esphome::display::DisplayWriter< T > Class Template Reference

Optimized display writer that uses function pointers for stateless lambdas. More...

#include <display.h>

Public Member Functions
	DisplayWriter ()
template<typename F > requires std::invocable<F, T &> && std::convertible_to<F, void (*)(T &)>
	DisplayWriter (F f)
template<typename F > requires std::invocable<F, T &> &&(!std::convertible_to<F, void (*)(T &)>)
	DisplayWriter (F f)
	DisplayWriter (const DisplayWriter &other)
	DisplayWriter (DisplayWriter &&other) noexcept
DisplayWriter &	operator= (const DisplayWriter &other)
DisplayWriter &	operator= (DisplayWriter &&other) noexcept
	~DisplayWriter ()
bool	has_value () const
void	call (T &display) const
void	operator() (T &display) const
DisplayWriter &	operator* ()
const DisplayWriter &	operator* () const

Protected Types
enum	: uint8_t { NONE , LAMBDA , STATELESS_LAMBDA }

Protected Attributes
enum esphome::display::DisplayWriter:: { ... }	type_
union {
std::function< void(T &)> *   f_
void(*   stateless_f_ )(T &)
};

Detailed Description

template<typename T>
class esphome::display::DisplayWriter< T >

Optimized display writer that uses function pointers for stateless lambdas.

Similar to TemplatableValue but specialized for display writer callbacks. Saves ~8 bytes per stateless lambda on 32-bit platforms (16 bytes std::function → ~8 bytes discriminator+pointer).

Supports both:

• Stateless lambdas (from YAML) → function pointer (4 bytes)
• Stateful lambdas/std::function (from C++ code) → std::function* (heap allocated)

Template Parameters

T	The display type (e.g., Display, Nextion, GPIOLCDDisplay)

Definition at line 190 of file display.h.

Member Enumeration Documentation

anonymous enum

template<typename T >

anonymous enum : uint8_t

protected

Enumerator
NONE
LAMBDA
STATELESS_LAMBDA

Definition at line 276 of file display.h.

Constructor & Destructor Documentation

DisplayWriter() [1/5]

template<typename T >

esphome::display::DisplayWriter< T >::DisplayWriter ( )

inline

Definition at line 192 of file display.h.

DisplayWriter() [2/5]

template<typename T >

template<typename F >
requires std::invocable<F, T &> && std::convertible_to<F, void (*)(T &)>

esphome::display::DisplayWriter< T >::DisplayWriter ( F f )

inline

Definition at line 196 of file display.h.

DisplayWriter() [3/5]

template<typename T >

template<typename F >
requires std::invocable<F, T &> &&(!std::convertible_to<F, void (*)(T &)>)

esphome::display::DisplayWriter< T >::DisplayWriter ( F f )

inline

Definition at line 204 of file display.h.

DisplayWriter() [4/5]

template<typename T >

esphome::display::DisplayWriter< T >::DisplayWriter ( const DisplayWriter< T > & other )

inline

Definition at line 209 of file display.h.

DisplayWriter() [5/5]

template<typename T >

esphome::display::DisplayWriter< T >::DisplayWriter ( DisplayWriter< T > && other )

inlinenoexcept

Definition at line 218 of file display.h.

~DisplayWriter()

template<typename T >

esphome::display::DisplayWriter< T >::~DisplayWriter ( )

inline

Definition at line 245 of file display.h.

Member Function Documentation

call()

template<typename T >

void esphome::display::DisplayWriter< T >::call ( T & display ) const

inline

Definition at line 254 of file display.h.

has_value()

template<typename T >

bool esphome::display::DisplayWriter< T >::has_value ( ) const

inline

Definition at line 252 of file display.h.

operator()()

template<typename T >

void esphome::display::DisplayWriter< T >::operator() ( T & display ) const

inline

Definition at line 269 of file display.h.

operator*() [1/2]

template<typename T >

DisplayWriter & esphome::display::DisplayWriter< T >::operator* ( )

inline

Definition at line 272 of file display.h.

operator*() [2/2]

template<typename T >

const DisplayWriter & esphome::display::DisplayWriter< T >::operator* ( ) const

inline

Definition at line 273 of file display.h.

operator=() [1/2]

template<typename T >

DisplayWriter & esphome::display::DisplayWriter< T >::operator= ( const DisplayWriter< T > & other )

inline

Definition at line 229 of file display.h.

operator=() [2/2]

template<typename T >

DisplayWriter & esphome::display::DisplayWriter< T >::operator= ( DisplayWriter< T > && other )

inlinenoexcept

Definition at line 237 of file display.h.

Field Documentation

[union]

union { ... } esphome::display::DisplayWriter< T >

f_

template<typename T >

std::function<void(T &)>* esphome::display::DisplayWriter< T >::f_

Definition at line 283 of file display.h.

stateless_f_

template<typename T >

void(* esphome::display::DisplayWriter< T >::stateless_f_) (T &)

Definition at line 284 of file display.h.

[]

enum { ... } esphome::display::DisplayWriter< T >::type_

---

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

• esphome/components/display/display.h