TextWriter Class Reference

A class dedicated to text drawing within a widget. More...

#include <widget_primitives.h>

Inheritance diagram for TextWriter:

Collaboration diagram for TextWriter:

Public Member Functions
	TextWriter (struct_ConfigTextWidget text_cfg, CanvasFormat canvas_format)
	Construct a new Text Writer object.
	TextWriter (struct_ConfigTextWidget text_cfg, CanvasFormat canvas_format, size_t frame_width, size_t frame_height)
	Construct a new Text Widget object.
void	update_text_line_column_number (const unsigned char *font)
	The max number of line with respect to frame height and font height.
void	clear_text_buffer ()
	et text buffer memory to "0" and set character current line and column to 0
void	update_canvas_buffer_size (const unsigned char *font)
	compute canvas width and height according to the size of the text (column x line ) and the size of the bitmap font. Delete the previous pixel buffer if any and create a new buffer.
void	write ()
	process characters in the internal text buffer and draw it into the pixel buffer.
void	write (const char *c_str)
	process the string c_str and then draw each character into the pixel buffer, without using the text buffer.
void	process_char (char character)
	interpret the character and draw it into the pixel buffer at the current line and column character position.
void	next_line ()
	character line steps one position downward.
void	next_char ()
	character column steps forward one position forward.
void	draw_border (ColorIndex color=ColorIndex::WHITE)
	draw a one-pixel width around the the frame
Public Member Functions inherited from GraphicDrawer
	GraphicDrawer (struct_ConfigGraphicWidget graph_cfg, CanvasFormat canvas_format)
	Constructor of the GraphicDrawer class.
	GraphicDrawer (struct_ConfigTextWidget text_cfg, CanvasFormat canvas_format)
	Constructor of the GraphicDrawer class.
	GraphicDrawer (struct_ConfigTextWidget text_cfg, CanvasFormat canvas_format, size_t frame_width, size_t frame_height)
	Constructor of the GraphicDrawer class.
void	clear_widget ()
	fill the graphic pixel buffer with 0x00.
void	hline (uint8_t x, uint8_t y, size_t w, ColorIndex color=ColorIndex::WHITE)
	Draw a color horizontal line, starting at frame position (x,y), on w number of pixel.
void	vline (uint8_t x, uint8_t y, size_t h, ColorIndex color=ColorIndex::WHITE)
	Draw a color vertical line, starting at frame position (x,y), on w number of pixel.
void	line (int x0, int y0, int x1, int y1, ColorIndex color=ColorIndex::WHITE)
	Draw a color line, starting at frame position (x0,y0), ending at frame position (x1,y1)
void	rect (uint8_t start_x, uint8_t start_y, size_t w, size_t h, bool fill=false, ColorIndex color=ColorIndex::WHITE)
	Draw a rectangle, starting at frame position (x,y), w wide and h high.
void	circle (int radius, int x_center, int y_center, bool fill=false, ColorIndex color=ColorIndex::WHITE)
	draw a cercle of size radius, centered at (x_center, y_center) https://fr.wikipedia.org/wiki/Algorithme_de_trac%C3%A9_d%27arc_de_cercle_de_Bresenham https://en.wikipedia.org/wiki/Midpoint_circle_algorithm procédure tracerCercle (entier rayon, entier x_centre, entier y_centre) déclarer entier x, y, m ; x ← 0 ; y ← rayon ; // on se place en haut du cercle m ← 5 - 4*rayon ; // initialisation Tant que x <= y // tant qu'on est dans le second octant tracerPixel( x+x_centre, y+y_centre ) ; tracerPixel( y+x_centre, x+y_centre ) ; tracerPixel( -x+x_centre, y+y_centre ) ; tracerPixel( -y+x_centre, x+y_centre ) ; tracerPixel( x+x_centre, -y+y_centre ) ; tracerPixel( y+x_centre, -x+y_centre ) ; tracerPixel( -x+x_centre, -y+y_centre ) ; tracerPixel( -y+x_centre, -x+y_centre ) ; si m > 0 alors //choix du point F y ← y - 1 ; m ← m - 8*y ; fin si ; x ← x + 1 ; m ← m + 8*x + 4 ; fin tant que ; fin de procédure ;

Public Attributes
uint8_t	number_of_column {0}
	The max number of line with respect to frame height and font height.
uint8_t	number_of_line {0}
	The max number of column with respect to frame width and font width.
size_t	text_buffer_size
	size of the buffer that contains text as string of characters.
char *	text_buffer = nullptr
	the buffer where text are written
Public Attributes inherited from GraphicDrawer
uint8_t	widget_border_width
	this is the border size of the widget. 0 if no border, 1 if border
Canvas *	canvas
	the associated canvas in which the widget writes text and draws graphics

Protected Member Functions
void	create_text_buffer ()
	create text buffer and delete the old one if already existing

Private Member Functions
void	write (char character, uint8_t char_column, uint8_t char_line)
	a graphic primitive to draw a character at a character position
void	clear_line ()
	clean th full current line (writing " " in the text buffer)
void	draw_glyph (const char character, const uint8_t anchor_x, const uint8_t anchor_y)
	a graphic primitive to draw a character at a pixel position. Strongly dependent on font memory organisation.

Private Attributes
uint8_t	current_char_line {0}
	the line number where the next character will be written.
uint8_t	current_char_column {0}
	the column where the next character will be written.
const unsigned char *	font {nullptr}
	The font used. Current font are defined according to IBM CP437. The font files are derived from https://github.com/Harbys/pico-ssd1306 works. They come is size 5x8, 8x8, 12x16 and 16x32.
uint8_t	tab_size {2}
	The number of space that ASCII character HT (aka TAB , "\t", 0x9) generates, default to 2.
bool	wrap {true}
	Wrap flag : if true, text wrap to the next line when end of line is reached.
bool	auto_next_char {true}
	auto_next_char flag : if true each char steps one position after being written.

Additional Inherited Members
Protected Attributes inherited from GraphicDrawer
bool	widget_with_border {false}
	if true, the widget is surrounded by a one-pixel border
size_t	widget_width {128}
	As a widget can be surrounded by a border, the actual widget width is not the associated framebuffer width.
size_t	widget_height {8}
	As a widget can be surrounded by a border, the actual widget height is not the associated framebuffer height.
uint8_t	widget_start_x
	this is the actual horizontal start of the widget drawing area, taken into account the presence of border.
uint8_t	widget_start_y
	this is the actual vertical start of the widget drawing area, taken into account the presence of border.

Detailed Description

A class dedicated to text drawing within a widget.

Constructor & Destructor Documentation

TextWriter() [1/2]

TextWriter::TextWriter	(	struct_ConfigTextWidget	text_cfg,
		CanvasFormat	canvas_format )

Construct a new Text Writer object.

Note

USAGE: when the text frame is defined by the number of characters width and height.

Parameters

text_cfg	the configuration data for the textual frame
canvas_format	the format of the associated canvas (see CanvasFormat)

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TextWriter() [2/2]

TextWriter::TextWriter	(	struct_ConfigTextWidget	text_cfg,
		CanvasFormat	canvas_format,
		size_t	frame_width,
		size_t	frame_height )

Construct a new Text Widget object.

Note

USAGE: when the text frame is defined by the frame size width and height in pixel.

Parameters

text_cfg	the configuration data for the textual frame
canvas_format	the format of the associated canvas (see CanvasFormat)
frame_width	the frame size width
frame_height	the frame size height

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Member Function Documentation

draw_border()

void TextWriter::draw_border ( ColorIndex color = ColorIndex::WHITE )

virtual

draw a one-pixel width around the the frame

Note

This border can overwrite the characters! To be improve with the use of pixel frame memory not based on byte page such as the OLED SSD1306.

Parameters

color

Reimplemented from GraphicDrawer.

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draw_glyph()

void TextWriter::draw_glyph ( const char character, const uint8_t anchor_x, const uint8_t anchor_y )

private

a graphic primitive to draw a character at a pixel position. Strongly dependent on font memory organisation.

Parameters

character	the character to draw
anchor_x	the pixel position on x-axis to start drawing the character (upper left corner)
anchor_y	the pixel position on y-axis to start drawing the character (upper left corner)

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process_char()

void TextWriter::process_char

(

char

character

)

interpret the character and draw it into the pixel buffer at the current line and column character position.

Text wrapping is done if wrap flag is true. Character position steps forward according to auto_next_char flag.

Some special characters are processed:

• "LINE_FEED" (\n 0x0A) : line position steps forward, column position is set to 0.
• "BACKSPACE" (\b 0x08) : column position steps backward, a space (" ") character is overwritten.
• "FORM_FEED" (\f 0x0C) : the text buffer is cleared.
• "CARRIAGE_RETURN" (\r 0x0D) : column position is set to 0.
• "HORIZONTAL_TAB" (\t 0x09) : " " characters are added according to tab_size configuration value.

  Parameters

  character

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update_canvas_buffer_size()

void TextWriter::update_canvas_buffer_size

(

const unsigned char *

font

)

compute canvas width and height according to the size of the text (column x line ) and the size of the bitmap font. Delete the previous pixel buffer if any and create a new buffer.

Parameters

font	the new font

update_text_line_column_number()

void TextWriter::update_text_line_column_number

(

const unsigned char *

font

)

The max number of line with respect to frame height and font height.

Compute the text size in column x line according to the size of the font and the size of the frame in pixel. Delete the previous text buffer if any and create a new buffer.

Parameters

font	the new font

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write() [1/3]

void TextWriter::write

(

)

process characters in the internal text buffer and draw it into the pixel buffer.

Note

USAGE: this is useful if we have to fill the text_buffer, e.g. with sprintf and formatted text.

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write() [2/3]

void TextWriter::write ( char character, uint8_t char_column, uint8_t char_line )

private

a graphic primitive to draw a character at a character position

Parameters

character	the foreground color of the character. The font is given by the frame_text_config
char_column	the column position of the character
char_line	the line position of the character

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write() [3/3]

void TextWriter::write

(

const char *

c_str

)

process the string c_str and then draw each character into the pixel buffer, without using the text buffer.

Parameters

c_str

A C_style character string.

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

• widget_primitives.h
• widget_primitives.cpp