pimoroni-pico/libraries/bitmap_fonts/bitmap_fonts.cpp

#include "bitmap_fonts.hpp"
#include "common/unicode_sorta.hpp"

namespace bitmap {
  int32_t measure_character(const font_t *font, const char c, const uint8_t scale) {
    if(c < 32 || c > 127 + 64) { // + 64 char remappings defined in unicode_sorta.hpp
      return 0;
    }

    uint8_t char_index = c;

    if(char_index > 127) {
      char_index = char_base[c - 128];
    }

    char_index -= 32;

    return font->widths[char_index] * scale;
  }

  int32_t measure_text(const font_t *font, const std::string &t, const uint8_t scale) {
    int32_t text_width = 0;
    for(auto c : t) {
      text_width += measure_character(font, c, scale);
    }
    return text_width;
  }

  void character(const font_t *font, rect_func rectangle, const char c, const int32_t x, const int32_t y, const uint8_t scale) {
    if(c < 32 || c > 127 + 64) { // + 64 char remappings defined in unicode_sorta.hpp
      return;
    }

    uint8_t char_index = c;

    if(char_index > 127) {
      char_index = char_base[c - 128];
    }

    char_index -= 32;

    const uint8_t *d = &font->data[char_index * font->max_width];
    for(uint8_t cx = 0; cx < font->widths[char_index]; cx++) {
      for(uint8_t cy = 0; cy < font->height; cy++) {
        if((1U << cy) & *d) {
          rectangle(x + (cx * scale), y + (cy * scale), scale, scale);
        }
      }

      d++;
    }
  }

  void text(const font_t *font, rect_func rectangle, const std::string &t, const int32_t x, const int32_t y, const int32_t wrap, const uint8_t scale) {
    uint32_t co = 0, lo = 0; // character and line (if wrapping) offset

    size_t i = 0;
    while(i < t.length()) {
      // find length of current word
      size_t next_space = t.find(' ', i + 1);

      if(next_space == std::string::npos) {
        next_space = t.length();
      }

      uint16_t word_width = 0;
      for(size_t j = i; j < next_space; j++) {
        word_width += measure_character(font, t[j], scale);
      }

      // if this word would exceed the wrap limit then
      // move to the next line
      if(co != 0 && co + word_width > (uint32_t)wrap) {
        co = 0;
        lo += (font->height + 1) * scale;
      }

      // draw word
      for(size_t j = i; j < next_space; j++) {
        character(font, rectangle, t[j], x + co, y + lo, scale);
        co += measure_character(font, t[j], scale);
      }

      // move character offset to end of word and add a space
      co += font->widths[0] * scale;
      i = next_space + 1;
    }
  }
}