Struct kas::text::raster::Config

pub struct Config { /* private fields */ }

Raster configuration

Implementations

impl Config

pub fn new( mode: u8, scale_steps: u8, subpixel_threshold: u8, subpixel_steps: u8 ) -> Config

Construct configuration

For large glyphs the effects of configuration will be mostly unnoticeable but for small glyphs effects are more significant. The defaults will usually be a good choice. Results may depend on the font used.

The mode parameter selects rendering mode (though depending on crate features, not all options will be available):

• mode == 0 (default): use ab_glyph for rastering
• mode == 1: use ab_glyph and align glyphs to side bearings
• mode == 2: use fontdue for rastering

Fonts sizes, in pixels per Em, are rounded to a multiple of 1 / scale_steps. The default is scale_steps == 4.

For font sizes (in pixels per Em) less than subpixel_threshold, sub-pixel positioning is enabled with subpixel_steps (supporting between 1 and 16 steps). Sub-pixel positioning allows better glyph spacing for small fonts potentially at the cost of minor blurring (though blurring may be present in any case), and makes words drawn with very small font sizes more faithfully represent scaled versions drawn with larger fonts.

Subjectively, readability and apparent quality is better up to around dpem=18 (~13.5pt), thus we recommend subpixel_threshold == 18 and subpixel_steps == 5.

Trait Implementations

impl Debug for Config

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

Formats the value using the given formatter.

impl Default for Config

fn default() -> Config

Returns the “default value” for a type.

impl PartialEq for Config

fn eq(&self, other: &Config) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Config