Struct BitmapFont 

pub struct BitmapFont {
    pub glyph_width: u8,
    pub glyph_height: u8,
    /* private fields */
}

A 1-bit-per-pixel bitmap glyph font.

Copy because it is just a static reference plus three small integers.

Fields

glyph_width: u8

Width of each glyph in pixels (≤ 8 for single-byte rows).

glyph_height: u8

Height of each glyph in pixels; also bytes per glyph.

Implementations

impl BitmapFont

pub const fn new( data: &'static [u8], glyph_width: u8, glyph_height: u8, glyph_count: u16, ) -> Self

Constructs a bitmap font from a static byte slice.

data must contain exactly glyph_count * glyph_height bytes.

pub fn rows(&self, index: u8) -> &[u8]

Returns the row bytes for glyph index.

Each byte is one row; bit 7 (MSB) is the leftmost pixel.

Panics

Panics if index as u16 >= self.glyph_count.

pub fn glyph_pixels(&self, index: u8) -> impl Iterator<Item = (u8, u8)> + '_

Iterates the set (“on”) pixels of glyph index as (x, y) coordinates, row-major from the top: x in 0..glyph_width, y in 0..glyph_height.

This is the single place the 1-bit format’s MSB-first bit order lives – pixel x of a row is bit glyph_width - 1 - x of that row’s byte – so consumers (the GL atlas builder, the software rasterizer’s glyph blit) decode through it instead of each re-deriving the shift and risking disagreement. It is also the one seam that has to change for wider-than-8px glyphs (multi-byte rows, #164): today a row is a single byte (glyph_width <= 8), so its bits are read straight out of that byte.

Panics

Panics if index as u16 >= self.glyph_count (via rows).

pub const fn glyph_count(&self) -> u16

The total number of glyphs stored in this font.

Glyph indices 0..glyph_count() are valid arguments to rows. A GPU backend uses this to size its glyph atlas (one texture-array layer per glyph).

pub const fn char_to_index(&self, ch: char) -> u8

Maps a Unicode char to a glyph index in this font using the CP437 encoding, falling back to a solid-block glyph for unmapped characters.

pub const fn try_char_to_index(&self, ch: char) -> Option<u8>

Attempts to map a Unicode char to a glyph index in this font, returning None instead of substituting the solid-block fallback glyph on a miss.

A miss is either ch not being in the CP437 mapping table at all, or its mapped index falling outside this font’s glyph_count (e.g. a font built with fewer than 256 glyphs). FallbackFontChain::resolve uses this to keep trying further fonts in the chain rather than settling for char_to_index’s unconditional solid-block substitution.

Trait Implementations

impl Clone for BitmapFont

fn clone(&self) -> BitmapFont

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for BitmapFont

impl Debug for BitmapFont

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

Formats the value using the given formatter.

impl Eq for BitmapFont

impl PartialEq for BitmapFont

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

Equality operator ==.

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

Inequality operator !=.