Font implementations that uses FreeType directly to load glyphs. More...

#include <TGUI/Backend/Font/FreeType/BackendFontFreeType.hpp>

Inheritance diagram for tgui::BackendFontFreetype:

Classes
struct	Glyph

struct	Row

Public Member Functions
	~BackendFontFreetype () override
	Destructor that cleans up the FreeType resources.

bool	loadFromMemory (std::unique_ptr< std::uint8_t[]> data, std::size_t sizeInBytes) override
	Loads a font from memory.

bool	hasGlyph (char32_t codePoint) const override
	Returns whether a font contains a certain glyph.

FontGlyph	getGlyph (char32_t codePoint, unsigned int characterSize, bool bold, float outlineThickness=0) override
	Retrieve a glyph of the font.

float	getKerning (char32_t first, char32_t second, unsigned int characterSize, bool bold) override
	Returns the kerning offset of two glyphs.

float	getLineSpacing (unsigned int characterSize) override
	Returns the line spacing.

float	getFontHeight (unsigned int characterSize) override
	Returns the height required to render a line of text.

float	getAscent (unsigned int characterSize) override
	Returns the maximum height of a glyph above the baseline.

float	getDescent (unsigned int characterSize) override
	Returns the maximum height of a glyph below the baseline.

float	getUnderlinePosition (unsigned int characterSize) override
	Get the position of the underline.

float	getUnderlineThickness (unsigned int characterSize) override
	Get the thickness of the underline.

std::shared_ptr< BackendTexture >	getTexture (unsigned int characterSize, unsigned int &textureVersion) override
	Returns the texture that is used to store glyphs of the given character size.

Vector2u	getTextureSize (unsigned int characterSize) override
	Returns the size of the texture that is used to store glyphs of the given character size.

void	setSmooth (bool smooth) override
	Enable or disable the smooth filter.

void	setFontScale (float scale) override

bool	loadFromMemory (const void *data, std::size_t sizeInBytes)
	Loads a font from memory.

Public Member Functions inherited from tgui::BackendFont
	BackendFont ()
	Default constructor.

	BackendFont (const BackendFont &)
	Copy constructor.

	BackendFont (BackendFont &&other) noexcept
	Move constructor.

virtual	~BackendFont ()
	Virtual destructor.

BackendFont &	operator= (const BackendFont &other)
	Copy assignment operator.

BackendFont &	operator= (BackendFont &&other) noexcept
	Move assignment operator.

virtual bool	loadFromFile (const String &filename)
	Loads a font from a file.

bool	loadFromMemory (const void *data, std::size_t sizeInBytes)
	Loads a font from memory.

bool	isSmooth () const
	Tell whether the smooth filter is enabled or not.

float	getFontScale () const
	Returns the scale at which glyphs are rendered.

Protected Member Functions
Glyph	loadGlyph (char32_t codePoint, unsigned int characterSize, bool bold, float outlineThickness)

Glyph	getInternalGlyph (char32_t codePoint, unsigned int characterSize, bool bold, float outlineThickness)

UIntRect	findAvailableGlyphRect (unsigned int width, unsigned int height)

bool	setCurrentSize (unsigned int characterSize)

void	cleanup ()

Protected Member Functions inherited from tgui::BackendFont
std::uint64_t	constructGlyphKey (char32_t codePoint, unsigned int characterSize, bool bold, float outlineThickness) const
	Creates a key for each unique character to render.

Protected Attributes
FT_Library	m_library = nullptr

FT_Face	m_face = nullptr

FT_Stroker	m_stroker = nullptr

std::unordered_map< unsigned int, float >	m_cachedLineSpacing

std::unordered_map< unsigned int, float >	m_cachedFontHeights

std::unordered_map< unsigned int, float >	m_cachedAscents

std::unordered_map< unsigned int, float >	m_cachedDescents

std::unordered_map< std::uint64_t, Glyph >	m_glyphs

unsigned int	m_nextRow = 3
	Y position of the next new row in the texture (first 2 rows contain pixels for underlining)

std::vector< Row >	m_rows

std::unique_ptr< std::uint8_t[]>	m_fileContents

std::unique_ptr< std::uint8_t[]>	m_pixels

std::shared_ptr< BackendTexture >	m_texture

unsigned int	m_textureSize = 0

unsigned int	m_textureVersion = 0

Protected Attributes inherited from tgui::BackendFont
bool	m_isSmooth = true

float	m_fontScale = 1

Detailed Description

Font implementations that uses FreeType directly to load glyphs.

Member Function Documentation

◆ getAscent()

float tgui::BackendFontFreetype::getAscent ( unsigned int characterSize )

nodiscardoverridevirtual

Returns the maximum height of a glyph above the baseline.

Parameters

characterSize Size of the characters

Returns: Ascent of the font

Implements tgui::BackendFont.

◆ getDescent()

float tgui::BackendFontFreetype::getDescent ( unsigned int characterSize )

nodiscardoverridevirtual

Returns the maximum height of a glyph below the baseline.

Parameters

characterSize Size of the characters

Returns: Descent of the font

Implements tgui::BackendFont.

◆ getFontHeight()

float tgui::BackendFontFreetype::getFontHeight ( unsigned int characterSize )

nodiscardoverridevirtual

Returns the height required to render a line of text.

Parameters

characterSize Size of the characters

Returns: Sum of font ascent and descent

Implements tgui::BackendFont.

◆ getGlyph()

FontGlyph tgui::BackendFontFreetype::getGlyph	(	char32_t	codePoint,
		unsigned int	characterSize,
		bool	bold,
		float	outlineThickness = 0 )

nodiscardoverridevirtual

Retrieve a glyph of the font.

If the font is a bitmap font, not all character sizes might be available. If the glyph is not available at the requested size, an empty glyph is returned.

Parameters

codePoint	Unicode code point of the character to get
characterSize	Reference character size
bold	Retrieve the bold version or the regular one?
outlineThickness	Thickness of outline (when != 0 the glyph will not be filled)

Returns: The glyph corresponding to codePoint and characterSize

Implements tgui::BackendFont.

◆ getKerning()

float tgui::BackendFontFreetype::getKerning	(	char32_t	first,
		char32_t	second,
		unsigned int	characterSize,
		bool	bold )

nodiscardoverridevirtual

Returns the kerning offset of two glyphs.

The kerning is an extra offset (negative) to apply between two glyphs when rendering them, to make the pair look more "natural". For example, the pair "AV" have a special kerning to make them closer than other characters. Most of the glyphs pairs have a kerning offset of zero, though.

Parameters

first	Unicode code point of the first character
second	Unicode code point of the second character
characterSize	Size of the characters
bold	Are the glyphs bold or regular?

Returns: Kerning value for first and second, in pixels

Implements tgui::BackendFont.

◆ getLineSpacing()

float tgui::BackendFontFreetype::getLineSpacing ( unsigned int characterSize )

nodiscardoverridevirtual

Returns the line spacing.

Line spacing is the vertical offset to apply between two consecutive lines of text.

Parameters

characterSize Size of the characters

Returns: Line spacing, in pixels

Implements tgui::BackendFont.

◆ getTexture()

std::shared_ptr< BackendTexture > tgui::BackendFontFreetype::getTexture	(	unsigned int	characterSize,
		unsigned int &	textureVersion )

nodiscardoverridevirtual

Returns the texture that is used to store glyphs of the given character size.

Parameters

characterSize	Size of the characters that should be part of the texture
textureVersion	Counter that is incremented each time the texture is changed, returned by this function

Returns: Texture to render text glyphs with

Implements tgui::BackendFont.

◆ getTextureSize()

Vector2u tgui::BackendFontFreetype::getTextureSize ( unsigned int characterSize )

nodiscardoverridevirtual

Returns the size of the texture that is used to store glyphs of the given character size.

Parameters

characterSize Size of the characters that should be part of the texture

Returns: Size of the texture that holds the glyphs

Implements tgui::BackendFont.

◆ getUnderlinePosition()

float tgui::BackendFontFreetype::getUnderlinePosition ( unsigned int characterSize )

nodiscardoverridevirtual

Get the position of the underline.

Underline position is the vertical offset to apply between the baseline and the underline.

Parameters

characterSize Reference character size

Returns: Underline position, in pixels

Implements tgui::BackendFont.

◆ getUnderlineThickness()

float tgui::BackendFontFreetype::getUnderlineThickness ( unsigned int characterSize )

nodiscardoverridevirtual

Get the thickness of the underline.

Underline thickness is the vertical size of the underline.

Parameters

characterSize Reference character size

Returns: Underline thickness, in pixels

Implements tgui::BackendFont.

◆ hasGlyph()

bool tgui::BackendFontFreetype::hasGlyph ( char32_t codePoint ) const

nodiscardoverridevirtual

Returns whether a font contains a certain glyph.

Parameters

codePoint Character to check

Returns: Does the font contain this character?

Implements tgui::BackendFont.

◆ loadFromMemory() [1/2]

bool tgui::BackendFont::loadFromMemory	(	const void *	data,
		std::size_t	sizeInBytes )

Loads a font from memory.

Parameters

data	Pointer to the file data in memory
sizeInBytes	Size of the data to load, in bytes

Returns: True if the font was loaded successfully, false otherwise

This function makes a copy of the data. Use the overload with a unique_ptr when possible to move instead of copy.

◆ loadFromMemory() [2/2]

bool tgui::BackendFontFreetype::loadFromMemory	(	std::unique_ptr< std::uint8_t[]>	data,
		std::size_t	sizeInBytes )

overridevirtual

Loads a font from memory.

Parameters

data	Moved pointer to the file data in memory
sizeInBytes	Size of the data to load, in bytes

Returns: True if the font was loaded successfully, false otherwise

Implements tgui::BackendFont.

◆ setFontScale()

void tgui::BackendFontFreetype::setFontScale ( float scale )

overridevirtual

Reimplemented from tgui::BackendFont.

◆ setSmooth()

void tgui::BackendFontFreetype::setSmooth ( bool smooth )

overridevirtual

Enable or disable the smooth filter.

When the filter is activated, the font appears smoother so that pixels are less noticeable. However if you want the font to look exactly the same as its source file then you should disable it. The smooth filter is enabled by default.

Parameters

smooth True to enable smoothing, false to disable it

Reimplemented from tgui::BackendFont.

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

include/TGUI/Backend/Font/FreeType/BackendFontFreeType.hpp

TGUI

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ getAscent()

◆ getDescent()

◆ getFontHeight()

◆ getGlyph()

◆ getKerning()

◆ getLineSpacing()

◆ getTexture()

◆ getTextureSize()

◆ getUnderlinePosition()

◆ getUnderlineThickness()

◆ hasGlyph()

◆ loadFromMemory() [1/2]

◆ loadFromMemory() [2/2]

◆ setFontScale()

◆ setSmooth()