font.hpp

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// SPDX-License-Identifier: Apache-2.0
// Copyright 2026 Chris Leishman
 
#pragma once
 
#include <cstddef>
#include <cstdint>
#include <string_view>
 
namespace idfxx::font {
 
struct mono_font {
    uint8_t width;         
    uint8_t height;        
    char first_char;       
    char last_char;        
    const uint8_t* bitmap; 
 
    [[nodiscard]] constexpr size_t bytes_per_row() const noexcept { return (width + 7u) / 8u; }
 
    [[nodiscard]] constexpr size_t bytes_per_glyph() const noexcept { return bytes_per_row() * height; }
 
    [[nodiscard]] constexpr bool contains(char c) const noexcept { return c >= first_char && c <= last_char; }
 
    [[nodiscard]] constexpr const uint8_t* glyph(char c) const noexcept {
        return bitmap + static_cast<size_t>(c - first_char) * bytes_per_glyph();
    }
 
    [[nodiscard]] constexpr bool ink_at(char c, size_t col, size_t row) const noexcept {
        return glyph(c)[row * bytes_per_row() + col / 8] & (0x80u >> (col % 8));
    }
 
    [[nodiscard]] constexpr size_t advance(char /*c*/) const noexcept { return width; }
};
 
[[nodiscard]] constexpr size_t text_width(const mono_font& font, std::string_view text, unsigned scale = 1) noexcept {
    if (scale == 0) {
        scale = 1;
    }
    size_t width = 0;
    for (char c : text) {
        width += font.advance(c);
    }
    return width * scale;
}
 
 
} // namespace idfxx::font