TextRenderer enables quick and easy string rendering in OpenGL applications. More...

#include <easy3d/renderer/text_renderer.h>

Public Types
enum	Align { ALIGN_LEFT , ALIGN_RIGHT , ALIGN_CENTER }
	Horizontal alignment.

Public Member Functions
	TextRenderer (float dpi_scale=1.0f, int texture_size=512, bool mipmaps=false)

	~TextRenderer ()

bool	add_font (const std::string &font_file)

std::size_t	num_fonts () const

const std::vector< std::string > &	font_names () const

float	draw (const std::string &text, float x, float y, float font_size, int font_id=0, const vec3 &font_color=vec3(0, 0, 0), bool upper_left=true) const

Rect	draw (const std::string &text, float x, float y, float font_size, Align align=ALIGN_LEFT, int font_id=0, const vec3 &font_color=vec3(0, 0, 0), float line_spacing=0.0f, bool upper_left=true) const
	Draw multi-line text with alignment support. This method produces line breaks for text with "\n". More...

void	set_character_spacing (float spacing)

float	character_spacing () const

void	set_kerning (bool kerning)

bool	kerning () const

float	font_height (float font_size) const

float	string_width (const std::string &str, float font_size) const

float	string_height (const std::string &str, float font_size) const

Rect	string_bounding_rect (const std::string &str, float x, float y, float font_size) const

Detailed Description

TextRenderer enables quick and easy string rendering in OpenGL applications.

It supports truetype (TTF) fonts and unicode strings. All glyphs are cached in OpenGL textures and font rasterization is done using 'stb_truetype.h." TextRenderer allows you to:

switch between fonts;
change character spacing;
enable/disable kerning;
Todo:
For a large number of strings/characters, it is necessary to separate buffer creation and rendering.

Performance evaluation.

Examples: Tutorial_204_Viewer_Qt, and Tutorial_309_TextRendering.

Constructor & Destructor Documentation

◆ TextRenderer()

TextRenderer	(	float	dpi_scale = `1.0f`,
		int	texture_size = `512`,
		bool	mipmaps = `false`
	)

explicit

Constructor.

Parameters

texture_size	The size of the font textures. Suggested values are 512, 1024, 2048 ...
mipmaps	True to create mipmaps for the font textures.

◆ ~TextRenderer()

~TextRenderer ( )

Destructor.

Member Function Documentation

◆ add_font()

bool add_font ( const std::string & font_file )

Add a font from a file. This function must be called at least once to add a font.

Parameters

font_file The font file (.ttf, etc).

Examples: Tutorial_203_Viewer_wxWidgets, and Tutorial_204_Viewer_Qt.

◆ character_spacing()

float character_spacing ( ) const

Query the spacing between consecutive characters.

Returns: The spacing between consecutive characters.

◆ draw() [1/2]

Rect draw	(	const std::string &	text,
		float	x,
		float	y,
		float	font_size,
		Align	align = `ALIGN_LEFT`,
		int	font_id = `0`,
		const vec3 &	font_color = `vec3(0, 0, 0)`,
		float	line_spacing = `0.0f`,
		bool	upper_left = `true`
	)		const

Draw multi-line text with alignment support. This method produces line breaks for text with "\n".

Parameters

text	The string to be drawn.
x	The x-coordinate of the starting position, relative to the left edge of the content area.
y	The y-coordinate of the starting position. If upper_left is true, this position is relative to the top edge of the content area. Otherwise, it is relative to the bottom edge of the content area.
font_size	The font size.
align	Specifies how the lines are aligned.
font_id	The id of the font used to draw the text, which is generated by calling to add_font(). 0 is the first font, 1 is the second, etc.
font_color	The font color.
line_spacing	The line spacing, which is a ratio relative to line height. A zero value means no extra space between lines.
upper_left	True to define the origin at the upper left corner of the content area. Otherwise it is defined at the bottom left corner of the content area.

Returns: The region occupied by the text.

◆ draw() [2/2]

float draw	(	const std::string &	text,
		float	x,
		float	y,
		float	font_size,
		int	font_id = `0`,
		const vec3 &	font_color = `vec3(0, 0, 0)`,
		bool	upper_left = `true`
	)		const

Draw the text.

Parameters

text	The string to be drawn.
x	The x-coordinate of the starting position, relative to the left edge of the content area.
y	The y-coordinate of the starting position. If upper_left is true, this position is relative to the top edge of the content area. Otherwise, it is relative to the bottom edge of the content area.
font_size	The font size.
font_id	The id of the font used to draw the text, which is generated by calling to add_font(). 0 is the first font, 1 is the second, etc.
font_color	The font color.
upper_left	True to define the origin at the upper left corner of the content area. Otherwise it is defined at the bottom left corner of the content area.

Returns: The end position of the x-coordinate. This allows you to draw another string after the previous one.

Note: : This function will draw the text in one line and thus line breaks (i.e., "\n") will be ignored.

Examples: Tutorial_203_Viewer_wxWidgets, and Tutorial_204_Viewer_Qt.

◆ font_height()

float font_height ( float font_size ) const

Query the height of the font.

Parameters

font_size The font size.

Returns: The height of the font in pixels.

◆ font_names()

const std::vector< std::string > & font_names ( ) const

inline

The names of available fonts.

◆ kerning()

bool kerning ( ) const

Query the kerning behavior. Kerning is disabled by default.

Returns: The kerning behavior.

◆ num_fonts()

std::size_t num_fonts ( ) const

inline

The number of available fonts.

Examples: Tutorial_203_Viewer_wxWidgets, and Tutorial_204_Viewer_Qt.

◆ set_character_spacing()

void set_character_spacing ( float spacing )

Set the spacing between consecutive characters. The default character spacing is 0.

Parameters

spacing The expected character spacing.

◆ set_kerning()

void set_kerning ( bool kerning )

Set kerning.

Parameters

kerning The expected kerning behavior.

◆ string_bounding_rect()

Rect string_bounding_rect	(	const std::string &	str,
		float	x,
		float	y,
		float	font_size
	)		const

Query the bounding rectangle of a string (treated as if with no space between characters).

Parameters

x	The x-coordinate of the starting position, relative to the left edge of the content area.
y	The y-coordinate of the starting position, relative to the top edge of the content area.
font_size	The font size.

Returns: The bounding rectangle of the string (in pixels).

◆ string_height()

float string_height	(	const std::string &	str,
		float	font_size
	)		const

Query the height of a string.

Parameters

font_size The font size.

Returns: The height of the string in pixels.

◆ string_width()

float string_width	(	const std::string &	str,
		float	font_size
	)		const

Query the width of a string (treated as if with no space between characters). Useful to position a string. For example, with the string width, its X-center can be computed as: viewer_width * 0.5 - string_width * 0.5.

Parameters

font_size The font size.

Returns: The width of the string in pixels.

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

/Users/lnan/Documents/Projects/Easy3D/easy3d/renderer/text_renderer.h
/Users/lnan/Documents/Projects/Easy3D/easy3d/renderer/text_renderer.cpp

Public Types

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ TextRenderer()

◆ ~TextRenderer()

Member Function Documentation

◆ add_font()

◆ character_spacing()

◆ draw() [1/2]

◆ draw() [2/2]

◆ font_height()

◆ font_names()

◆ kerning()

◆ num_fonts()

◆ set_character_spacing()

◆ set_kerning()

◆ string_bounding_rect()

◆ string_height()

◆ string_width()