LcdHelper Class Reference

Helper class to write on LCD. More...

Public Member Functions
	LcdHelper (void)
	Class default constructor.
void	begin (LiquidCrystal *const lcd, const int32_t backlight_dpin=-1)
	Initializes this instance with current LCD instance.
void	turn_on_backlight (void)
	Turns on the LCD backlight if configured.
void	turn_off_backlight (void)
	Turns off the LCD backlight if configured.
void	clear (void)
	Clears the current LCD content (the internal buffer) and resets the cursor position.
void	setCursor (const uint16_t c, const uint16_t r)
	Sets the cursor position if valid (in LCD sizes).
void	home (void)
	Sets the cursor position to (0, 0).
void	print (const char *str, const uint16_t str_length=LCD_COLS)
	Prints a string to the internal buffer without exceeding the limits of the LCD.
void	print (const int32_t number)
	Prints a number to the LCD.
void	print (const String &str)
	Prints a String to the LCD.
void	print (const int16_t number)
	Prints a integer number to the LCD.
void	print (const uint16_t number)
	Prints a integer number to the LCD.
void	print (const float64_t number)
	Prints a floating point number to the LCD.
void	write (const int32_t special_char_index)
	Writes a special character to the LCD.
void	update_lcd (void)
	Updates the LCD HW with the current written data.

Private Member Functions
bool	is_special_symbol (const uint16_t r, const uint16_t c)
	Checks if the symbol in the given position is special or not.
bool	need_update (void)
	Checks if the LCD HW view needs an update.

Private Attributes
uint16_t	cursor_r
uint16_t	cursor_c
int32_t	backlight_digital_pin
char	lcd_matrix [LCD_ROWS][LCD_COLS]
char	last_lcd_matrix [LCD_ROWS][LCD_COLS]
bool	special_char_map [LCD_ROWS][LCD_COLS]
bool	last_special_char_map [LCD_ROWS][LCD_COLS]
LiquidCrystal *	lcd_instance

Static Private Attributes
static const char	EMPTY_CHAR = ' '

Detailed Description

Helper class to write on LCD.

The purpose is to try the optimization of writings on LCD to prevent unwanted screen flickering. It uses a buffer to keep the current LCD content. When the user writes using the "print" or "write" methods, data are written in the buffer. The user has in charge the responsibility to update the LCD view by explicitly invoking the "update_lcd" method. The latter verifies which characters have been changed from previous view and updates only the different ones.

Constructor & Destructor Documentation

LcdHelper()

LcdHelper::LcdHelper ( void )

inline

Class default constructor.

Member Function Documentation

begin()

void LcdHelper::begin ( LiquidCrystal *const lcd, const int32_t backlight_dpin = -1 )

inline

Initializes this instance with current LCD instance.

Parameters

[in]	lcd	The pointer to the LiquidCrystal lcd instance.
[in]	backlight_dpin	The digital pin number used to control LCD backlight (default: -1, if not controllable).

clear()

void LcdHelper::clear ( void )

inline

Clears the current LCD content (the internal buffer) and resets the cursor position.

home()

void LcdHelper::home ( void )

inline

Sets the cursor position to (0, 0).

is_special_symbol()

bool LcdHelper::is_special_symbol ( const uint16_t r, const uint16_t c )

inlineprivate

Checks if the symbol in the given position is special or not.

Checks if the symbol is a number in 0-9 and it flagged true in special_char_map.

Parameters

[in]	r	The row.
[in]	c	The column.

Returns

true if the symbol in ( r, c ) is special or false otherwise.

need_update()

bool LcdHelper::need_update ( void )

inlineprivate

Checks if the LCD HW view needs an update.

Checks if there is a symbol different from the currently displayed data

Returns

true if there is a difference to display or false otherwise.

print() [1/6]

void LcdHelper::print ( const char * str, const uint16_t str_length = LCD_COLS )

inline

Prints a string to the internal buffer without exceeding the limits of the LCD.

Parameters

[in]	str	The string (char pointer).
[in]	str_length	The string length.

print() [2/6]

void LcdHelper::print ( const float64_t number )

inline

Prints a floating point number to the LCD.

Parameters

[in]

number

The number to write.

print() [3/6]

void LcdHelper::print ( const int16_t number )

inline

Prints a integer number to the LCD.

Parameters

[in]

number

The number to write.

print() [4/6]

void LcdHelper::print ( const int32_t number )

inline

Prints a number to the LCD.

Parameters

[in]

number

The integer number to write.

print() [5/6]

void LcdHelper::print ( const String & str )

inline

Prints a String to the LCD.

Parameters

[in]

str

The string to write.

print() [6/6]

void LcdHelper::print ( const uint16_t number )

inline

Prints a integer number to the LCD.

Parameters

[in]

number

The number to write.

setCursor()

void LcdHelper::setCursor ( const uint16_t c, const uint16_t r )

inline

Sets the cursor position if valid (in LCD sizes).

Parameters

[in]	c	The column index.
[in]	r	The row index.

turn_off_backlight()

void LcdHelper::turn_off_backlight ( void )

inline

Turns off the LCD backlight if configured.

turn_on_backlight()

void LcdHelper::turn_on_backlight ( void )

inline

Turns on the LCD backlight if configured.

update_lcd()

void LcdHelper::update_lcd ( void )

inline

Updates the LCD HW with the current written data.

write()

void LcdHelper::write ( const int32_t special_char_index )

inline

Writes a special character to the LCD.

It writes the number on the buffer and set to true the special_char_map matrix in the corresponding position on screen.

Parameters

[in]

special_char_index

The special character number.

Member Data Documentation

backlight_digital_pin

int32_t LcdHelper::backlight_digital_pin

private

cursor_c

uint16_t LcdHelper::cursor_c

private

cursor_r

uint16_t LcdHelper::cursor_r

private

EMPTY_CHAR

const char LcdHelper::EMPTY_CHAR = ' '

staticprivate

last_lcd_matrix

char LcdHelper::last_lcd_matrix[LCD_ROWS][LCD_COLS]

private

last_special_char_map

bool LcdHelper::last_special_char_map[LCD_ROWS][LCD_COLS]

private

lcd_instance

LiquidCrystal* LcdHelper::lcd_instance

private

lcd_matrix

char LcdHelper::lcd_matrix[LCD_ROWS][LCD_COLS]

private

special_char_map

bool LcdHelper::special_char_map[LCD_ROWS][LCD_COLS]

private

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

• livello_serbatoio.ino