ElectronicShutdownEffect Class Reference

A QGraphicsEffect that simulates an old CRT monitor or electronic device shutting down. More...

#include <electronic_shutdown_effect.h>

Inheritance diagram for ElectronicShutdownEffect:

Collaboration diagram for ElectronicShutdownEffect:

Public Member Functions
	ElectronicShutdownEffect (QObject *parent=nullptr)
	Constructs an ElectronicShutdownEffect. Initializes the effect, sets up the result cache, and seeds the random generator.
qreal	GetProgress () const
	Gets the current progress of the shutdown animation.
void	SetProgress (qreal progress)
	Sets the progress of the shutdown animation. Clamps the value between 0.0 and 1.0 and triggers an update of the effect.

Protected Member Functions
void	draw (QPainter *painter) override
	Overridden draw method that renders the shutdown effect. Retrieves the source pixmap. If progress is minimal, draws the source directly. If progress is maximal, draws nothing. Otherwise, checks a cache for a pre-rendered result at a similar progress level. If not cached or progress changed significantly, it generates the effect based on the current phase (collapsing or fading line), applying glitches, scanlines, brightness changes, and glow effects. The result is stored in the cache. Finally, the cached (or newly generated) pixmap is drawn.

Properties
qreal	progress
	Property controlling the progress of the shutdown animation (0.0 to 1.0). Animatable.

Private Attributes
qreal	last_progress_
	Stores the progress value from the last time the cache was updated, used to optimize cache usage.
qreal	progress_
	Current progress level of the shutdown animation (0.0 to 1.0).
QCache< QString, QPixmap >	result_cache_
	Cache storing pre-rendered effect pixmaps keyed by progress level string for performance.

Detailed Description

A QGraphicsEffect that simulates an old CRT monitor or electronic device shutting down.

This effect animates in two phases based on the progress property (0.0 to 1.0):

1. (0.0-0.7): The source image vertically collapses into a thin horizontal line, accompanied by visual glitches (random line shifts) and scanline effects.
2. (0.7-1.0): The horizontal line fades out, shrinks horizontally, increases in brightness, and exhibits flickering and glow effects before disappearing completely.

The effect uses caching (QCache) to store intermediate results for performance.

Constructor & Destructor Documentation

ElectronicShutdownEffect()

ElectronicShutdownEffect::ElectronicShutdownEffect ( QObject * parent = nullptr )

explicit

Constructs an ElectronicShutdownEffect. Initializes the effect, sets up the result cache, and seeds the random generator.

Parameters

parent

Optional parent QObject.

Member Function Documentation

draw()

void ElectronicShutdownEffect::draw ( QPainter * painter )

overrideprotected

Overridden draw method that renders the shutdown effect. Retrieves the source pixmap. If progress is minimal, draws the source directly. If progress is maximal, draws nothing. Otherwise, checks a cache for a pre-rendered result at a similar progress level. If not cached or progress changed significantly, it generates the effect based on the current phase (collapsing or fading line), applying glitches, scanlines, brightness changes, and glow effects. The result is stored in the cache. Finally, the cached (or newly generated) pixmap is drawn.

Parameters

painter

The QPainter to use for drawing.

GetProgress()

qreal ElectronicShutdownEffect::GetProgress ( ) const

inline

Gets the current progress of the shutdown animation.

Returns

The current progress level (0.0 to 1.0).

SetProgress()

void ElectronicShutdownEffect::SetProgress

(

qreal

progress

)

Sets the progress of the shutdown animation. Clamps the value between 0.0 and 1.0 and triggers an update of the effect.

Parameters

progress

The desired progress level (0.0 to 1.0).

Member Data Documentation

last_progress_

qreal ElectronicShutdownEffect::last_progress_

private

Stores the progress value from the last time the cache was updated, used to optimize cache usage.

progress_

qreal ElectronicShutdownEffect::progress_

private

Current progress level of the shutdown animation (0.0 to 1.0).

result_cache_

QCache<QString, QPixmap> ElectronicShutdownEffect::result_cache_

private

Cache storing pre-rendered effect pixmaps keyed by progress level string for performance.

Property Documentation

progress

qreal ElectronicShutdownEffect::progress

readwrite

Property controlling the progress of the shutdown animation (0.0 to 1.0). Animatable.

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

• src/ui/chat/effects/electronic_shutdown_effect.h
• src/ui/chat/effects/electronic_shutdown_effect.cpp