epaper::Font Class Reference

#include <font.hpp>

Public Member Functions
constexpr	Font (const std::uint8_t *table, std::uint16_t width, std::uint16_t height)
constexpr auto	metrics () const noexcept -> FontMetrics
	Get font dimensions.
constexpr auto	width () const noexcept -> std::uint16_t
	Get character width in pixels.
constexpr auto	height () const noexcept -> std::uint16_t
	Get character height in pixels.
auto	char_data (char c) const -> std::span< const std::uint8_t >
	Get bitmap data for a specific character.
constexpr auto	bytes_per_char () const noexcept -> std::size_t
	Calculate storage size for a single character.

Static Public Member Functions
static auto	font8 () -> const Font &
	Get 8-pixel font.
static auto	font12 () -> const Font &
	Get 12-pixel font.
static auto	font16 () -> const Font &
	Get 16-pixel font.
static auto	font20 () -> const Font &
	Get 20-pixel font.
static auto	font24 () -> const Font &
	Get 24-pixel font.

Constructor & Destructor Documentation

Font()

constexpr epaper::Font::Font ( const std::uint8_t *  table, std::uint16_t  width, std::uint16_t  height  )

inlineconstexpr

Member Function Documentation

bytes_per_char()

constexpr auto epaper::Font::bytes_per_char ( ) const -> std::size_t

inlineconstexprnoexcept

Calculate storage size for a single character.

Computes the number of bytes needed to store one character's bitmap based on font dimensions.

Formula:

width_bytes = ceil(width / 8)
bytes_per_char = width_bytes × height

Examples:

• 8×8 font: 1 × 8 = 8 bytes
• 12×12 font: 2 × 12 = 24 bytes
• 16×16 font: 2 × 16 = 32 bytes
• 24×24 font: 3 × 24 = 72 bytes

Total Font Size:

total_bytes = 95 × bytes_per_char()  // 95 ASCII printable chars

Returns

Number of bytes per character

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

char_data()

auto epaper::Font::char_data

(

char

c

)

const -> std::span<const std::uint8_t>

Get bitmap data for a specific character.

Returns a span containing the packed bitmap bytes for the requested character. Bitmap is MSB-first, row-major encoded.

Supported Range:

• Printable ASCII: 0x20 (space) to 0x7E (tilde)
• Control characters (< 0x20) return empty span
• Extended ASCII (> 0x7E) return empty span

Bitmap Layout:

For 12px wide font:
[Row 0 byte 0][Row 0 byte 1]  ← First row (MSB-first)
[Row 1 byte 0][Row 1 byte 1]  ← Second row
...
[Row N byte 0][Row N byte 1]  ← Last row

Decoding:

auto bitmap = font.char_data('A');
for (size_t row = 0; row < font.height(); ++row) {
  for (size_t col = 0; col < font.width(); ++col) {
    size_t byte_idx = row * width_bytes + col / 8;
    bool pixel = (bitmap[byte_idx] & (0x80 >> (col % 8))) != 0;
    // pixel: true = foreground, false = background
  }
}

Parameters

c	Character to retrieve (ASCII 0x20-0x7E)

Returns

Span containing bitmap bytes (size = bytes_per_char()) Returns empty span for unsupported characters

See also

bytes_per_char(), Graphics::draw_text()

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

font12()

auto epaper::Font::font12 ( ) -> const Font &

static

Get 12-pixel font.

Returns

Font reference

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

font16()

auto epaper::Font::font16 ( ) -> const Font &

static

Get 16-pixel font.

Returns

Font reference

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

font20()

auto epaper::Font::font20 ( ) -> const Font &

static

Get 20-pixel font.

Returns

Font reference

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

font24()

auto epaper::Font::font24 ( ) -> const Font &

static

Get 24-pixel font.

Returns

Font reference

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

font8()

auto epaper::Font::font8 ( ) -> const Font &

static

Get 8-pixel font.

Returns

Font reference

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

height()

constexpr auto epaper::Font::height ( ) const -> std::uint16_t

inlineconstexprnoexcept

Get character height in pixels.

Returns

Height

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

metrics()

constexpr auto epaper::Font::metrics ( ) const -> FontMetrics

inlineconstexprnoexcept

Get font dimensions.

Returns

FontMetrics structure

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

width()

constexpr auto epaper::Font::width ( ) const -> std::uint16_t

inlineconstexprnoexcept

Get character width in pixels.

Returns

Width

Examples

/mnt/nas/libepaper/include/epaper/graphics/font.hpp.

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The documentation for this class was generated from the following files:

• include/epaper/graphics/font.hpp
• src/font.cpp