Struct font_kit::loaders::freetype::Font

pub struct Font {
    freetype_face: FT_Face,
    font_data: Arc<Vec<u8>>,
}

A cross-platform loader that uses the FreeType library to load and rasterize fonts.

On macOS and Windows, the Cargo feature loader-freetype-default can be used to opt into this loader by default.

Fields

freetype_face: FT_Face

font_data: Arc<Vec<u8>>

Implementations

impl Font

pub fn from_bytes( font_data: Arc<Vec<u8>>, font_index: u32, ) -> Result<Font, FontLoadingError>

Loads a font from raw font data (the contents of a .ttf/.otf/etc. file).

If the data represents a collection (.ttc/.otc/etc.), font_index specifies the index of the font to load from it. If the data represents a single font, pass 0 for font_index.

pub fn from_file( file: &mut File, font_index: u32, ) -> Result<Font, FontLoadingError>

Loads a font from a .ttf/.otf/etc. file.

If the file is a collection (.ttc/.otc/etc.), font_index specifies the index of the font to load from it. If the file represents a single font, pass 0 for font_index.

pub fn from_path<P>(path: P, font_index: u32) -> Result<Font, FontLoadingError>

where P: AsRef<Path>,

Loads a font from the path to a .ttf/.otf/etc. file.

If the file is a collection (.ttc/.otc/etc.), font_index specifies the index of the font to load from it. If the file represents a single font, pass 0 for font_index.

pub unsafe fn from_native_font(freetype_face: NativeFont) -> Font

Creates a font from a native API handle.

pub fn from_handle(handle: &Handle) -> Result<Self, FontLoadingError>

Loads the font pointed to by a handle.

pub fn analyze_bytes( font_data: Arc<Vec<u8>>, ) -> Result<FileType, FontLoadingError>

Determines whether a blob of raw font data represents a supported font, and, if so, what type of font it is.

pub fn analyze_file(file: &mut File) -> Result<FileType, FontLoadingError>

Determines whether a file represents a supported font, and, if so, what type of font it is.

pub fn analyze_path<P>(path: P) -> Result<FileType, FontLoadingError>

where P: AsRef<Path>,

Determines whether a path points to a supported font, and, if so, what type of font it is.

pub fn native_font(&self) -> NativeFont

Returns the wrapped native font handle.

This function increments the reference count of the FreeType face before returning it. Therefore, it is the caller’s responsibility to free it with FT_Done_Face.

pub fn postscript_name(&self) -> Option<String>

Returns the PostScript name of the font. This should be globally unique.

pub fn full_name(&self) -> String

Returns the full name of the font (also known as “display name” on macOS).

pub fn family_name(&self) -> String

Returns the name of the font family.

pub fn is_monospace(&self) -> bool

Returns true if and only if the font is monospace (fixed-width).

pub fn properties(&self) -> Properties

Returns the values of various font properties, corresponding to those defined in CSS.

pub fn glyph_for_char(&self, character: char) -> Option<u32>

Returns the usual glyph ID for a Unicode character.

Be careful with this function; typographically correct character-to-glyph mapping must be done using a shaper such as HarfBuzz. This function is only useful for best-effort simple use cases like “what does character X look like on its own”.

pub fn glyph_by_name(&self, name: &str) -> Option<u32>

Returns the glyph ID for the specified glyph name.

pub fn glyph_count(&self) -> u32

Returns the number of glyphs in the font.

Glyph IDs range from 0 inclusive to this value exclusive.

pub fn outline<S>( &self, glyph_id: u32, hinting: HintingOptions, sink: &mut S, ) -> Result<(), GlyphLoadingError>

where S: OutlineSink,

Sends the vector path for a glyph to a path builder.

If hinting_mode is not None, this function performs grid-fitting as requested before sending the hinding outlines to the builder.

TODO(pcwalton): What should we do for bitmap glyphs?

pub fn typographic_bounds( &self, glyph_id: u32, ) -> Result<RectF, GlyphLoadingError>

Returns the boundaries of a glyph in font units.

pub fn advance(&self, glyph_id: u32) -> Result<Vector2F, GlyphLoadingError>

Returns the distance from the origin of the glyph with the given ID to the next, in font units.

pub fn origin(&self, _: u32) -> Result<Vector2F, GlyphLoadingError>

Returns the amount that the given glyph should be displaced from the origin.

FIXME(pcwalton): This always returns zero on FreeType.

pub fn metrics(&self) -> Metrics

Retrieves various metrics that apply to the entire font.

pub fn supports_hinting_options( &self, hinting_options: HintingOptions, for_rasterization: bool, ) -> bool

Returns true if and only if the font loader can perform hinting in the requested way.

Some APIs support only rasterizing glyphs with hinting, not retrieving hinted outlines. If for_rasterization is false, this function returns true if and only if the loader supports retrieval of hinted outlines. If for_rasterization is true, this function returns true if and only if the loader supports rasterizing hinted glyphs.

fn get_type_1_or_sfnt_name( &self, type_1_id: u32, sfnt_id: u16, ) -> Option<String>

fn get_os2_table(&self) -> Option<*const TT_OS2>

pub fn raster_bounds( &self, glyph_id: u32, point_size: f32, transform: Transform2F, hinting_options: HintingOptions, rasterization_options: RasterizationOptions, ) -> Result<RectI, GlyphLoadingError>

Returns the pixel boundaries that the glyph will take up when rendered using this loader’s rasterizer at the given size and origin.

pub fn rasterize_glyph( &self, canvas: &mut Canvas, glyph_id: u32, point_size: f32, transform: Transform2F, hinting_options: HintingOptions, rasterization_options: RasterizationOptions, ) -> Result<(), GlyphLoadingError>

Rasterizes a glyph to a canvas with the given size and origin.

Format conversion will be performed if the canvas format does not match the rasterization options. For example, if bilevel (black and white) rendering is requested to an RGBA surface, this function will automatically convert the 1-bit raster image to the 32-bit format of the canvas. Note that this may result in a performance penalty, depending on the loader.

If hinting_options is not None, the requested grid fitting is performed.

fn hinting_and_rasterization_options_to_load_flags( &self, hinting: HintingOptions, rasterization: RasterizationOptions, ) -> i32

pub fn handle(&self) -> Option<Handle>

Returns a handle to this font, if possible.

This is useful if you want to open the font with a different loader.

pub fn copy_font_data(&self) -> Option<Arc<Vec<u8>>>

Attempts to return the raw font data (contents of the font file).

If this font is a member of a collection, this function returns the data for the entire collection.

fn get_fallbacks(&self, text: &str, _locale: &str) -> FallbackResult<Font>

Get font fallback results for the given text and locale.

Note: this is currently just a stub implementation, a proper implementation would likely use FontConfig, at least on Linux. It’s not clear what a FreeType loader with a non-FreeType source should do.

pub fn load_font_table(&self, table_tag: u32) -> Option<Box<[u8]>>

Returns the raw contents of the OpenType table with the given tag.

Tags are four-character codes. A list of tags can be found in the OpenType specification.

Trait Implementations

impl Clone for Font

fn clone(&self) -> Font

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Font

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Drop for Font

fn drop(&mut self)

Executes the destructor for this type.

impl Loader for Font

type NativeFont = *mut FT_FaceRec

The handle that the API natively uses to represent a font.

fn from_bytes( font_data: Arc<Vec<u8>>, font_index: u32, ) -> Result<Self, FontLoadingError>

Loads a font from raw font data (the contents of a .ttf/.otf/etc. file).

fn from_file(file: &mut File, font_index: u32) -> Result<Font, FontLoadingError>

Loads a font from a .ttf/.otf/etc. file.

fn analyze_bytes(font_data: Arc<Vec<u8>>) -> Result<FileType, FontLoadingError>

Determines whether a blob of raw font data represents a supported font, and, if so, what type of font it is.

fn analyze_file(file: &mut File) -> Result<FileType, FontLoadingError>

Determines whether a file represents a supported font, and, if so, what type of font it is.

fn native_font(&self) -> Self::NativeFont

Returns the wrapped native font handle.

unsafe fn from_native_font(native_font: Self::NativeFont) -> Self

Creates a font from a native API handle.

fn postscript_name(&self) -> Option<String>

Returns the PostScript name of the font. This should be globally unique.

fn full_name(&self) -> String

Returns the full name of the font (also known as “display name” on macOS).

fn family_name(&self) -> String

Returns the name of the font family.

fn is_monospace(&self) -> bool

Returns true if and only if the font is monospace (fixed-width).

fn properties(&self) -> Properties

Returns the values of various font properties, corresponding to those defined in CSS.

fn glyph_for_char(&self, character: char) -> Option<u32>

Returns the usual glyph ID for a Unicode character.

fn glyph_by_name(&self, name: &str) -> Option<u32>

Returns the glyph ID for the specified glyph name.

fn glyph_count(&self) -> u32

Returns the number of glyphs in the font.

fn outline<S>( &self, glyph_id: u32, hinting_mode: HintingOptions, sink: &mut S, ) -> Result<(), GlyphLoadingError>

where S: OutlineSink,

Sends the vector path for a glyph to a sink.

fn typographic_bounds(&self, glyph_id: u32) -> Result<RectF, GlyphLoadingError>

Returns the boundaries of a glyph in font units. The origin of the coordinate space is at the bottom left.

fn advance(&self, glyph_id: u32) -> Result<Vector2F, GlyphLoadingError>

Returns the distance from the origin of the glyph with the given ID to the next, in font units.

fn origin(&self, origin: u32) -> Result<Vector2F, GlyphLoadingError>

Returns the amount that the given glyph should be displaced from the origin.

fn metrics(&self) -> Metrics

Retrieves various metrics that apply to the entire font.

fn copy_font_data(&self) -> Option<Arc<Vec<u8>>>

Attempts to return the raw font data (contents of the font file).

fn supports_hinting_options( &self, hinting_options: HintingOptions, for_rasterization: bool, ) -> bool

Returns true if and only if the font loader can perform hinting in the requested way.

fn rasterize_glyph( &self, canvas: &mut Canvas, glyph_id: u32, point_size: f32, transform: Transform2F, hinting_options: HintingOptions, rasterization_options: RasterizationOptions, ) -> Result<(), GlyphLoadingError>

Rasterizes a glyph to a canvas with the given size and transform.

fn get_fallbacks(&self, text: &str, locale: &str) -> FallbackResult<Self>

Get font fallback results for the given text and locale.

fn load_font_table(&self, table_tag: u32) -> Option<Box<[u8]>>

Returns the OpenType font table with the given tag, if the table exists.

fn from_path<P>(path: P, font_index: u32) -> Result<Self, FontLoadingError>

where P: AsRef<Path>,

Loads a font from the path to a .ttf/.otf/etc. file.

fn from_handle(handle: &Handle) -> Result<Self, FontLoadingError>

Loads the font pointed to by a handle.

fn analyze_path<P>(path: P) -> Result<FileType, FontLoadingError>

where P: AsRef<Path>,

Determines whether a path points to a supported font, and, if so, what type of font it is.

fn handle(&self) -> Option<Handle>

Returns a handle to this font, if possible.

fn raster_bounds( &self, glyph_id: u32, point_size: f32, transform: Transform2F, _: HintingOptions, _: RasterizationOptions, ) -> Result<RectI, GlyphLoadingError>

Returns the pixel boundaries that the glyph will take up when rendered using this loader’s rasterizer at the given point_size and transform. The origin of the coordinate space is at the top left.