// Prototype of fixed font rendering for Zorzpad memory-in-pixel LCD.
#include <string.h>
#include "yeso.h"
// This image contains a "glyph atlas" of our font:
#include "tamsyn8x16r.xbm"      // 4683 bytes at 1777x21
// If each scan line is padded out to a byte boundary, we expect 223
// bytes per line, multiplying by 22 gives 4683.  So that's probably
// how it works.  Also, 21 > 16 so there's probably 2 or 3 pixels of
// padding above and below; 3 above and 2 below seems most likely.

enum {
      glyph_width = 8,
      glyph_height = 16,
      font_line_bytes = (tamsyn8x16r_width + 7) / 8,
      first_font_line = 3,
};

int main()
{
  yp_p2 size = yp_p(400, 240);  // Size of SHARP LS027B7DH01 LCD
  ywin w = yw_open("font rend", size, "");
  ypic buf = yp_new(size);

  char s[] = "Sphinx of black quartZz,\njudge my vow.\n1+1 = 2, 2*3 = 6.\n"
    "o/~ Sad songs, they say SOO MUCH! o/~\n"
    "`x' < `y' {in ASCII} [ok?]\n"
    "@Una pe@a no es una pena!";
  // The font is nominally an ISO-8859-1 font, so let's make an
  // ISO-8859-1 string.
  *strchr(s, '@') = 0xa1;      // '¡'
  *strchr(s, '@') = 0xf1;      // 'ñ'
    
  int x = 3, y = 1;             // Cursor position, upper left corner.

  for (char *p = s; *p; p++) {
    int c = *(unsigned char*)p;
    if (c == '\n' || x + glyph_width >= size.x) { // wrap onto next line
      x = 3;
      y += glyph_height;
      continue;
    }
    if (y + glyph_height > size.y) { // off bottom of screen
      break;
    }
    if (c < '!') { // unprintable control characters
      x += glyph_width;
      continue;
    }
                 
    /* Index into font */
    if (c >= '\\') c--; // XXX missing char
    int fx = 1 + glyph_width * (c - 33); /* font X */
    if (fx + glyph_width > tamsyn8x16r_width) continue;

    for (int cy = 0; cy < glyph_height; cy++) {
      ypix *line = yp_line(buf, y + cy);
      int bo = font_line_bytes * (first_font_line + cy); /* byte offset */
      for (int cx = 0; cx < glyph_width; cx++) {
        int fxp = fx + cx;      /* font x-pixel */
        int bit = 1 & (tamsyn8x16r_bits[bo + fxp / 8] >> fxp % 8);
        line[x + cx] = bit ? 0xf75353 : 0x030303;
      }
    }

    x += glyph_width;
  }

  for (;;) {
    yp_copy(yw_frame(w), buf);
    yw_flip(w);
    yw_wait(w, 0);
  }
}