Close #322: getWidget -> template<W = Widget>

include/sfw/GUI-main.hpp

@@ -142,7 +142,7 @@ class GUI: public VBox
 	// Convert screen pixel coordinates to window position (See the sf::Mouse docs!)
 	sf::Vector2f convertMousePosition(int x, int y) const;
 
-// ---- Callbacks ---------------------------------------------------------
+// ---- Callbacks ------------------------------------------------------------
 	void draw(const gfx::RenderContext& ctx) const override;
 
 	// If the GUI doesn't manage the entire window, and its size hasn't been
@@ -155,14 +155,15 @@ class GUI: public VBox
 	// for all the other widgets)
 	void onThemeChanged() override;
 
-// ---- Helpers -----------------------------------------------------------
+// ---- Helpers --------------------------------------------------------------
 
 	// Fill the window if managing (owning) it, else just the GUI rect,
 	// with the current Theme::bgColor, then show the wallpaper, if set
 	// Note: a clearing background fill is needed even when there's a
 	// wallpaper, because the image may be translucent!
 	void renderBackground();
 
+// ---- Data -----------------------------------------------------------------
 	std::error_code m_error;
 	sf::RenderWindow& m_window;
 	bool m_own_window;
@@ -173,6 +174,13 @@ class GUI: public VBox
 	sf::Time m_sessionTime;
 	std::unordered_map<std::string, Widget*> widgets;
 	bool m_closed = false;
+
+// ---- Misc. hackery... -----------------------------------------------------
+	// Convenience helper to find the GUI instance easily (assuming the client
+	// app only has one). Init'ed/updated by the GUI::ctor.
+	static GUI* DefaultInstance;
+	// And allow (only) the Widget class to actually use it:
+	friend class Widget;
 };
 
 } // namespace

include/sfw/Widget.hpp

@@ -84,35 +84,25 @@ class Widget : public gfx::Drawable, public Event::Handler
 
 	bool focused() const;
 
-	// Set/Reset the internal name of the widget
+	// Set/Reset widget name
 	//
 	// Notes:
 	// - If a widget is not assigned a name explicitly, it will have a unique
-	//   default ID (e.g. the hex. representation of its address).
+	//   default ID (e.g. the hex. representation of its (original) mem. address).
+	//   (Note: while widgets are not copied/moved after being added to the GUI,
+	//   they can be during setup.)
 	//
-	// - If the name has already been assigned to another widget, it will lose
-	//   its explicit name (reverting to the default), and the new widget will
-	//   take over, having that name thereafter.
+	// - If the name has already been assigned to another widget, the newly named
+	//   widget will win, stealing the name from the other widget, which will then
+	//   revert to having a default ID instead.
+	//   (Perhaps unsurprisingly, this behavior might change in the future. ;) )
 	void setName(const std::string&);
 
-	// Get the internal name of a widget (or its default ID if hasn't been named)
-	// If a widget is specified, that one will be looked up, instead of the current one.
-	//
-	// Note: This may be a slow operation, intended mainly for diagnostic use!
+	// Get the optional name of a widget (or its internal ID, if unnamed)
+	// If a widget is specified then that one will be looked up, not the current one.
+	// Note: This may be a slow operation (intended mainly for diagnostics).
 	std::string getName(Widget* widget = nullptr) const;
 
-	// Find a registered widget by name
-	// Returns nullptr if the name was not found.
-	Widget* getWidget(const std::string& name) const;
-
-	// Method-chaining helper for setting up nested widget structures
-	// (Note: getParent is not public, plus this may get arguments in the future.)
-	WidgetContainer* parent(/*!!enum FailMode mode = or_burn!!*/)       { return getParent(); }
-	WidgetContainer* parent(/*!!enum FailMode mode = or_burn!!*/) const { return getParent(); }
-
-	// Similarly (!!but it might finally be hidden/removed, if the above goes live):
-	const sf::Transform& getTransform() const;
-
 	Widget* setTooltip(const std::string& text);
 
 protected:
@@ -221,8 +211,69 @@ friend class Tooltip; // just to access getMain() via Tooltip::m_owner->!
 	void draw_outline(const gfx::RenderContext& ctx, sf::Color outlinecolor = sf::Color::Red,
 		sf::Color fillcolor = sf::Color::Transparent) const; // Well, with fillColor, now it can also do interior, not just "outline"
 #endif
+
+// ---- Misc. hackery... -----------------------------------------------------
+
+	// Rotation, scale and translation adjustments for the widget-local
+	// gfx. context, relative to the parent's
+	//!!Shouldn't really be public, or even exist, if we had a proper render-context API already...
+	public:
+	const sf::Transform& getTransform() const;
+
+	// Internal helper to shield this header from some extra dependencies
+	// See the freestanding functions that need this, below the class!
+	//
+	// Note: the only reason this is a (public static) member, not a free
+	// fn. itself is because it needs access to protected/private stuff
+	// in both the Widget and the GUI classes, and this way the (brittle)
+	// friend declarations can be minimized.
+	// Alas, it needs to be public in exchange, so those free template functions
+	// can use it... (Well, at least it's hidden at the bottom of a class;
+	// kinda considered private enough then, right?...)
+	//
+	public:
+	static Widget* getWidget_proxy(const std::string& name, const Widget* w = nullptr);
+	// If w == null, try the global default (singleton) GUI manager.
+	// If w is set, use that to look up its actual manager object.
+
 }; // class Widget
 
+
+//----------------------------------------------------------------------------
+// Misc...
+//----------------------------------------------------------------------------
+// Find widget by name
+// Returns nullptr if the name was not found.
+template <class W = Widget> W* getWidget(const std::string& name, const Widget* w) { return (W*)Widget::getWidget_proxy(name, w); }
+template <class W = Widget> W* getWidget(const std::string& name, const Widget& w) { return (W*)Widget::getWidget_proxy(name, &w); }
+// Plus this one for convenience: the last created GUI instance will register itself as the default
+// (singleton) widget manager, so we can talk to it, provided we know for sure there can't be
+// another one in our app.
+template <class W = Widget> W* getWidget(const std::string& name) { return (W*)Widget::getWidget_proxy(name); }
+/*!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+  !!
+  !! Why aren't these above just Widget:: (or GUI::) members?
+  !! Well, this remnant, removed from the class (as (part) of #322) may help
+  !! illuminate it:
+  !!
+	Widget* getWidget(const std::string& name) const;
+	//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+	//!!
+	//!! JESUS CHRIST, C++, WTF?! :-ooo Get your shit together! ;) See #322...
+	//!! Not even this sad workaround can work (except in MSVC, amen to that...)!
+	//!! See the freestanding getWidget() functions after this class for the current
+	//!! alternative solution.
+	//!!
+	//!!	template <class W = Widget>
+	//!!	W* getWidget(const std::string& name) const { return (W*)getWidget_internal(name); }
+	//!!		//! Would be nice to have it templated directly, but that would introduce
+	//!!		//! a nasty cross-dependency on the top-level GUI stuff.
+	//!!		Widget* getWidget_internal(const std::string& name) const;
+	//!!
+	//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+ !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
+
 } // namespace
 
 #endif // GUI_WIDGET_HPP

src/examples/demo.cpp

@@ -262,7 +262,7 @@ int main()
 	auto buttfactory = buttons_vbox->add(new HBox);
 	auto labeller = buttfactory->add(sfw::TextBox(100))->set("Edit Me!")->setPlaceholder("Button label")
 		->setCallback([&] {
-			if (auto b = (sfw::Button*)demo.getWidget("button spawner"); b) b->click();
+			if (auto b = sfw::getWidget<sfw::Button>("button spawner", demo); b) b->click();
 		});
 	buttfactory->add(sfw::Button("Create button", [&] {
 		buttons_vbox->addAfter(buttfactory, new sfw::Button(labeller->get()));
@@ -273,7 +273,7 @@ int main()
 
 	auto utf8button_tag = "UTF-8 by default:"; // We'll also use this text to find the button.
 	buttons_form->add(utf8button_tag, sfw::Button("Ψ ≠ 99° ± β")); // Note: this source is already UTF-8 encoded!
-	cout << "UTF-8 button text got back as: \"" << ((sfw::Button*)demo.getWidget(utf8button_tag))->getText() << "\"\n";
+	cout << "UTF-8 button text got back as: \"" << sfw::getWidget<sfw::Button>(utf8button_tag, demo)->getText() << "\"\n";
 
 	// Bitmap buttons
 	auto imgbuttons_form = left_panel->add(sfw::Form());
@@ -325,9 +325,9 @@ int main()
 	// (`jumpy_thumb_click = true` allows immediately readjusting the pos.
 	// of the slider thumb on clicking it)
 	auto cropslider = (new sfw::Slider({.jumpy_thumb_click = true}, 100))->setCallback([&](auto* w) {
-		((sfw::ProgressBar*)w->getWidget("cropbar"))->set(w->get());
+		sfw::getWidget<sfw::ProgressBar>("cropbar")->set(w->get());
 		// Show the slider value in a text box retrieved by its name:
-		auto tbox = (sfw::TextBox*)w->getWidget("crop%");
+		auto tbox = sfw::getWidget<sfw::TextBox>("crop%");
 		if (!tbox) cerr << "Named TextBox not found! :-o\n";
 		else tbox->set(w->get() ? to_string((int)w->get()) : "");
 		imgCrop->setCropRect({{(int)(w->get() / 4), (int)(w->get() / 10)},
@@ -357,14 +357,14 @@ int main()
 		if (demo.setTheme(themecfg))
 		{
 			// Update the wallpaper controls:
-			if (auto wptoggle = (sfw::CheckBox*)demo.getWidget("Wallpaper"); wptoggle)
+			if (auto wptoggle = sfw::getWidget<sfw::CheckBox>("Wallpaper"); wptoggle)
 				wptoggle->set(demo.hasWallpaper())     // set() first, as it returns CheckBox*
-				        ->enable(demo.hasWallpaper()); // (enable() would "degrade" to Widget*)
-			if (auto wpalpha = demo.getWidget("Wallpaper α"); wpalpha) // auto -> Widget*
+				        ->enable(demo.hasWallpaper()); // (enable() would degrade to Widget*)
+			if (auto wpalpha = sfw::getWidget("Wallpaper α"); wpalpha) // auto -> Widget*
 				wpalpha->enable(demo.hasWallpaper());
 
 			// Update the bg. color selector's "Default" value:
-			if (auto bgsel = (OBColor*)demo.getWidget("Bg. color"); bgsel)
+			if (auto bgsel = sfw::getWidget<OBColor>("Bg. color"); bgsel)
 				bgsel->assign("Default", themecfg.bgColor);
 
 			//!! Update the font size slider:
@@ -385,11 +385,11 @@ int main()
 	right_bar->add(sfw::Slider({.range = {8, 18}}, 100), "font size slider")
 		//!! Would be tempting to sync the initial font size directly with
 		//!! the theme selector widget -- but can't: the GUI is not up yet, so:
-		//!! ->set(((OBTheme*)(w->getWidget("theme-selector")))->currentRef().textSize) //! This would fail here!
+		//!! ->set(w->getWidget<OBTheme>("theme-selector")->currentRef().textSize) //! This would fail here!
 		->set((float)themes[DEFAULT_THEME].textSize)
 		->setCallback([&] (auto* w){
-			assert(w->getWidget("theme-selector"));
-			auto& themecfg = ((OBTheme*)(w->getWidget("theme-selector")))->currentRef();
+			assert(sfw::getWidget("theme-selector", w));
+			auto& themecfg = sfw::getWidget<OBTheme>("theme-selector", w)->currentRef();
 			themecfg.textSize = (size_t)w->get();
 cerr << "font size: "<< themecfg.textSize << endl; //!!#196
 			demo.setTheme(themecfg);
@@ -422,8 +422,8 @@ cerr << "font size: "<< themecfg.textSize << endl; //!!#196
 	bgform->add("Wallpaper α", sfw::Slider({.range={0, 255}}, 75))
 		->set(demo.getWallpaper().getColor().a)
 		->setCallback([&](auto* w) {
-			assert(w->getWidget("theme-selector"));
-			auto& themecfg = ((OBTheme*)(w->getWidget("theme-selector")))->currentRef();
+			assert(sfw::getWidget("theme-selector", w));
+			auto& themecfg = sfw::getWidget<OBTheme>("theme-selector", w)->currentRef();
 			themecfg.wallpaper.tint = {themecfg.wallpaper.tint.r,
 			                           themecfg.wallpaper.tint.g,
 			                           themecfg.wallpaper.tint.b,
@@ -455,8 +455,8 @@ cerr << "font size: "<< themecfg.textSize << endl; //!!#196
 	// (after setup, as these may trigger callbacks etc.)
 	//
 
-	// Change the font size (to bigger?) to "prime" SFML to avoid #196! :-o
-	if (auto w = (sfw::Slider*)demo.getWidget("font size slider"); w)
+	//!! Change the font size (to bigger?) to "prime" SFML to avoid #196! :-o
+	if (auto w = sfw::getWidget<sfw::Slider>("font size slider", demo); w)
 		w->update(14);
 
 	sliderForRotation->set(104);
@@ -500,7 +500,7 @@ cerr << "font size: "<< themecfg.textSize << endl; //!!#196
 //----------------------------------------------------------------------------
 void background_thread_main(sfw::GUI& gui)
 {
-	auto rot_slider = (sfw::Slider*)gui.getWidget("rotation-slider");
+	auto rot_slider = sfw::getWidget<sfw::Slider>("rotation-slider", gui);
 	if (!rot_slider)
 		return;
 

src/lib/GUI.cpp

@@ -16,6 +16,10 @@ using namespace std;
 namespace sfw
 {
 
+// See the header for more on this:
+GUI* GUI::DefaultInstance = nullptr;
+
+
 //----------------------------------------------------------------------------
 GUI::GUI(sf::RenderWindow& window, const sfw::Theme::Cfg& themeCfg, bool own_the_window):
 	m_error(), // no error by default
@@ -29,6 +33,12 @@ GUI::GUI(sf::RenderWindow& window, const sfw::Theme::Cfg& themeCfg, bool own_the
 	// Also register ourselves to our own widget registry:
 	widgets["/"] = this;
 
+	// Add as the "most recent" GUI manager:
+	if (GUI::DefaultInstance) {
+		cerr << "- Note: overriding previous default GUI instance (" << DefaultInstance << " with newly created " << this << ")\n";
+	}
+	GUI::DefaultInstance = this;
+
 	reset();
 }
 

src/lib/Widget.cpp

@@ -16,6 +16,33 @@
 namespace sfw
 {
 
+//----------------------------------------------------------------------------
+// See the header...
+/*static*/ Widget* Widget::getWidget_proxy(const std::string& name, const Widget* w/* = nullptr*/)
+{
+	assert(GUI::DefaultInstance);
+	auto Main = w ? w->getMain() : GUI::DefaultInstance;
+
+	assert(Main);
+	return Main->recall(name);
+}
+
+/*!!Obsolete since #322:
+Widget* Widget::getWidget(const std::string& name) const
+{
+	//!!Log if dangling or 'name' not found!
+
+	if (GUI* Main = getMain(); Main)
+	{
+		return Main->recall(name);
+	}
+	return nullptr;
+}
+!!*/
+
+
+
+//----------------------------------------------------------------------------
 Widget::Widget() :
 	m_focusable(true),
 	m_state(WidgetState::Default),
@@ -121,16 +148,6 @@ std::string Widget::getName(Widget* widget) const
 }
 
 
-Widget* Widget::getWidget(const std::string& name) const
-{
-	if (GUI* Main = getMain(); Main)
-	{
-		return Main->recall(name);
-	}
-	return nullptr;
-}
-
-
 //----------------------------------------------------------------------------
 Widget* Widget::setPosition(const sf::Vector2f& pos)
 {

src/lib/WidgetContainer.cpp

@@ -178,7 +178,7 @@ Widget* WidgetContainer::addAfter(Widget* anchor, Widget* widget, const std::str
 
 Widget* WidgetContainer::addAfter(const std::string& anchor_name, Widget* widget, const std::string& name)
 {
-	Widget* a = getWidget(anchor_name);
+	Widget* a = sfw::getWidget(anchor_name); //!! See #322 for why not just this->...
 	return a ? addAfter(a, widget, name) : add(widget, name);
 }
 
@@ -187,8 +187,8 @@ Widget* WidgetContainer::addBefore(Widget* anchor, Widget* widget, const std::st
 {
 	if (anchor == nullptr)
 	{
-        // addFirst
-        return insert_after(nullptr, widget, name);
+        	// addFirst
+        	return insert_after(nullptr, widget, name);
 	}
 	else if (is_child(anchor))
 	{
@@ -200,7 +200,7 @@ Widget* WidgetContainer::addBefore(Widget* anchor, Widget* widget, const std::st
 
 Widget* WidgetContainer::addBefore(const std::string& anchor_name, Widget* widget, const std::string& name)
 {
-	Widget* a = getWidget(anchor_name);
+	Widget* a = sfw::getWidget(anchor_name); //!! See #322 for why not just this->...
 	return a ? addBefore(a, widget, name) : add(widget, name);
 }