ml::Fadeable Class Reference

Trait that adds time-based alpha animation to any component. More...

#include <Malena/Traits/Visual/Fadeable.h>

Inheritance diagram for ml::Fadeable:

Public Member Functions
	Fadeable ()
virtual	~Fadeable ()
void	fadeIn (float duration=0.5f, Tween tween=LINEAR, std::function< void()> onComplete=nullptr)
	Animate alpha from 0 to 255 (fully opaque).
void	fadeOut (float duration=0.5f, Tween tween=LINEAR, std::function< void()> onComplete=nullptr)
	Animate alpha from its current value to 0 (fully transparent).
void	fadeTo (uint8_t targetAlpha, float duration=0.5f, Tween tween=LINEAR, std::function< void()> onComplete=nullptr)
	Animate alpha from its current value to targetAlpha.
uint8_t	getAlpha () const
	Return the current alpha as a uint8_t (0–255).
void	holdFor (float duration, std::function< void()> onComplete=nullptr)
	Hold at the current alpha for duration seconds, then fire onComplete.
bool	isFading () const
	Return true while a fade or hold animation is running.
void	setAlpha (uint8_t alpha)
	Set alpha immediately with no animation.

Detailed Description

Trait that adds time-based alpha animation to any component.

Fadeable manages a float alpha value (0.0–255.0) and animates it toward a target over a specified duration using linear or exponential easing. The animation tick is driven automatically by the framework's update event — no manual onUpdate call is needed in the component.

An optional completion callback fires exactly once when the animation reaches its target, enabling chained sequences:

fadeIn(0.3f, ml::LINEAR, [this]{
    holdFor(2.f, [this]{ fadeOut(0.5f); });
});

Adding Fadeable to a component

class MyComp : public ml::Component<ml::Fadeable> { ... };
// Or combined with other traits:
class MyComp : public ml::Component<ml::Fadeable, ml::Messenger> { ... };

Applying the alpha in draw()

Fadeable does not modify any drawable automatically — call getAlpha() in your draw() override and apply the value to whatever you are drawing:

void draw(sf::RenderTarget& t, const sf::RenderStates& s) const override
{
    sf::Color c = _body.getFillColor();
    c.a = getAlpha();
    _body.setFillColor(c);
    t.draw(_body, s);
}

See also

Draggable, Positionable, Tween

Definition at line 56 of file Fadeable.h.

Constructor & Destructor Documentation

Fadeable()

ml::Fadeable::Fadeable

(

)

~Fadeable()

virtual ml::Fadeable::~Fadeable ( )

virtual

Member Function Documentation

fadeIn()

void ml::Fadeable::fadeIn	(	float	duration = 0.5f,
		Tween	tween = LINEAR,
		std::function< void()>	onComplete = nullptr )

Animate alpha from 0 to 255 (fully opaque).

Shorthand for fadeTo(255, duration, tween, onComplete).

Parameters

duration	Animation duration in seconds. Defaults to 0.5s.
tween	Easing curve. Defaults to LINEAR.
onComplete	Optional callback fired once when the animation ends.

fadeOut()

void ml::Fadeable::fadeOut	(	float	duration = 0.5f,
		Tween	tween = LINEAR,
		std::function< void()>	onComplete = nullptr )

Animate alpha from its current value to 0 (fully transparent).

Shorthand for fadeTo(0, duration, tween, onComplete).

Parameters

duration	Animation duration in seconds. Defaults to 0.5s.
tween	Easing curve. Defaults to LINEAR.
onComplete	Optional callback fired once when the animation ends.

fadeTo()

void ml::Fadeable::fadeTo	(	uint8_t	targetAlpha,
		float	duration = 0.5f,
		Tween	tween = LINEAR,
		std::function< void()>	onComplete = nullptr )

Animate alpha from its current value to targetAlpha.

Parameters

targetAlpha	Target alpha (0–255).
duration	Animation duration in seconds. Defaults to 0.5s.
tween	Easing curve. Defaults to LINEAR.
onComplete	Optional callback fired once when the animation ends.

getAlpha()

uint8_t ml::Fadeable::getAlpha

(

)

const

Return the current alpha as a uint8_t (0–255).

Call this in your draw() override to apply the animated value to your drawable's color.

Returns

Current alpha value.

holdFor()

void ml::Fadeable::holdFor	(	float	duration,
		std::function< void()>	onComplete = nullptr )

Hold at the current alpha for duration seconds, then fire onComplete.

Useful for sequencing: fade in → hold → fade out.

fadeIn(0.3f, LINEAR, [this]{
    holdFor(2.f, [this]{ fadeOut(0.5f); });
});

Parameters

duration	Hold duration in seconds.
onComplete	Optional callback fired once the hold period ends.

isFading()

bool ml::Fadeable::isFading

(

)

const

Return true while a fade or hold animation is running.

Returns

true if an animation or hold is currently in progress.

setAlpha()

void ml::Fadeable::setAlpha

(

uint8_t

alpha

)

Set alpha immediately with no animation.

Cancels any animation in progress.

Parameters

alpha

The new alpha value (0–255).

---

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

• Traits/Visual/Fadeable.h