Struct ttf_parser::Face
source · [−]pub struct Face<'a> { /* private fields */ }Expand description
A font face.
Provides a high-level API for working with TrueType fonts.
If you’re not familiar with how TrueType works internally, you should use this type.
If you do know and want a bit more low-level access - checkout FaceTables.
Note that Face doesn’t own the font data and doesn’t allocate anything in heap.
Therefore you cannot “store” it. The idea is that you should parse the Face
when needed, get required data and forget about it.
That’s why the initial parsing is highly optimized and should not become a bottleneck.
If you still want to store Face - checkout
owned_ttf_parser. Requires unsafe.
While Face is technically copyable, we disallow it because it’s almost 2KB big.
Implementations
sourceimpl<'a> Face<'a>
impl<'a> Face<'a>
sourcepub fn from_slice(data: &'a [u8], index: u32) -> Result<Self, FaceParsingError>
pub fn from_slice(data: &'a [u8], index: u32) -> Result<Self, FaceParsingError>
Creates a new Face from a raw data.
index indicates the specific font face in a font collection.
Use fonts_in_collection to get the total number of font faces.
Set to 0 if unsure.
This method will do some parsing and sanitization, but in general can be considered free. No significant performance overhead.
Required tables: head, hhea and maxp.
If an optional table has invalid data it will be skipped.
sourcepub fn from_raw_tables(
raw_tables: RawFaceTables<'a>
) -> Result<Self, FaceParsingError>
pub fn from_raw_tables(
raw_tables: RawFaceTables<'a>
) -> Result<Self, FaceParsingError>
Creates a new Face from provided RawFaceTables.
sourcepub fn tables(&self) -> &FaceTables<'a>
pub fn tables(&self) -> &FaceTables<'a>
Returns low-level face tables.
sourcepub fn table_data(&self, tag: Tag) -> Option<&'a [u8]>
pub fn table_data(&self, tag: Tag) -> Option<&'a [u8]>
Returns the raw data of a selected table.
Useful if you want to parse the data manually.
Available only for faces created using Face::from_slice().
sourcepub fn names(&self) -> Names<'a>
pub fn names(&self) -> Names<'a>
Returns a list of names.
Contains face name and other strings.
sourcepub fn is_regular(&self) -> bool
pub fn is_regular(&self) -> bool
Checks that face is marked as Regular.
Returns false when OS/2 table is not present.
sourcepub fn is_italic(&self) -> bool
pub fn is_italic(&self) -> bool
Checks that face is marked as Italic.
Returns false when OS/2 table is not present.
sourcepub fn is_bold(&self) -> bool
pub fn is_bold(&self) -> bool
Checks that face is marked as Bold.
Returns false when OS/2 table is not present.
sourcepub fn is_oblique(&self) -> bool
pub fn is_oblique(&self) -> bool
Checks that face is marked as Oblique.
Returns false when OS/2 table is not present or when its version is < 4.
sourcepub fn is_monospaced(&self) -> bool
pub fn is_monospaced(&self) -> bool
Checks that face is marked as Monospaced.
Returns false when post table is not present.
sourcepub fn is_variable(&self) -> bool
pub fn is_variable(&self) -> bool
Checks that face is variable.
Simply checks the presence of a fvar table.
sourcepub fn weight(&self) -> Weight
pub fn weight(&self) -> Weight
Returns face’s weight.
Returns Weight::Normal when OS/2 table is not present.
sourcepub fn width(&self) -> Width
pub fn width(&self) -> Width
Returns face’s width.
Returns Width::Normal when OS/2 table is not present or when value is invalid.
sourcepub fn italic_angle(&self) -> Option<f32>
pub fn italic_angle(&self) -> Option<f32>
Returns face’s italic angle.
Returns None when post table is not present.
sourcepub fn ascender(&self) -> i16
pub fn ascender(&self) -> i16
Returns a horizontal face ascender.
This method is affected by variation axes.
sourcepub fn descender(&self) -> i16
pub fn descender(&self) -> i16
Returns a horizontal face descender.
This method is affected by variation axes.
sourcepub fn line_gap(&self) -> i16
pub fn line_gap(&self) -> i16
Returns a horizontal face line gap.
This method is affected by variation axes.
sourcepub fn typographic_ascender(&self) -> Option<i16>
pub fn typographic_ascender(&self) -> Option<i16>
Returns a horizontal typographic face ascender.
Prefer Face::ascender unless you explicitly want this. This is a more
low-level alternative.
This method is affected by variation axes.
Returns None when OS/2 table is not present.
sourcepub fn typographic_descender(&self) -> Option<i16>
pub fn typographic_descender(&self) -> Option<i16>
Returns a horizontal typographic face descender.
Prefer Face::descender unless you explicitly want this. This is a more
low-level alternative.
This method is affected by variation axes.
Returns None when OS/2 table is not present.
sourcepub fn typographic_line_gap(&self) -> Option<i16>
pub fn typographic_line_gap(&self) -> Option<i16>
Returns a horizontal typographic face line gap.
Prefer Face::line_gap unless you explicitly want this. This is a more
low-level alternative.
This method is affected by variation axes.
Returns None when OS/2 table is not present.
sourcepub fn vertical_ascender(&self) -> Option<i16>
pub fn vertical_ascender(&self) -> Option<i16>
Returns a vertical face ascender.
This method is affected by variation axes.
sourcepub fn vertical_descender(&self) -> Option<i16>
pub fn vertical_descender(&self) -> Option<i16>
Returns a vertical face descender.
This method is affected by variation axes.
sourcepub fn vertical_height(&self) -> Option<i16>
pub fn vertical_height(&self) -> Option<i16>
Returns a vertical face height.
This method is affected by variation axes.
sourcepub fn vertical_line_gap(&self) -> Option<i16>
pub fn vertical_line_gap(&self) -> Option<i16>
Returns a vertical face line gap.
This method is affected by variation axes.
sourcepub fn units_per_em(&self) -> u16
pub fn units_per_em(&self) -> u16
Returns face’s units per EM.
Guarantee to be in a 16..=16384 range.
sourcepub fn x_height(&self) -> Option<i16>
pub fn x_height(&self) -> Option<i16>
Returns face’s x height.
This method is affected by variation axes.
Returns None when OS/2 table is not present or when its version is < 2.
sourcepub fn capital_height(&self) -> Option<i16>
pub fn capital_height(&self) -> Option<i16>
Returns face’s capital height.
This method is affected by variation axes.
Returns None when OS/2 table is not present or when its version is < 2.
sourcepub fn underline_metrics(&self) -> Option<LineMetrics>
pub fn underline_metrics(&self) -> Option<LineMetrics>
Returns face’s underline metrics.
This method is affected by variation axes.
Returns None when post table is not present.
sourcepub fn strikeout_metrics(&self) -> Option<LineMetrics>
pub fn strikeout_metrics(&self) -> Option<LineMetrics>
Returns face’s strikeout metrics.
This method is affected by variation axes.
Returns None when OS/2 table is not present.
sourcepub fn subscript_metrics(&self) -> Option<ScriptMetrics>
pub fn subscript_metrics(&self) -> Option<ScriptMetrics>
Returns face’s subscript metrics.
This method is affected by variation axes.
Returns None when OS/2 table is not present.
sourcepub fn superscript_metrics(&self) -> Option<ScriptMetrics>
pub fn superscript_metrics(&self) -> Option<ScriptMetrics>
Returns face’s superscript metrics.
This method is affected by variation axes.
Returns None when OS/2 table is not present.
sourcepub fn number_of_glyphs(&self) -> u16
pub fn number_of_glyphs(&self) -> u16
Returns a total number of glyphs in the face.
Never zero.
The value was already parsed, so this function doesn’t involve any parsing.
sourcepub fn glyph_index(&self, code_point: char) -> Option<GlyphId>
pub fn glyph_index(&self, code_point: char) -> Option<GlyphId>
Resolves a Glyph ID for a code point.
Returns None instead of 0 when glyph is not found.
All subtable formats except Mixed Coverage (8) are supported.
If you need a more low-level control, prefer Face::tables().cmap.
sourcepub fn glyph_variation_index(
&self,
code_point: char,
variation: char
) -> Option<GlyphId>
pub fn glyph_variation_index(
&self,
code_point: char,
variation: char
) -> Option<GlyphId>
Resolves a variation of a Glyph ID from two code points.
Implemented according to Unicode Variation Sequences.
Returns None instead of 0 when glyph is not found.
sourcepub fn glyph_hor_advance(&self, glyph_id: GlyphId) -> Option<u16>
pub fn glyph_hor_advance(&self, glyph_id: GlyphId) -> Option<u16>
Returns glyph’s horizontal advance.
This method is affected by variation axes.
sourcepub fn glyph_ver_advance(&self, glyph_id: GlyphId) -> Option<u16>
pub fn glyph_ver_advance(&self, glyph_id: GlyphId) -> Option<u16>
Returns glyph’s vertical advance.
This method is affected by variation axes.
sourcepub fn glyph_hor_side_bearing(&self, glyph_id: GlyphId) -> Option<i16>
pub fn glyph_hor_side_bearing(&self, glyph_id: GlyphId) -> Option<i16>
Returns glyph’s horizontal side bearing.
This method is affected by variation axes.
sourcepub fn glyph_ver_side_bearing(&self, glyph_id: GlyphId) -> Option<i16>
pub fn glyph_ver_side_bearing(&self, glyph_id: GlyphId) -> Option<i16>
Returns glyph’s vertical side bearing.
This method is affected by variation axes.
sourcepub fn glyph_y_origin(&self, glyph_id: GlyphId) -> Option<i16>
pub fn glyph_y_origin(&self, glyph_id: GlyphId) -> Option<i16>
Returns glyph’s vertical origin according to Vertical Origin Table.
sourcepub fn glyph_name(&self, glyph_id: GlyphId) -> Option<&str>
pub fn glyph_name(&self, glyph_id: GlyphId) -> Option<&str>
Returns glyph’s name.
Uses the post and CFF tables as sources.
Returns None when no name is associated with a glyph.
sourcepub fn outline_glyph(
&self,
glyph_id: GlyphId,
builder: &mut dyn OutlineBuilder
) -> Option<Rect>
pub fn outline_glyph(
&self,
glyph_id: GlyphId,
builder: &mut dyn OutlineBuilder
) -> Option<Rect>
Outlines a glyph and returns its tight bounding box.
Warning: since ttf-parser is a pull parser,
OutlineBuilder will emit segments even when outline is partially malformed.
You must check outline_glyph() result before using
OutlineBuilder’s output.
gvar, glyf, CFF and CFF2 tables are supported.
And they will be accesses in this specific order.
This method is affected by variation axes.
Returns None when glyph has no outline or on error.
Example
use std::fmt::Write;
use ttf_parser;
struct Builder(String);
impl ttf_parser::OutlineBuilder for Builder {
fn move_to(&mut self, x: f32, y: f32) {
write!(&mut self.0, "M {} {} ", x, y).unwrap();
}
fn line_to(&mut self, x: f32, y: f32) {
write!(&mut self.0, "L {} {} ", x, y).unwrap();
}
fn quad_to(&mut self, x1: f32, y1: f32, x: f32, y: f32) {
write!(&mut self.0, "Q {} {} {} {} ", x1, y1, x, y).unwrap();
}
fn curve_to(&mut self, x1: f32, y1: f32, x2: f32, y2: f32, x: f32, y: f32) {
write!(&mut self.0, "C {} {} {} {} {} {} ", x1, y1, x2, y2, x, y).unwrap();
}
fn close(&mut self) {
write!(&mut self.0, "Z ").unwrap();
}
}
let data = std::fs::read("tests/fonts/demo.ttf").unwrap();
let face = ttf_parser::Face::from_slice(&data, 0).unwrap();
let mut builder = Builder(String::new());
let bbox = face.outline_glyph(ttf_parser::GlyphId(1), &mut builder).unwrap();
assert_eq!(builder.0, "M 173 267 L 369 267 L 270 587 L 173 267 Z M 6 0 L 224 656 \
L 320 656 L 541 0 L 452 0 L 390 200 L 151 200 L 85 0 L 6 0 Z ");
assert_eq!(bbox, ttf_parser::Rect { x_min: 6, y_min: 0, x_max: 541, y_max: 656 });sourcepub fn glyph_bounding_box(&self, glyph_id: GlyphId) -> Option<Rect>
pub fn glyph_bounding_box(&self, glyph_id: GlyphId) -> Option<Rect>
Returns a tight glyph bounding box.
This is just a shorthand for outline_glyph() since only the glyf table stores
a bounding box. We ignore glyf table bboxes because they can be malformed.
In case of CFF and variable fonts we have to actually outline
a glyph to find it’s bounding box.
When a glyph is defined by a raster or a vector image,
that can be obtained via glyph_image(),
the bounding box must be calculated manually and this method will return None.
Note: the returned bbox is not validated in any way. A font file can have a glyph bbox set to zero/negative width and/or height and this is perfectly ok. For calculated bboxes, zero width and/or height is also perfectly fine.
This method is affected by variation axes.
sourcepub fn global_bounding_box(&self) -> Rect
pub fn global_bounding_box(&self) -> Rect
Returns a bounding box that large enough to enclose any glyph from the face.
sourcepub fn glyph_raster_image(
&self,
glyph_id: GlyphId,
pixels_per_em: u16
) -> Option<RasterGlyphImage<'_>>
pub fn glyph_raster_image(
&self,
glyph_id: GlyphId,
pixels_per_em: u16
) -> Option<RasterGlyphImage<'_>>
Returns a reference to a glyph’s raster image.
A font can define a glyph using a raster or a vector image instead of a simple outline. Which is primarily used for emojis. This method should be used to access raster images.
pixels_per_em allows selecting a preferred image size. The chosen size will
be closer to an upper one. So when font has 64px and 96px images and pixels_per_em
is set to 72, 96px image will be returned.
To get the largest image simply use std::u16::MAX.
Note that this method will return an encoded image. It should be decoded by the caller. We don’t validate or preprocess it in any way.
Currently, only PNG images are supported.
Also, a font can contain both: images and outlines. So when this method returns None
you should also try outline_glyph() afterwards.
There are multiple ways an image can be stored in a TrueType font
and this method supports only sbix, CBLC+CBDT.
Font’s tables be accesses in this specific order.
sourcepub fn glyph_svg_image(&self, glyph_id: GlyphId) -> Option<&'a [u8]>
pub fn glyph_svg_image(&self, glyph_id: GlyphId) -> Option<&'a [u8]>
Returns a reference to a glyph’s SVG image.
A font can define a glyph using a raster or a vector image instead of a simple outline. Which is primarily used for emojis. This method should be used to access SVG images.
Note that this method will return just an SVG data. It should be rendered or even decompressed (in case of SVGZ) by the caller. We don’t validate or preprocess it in any way.
Also, a font can contain both: images and outlines. So when this method returns None
you should also try outline_glyph() afterwards.
sourcepub fn variation_axes(&self) -> LazyArray16<'a, VariationAxis>
pub fn variation_axes(&self) -> LazyArray16<'a, VariationAxis>
Returns an iterator over variation axes.
sourcepub fn set_variation(&mut self, axis: Tag, value: f32) -> Option<()>
pub fn set_variation(&mut self, axis: Tag, value: f32) -> Option<()>
Sets a variation axis coordinate.
This is the only mutable method in the library. We can simplify the API a lot by storing the variable coordinates in the face object itself.
Since coordinates are stored on the stack, we allow only 32 of them.
Returns None when face is not variable or doesn’t have such axis.
sourcepub fn variation_coordinates(&self) -> &[NormalizedCoordinate]
pub fn variation_coordinates(&self) -> &[NormalizedCoordinate]
Returns the current normalized variation coordinates.
sourcepub fn has_non_default_variation_coordinates(&self) -> bool
pub fn has_non_default_variation_coordinates(&self) -> bool
Checks that face has non-default variation coordinates.
Trait Implementations
Auto Trait Implementations
impl<'a> RefUnwindSafe for Face<'a>
impl<'a> Send for Face<'a>
impl<'a> Sync for Face<'a>
impl<'a> Unpin for Face<'a>
impl<'a> UnwindSafe for Face<'a>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more