ml::Focusable Class Reference

Trait that adds keyboard-focus and blur callbacks to any Core object. More...

#include <Malena/Traits/Interaction/Focusable.h>

Inheritance diagram for ml::Focusable:

Public Member Functions
void	onBlur (std::function< void()> callback, bool overwrite=true)
	Register a no-argument callback invoked when this component loses keyboard focus.
void	onBlur (std::function< void(const std::optional< sf::Event > &)> callback, bool overwrite=true)
	Register a callback invoked when this component loses keyboard focus, receiving the raw SFML event.
void	onFocus (std::function< void()> callback, bool overwrite=true)
	Register a no-argument callback invoked when this component gains keyboard focus.
void	onFocus (std::function< void(const std::optional< sf::Event > &)> callback, bool overwrite=true)
	Register a callback invoked when this component gains keyboard focus, receiving the raw SFML event.
virtual void	process (const std::string &key, const std::optional< sf::Event > &event)
	Invoke all callbacks registered for key.
template<typename ENUM_TYPE>
void	process (ENUM_TYPE eventName, const std::optional< sf::Event > &event)
	Invoke all callbacks registered for eventName.

Public Attributes
Core *	_selfCore = nullptr

Detailed Description

Trait that adds keyboard-focus and blur callbacks to any Core object.

Focusable is automatically inherited by every ml::Core object. A component gains focus when the user clicks it; it loses focus (blurs) when the user clicks elsewhere or focus is programmatically transferred. While focused, a component receives keyboard events via Keyable.

Usage

// Show a focus ring on focus, hide it on blur
myInput.onFocus([&]{ focusRing.setOutlineThickness(2.f); });
myInput.onBlur([&]{ focusRing.setOutlineThickness(0.f); });
 
// With SFML event data
myInput.onFocus([](const std::optional<sf::Event>& e){
    // e holds the MouseButtonReleased event that triggered focus
});

To unsubscribe:

myInput.unsubscribe(ml::Event::FOCUS);
myInput.unsubscribe(ml::Event::BLUR);

See also

Keyable, Clickable, ml::Event::FOCUS, ml::Event::BLUR, Unsubscribable

Definition at line 45 of file Focusable.h.

Member Function Documentation

onBlur() [1/2]

void ml::Focusable::onBlur	(	std::function< void()>	callback,
		bool	overwrite = true )

Register a no-argument callback invoked when this component loses keyboard focus.

Parameters

callback	Function invoked with no arguments when focus is lost.
overwrite	When true, replaces any existing callback; when false, appends an additional one.

onBlur() [2/2]

void ml::Focusable::onBlur	(	std::function< void(const std::optional< sf::Event > &)>	callback,
		bool	overwrite = true )

Register a callback invoked when this component loses keyboard focus, receiving the raw SFML event.

Parameters

callback	Function invoked with the SFML event when focus is lost.
overwrite	When true, replaces any existing callback; when false, appends an additional one.

onFocus() [1/2]

void ml::Focusable::onFocus	(	std::function< void()>	callback,
		bool	overwrite = true )

Register a no-argument callback invoked when this component gains keyboard focus.

Parameters

callback	Function invoked with no arguments when focus is gained.
overwrite	When true, replaces any existing callback; when false, appends an additional one.

onFocus() [2/2]

void ml::Focusable::onFocus	(	std::function< void(const std::optional< sf::Event > &)>	callback,
		bool	overwrite = true )

Register a callback invoked when this component gains keyboard focus, receiving the raw SFML event.

Parameters

callback	Function invoked with the SFML event when focus is gained.
overwrite	When true, replaces any existing callback; when false, appends an additional one.

process() [1/2]

virtual void ml::EventReceiver::process ( const std::string & key, const std::optional< sf::Event > & event )

virtualinherited

Invoke all callbacks registered for key.

Called by framework dispatchers. key is the string produced by EnumKey::get(eventEnum).

Parameters

key	String key identifying the event.
event	SFML event forwarded to each callback.

process() [2/2]

template<typename ENUM_TYPE>

void ml::EventReceiver::process ( ENUM_TYPE eventName, const std::optional< sf::Event > & event )

inherited

Invoke all callbacks registered for eventName.

Template overload that accepts any enum value directly, converting to a string key via EnumKey::get() internally.

Template Parameters

ENUM_TYPE

Any enum type.

Parameters

eventName	The enum value identifying the event.
event	SFML event forwarded to each callback.

Member Data Documentation

_selfCore

Core* ml::EventReceiver::_selfCore = nullptr

inherited

The owning Core, stamped by Core's constructor.

Traits subscribe from inside their OWN constructors (ml::TextInput calls onFocus(), ComponentCore subscribes to CLICK/HOVER/DRAG), at which point the derived type does not exist yet. Recovering the Core by dynamic_cast there is undefined: Clang returns something usable, MSVC throws "Access violation - no RTTI data!" and aborts the process. Core sets this on every one of its EventReceiver subobjects before any derived constructor runs, so no RTTI is ever needed.

Definition at line 93 of file EventReceiver.h.

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The documentation for this class was generated from the following file:

• Traits/Interaction/Focusable.h