A character font. More...

#include <gf/Font.h>

Public Member Functions
	Font ()
	Default constructor. More...

	~Font ()
	Destructor. More...

	Font (const Font &)=delete
	Deleted copy constructor. More...

Font &	operator= (const Font &)=delete
	Deleted copy assignement. More...

	Font (Font &&other)
	Move constructor. More...

Font &	operator= (Font &&other)
	Move assignement. More...

bool	loadFromFile (const Path &filename)
	Load the font from a file. More...

bool	loadFromStream (InputStream &stream)
	Load the font from a custom stream. More...

bool	loadFromMemory (const uint8_t *data, std::size_t length)
	Load the font from a file in memory. More...

const Glyph &	getGlyph (char32_t codepoint, unsigned characterSize, float outlineThickness=0.0f)
	Retrieve a glyph of the font. More...

float	getKerning (char32_t left, char32_t right, unsigned characterSize)
	Get the kerning offset of two glyphs. More...

float	getLineSpacing (unsigned characterSize)
	Get the line spacing. More...

const AlphaTexture *	getTexture (unsigned characterSize)
	Retrieve the texture containing the loaded glyphs of a certain size. More...

void	generateTexture (unsigned characterSize)
	Generate the texture for a given character size. More...

Detailed Description

A character font.

Fonts can be loaded from a file, from memory or from a custom stream, and supports the most common types of fonts. See the loadFromFile() function for the complete list of supported formats.

Once it is loaded, a gf::Font instance provides three types of information about the font:

Global metrics, such as the line spacing
Per-glyph metrics, such as bounding box or kerning
Pixel representation of glyphs

Fonts alone are not very useful: they hold the font data but cannot make anything useful of it. To do so you need to use the gf::Text class, which is able to properly output text with several options such as character size, style, color, position, rotation, etc.

This separation allows more flexibility and better performances: indeed a gf::Font is a heavy resource, and any operation on it is slow (often too slow for real-time applications). On the other side, a gf::Text is a lightweight object which can combine the glyphs data and metrics of a gf::Font to display any text on a render target.

Note that it is also possible to bind several gf::Text instances to the same gf::Font.

It is important to note that the gf::Text instance doesn't copy the font that it uses, it only keeps a reference to it. Thus, a gf::Font must not be destructed while it is used by a gf::Text (i.e. never write a function that uses a local gf::Font instance for creating a text).

Usage example:

// Declare a new font
gf::Font font;
// Load it from a file
if (!font.loadFromFile("arial.ttf"))
{
    // error...
}
// Create a text which uses our font
gf::Text text1;
text1.setString("Hello World!")
text1.setFont(font);
text1.setCharacterSize(30);
// Create another text using the same font, but with different parameters
gf::Text text2;
text2.setString("Goodbye world!");
text2.setFont(font);
text2.setCharacterSize(50);

Apart from loading font files, and passing them to instances of gf::Text, you should normally not have to deal directly with this class. However, it may be useful to access the font metrics or rasterized glyphs for advanced usage.

Constructor & Destructor Documentation

gf::Font::Font ( )

Default constructor.

This constructor defines an empty font.

gf::Font::~Font ( )

Destructor.

gf::Font::Font ( const Font & )

delete

Deleted copy constructor.

gf::Font::Font ( Font && other )

Move constructor.

Member Function Documentation

void gf::Font::generateTexture ( unsigned characterSize )

Generate the texture for a given character size.

After this call, the texture corresponding to the size is available through getTexture.

Parameters

characterSize Reference character size

const Glyph& gf::Font::getGlyph	(	char32_t	codepoint,
		unsigned	characterSize,
		float	outlineThickness = `0.0f`
	)

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
outlineThickness	Thickness of outline (when != 0 the glyph will not be filled)

Returns: The corresponding glyph

float gf::Font::getKerning	(	char32_t	left,
		char32_t	right,
		unsigned	characterSize
	)

Get 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

left	Unicode code point of the left character
right	Unicode code point of the right character
characterSize	Reference character size

Returns: Kerning value, in pixels

float gf::Font::getLineSpacing ( unsigned characterSize )

Get the line spacing.

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

Parameters

characterSize Reference character size

Returns: Line spacing, in pixels

const AlphaTexture* gf::Font::getTexture ( unsigned characterSize )

Retrieve the texture containing the loaded glyphs of a certain size.

The contents of the returned texture changes as more glyphs are requested, thus it is not very relevant. It is mainly used internally by gf::Text.

Parameters

characterSize Reference character size

Returns: Texture containing the glyphs of the requested size

bool gf::Font::loadFromFile ( const Path & filename )

Load the font from a file.

The supported font formats are: TrueType, Type 1, CFF, OpenType, SFNT, X11 PCF, Windows FNT, BDF, PFR and Type 42. Note that this function know nothing about the standard fonts installed on the user's system, thus you can't load them directly.

Warning: gf cannot preload all the font data in this function, so the file has to remain accessible until the gf::Font object loads a new font or is destroyed.

Parameters

filename Path of the font file to load

Returns: True if loading succeeded, false if it failed

See also: loadFromMemory(), loadFromStream()

bool gf::Font::loadFromMemory	(	const uint8_t *	data,
		std::size_t	length
	)

Load the font from a file in memory.

The supported font formats are: TrueType, Type 1, CFF, OpenType, SFNT, X11 PCF, Windows FNT, BDF, PFR and Type 42.

Warning: gf cannot preload all the font data in this function, so the stream has to remain accessible until the gf::Font object loads a new font or is destroyed.

Parameters

data	Pointer to the file data in memory
length	Length of the data to load, in bytes

Returns: True if loading succeeded, false if it failed

See also: loadFromFile(), loadFromStream()

bool gf::Font::loadFromStream ( InputStream & stream )

Load the font from a custom stream.

The supported font formats are: TrueType, Type 1, CFF, OpenType, SFNT, X11 PCF, Windows FNT, BDF, PFR and Type 42.

Warning: gf cannot preload all the font data in this function, so the stream has to remain accessible until the gf::Font object loads a new font or is destroyed.

Parameters

stream Source stream to read from

Returns: True if loading succeeded, false if it failed

See also: loadFromFile(), loadFromMemory()

Font& gf::Font::operator= ( const Font & )

delete

Deleted copy assignement.

Font& gf::Font::operator= ( Font && other )

Move assignement.

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation