src/km-draw.c


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#include <stdint.h> // size_t
#include "util.h"
#include "km.h"

void
km_set_draw(
  const km_set_t * const set,
  uint8_t * const rgb,
  const size_t width,
  const size_t height,
  const int dot_size,
  const uint32_t color
) {
  for (size_t i = 0; i < set->num_rows; i++) {
    const float *row = km_set_get_row(set, i);

    for (int yo = 0; yo < dot_size; yo++) {
      for (int xo = 0; xo < dot_size; xo++) {
        const int x = (width - 1) * row[0] - dot_size / 2 + xo,
                   y = (height - 1) * row[1] - dot_size / 2 + yo,
                   ofs = 3 * (width * y + x);

        if (x >= 0 && x < (int) width && y >= 0 && y < (int) height) {
          rgb[ofs + 0] = (color & 0xff0000) >> 16;
          rgb[ofs + 1] = (color & 0x00ff00) >> 8;
          rgb[ofs + 2] = (color & 0x0000ff);
        }
      }
    }
  }
}