Struct femtovg::TextContext

pub struct TextContext(/* private fields */);

TextContext provides functionality for text processing in femtovg. You can add fonts using the Self::add_font_file(), Self::add_font_mem() and Self::add_font_dir() functions. For each registered font a FontId is returned.

The FontId can be supplied to crate::Paint along with additional parameters such as the font size.

The paint is needed when using TextContext’s measurement functions such as Self::measure_text().

Note that the measurements are done entirely with the supplied sizes in the paint parameter. If you need measurements that take a crate::Canvas’s transform or dpi into account (see crate::Canvas::set_size()), you need to use the measurement functions on the canvas.

Implementations

impl TextContext

pub fn add_font_dir<T: AsRef<FilePath>>( &self, path: T ) -> Result<Vec<FontId>, ErrorKind>

Registers all .ttf files from a directory with this text context. If successful, the font ids of all registered fonts are returned.

pub fn add_font_file<T: AsRef<FilePath>>( &self, path: T ) -> Result<FontId, ErrorKind>

Registers the .ttf file from the specified path with this text context. If successful, the font id is returned.

pub fn add_font_mem(&self, data: &[u8]) -> Result<FontId, ErrorKind>

Registers the in-memory representation of a TrueType font pointed to by the data parameter with this text context. If successful, the font id is returned.

pub fn add_shared_font_with_index<T: AsRef<[u8]> + 'static>( &self, data: T, face_index: u32 ) -> Result<FontId, ErrorKind>

Registers the in-memory representation of a TrueType font pointed to by the shared data parameter with this text context. If successful, the font id is returned. The face_index specifies the face index if the font data is a true type font collection. For plain true type fonts, use 0 as index.

pub fn measure_text<S: AsRef<str>>( &self, x: f32, y: f32, text: S, paint: &Paint ) -> Result<TextMetrics, ErrorKind>

Returns information on how the provided text will be drawn with the specified paint.

pub fn break_text<S: AsRef<str>>( &self, max_width: f32, text: S, paint: &Paint ) -> Result<usize, ErrorKind>

Returns the maximum index-th byte of text that will fit inside max_width.

The retuned index will always lie at the start and/or end of a UTF-8 code point sequence or at the start or end of the text

pub fn break_text_vec<S: AsRef<str>>( &self, max_width: f32, text: S, paint: &Paint ) -> Result<Vec<Range<usize>>, ErrorKind>

Returnes a list of ranges representing each line of text that will fit inside max_width

pub fn measure_font(&self, paint: &Paint) -> Result<FontMetrics, ErrorKind>

Returns font metrics for a particular Paint.

pub fn resize_shaping_run_cache(&self, capacity: NonZeroUsize)

Adjusts the capacity of the shaping run cache. This is a cache for measurements of whole strings.

pub fn resize_shaped_words_cache(&self, capacity: NonZeroUsize)

Adjusts the capacity of the shaped words cache. This is a cache for measurements of individual words. Words are separated by UAX#29 word boundaries.

Trait Implementations

impl Clone for TextContext

fn clone(&self) -> TextContext

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Default for TextContext

fn default() -> TextContext

Returns the “default value” for a type.