	}
 	
+	listview_timestamp = inventory->timestamp();
+	
 	event_resize();
 }
 
+void InventoryListView::draw()
+{
+	if (listview_timestamp != listview_inventory->timestamp()) {
+		set_inventory(listview_inventory, listview_infotype);
+	}
+	
+	ListView::draw();
+}
+
 } // namespace client
\ No newline at end of file
diff --git a/src/client/inventorylistview.h b/src/client/inventorylistview.h
index 82a9cc4..0d14072 100644
--- a/src/client/inventorylistview.h
+++ b/src/client/inventorylistview.h
@@ -19,7 +19,16 @@ public:
 	InventoryListView(ui::Widget *parent = 0);
 	~InventoryListView();
 	
-	void set_inventory(core::Inventory *inventory, core::InfoType *info_type);
+	void set_inventory(core::Inventory *inventory, core::InfoType *infotype);
+	
+protected:
+	
+	virtual void draw();
+	
+private:
+	unsigned long 		listview_timestamp;
+	core::Inventory		*listview_inventory;
+	core::InfoType		*listview_infotype;
 };
 
 } // namespace client
diff --git a/src/client/trademenu.cc b/src/client/trademenu.cc
index 837ee87..d93864d 100644
--- a/src/client/trademenu.cc
+++ b/src/client/trademenu.cc
@@ -42,6 +42,15 @@ TradeMenu::TradeMenu(ui::Widget *parent, const char * label) : ui::Window(parent
 	menu_inventorylistview->set_background(false);
 	menu_inventorylistview->set_border(true);
 	
+	menu_inventorylabel = new ui::Label(menu_tradewindow);
+	menu_inventorylabel->set_label("label");
+	menu_inventorylabel->set_background(false);
+	menu_inventorylabel->set_border(false);
+	menu_inventorylabel->set_font(ui::root()->font_small());
+	menu_inventorylabel->set_alignment(ui::AlignLeft);
+	
+	
+	
 	menu_modelview = new ui::ModelView(menu_tradewindow);
 	menu_modelview->set_label("modelview");
 	menu_modelview->set_background(false);
@@ -57,12 +66,19 @@ TradeMenu::TradeMenu(ui::Widget *parent, const char * label) : ui::Window(parent
 	menu_traderlistview->set_background(false);
 	menu_traderlistview->set_border(true);
 	
+	menu_traderlabel = new ui::Label(menu_tradewindow);
+	menu_traderlabel->set_label("label");
+	menu_traderlabel->set_background(false);
+	menu_traderlabel->set_border(false);
+	menu_traderlabel->set_font(ui::root()->font_small());
+	menu_traderlabel->set_alignment(ui::AlignLeft);
+		
 	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_sellallbutton  = new ui::Button(menu_modelview, ">>");
+	menu_sellbutton  = new ui::Button(menu_modelview, ">");
 
 	
 	std::string test("test");
@@ -99,7 +115,8 @@ void TradeMenu::set_item_type(core::InfoType *item_type)
 void TradeMenu::set_item(ui::ListItem *item)
 {
 	menu_infotext.clear();
-	menu_namelabel->clear();
+	menu_namelabel->set_text("Trade");
+	menu_traderlabel->clear();
 	
 	if (!item || !item->info()) {
 		menu_traderlistview->deselect();
@@ -135,6 +152,10 @@ void TradeMenu::set_item(ui::ListItem *item)
 		menu_buybutton->show();
 		menu_buybutton->set_command("remote buy " + item->info()->type()->label() + " " + item->info()->label() + " 1; ");
 		
+		std::ostringstream str;
+		str << "Price: " << item->item()->price();
+		menu_traderlabel->set_text(str.str());
+		
 		menu_sellallbutton->hide();
 		menu_sellbutton->hide();
 		
@@ -177,9 +198,12 @@ void TradeMenu::resize()
 	menu_namelabel->set_location(fontmargin, fontmargin);
 	
 	// resize inventory listview
-	menu_inventorylistview->set_size(ui::UI::elementsize.width(), menu_tradewindow->height() - smallmargin * 2.0f - fontmargin * 3.0f);
+	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_inventorylabel->set_size(menu_inventorylistview->width(), fontmargin);
+	menu_inventorylabel->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);
@@ -198,13 +222,16 @@ void TradeMenu::resize()
 	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() - fontmargin - ui::UI::elementsize.width());
+	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());
 		
 	// resize trader listview
-	menu_traderlistview->set_size(ui::UI::elementsize.width(), menu_tradewindow->height() - smallmargin * 2.0f - fontmargin * 3.0f);
+	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_traderlabel->set_size(menu_traderlistview->width(), fontmargin);
+	menu_traderlabel->set_location(menu_traderlistview->left(),  menu_traderlistview->bottom() + fontmargin);
+		
 	// resize close button
 	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 );
@@ -220,4 +247,13 @@ bool TradeMenu::on_emit(Widget *sender, const Event event, void *data)
 	return ui::Window::on_emit(sender, event, data);
 }
 
+void TradeMenu::draw()
+{
+	std::stringstream str;
+	str << "Credits: " << core::localplayer()->credits();
+	menu_inventorylabel->set_text(str.str());
+	
+	Window::draw();
+}
+
 }
diff --git a/src/client/trademenu.h b/src/client/trademenu.h
index 477a372..5f56a08 100644
--- a/src/client/trademenu.h
+++ b/src/client/trademenu.h
@@ -34,6 +34,8 @@ protected:
 	/// resize event handler
 	virtual void resize();
 	
+	virtual void draw();
+	
 	/// emit event handler
 	virtual bool on_emit(Widget *sender, const Event event, void *data);
 	
@@ -43,6 +45,8 @@ private:
 	ui::Window		*menu_tradewindow;
 	ui::Button		*menu_closebutton;
 	ui::Label		*menu_namelabel;
+	ui::Label		*menu_inventorylabel;
+	ui::Label		*menu_traderlabel;
 	ui::ModelView		*menu_modelview;
 	ui::ScrollPane		*menu_scrollpane;
 	
diff --git a/src/core/inventory.cc b/src/core/inventory.cc
index 6afa76f..c659178 100644
--- a/src/core/inventory.cc
+++ b/src/core/inventory.cc
@@ -29,7 +29,7 @@ void Inventory::set_timestamp(const unsigned long timestamp)
 	inventory_timestamp = timestamp;
 }
 
-void Inventory::mark()
+void Inventory::set_dirty()
 {
 	inventory_timestamp = core::game()->timestamp();
 }
diff --git a/src/core/inventory.h b/src/core/inventory.h
index c715116..0a412b0 100644
--- a/src/core/inventory.h
+++ b/src/core/inventory.h
@@ -74,7 +74,7 @@ public:
 	/**
 	 * @brief set the timestamp to the current game time
 	 */	 
-	 void mark();
+	 void set_dirty();
 	 
 private:
 	Items			inventory_items;
diff --git a/src/core/item.cc b/src/core/item.cc
index 3528c1a..ca51775 100644
--- a/src/core/item.cc
+++ b/src/core/item.cc
@@ -16,7 +16,7 @@ Item::Item(const Info *info)
 {
 	item_info = info;
 	item_amount = 0;
-	item_price = 0;
+	item_price = info->price();
 }
 
 Item::~Item()
diff --git a/src/game/base/cargo.cc b/src/game/base/cargo.cc
index 420d4d3..689ae92 100644
--- a/src/game/base/cargo.cc
+++ b/src/game/base/cargo.cc
@@ -103,16 +103,81 @@ Cargo *Cargo::find(const std::string & label)
 	return (Cargo *) core::Info::find(cargo_infotype, label);
 }
 
+// main 'sell cargo' function
+void Cargo::sell(core::EntityControlable *seller, core::Entity *buyer, const int amount)
+{
+	if (!buyer || !seller)
+		return;
+	
+	// can only sell at planets and stations
+	if ((buyer->moduletype() != station_enttype) && (buyer->moduletype() != planet_enttype)) {
+		seller->owner()->send("^BCan not sell here");
+		return;
+	}
+	
+	if (!seller->owner()) 
+		return;
+	
+	if (!buyer->inventory() || !seller->inventory()) {
+		seller->owner()->send("^BCan not sell here");
+		return;
+	}
+	
+	if (!amount) {
+		return;
+	}
+	
+	core::Item *seller_item = seller->inventory()->find(this);
+	if (!seller_item) {
+		if (seller->owner()) {
+			seller->owner()->send("^BYou do not own any " + name());
+		}
+		return;	
+	}
+	
+	int negotiated_amount = amount;
+	if (negotiated_amount < 0) {
+		negotiated_amount = seller_item->amount();
+	} else if (negotiated_amount > seller_item->amount()) {
+		negotiated_amount = seller_item->amount();
+	}
+		
+	int negotiated_price = price();	// base price
+	core::Item *buyer_item = buyer->inventory()->find(this);
+	if (buyer_item) {
+		negotiated_price = buyer_item->price();
+	}
+	
+	
+	seller_item->set_amount(seller_item->amount() - negotiated_amount);
+	seller->owner()->set_credits(seller->owner()->credits() + negotiated_price * negotiated_amount);
+	seller->inventory()->set_dirty();
+	
+	// send a cargo purchased message
+	std::stringstream msgstr;
+	msgstr << "^BSold " << negotiated_amount << " " << aux::plural("unit", negotiated_amount) << " of " << name() << " for " << negotiated_price * negotiated_amount << " credits";
+	seller->owner()->send(msgstr.str());
+	seller->owner()->sound("game/buy");
+	
+}
+
 // main 'buy cargo' function
 void Cargo::buy(core::EntityControlable *buyer, core::Entity *seller, const int amount)
 {
 	if (!buyer || !seller)
 		return;
+
+	// can only buy at planets and stations
+	if ((seller->moduletype() != station_enttype) && (seller->moduletype() != planet_enttype)) {
+		buyer->owner()->send("^BCan not buy here");
+		return;
+	}
 	
 	if (!buyer->owner()) 
 		return;
 	
 	if (!buyer->inventory() || !seller->inventory()) {
+		buyer->owner()->send("^BCan not buy here");
 		return;
 	}
 	
@@ -156,6 +221,8 @@ void Cargo::buy(core::EntityControlable *buyer, core::Entity *seller, const int
 	buyer_item->inc_amount(negotiated_amount);
 	buyer->owner()->set_credits(buyer->owner()->credits() - negotiated_price * negotiated_amount);
 	
+	buyer->inventory()->set_dirty();
+	
 	// send a cargo purchased message
 	std::stringstream msgstr;
 	msgstr << "^BPurchased " << negotiated_amount << " " << aux::plural("unit", negotiated_amount) << " of " << name() << " for " << negotiated_price * negotiated_amount << " credits";
diff --git a/src/game/base/cargo.h b/src/game/base/cargo.h
index 9b2bca5..1e97d40 100644
--- a/src/game/base/cargo.h
+++ b/src/game/base/cargo.h
@@ -19,6 +19,8 @@ public:
 
 	void buy(core::EntityControlable *buyer, core::Entity *seller, const int amount);
 	
+	void sell(core::EntityControlable *seller, core::Entity *buyer, const int amount);
+	
 	/* -- static functions -- */
 	static core::InfoType *cargo_infotype;
 	
diff --git a/src/game/base/game.cc b/src/game/base/game.cc
index 9f8dabc..83d0be8 100644
--- a/src/game/base/game.cc
+++ b/src/game/base/game.cc
@@ -267,34 +267,71 @@ void Game::func_give(core::Player *player, const std::string &args)
 	}
 }
 
+// sell request from a player
+void Game::func_sell(core::Player *player, const std::string &args)
+{
+	std::istringstream is(args);
+	std::string typestr;
+	std::string labelstr;
+
+	if (!(is >> typestr)) {
+		player->send("Usage: sell [string] [string] [int] sell an item: specify type, label and amount");
+		return;
+	} else {
+		aux::to_label(typestr);
+	}
+
+	if (!(is >> labelstr)) {
+		player->send("Usage: sell [string] [string] [int] sell an item: specify type, label and amount");
+		return;
+	} else {
+		aux::to_label(labelstr);
+	}
+
+	int amount = 0;
+	if (!(is >> amount)) 
+		amount = 0;
+	
+	if (typestr.compare("cargo") == 0) {
+		Cargo *cargo = Cargo::find(labelstr);
+		if (cargo) {
+			cargo->sell(player->control(), player->view(), amount);
+		} else {
+			player->send("Unkown cargo type '" + labelstr + "'");
+		}
+	} else {
+		player->send("Unkown item type '" + typestr + "'");
+	}
+	return;
+}
+
 // buy request from a player
 void Game::func_buy(core::Player *player, const std::string &args)
 {
 	std::istringstream is(args);
 	std::string typestr;
 	std::string labelstr;
-	int amount = 0;
 
 	if (!(is >> typestr)) {
-		player->send("Usage: buy [string] [string] buy an item, specify type and label");
+		player->send("Usage: buy [string] [string] [int] buy an item: specify type, label and amount");
 		return;
 	} else {
 		aux::to_label(typestr);
 	}
 
 	if (!(is >> labelstr)) {
-		labelstr.clear();
+		player->send("Usage: buy [string] [string] [int] buy an item: specify type, label and amount");
+		return;
 	} else {
 		aux::to_label(labelstr);
 	}
-	
+
+	int amount = 0;
 	if (!(is >> amount)) 
 		amount = 0;
 
 	if (typestr.compare("ship") == 0) {
-		ShipDealer::func_buy(player, labelstr);
-	
-		
+		ShipDealer::func_buy(player, labelstr);		
 	} else if (typestr.compare("cargo") == 0) {
 		Cargo *cargo = Cargo::find(labelstr);
 		if (cargo) {
@@ -305,7 +342,6 @@ void Game::func_buy(core::Player *player, const std::string &args)
 	} else {
 		player->send("Unkown item type '" + typestr + "'");
 	}
-
 	return;
 }
 
@@ -495,8 +531,11 @@ Game::Game() : core::Module("Project::OSiRiON", true)
 	func->set_info("leave the game and spectate");
 
 	func = core::Func::add("buy", Game::func_buy);
-	func->set_info("[string] [string] buy type of item, name of item");
+	func->set_info("[string] [string] [int] buy an item: specify type, label and amount");
 
+	func = core::Func::add("sell", Game::func_sell);
+	func->set_info("[string] [string] [int] sell an item: specify type, label and amount");
+	
 	func = core::Func::add("give", Game::func_give);
 	func->set_info("cheat functions");
 		
diff --git a/src/game/base/game.h b/src/game/base/game.h
index e091630..ce37fa6 100644
--- a/src/game/base/game.h
+++ b/src/game/base/game.h
@@ -107,6 +107,7 @@ private:
 	static void func_respawn(core::Player *player, std::string const &args);
 	static void func_goto(core::Player *player, const std::string &args);
 	static void func_buy(core::Player *player, std::string const &args);
+	static void func_sell(core::Player *player, const std::string &args);
 	static void func_give(core::Player *player, const std::string &args);
 };
 
diff --git a/src/ui/listitem.cc b/src/ui/listitem.cc
index dcd4e2a..601d5a8 100644
--- a/src/ui/listitem.cc
+++ b/src/ui/listitem.cc
@@ -15,6 +15,7 @@ ListItem::ListItem(ListView *parent, const char * text) : Label(parent, text) {
 	set_label("listitem");
 	
 	listitem_info = 0;
+	listitem_item = 0;
 }
 
 ListItem::~ListItem() {
diff --git a/src/ui/listitem.h b/src/ui/listitem.h
index cc03621..1d4cd33 100644
--- a/src/ui/listitem.h
+++ b/src/ui/listitem.h
@@ -10,6 +10,7 @@
 #include <string>
 
 #include "core/info.h"
+#include "core/item.h"
 #include "ui/label.h"
 
 namespace ui
@@ -30,9 +31,17 @@ public:
 		return listitem_info;
 	}
 	
+	inline const core::Item *item() const {
+		return listitem_item;
+	}
+	
 	inline void set_info(const core::Info *info) {
 		listitem_info = info;
 	}
+	
+	inline void set_item(const core::Item *item) {
+		listitem_item = item;
+	}
 
 protected:
 	/// keypress event handler
@@ -45,6 +54,7 @@ protected:
 
 private:
 	const core::Info	*listitem_info;
+	const core::Item	*listitem_item;
 };
 
 } // namespace ui
diff --git a/src/ui/listview.cc b/src/ui/listview.cc
index 646b168..e503807 100644
--- a/src/ui/listview.cc
+++ b/src/ui/listview.cc
@@ -73,6 +73,13 @@ void ListView::deselect()
 	listview_selecteditem = 0;
 }
 
+void ListView::select(ListItem *item)
+{
+	if (is_child(item)) {
+		listview_selecteditem = item;
+	}
+}
+
 void ListView::clear()
 {
 	listview_selecteditem = 0;
diff --git a/src/ui/listview.h b/src/ui/listview.h
index a650348..a0c185b 100644
--- a/src/ui/listview.h
+++ b/src/ui/listview.h
@@ -53,6 +53,9 @@ public:
 	/// clear all listitems
 	void clear();
 	
+	/// set selection to specified ListItem
+	void select(ListItem *item);
+	
 	/// set selection to nothing	
 	void deselect();
 	
diff --git a/src/ui/widget.cc b/src/ui/widget.cc
index 5fe6f17..79281a1 100644
--- a/src/ui/widget.cc
+++ b/src/ui/widget.cc
@@ -47,6 +47,15 @@ void Widget::remove_children()
 	widget_children.clear();
 }
 
+bool Widget::is_child(const Widget *widget) const
+{
+	for (Children::const_iterator it = widget_children.begin(); it != widget_children.end(); it++) {
+		if (widget == (*it))
+			return true;
+	}
+	return false;
+}
+
 size_t Widget::list(const size_t indent, const bool visible_only) const
 {
 	if (visible_only && !visible())
diff --git a/src/ui/widget.h b/src/ui/widget.h
index 880b71c..3ae75d2 100644
--- a/src/ui/widget.h
+++ b/src/ui/widget.h
@@ -139,6 +139,9 @@ public:
 
 	/// returns true if the widget has mouse focus
 	bool has_mouse_focus() const;
+	
+	/// return true of the widget is a child widget
+	bool is_child(const Widget *widget) const;
 
 	/* -- mutators --------------------------------------------- */