Base class for font implementations that depend on the backend. More...

#include <TGUI/Backend/Font/BackendFont.hpp>

Inheritance diagram for tgui::BackendFont:

Public Member Functions
	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.

virtual bool	loadFromMemory (std::unique_ptr< std::uint8_t[]> data, std::size_t sizeInBytes)=0
	Loads a font from memory.

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

virtual TGUI_NODISCARD bool	hasGlyph (char32_t codePoint) const =0
	Returns whether a font contains a certain glyph.

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

virtual TGUI_NODISCARD float	getKerning (char32_t first, char32_t second, unsigned int characterSize, bool bold)=0
	Returns the kerning offset of two glyphs.

virtual TGUI_NODISCARD float	getLineSpacing (unsigned int characterSize)=0
	Returns the line spacing.

virtual TGUI_NODISCARD float	getFontHeight (unsigned int characterSize)=0
	Returns the height required to render a line of text.

virtual TGUI_NODISCARD float	getAscent (unsigned int characterSize)=0
	Returns the maximum height of a glyph above the baseline.

virtual TGUI_NODISCARD float	getDescent (unsigned int characterSize)=0
	Returns the maximum height of a glyph below the baseline.

virtual TGUI_NODISCARD float	getUnderlinePosition (unsigned int characterSize)=0
	Get the position of the underline.

virtual TGUI_NODISCARD float	getUnderlineThickness (unsigned int characterSize)=0
	Get the thickness of the underline.

virtual TGUI_NODISCARD std::shared_ptr< BackendTexture >	getTexture (unsigned int characterSize, unsigned int &textureVersion)=0
	Returns the texture that is used to store glyphs of the given character size.

virtual TGUI_NODISCARD Vector2u	getTextureSize (unsigned int characterSize)=0
	Returns the size of the texture that is used to store glyphs of the given character size.

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

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

virtual void	setFontScale (float scale)

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

Protected Member Functions
TGUI_NODISCARD 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
bool	m_isSmooth = true

float	m_fontScale = 1

Detailed Description

Base class for font implementations that depend on the backend.

Member Function Documentation

◆ constructGlyphKey()

TGUI_NODISCARD std::uint64_t tgui::BackendFont::constructGlyphKey	(	char32_t	codePoint,
		unsigned int	characterSize,
		bool	bold,
		float	outlineThickness ) const

protected

Creates a key for each unique character to render.

Parameters

codePoint	Unicode code of the character
characterSize	Reference character size
bold	Whether the character has to be rendered with a bold font
outlineThickness	Thickness of the outline to draw around the character (0 means no outline)

Returns: Id that is specific to the provided parameters

Calling this function with the same parameters results in the same id, while other parameters result in another id.

◆ getAscent()

virtual TGUI_NODISCARD float tgui::BackendFont::getAscent ( unsigned int characterSize )

pure virtual

Returns the maximum height of a glyph above the baseline.

Parameters

characterSize Size of the characters

Returns: Ascent of the font

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getDescent()

virtual TGUI_NODISCARD float tgui::BackendFont::getDescent ( unsigned int characterSize )

pure virtual

Returns the maximum height of a glyph below the baseline.

Parameters

characterSize Size of the characters

Returns: Descent of the font

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getFontHeight()

virtual TGUI_NODISCARD float tgui::BackendFont::getFontHeight ( unsigned int characterSize )

pure virtual

Returns the height required to render a line of text.

Parameters

characterSize Size of the characters

Returns: Sum of font ascent and descent

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getFontScale()

TGUI_NODISCARD float tgui::BackendFont::getFontScale ( ) const

Returns the scale at which glyphs are rendered.

Text may be rendered blurry if the font scale doesn't match the ratio between the window size and gui view. Default scaling is 1. If the scale is set to 1.5 then a font with text size 20 would be internally rendered at 30px.

◆ getGlyph()

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

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getKerning()

virtual TGUI_NODISCARD float tgui::BackendFont::getKerning	(	char32_t	first,
		char32_t	second,
		unsigned int	characterSize,
		bool	bold )

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getLineSpacing()

virtual TGUI_NODISCARD float tgui::BackendFont::getLineSpacing ( unsigned int characterSize )

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getTexture()

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

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getTextureSize()

virtual TGUI_NODISCARD Vector2u tgui::BackendFont::getTextureSize ( unsigned int characterSize )

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getUnderlinePosition()

virtual TGUI_NODISCARD float tgui::BackendFont::getUnderlinePosition ( unsigned int characterSize )

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ getUnderlineThickness()

virtual TGUI_NODISCARD float tgui::BackendFont::getUnderlineThickness ( unsigned int characterSize )

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ hasGlyph()

virtual TGUI_NODISCARD bool tgui::BackendFont::hasGlyph ( char32_t codePoint ) const

pure virtual

Returns whether a font contains a certain glyph.

Parameters

codePoint Character to check

Returns: Does the font contain this character?

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ isSmooth()

TGUI_NODISCARD bool tgui::BackendFont::isSmooth ( ) const

Tell whether the smooth filter is enabled or not.

Returns: True if smoothing is enabled, false if it is disabled

See also: setSmooth

◆ loadFromFile()

virtual bool tgui::BackendFont::loadFromFile ( const String & filename )

virtual

Loads a font from a file.

Parameters

filename Filename of the font to load

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

◆ 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]

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

pure virtual

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

Implemented in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, tgui::BackendFontSFML, tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

◆ setSmooth()

virtual void tgui::BackendFont::setSmooth ( bool smooth )

virtual

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 in tgui::BackendFontFreetype, tgui::BackendFontRaylib, tgui::BackendFontSDLttf, and tgui::BackendFontSFML.

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

include/TGUI/Backend/Font/BackendFont.hpp

TGUI

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ constructGlyphKey()

◆ getAscent()

◆ getDescent()

◆ getFontHeight()

◆ getFontScale()

◆ getGlyph()

◆ getKerning()

◆ getLineSpacing()

◆ getTexture()

◆ getTextureSize()

◆ getUnderlinePosition()

◆ getUnderlineThickness()

◆ hasGlyph()

◆ isSmooth()

◆ loadFromFile()

◆ loadFromMemory() [1/2]

◆ loadFromMemory() [2/2]

◆ setSmooth()